Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED...

48
Lola manual and assembly guide Hairball Audio, LLC V1.2

Transcript of Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED...

Page 1: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

Lola

manual and assembly guideHairball Audio, LLC

V1.2

Page 2: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

Saftey Precausions

Read and understand all of the instructions before assembling this DIY project.

Improper assembly could result in damage to your property or serious injuries. Hairball Audio, LLC is not liable for any damage or injury resulting from the assembly or use of this DIY project.

Use caution when assembling and testing. Make sure you are using the appropriate tools and following the manufatures safey instructions.

Disclaimer of Liability and Warranties

The assembly manual for this DIY project is complete and accurate to the best of Hairball Audio, LLC’s knowledge and is provided free of charge. Hairball Audio, LLC disclaims any and all liability for injuries or damage resulting from the assembly or use of this DIY project, including any consequential damages. Anyone assembling or using this DIY project does so at their own risk.

Hairball Audio, LLC makes no warranty of any kind with respect to the assembly or use of this DIY project and explicitly disclaims any Implied Warranty of Merchantability. Hairball Audio, LLC warrantee coverage insures that parts arrive in working order. Assembly support is not offered or included with this DIY project.

By downloading and/or following these plans, the user acknowledges that he or she has read and followed the Assembly Instructions and Safety Precautions.

© 2012 Hairball Audio, LLC

Page 3: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | iii

Contents1 Welcome 1

User Guide 1

Gain 1

Output 1

Pushbutton Controls 1

DI 1

LED Meter 2

Assembly Overview 2

Patience 2

Tools 2

Soldering Guide 3

Component Sorting 3

2 Populating the PCBs 5

The Printed Circuit Boards 5

Populating The Main PCB 5

Op-Amp Sockets 5

Gain Resistors 6

Main PCB Resistors 7

Semi Conductors 7

Capacitors 9

Pushbutton Switches 11

Grayhill Gain Switch 11

Output Attenuator 12

DI Jack 14

Gain Capacitor 16

Input Transformer 16

Page 4: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

iv | Table of Contents

Output Transformer 17

Testing The Main Board 19

Populating The Meter PCB 19

Semi Conductors 19

Resistors 20

Toggle Switch and Connectors 21

Populating The LED PCB 21

3 Assembly 24

Putting It All Together 24

Mounting The LED PCB 24

Inserting The LED Light Pipes 25

Mounting the PCB to the Bracket 25

The Ribbon Connector 26

Mounting The Faceplate 26

Mounting the Knobs 26

Final Testing 28

4 Appendix 29

5 Band Resistor Color Code Guide A

Gain Resistors B

Main PCB Resistors (10Ω - 33KΩ) C

Main PCB Resistors (100KΩ - Inductors) D

Main PCB Semi Conductors E

Main PCB Capacitors F

Meter PCB Resistors G

Meter PCB Semi Conductors H

Meter PCB Capacitors I

Gain Resistor Detail J

Meter Resistor Detail K

Page 5: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | 1

User GuideThe Lola mic pre is a fully differential circuit featur-ing the EA-10468 input transformer, EA-1166 output transformer, and optional John Hardy 990C op-amps.

The Lola maintains a completely differential signal path from input to output. The benefit to this topol-ogy is lower noise and a high CMRR. It also takes advantage of the excellent balance of the EA-10468 input transformer. In addition, because there are two op-amps in parallel, available output drive current is increased. This lowers output impedance; improving output transformer performance and increasing the maximum undistorted gain. In this regard it’s similar to running a single op-amp design on 24V rails.

GainThe gain stage provides 65dB of clean gain in 4.5dB steps utilizing a Grayhill rotary switch. With 48dB of adjustable gain, there is no need for an input pad.

OutputThe 600Ω Bourns t-pad attenuator sits on the sec-ondary of the output transformer and attenuatates the output level while maintaining a nominal 600Ω load. This allows the user to fine tune the output once the preferred gain setting is selected. It also allows the user to “push” the gain while maintaining

1 Welcome

an appropriate output level to add analog distortion to the source material.

Pushbutton ControlsThere are three illuminated pushbutton switches to select phantom power, phase, and line mode.

The phantom power control (+48) provides +48VDC to pin 2 and 3 of the input XLR through two 0.1% tolerance 6.8KΩ resistors. Phantom power is activated when the control is illuminated.

The phase control (ø) flips the phase of the source material by 180 degrees. The differential signal is phase flipped at the primary of the output trans-former. This control uses a DPDT relay.

The line (LINE) control flips the primary and secondary of the input transformer making it a step down input and reducing the overall gain by approximately 14dB. This allows the user to use the Lola on line level material. The line control uses two DPDT relays.

DIThe DI jack accepts a ¼” unbalanced cable. Insert-ing a cable triggers the DI relay to switch the input from the XLR input to the DI jack. The DI passes through 2 FET buffers creating a differential signal to feed the EA-10468 primary.

Page 6: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

2 | Lola Assembly Guide

LED MeterThe Lola features a 10 segment integrated circuit controlled LED meter. Located below the meter is a toggle switch to select VU (low position) and Peak Programme Metering (high position). Though the VU mode is actually average metering (90% of RMS), it’s calibrated to VU metering with little effect on PPM mode. 0dB on the meter scale is equal to +4 dBu (1.23V) in VU mode. Peak mode displays the peak value of the waveform in the same scale.

Assembly OverviewChoosing to build your own piece of gear is a rewarding and great learning experience. If it’s your first time, this guide will walk you through all of the steps to complete your build. If you’re a grizzly old pro, you’re probably not even reading this!

PatienceWant to have a failed build and a huge headache? Rush through the build paying little attention to the instructions and be as sloppy as you can with your soldering and assembly. As much as you want that cool new piece of gear up and running NOW, take your time and take brakes. It’s the best way to ensure success with your build.

ToolsYou’ll need a few basic tools to complete this build. Though this list may not be complete, it’ll give you an idea of what you should have on hand.

Soldering IronIt goes without saying that you need a soldering iron. Get a decent one. At the very least you should have 25 watt pencil style soldering iron. Weller sells the WP-25 for about $40 USD and it’s a solid entry level soldering iron. Radio Shack sells a 40 watt model for about $10 USD. I’ve not used that model, but I bet it’s better than a lighter.

If you’re going to build a few units and do some repairs, consider getting an adjustable temperature solder station. The Hakko 936 is a tried and tested unit that sells for about $70 USD. It’s a fabulous tool.

Soldering TipMost decent irons will allow you to insert different tip styles. For most PCB work, including this build, you’ll want a small chisel tip. I use the Hakko 936 iron with a D18-D16 tip. This is a 1.6mm radius chisel tip.

SolderSolder is kind of like guitar strings in that you re-ally need to feel which one is right for you. I went through a few types before I found one I liked. There are a few different considerations such as lead or lead free, no clean type, and diameter. I use Kester #245 no clean solder. It is a 0.031” diameter 63/37 alloy. It needs no flux cleaning and is avail-able at many local and online retailers (Part #24-6337-8800).

Digital Multi-Meter (DMM)A good DDM is as important as a soldering iron. An auto-ranging DDM will make sorting resis-tors a breeze and help avoid time consuming errors.

Page 7: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | 3

Testing and troubleshooting will make having a good DDM a must. An inexpensive model is better than nothing, but a good model will be a trusted tool on your bench and in your studio for years. It’s important to note that cheap meters generally do not measure AC (audio) level accurately above a few hundred Hertz at best. In audio we like to deal with 1KHz test signals so get a nice meter.

Fluke is the standard for DMMs. A Fluke 177 is another tried and tested workhorse. It’s not cheap, but it’s not that expensive for something you will use and depend on every day.

PanaviseDo you need a Panavise? No. Will it make your PCB stuffing much easier? Yes. These are not that expensive. Consider getting one.

Pliers, Cutters, and StrippersA pair of fine needle nose pliers will come in handy for some of the final assembly work. I bet you already have a pair of these!

Small diagonal cutters are a must. You’ll need these for trimming the component leads.

Having a decent pair or wire strippers in the 16-26 AWG range is something you should have.

1/16” Hex KeyAlso known as a Hex Wrench, Allen Wrench, and Allen Key. Whatever you call it, you need one to install the knobs. Consider getting a set with a nice storage case.

Nut DriversThese are not as fun as they sound. You need four: 1/4”, 5/16”, 7/16”, and 1/2”. These are used to tighten various nuts in assembly, including the face plate components. Due to the length the Grayhill and t-pad shafts, you’ll need a nut driver with a fairly deep channel. I used to use pliers to tighten these. I’d mare the nuts, scratch the panel and drop a few F-bombs. Do yourself a favor and get a Nut Driver set. I picked up a 7 piece set at a hardware mega-store for about $15.

Soldering GuideSoldering WELL is one of those things that seems easy until you try it. Once you try, it starts to seem kind of difficult. Then finally you figure it out and it seems easy again.

Rather than trying to explain it to you, I went online trying to find the best video tutorial I could. I settled on Dave Jones’ tutorial on the EEVBlog. Dave’s a wacky a cat, but so are most guys who inhale lead all day. The tutorial is presented in three parts: tools, soldering through hole components, and soldering surface mount components. For our purposes, I recommend you watch part 1 and 2. The videos are lengthy at about 25 minutes each, but they are well worth watching. Even I learned a few things.

The videos can be seen by visiting:

hairballaudio.com/solder

Component SortingThe appendices of this manual contains printable sheets for sorting the components located in the various bags. DOUBLE CHECK all resistors with a DDM before soldering them into place. Appen-dix A is a 5 band resistor color code chart.

Page 8: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

4 | Lola Assembly Guide

Page 9: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | 5

The Printed Circuit BoardsYour Lola mic pre is comprised of three printed circuit boards (PCBs):

2 Populating the PCBs

Populating The Main PCB

Op-Amp SocketsLet’s get started! Personally, I like to begin by inserting the op-amp sockets (Fig. 2).

Fig. 1

Fig. 2

Fig. 3

1. Main PCB. Contains the mic pre circuit.

2. Meter PCB. Contains the LED meter circuit.

3. LED PCB. Contains the LEDs and current limiting resistors.

There may be some visual and numerical value differences between your PCBs and the PCBs used in this manual. The PCBs used in this manual are prototype versions.

The PCBs are located in the bags containing the components for each PCB. Start by locating the main PCB bag and removing the main PCB.

You should have 12 op-amp sockets in bag F, 6 for each op-amp. The sockets must be inserted from the top side (silkscreen side) of the PCB. This will ensure there is enough space between the op-amp and PCB suface for the feedback network that mounts under the op-amp.

Page 10: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

6 | Lola Assembly Guide

There are a few different ways to solder the op-amp sockets. You can solder from the top, bottom, or both. The most important part is that you get good solder flow around the entire socket and PCB pad connection. I like to tilt my PanaVise so it’s parallel to my table surface with the silkscreen side up (Fig 3). Place the sockets in the socket pads. The hollow end should be facing up, this hollow shaft accepts the op-amp pins. Working from the topside, place you solder tip so it makes contact with the socket and pad, just like you would with any other compo-nent. Be sure not to apply too much pressure to the socket or it may lift slighty causing it to sit slanted on the board. The socket is a large part that will need about 5 sec of heating time to get good flow. Applying a touch of solder to the solder tip, PCB, and socket connection point should allow for good heat transfer (see 20:00 of solder video 2). When you start to see that solder flow, apply some solder to the opposite side of the pad while keeping your iron tip in the original location. This should give you a good flow around the pad. Remember less is more when it comes to solder. If you’ve acheived a good connection on the topside there is no need to solder the bottom side. Once you have all the sock-ets soldered, you can wiggle them to confirm you have a good electrical and mechanical connection.

Gain ResistorsNext let’s stuff those gain resistors! These are the 12 resistors that set the gain of the Lola mic pre. They are located near the Grayhill switch and are labeled R1-R12. Because of the tight spacing in this region of the PCB, these resistors are mounted vertically.

Start by removing the 12 resistors from bag D and check them with your DMM. Appendix B at the end of the manual is a resistor sorting sheet you can print and use to simplify this process. You can insert them in any order you like, but doing them in order R1-R12 might help you avoid mistakes.

It can be a little tricky to identify the resistor place-ment, so use detailed view in appendix J to confirm you have the resitors in the right location. Start by using your finger to bend one of the resistors legs 180 degrees back towards the resistor (Fig 4).

Fig. 4

Fig. 5

The virtical reistor symbol has a circle around one pad and a line the points to a pad without a circle. The resisor body sits on the pad with the circle sur-rounding it (Fig 5). The circle represents the resistor

body and the line points to the pad where you will insert the other lead.

These parts are not polarized, they can be inserted in either direction. Following the silkscreen footprint simply helps avoid exposed legs from touching and creating a short. Once the componet is soldered to the PCB you can trim off any remaining leads.

Page 11: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | 7

When you’re done you’ll have something that looks like Fig 6.

Main PCB ResistorsNow let’s go ahead and stuff the rest of the hori-zontal resistors located in bag D. Appendix C and D are main PCB resistor sorting sheets. Note that the last spot on appendix D is for the two 4.7 uH inductors. They may be brown like in Fig. 7 or green

The pad spacing for the horizontal resistors, diodes, and inductors is identical to the body length with one exception being the green inductors. This al-lows us to avoid any specialized bending jigs. Just use your fingers to apply bending force to the leads while holding the body.

Carefully work your way through the circuit. Again double, or even triple, check all of your resistor values and numerical designations.

Note that R29, R30, R34 and R35 are 2.2KΩ op-amp resistors with 0.1% tolerence. R16 and R17 6.8KΩ phantom power resistors with 0.1% tolerence. The 3.4KΩ R40 and R41 resistors have been hand matched to 0.1%. These tight tolerences are required for low noise, make sure you identify them and solder them in the correct loaction.

Semi ConductorsLet’s talk semi conductors. These are located in bag B and can be sorted using appendix E. There are 6 protection diodes on the main PCB. They make sure current is flowing the right way in your Lola. There is one across the power terminals of each relay and one on each of the 16V power rails. They are installed just like a resistor with one MAJOR difference, they are polarized. Meaning the must be installed in the proper direction. Luckily this is pretty simple. All you need to to is line up the grey stripe on the diode with the stripe on the diode

Fig. 6

Fig. 8

Fig. 7

like in Fig. 8. These are not resistors and cannot be tested using the resistance tester on your DMM. Since there are only two and they are of identical value there is no need to test them. Simply install them as you would a resistor. Placed in parellel with 39Ω resistors, these create an output isolator between your op-amp out and output transformer.

Use extreme care when testing and sorting your resistors! Check every resistor twice. It may take you an extra couple of minutes now, but it can save you days of troubleshooting to find where you mistakingly swapped a 10KΩ for a 10Ω. Take your time and get it right the first time.

Page 12: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

8 | Lola Assembly Guide

Fig. 9

Fig. 10

Fig. 11

K1 and K2 work in tandem. They are triggered by the “Line” pushbutton switch and their job is to flip your input transformer from a mic in (step up) to a line in (step down). I told you they do crazy things! K3 is the phase reverse and is located between the op-amp outputs and output transformer primary. It. of course. is controled by the “Phase” pushbutton switch. K4 is the switches the Lola input from the XLR in to the 1/4” DI jack. This one is different in two ways. First, it’s not switched by a pushbutton switch. It’s triggered when you insert an unbalanced cable into the 1/4” DI jack. Second, it’s normally “on”, meaning current is flowing through the relay and breaking the ground connection with the DI jack turns it “off ”. That part really isn’t important, but you may hear it “click” on when you power up your Lola.

Enough of this crazy circuit talk, let’s stuff that PCB! When inserting the relays orientation mat-ters. Like the diodes, make sure you align the white line of the relay with the line on the silkscreen layer (Fig 11).

symbol of your silkscreen (Fig 9).

The remaining TO-92 pacakge semi conductors get installed by following the silkscreen footprint on the PCB. These include the LM317 constant cur-rent source for the LED pushbutton switches, the 2N3906 relay trigger, and two J201 DI FET butters.

RelaysOnce you’ve installed the semi conductors we can move on to the relays in bag C. These are the electromechanical switches that do all kinds of crazy things inside the Lola circuit (Fig 10).

Once you have them slipped into place, flip your PCB and bend back a couple leads to hold them in place while you solder (Fig 12).

The leads are small enough that they don’t need to be clipped.

Page 13: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | 9

CapacitorsThere are a handful of capacitors in the Lola, certainly a lot less than many circuits you may have encountered. This is a real advantage since it is generally precived that the less capacitors you have in your audio path, the better. The capacitors are lo-cated in bag A and can be sorted useing appendix F.

There are two op-amp feedback capacitors and one input zobel network capacitor. These capacitors are the small blue multilayer ceramic capacitors (Fig 13).

Fig. 12

To Identify which two are the 100pF feeback ca-pacitors (C7 and C9) and which is the 680pF input transformer zobel capacitor (C2) we’ll have to do

some tiny reading. The two 100pF feedback caps will have the value 101J printed on them. The zobel cap will have the value 681J printed on it. Once you have identified them, you can insert and solder them. They are non-polarized capacitors so the orientation in not important.

Now move on to the two grey film capacitors. These are two 0.1uF capacitors (C10 and C11) used to

block DC from the DI buffer circuit. They have the value 104 printed on them (Fig 14).

These are also non-polarized and can be installed in any direction.

Since we have op-amps we should probably add some bypass capacitors. This is usally done with a 0.1uF and a 47uF on each op-amp power supply pin to ground. The JH-990 has the 0.1uF bypass capacitors inside the op-amp (awesome), so all we need to do is add some polarized 47uF electrolitic capacitors to each op-amp power supply pin. These are the 47uF/25V polarized electrolic capacitors (C3, C4, C5, and C6) in your kit (Fig 15).

Use extreme care when inserting these capacitors. They are polarized and must be inserted with the proper polarity. Failing to do so will result in a small match like fire and a stink you won’t be able to get rid of for days.

Fig. 13

Fig. 14

Page 14: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

10 | Lola Assembly Guide

Along one side of the capacitor there is a gray stripe containing several “-” or negative symbols. That stripe lines up with the negative termainal. On your PCB, one of the pads will have a “+” or poitive sym-bol beside it. This is the pad which will recieve the positive lead. Another indicator is that the square pad is for the positive lead and the round pad is for the negative lead.

Next up is the 47uF/50V capacitor for the phantom power circuit (C1). It looks simular to the previous capacitors except it is slightly larger and rated for the 48V phantom power supply (Fig 15). It is also polarized so be sure to insert it correctly before you solder.

You still have a giant 1000uF (C8) polarized capaci-tor in your kit but let’s set that one aside for now. It can interfere with your PanaVise so we’ll install it towards the end.

Ribbon HeaderNow is a good time to insert the header for the ribbon cable that connects your main PCB to your Meter PCB (Fig 16). It’s located in the large Meter package in bag D. There are two but you just need one for now.

Inserting this connector should be fairly straight-forward. Obviously you do not solder the plastic locating pegs. When soldering the 6 connector pins try to work fairly quickly to limit the heat applied to the header material.

If you have not done so already, TAKE A BREAK. You’ve reached a pretty big milestone!

Most of what’s left are the larger parts. You’ll need to take your time to get through these so try to avoid rushing at this point.

You may have noticed that there is a capacitor labeled “OPT-C” and a resistor labeled “OPT-R” that you’ve not populated on your PCB. This is the op-tional output zobel network needed for some non Hardy op-amps. If you are using the JH-990 leave these empty.

Fig. 15 Fig. 16

Page 15: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | 11

Pushbutton SwitchesLet’s mount the switches. The three illuminate pushbutton switches (SW1, SW2, and SW3) are polarized. However, they can only be inserted in one direction. The most important thing to ensure when mounting these switches is that they are sit-ting completely flush with the PCB surface (Fig 17).

Notice how the four feet of the pushbutton switch are pressed flush to the PCB surface. Since the switches are designed to snap into place, they should naturally sit flush. Just make sure not to push them out when you solder the pins on the reverse side. These need to be flush to match the pushbutton holes on the L-bracket and faceplate.

Grayhill Gain SwitchLet’s talk about the gain switch. It’s a single deck 12 position shorting Grayhill rotary switch. This switch sits between your op-amp feedback networks and allows you to select a gain range from 16.5dB - 65 dB in 4.5 dB steps. There are three parts in the Grayhill assembley (Fig 18).

1. The Grayhill Switch w/ Nut and Washer

2. The Stop Pin

3. The Retaining Sticker

Remove the nut and washer and set them aside in a safe place. Your kit may have included 2 stop pins. You only need one, but keep the other handy. If you drop one you’ll never find it. Before it get’s lost, lets insert that stop pin. Without the stop pin the switch will just endlessly turn. When you get to the maximum gain setting it will allow you to turn through to the lowest setting. Maybe you want that? Then don’t insert the pin. However most people would probably find this annoying so let’s get it in there. It needs to be placed in a specific hole that will tell it which position is the end position. Hold the switch so that the PCB mounting pins are facing down and place the stop pin in the 12 o’clock position (Fig 19). Needle nose pliers work well for this step.

Fig. 17

Fig. 18

Fig. 19

Page 16: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

12 | Lola Assembly Guide

Output AttenuatorBetween the output transformer secondary and the output XLR you’ll find a Bourns 600Ω t-pad attenuator. The default position should be the fully clockwise position. The attenuator accomplishes three things.

1. Allows you to fine tune your gain setting within the 4.5dB Grayhill switch steps.

2. Allows you to lower the output signal when pushing the input gain so the Lola distorts (good) while protecting your A/D converters from distortion (bad).

3. Maintains a nominal 600Ω impedance on the output transformer secondary. This will keep Lola happy.

Now what exactly does this magical component look like? If you purchased a kit before mid-June 2016 it’s the blue t-pad shown in fig.22.

Push the stop pin into the hole until it sits flush with the switch surface. Next peel the retaining sticker from its backing and place it over the shaft and on to the switch surface (Fig 20).

Remove the plastic PCB pin protective covering and insert the Grayhill into the PCB. Like the pushbutton switches, they Grayhill switch must sit flush to the PCB. Try to keep it as upright as pos-sible so that the shaft is parallel to the PCB surface. There will be a little room for fine tuning once the component is soldered in place. For now, make sure it is pressed flush to the PCB (Fig 21).

If it looks something like Fig 21, then well done!

Fig. 20

Fig. 21

Fig. 22

If you purchased a kit after mid-June 2016, it’s the grey t-pad with a 1/8” shaft shown in the grey t-pad install section on the following pages. If you have the grey t-pad it will come with a PCB spacer for setting it at the correct height off the PCB. The grey t-pad also has an anti-rotation tab on the front that you should clip off with your lead cutters. It will keep you from being able to mount the faceplate later in the guide.

Page 17: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | 13

Note the t-pad attenuator and DI jack do not sit flush on the board. To ensure that these parts align with the L-bracket and faceplate holes please fol-low these steps carefully.

Here’s the thing. You probably want your gain switch, t-pad and DI jack to line up on your face-plate. I wanted the same thing, that’s why it is so on the Lola. Let’s go through the steps to make this happen. Don’t skip any, it’s just not worth it.

Blue T-Pad Install (Pre Mid-June 2016)

For both the attenuator mounting and DI jack mounting, you are going to need your L-bracket, faceplate, Grayhill nut and washer, (4) #4 nuts, (4) 4-40 1/2” flat screws, and (4) 1/4” standoffs. Mount the 1/2” machine screws and standoffs onto the L-bracket as shown in Fig 23.

Do not tighten the standoffs so they are flush to the bracket. They need to be loose because we’ll need a little wiggle room shortly.

Next insert the attenuator into the PCB. It’s not going to be easy, you have 9 PCB pins and 4 bracket pins that all need to line up properly. Take your time and use pliers to line up each pin. After a min-ute or two and 3-4 F-bombs you should have it in. Leave it floating off the PCB unsoldered (Fig 24).

Now take the PCB and insert it at an angle into the L-bracket (Fig 25). Now place a #4 nut on each screw to set the PCB in place on the bracket

(Fig 26). At this point there is no need to use the locking washer or over tighten. Just tighten the screw and nut enough to set the final mounting position. Now slip the Lola faceplate into place and hand tighten the Grayhill nut and attenuator nut (Fig 27). Again you don’t need to use the locking washers for this step. There is a little room to move the t-pad around in the hole. Position it so it’s as centered as possble with the scale before you tigten

Fig. 23

Fig. 24

Fig. 25

Fig. 26

Page 18: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

14 | Lola Assembly Guide

With these three pins soldered, your t-pad will be locked into place for final soldering. Remove the faceplate and L-bracket. You can now solder the t-pad PCB pins and remaining unsoldered bracket pin from the bottom of the PCB (Fig 29). Be sure, as always, to trim and excess leads after soldering.

Slide the PCB spacer onto the pins of the t-pad. It’s made to slide on in any direction (Fig G1). Now sandwich the spacer between the t-pad and PCB and solder the 9 t-pad pins on the bottom side. Make sure it’s all snug against the PCB. Easy!

the nut. Your t-pad should now be at the right height for final soldering. With the face place still attached, solder the three accessible t-pad rail pins from the top side. These are marked with red circles in Fig 28.

Grey T-Pad Install (Post Mid-June 20016)

You do not need to assemble the bracket to mount the grey t-pad, it comes with a PCB spacer. You will still need to follow the bracket assembly in the blue t-pad install to install the DI jack in the next section.Fig. 27

Fig. 28

Fig. 29

Fig. 30

Fig. G1

DI JackThe next component to mount is the Neutrik 1/4” ste-reo PCB mount jack. Although this is a stereo jack, it’s meant to only receive an unbalanced cable. The extra contact is need as part of the relay trigger circuit.

Page 19: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | 15

The Neutrik DI jack has three parts.

1. The DI Jack

2. The Silver Nut

3. The Black Washer

This part also needs to be mounted off the PCB. Place the jack on the PCB and repeat the temporary assembly steps in the attenuator section. Mount the L-bracket, faceplate, and attach the Grayhill and attenuator nuts. Add the DI jack nut and washer as illustrated in Fig 31.

Now that the DI jack is locked into place you can solder the exposed pins on from the top side of the PCB. In this case the only accessible pins are the three on the PCB edge circled in Red in Fig 32.

You can now remove the faceplate and L-bracket and set them aside. We won’t need them for a while. Be sure to place you Grayhill switch, attenu-ator, and DI jack nuts and washers in a safe place.

The safest place is probably on the component shafts!

Your DI jack will not be fully stable. Because only

one side it soldered it’ll move a little on the unsol-dered side. We want to solder all the pins in place but also ensure it stays perfectly parallel to the PCB. If you have a little spacer to use between the jack and the PCB, use it! If not here’s how I do it.

Load a little solder on your iron tip. You know, ex-actly like they tell you NOT to do. Hold the PCB in one hand and use a finger on that same hand to hold the jack parallel to the PCB (Fig 33).

While holding it in place turn the PCB over and place your solder blobbed tip to one of the unsol-dered leads. Yes, that right, make a cold solder joint. Don’t worry, we’re going to fix this. This is just tem-porary.. Before properly soldering the remaining 2 pins on the unsoldered side, confirm your jack is parallel to the PCB. If it’s off, fix it now while you only have one pin tacked in place. Once all the pins are soldered, it’ll be a pain to fix. If it looks good, go ahead and solder the 2 remaining pins properly. Once they are done go back and reheat and solder the tacked joint. You should also solder the three top soldered pins on the outer edge from the bot-tom at this point.

Looks good? Congratulations! Mounting the at tenuator and DI jack is probably the most technical part of the build.

Fig. 31

Fig. 32

Fig. 33

Page 20: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

16 | Lola Assembly Guide

Gain CapacitorThis is that large polarized 1000uF/50V electrolytic capacitor we set aside earlier (Fig 35). It’s an insur-ance policy to eliminate any DC that finds its way into the feedback/gain network. Be sure to mount the capacitor flush to the board and straight to avoid interference with other components.

Input TransformerThe Lola uses an EA-10468 (Fig 36) input trans-former. The EA-10468 is a talented transformer, designer Ed Anderson’s take on the classic Marinair 10468. The 10468 is most known for being the mic in transformer for the classic Neve 1073 channel strips.

Mount transformer using the supplied (2) 1/2” 4-40 panhead screws from the bottom of the PCB into the threaded holes on the bottom of the transform-er. Trim the leads to prepare for soldering. Be very careful not to over trim.

The leads are not hair, they won’t grow back. You can always trim each lead to the perfect length as you solder them into place. The leads have corre-sponding pads labeled by lead color.

Starting at the board edge and moving towards the center these are:

♦ BLK=Black

♦ BRN=Brown

♦ GRY=Grey

♦ YLW=Yellow

♦ RED=Red (Wow!)

♦ WHT=White

♦ VLT=Violet

♦ ORG=Orange

♦ GND=Green

Fig. 35

Fig. 36

Fig. 37

Page 21: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | 17

The GND label is for the two pads that are overlap-ping. These are for the 2 green leads. There are two separate transformer grounds that we are connect-ing to the ground at this point. It does not matter which green lead goes to which GND pad.

Strip about 1/4” of shielding off the first lead, in this case black, tin the lead, and insert it into the pad with the BLK label (Fig 38).

Output TransformerThe output transformer used in the Lola is Ed An-derson’s version of the classic LO-1166 line output transformer (Fig 41). It is used in many designs, most notably the Neve 1073 channel strip.

On the bottom side of the PCB. pull the lead through so the cut edge of the wire insulation sit flush with the top side of the PCB. Bend the exposed wire like you would a component lead (Fig 39).

to avoid any shorts. If you take your time you can probably even make it a little cleaner than I have (Fig 40).

Fig. 38

Fig. 39

Fig. 40

Solder the lead and trim the excess. Now start moving across the board stripping and soldering each lead into place. Make sure you do not leave any exposed wire on the top side of the PCB pads and keep your leads trimmed on the reverse side

Let’s start by laying out the hardware we’ll need to mount the transformer to the PCB (Fig 42).

You’ll need (2) 4-40 7/8” pan screws, (2) flat #4 washers, (2) #4 lock washers, and (2) #4 nuts. These are located in hardware bag A. Start by sliding the flat washer onto the screw (Fig 43).

Fig. 41

Page 22: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

18 | Lola Assembly Guide

Now do this with the other flat washer and screw and drop them into the transformer holes from the side with the leads on the top side (Fig 44).

too short. Those solder pads on the edge are further out than you think (Fig 46).

Fig. 42

Fig. 43

Fig. 44

Now drop the transformer onto the PCB with the lead out facing towards the board edge and the transformer solder pads. Flip the PCB over and place a locking washer and nut on each screw to secure the transformer in place (Fig 45).Now trim your leads. Be careful, it’s very easy to trim these

Fig. 45

Fig. 46

Solder them in to place using the input transformer method.

♦ BLU=Blue

♦ PLR=Purple

♦ GRN=Green

♦ GRY=Grey

♦ BRN=Brown

♦ RED=Red

Grab your JH-990 or op-amp of choice and seat them into the op-amp sockets (Fig 47). Congratu-lations! You now have a working Lola!

Page 23: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | 19

The mic pre circuit is now fully functional. It’s not a bad idea at this point to test your build. Confirm-ing the main board works correctly can help with troubleshooting should you run into issues when adding the meter daughter board. If you want to test your main board, go ahead and remount the bracket and faceplate and skip to page 26 if you need help mounting the knobs and shaft adaptor.

Testing The Main BoardLet’s get testing! After mounting your Lola in a 500 series rack, power up the rack. Hopefully you won’t see any smoke. Check the 3 pushbutton LEDs and confirm the light to a nice soft blue. You should hear a relay internally “click” when turning on the PHASE (ø) and LINE push buttons. The PHANTOM (+48) button is not connected to a relay so it won’t have a “click” other than the latch-ing of the pushbutton.

You can use a condenser microphone (not your U47) to test the phantom power and confirm your Lola is passing signal. With the OUTPUT knob fully clockwise, start with the GAIN knob at its lowest setting and confirm your signal increases as you tun it clockwise. Now turn the OUTPUT counterclockwise to confirm the signal decreases to zero.

Now insert a 1/4” unbalanced instrument cable into the DI jack. A relay will “click” but you may not be able to hear it over the sound of the cable insertion. If the instrument you play through the Lola DI jack is amplified you’ll know the relay is flipped. You’ll also know that your Lola passes basic functionality tests!

Populating The Meter PCBYou know what’s awesome? Audio level meters. Let’s give your Lola an awesome LED audio level meter. Start by locating the red “Meter PCB” bag and pull out the contents. Inside you should find five smaller bags. Four are labeled A, B, C, and D and the fifth contains the meter PCB.

Semi ConductorsOpen meter bag B, sort using appendix H and locate the four 1N914 diodes (Fig 48).

Fig. 47

Fig. 48

These diodes are of course polarized and must be inserted in the correct orientation. The line that indicates the cathode on the meter board screen is a bit hidden. Another indicator is the square pad solder pad. The cathode (side with the line) should be soldered to the square solder pad (Fig 49).

Once you’ve installed all four diodes, install the three integrated circuits (Fig 50).

These can be a bit tricky to install as your board

Page 24: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

20 | Lola Assembly Guide

becomes populated so lets get them in there now. The two smaller ICs are labeled TL071CP and TL072CP. Make sure you place these in the correct footprint. They are NOT interchangeable. You’ll notice the larger IC (meter controller) has a notch at one end and the two smaller ICs have a dot at

one end. You’ll also notice that the PCB foot-prints have little notches out of one end. You must align these notch or dots for the IC to be properly installed.

You’ll have to pinch the IC legs in a little to get it to fit into the footprint. You’ll be a pro once you’ve installed about 200 of these.

You’ll notice that one side of the LM3916 pads are joined or bridged to other pads (Fig 51). These 11 pads are for the right angle connector that will at-tach the LED PCB to the meter PCB.

These 11 pad holes must be kept free of solder until the right angle connector is installed. When solder-ing the LM3916 make sure you don’t use too much solder or it may flow into these holes. If you’re not confident in your soldering skills, leave this side unsoldered and solder it after the connector is inserted.

Lastly, install the LM317 voltage regulator paying close attention to the silk-screen orientation shape.

ResistorsNext grab meter bag C. It contains all of the resistor required for the meter PCB. Just like the gain resistors, they will be inserted vertically. Use appendix G to carefully sort your resistors for this

Fig. 49

Fig. 50

Fig. 51

Fig. 52

Page 25: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | 21

next step. Appendix K is a detailed view to help you confirm reisitor placment.

CapacitorsNext install the contents on meter bag A and sort them using appendix I. These are the various capac-itors needed for the meter circuit. You have three polarized electrolytic capacitors. Two are labeled 47uF and one is labeled 2.2uF. or 3.3uF These must be oriented correctly. Again, the negative lead is labeled by a stripe containing a negative or - Symbol on the side. Insert the positive lead with the + sym-bol on the PCB. The + lead is also the square pad which is opposite to the diode where the cathode or negative is a square pad (don’t ask).

You also have three non-polarized capacitors. These can be inserted in either orientation. You have two 0.22uF (labeled XXXX) capacitors and one 0.47uF (labeled XXXX) capacitor. Insert these into their proper footprints.

Toggle Switch and ConnectorsFinally you’ll be left with meter bag D. Remove the toggle switch and one of the two small PCB mount ribbon connector headers. Set the rest of the bag aside for now.

Inserting the toggle switch and header are fairly straight forward. They footprint will help you with orientation. All you need to do is make sure they are solder flush to the PCB. It’s best to start by soldering one pin and confirming the part is flush to the PCB before moving on. When you’re done. you should have something that looks like Fig 53.

Remember, your PCB is a newer production version that may look slightly different. For example, the right side of your meter PCB will look slightly differ-ent than the one pictured in this manual.

Fig. 53

Populating The LED PCBCongrats, you only have one PCB left to populate and it’s the smallest. Don’t be fooled however, take your time with this one to ensure the LEDs will align properly with the light pips. Without further adieu, let’s populate the LED PCB!

There are two versions of the LED PCB. If you have the current blue faceplate your LED PCB will be marked “Rev B” and have 6 small horizontally mounted resistors (Fig 54). If you have an older kit with a green hammered faceplate, your LED PCB will be marked “Rev A” and have 10 vertically mounted resistors (Fig 55).

The LED PCB allows us to mount the LEDs flush to the PCB eliminating the need for any trickery or LED lead bending. It also allows us to have current limiting resistors for LEDs as needed which creates a lot of flexibility for different LEDs and different LED color combinations.

Start by mounting the current limiting resistors. For the current rev B PCBs horizontally mount the 6 47K resistors into DR1-DR6. If you have an older rev A PCB, the 6 white LEDs each get a 10K resis-tor, the 3 orange LEDs get 8.2K resistors, and the violet LED gets a 3.4K resistor.

Page 26: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

22 | Lola Assembly Guide

When you flip the board you should see something like Fig 57. Solder the LED into place and clip the leads.

Continue along down the line. Note that the top red/violet LED solder pads will back up close to the Meter board 0.22uF caps once it’s installed. To keep things tidy don’t put a big glob of solder here (or anywhere) and clip the leads very short after soldering.

Next let’s mount that right angle connector (Fig 58). It mounts to the opposite side of the PCB than the LEDs and resistors. This is yet another compo-nent that must be mounted flush and straight. It’s not difficult at all, just take your time and solder one or two pads then double check that they are still flush to the PCB. I find that if you orient the part

Fig. 56

Next we’ll mount the LEDs. Try not to mix them up! You want these to sit as flush and as straight to the PCB as you can get them. It’s not 100% critical that they are perfect, just take your time and get them close.

The longer lead is the anode (positive) and should be inserted into the sqaure pad...which is opposite to the diodes...again, don’t ask.

I like to hold the PCB with one hand and insert the LED with the other. Press the LED close to the board with you index finger and use your thumb to spread the leads apart bending them against the PCB (Fig 56).

You have a fleshy chunk of skin hanging off your cuticle (Fig 56 circled in red), now would be the time to trim that off with nail clippers or your wire cutters.

Note that the LEDs footprints on the current rev B PCBs are labeled W for white, Y for yellow, and R for red. Older Rev A PCBs are labled W for white, O for orange, and V for violet.

Fig. 57

Fig. 55

Fig. 54

Page 27: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | 23

like in Fig 54/55 and solder it in place using some downward force with the iron you can get it just right.

Note the smaller leads on the right angle connector are soldered to the LED PCB and the longer leads will be soldered to the meter PCB.

Let’s finish this off! Grab the meter PCB and insert the LED PCB so the LED face the same side as the toggle switch. As you may have guessed, it’s important the LED PCB sit flush and at a 90 degree angle to the meter PCB (Fig 59).

Flip the board and solder the right angle connector into place. Again, confirm the LED PCB is flush and straight after the first few pads are soldered.

Flip the PCB and trim the long leads of the connec-tor. When you trim these leads place your hand over them as a shield or hold them as they are clipped. These leads fly far and fast when the are cut.

Now let’s take a moment to survey our work.

Congratulations! All of the electronics work is done! All that’s left is final assembly.

Fig. 59

Fig. 60

Stuffed PCB’s ready for final assembly!

Page 28: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

24 | Lola Assembly Guide

Putting It All TogetherWe’ve reached the point where we finally get to put it all together. Most of this is fairly straight forward, as always take your time. Rushing through this is a great way to strip a screw or add a hideous scratch to your build.

Mounting The LED PCBGrab the hardware bag and locate bag A. Carefully empty the contents on to your work bench (aka dining room table) and Grab four 5/16” 4-40 pan screws and two 5/8” #4 standoffs (Fig 61).

3 Assembly

Now place the meter PCB over the standoffs and use the two remaining screws to screw it into place. (Fig 63)

Fig. 61

Fig. 62

Fig. 63

Locate the two large holes near the pushbut-ton switches and feed two of the pan head screws through the bottom of the PCB. Now take the standoffs and thread them over the screw shafts and tighten them (Fig 62).

Do not tighten these top screws until you have the bracket and faceplate in place.

Page 29: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | 25

Inserting The LED Light PipesGet out that sexy faceplate!

Grab bag B and VERY carefully remove the con-tents. The light pipes are not easy to find if dropped on the floor. so be careful. You should find 10 clear light pipes and 10 black rubber retainers (Fig 65).

Insert the shaft of the light pipe through the front on the faceplate. Pressing your index finger against the top of the light pipe, slip the retaining ring over the light pipe shaft. Once you have all of the light pipes and retainers installed, tighten the fit on each retainer by holding the light pipe tight with your index finger and sliding the retainer down tight with the edge of a pair of needle nose pliers. Don’t squeeze the retainer or pipe with the pliers. Just use

the edge to push it toward the back of the faceplate (Fig 66).

Mounting the PCB to the BracketBy now you’ve done this a few times. The only dif-ference is that this time use a #4 lock washer located in bag A on each of the mounting screws before tightening the #4 nut (Fig 67).

Fig. 64

Fig. 65

Fig. 66

Fig. 67

Page 30: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

26 | Lola Assembly Guide

The Ribbon ConnectorIn the meter bag D you have a ribbon connector. The ribbon connector is polarized in that one side of the PCB header has a thin vertical tab, and the other has a thick vertical tab. If you look at the side of the connector you’ll see a thin slot and a thick slot. Line up the tabs and press the cable into place at the meter and at the main PCB between the transformers (Fig 68).

Mounting The FaceplateDig out the DI nut and washer as well as the nut and lock washer for the t-pad and Grayhill switch. Mount the face plate and loosely screw the nuts and washers into place. Align the face plate by running your finger along the edge on the faceplate and rear of the L-bracket (Fig 69).

Now tighten all three nuts with a nut driver or tool of choice (Fig 70). The required nut drivers are:

♦ DI Jack - 7/16”

♦ Output T-Pad - 1/2”

♦ Gain Grayhill Switch 5/16”

Mounting the KnobsThis is it, the last step. Let’s wipe the tears from our eyes and get this done. Open up hardware bag C and grab the two knobs with 1/8” and 1/4” shaft holes. Older kits will have two 1/4” shaft knobs and a shaft adaptor (Fig 71).

Fig. 68

Fig. 69

Fig. 71

Fig. 70

Page 31: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

HAIRBALL AUDIO, LLC | 27

The 1/16” hex wrench is not included but you’ll need one for this step.

Mounting the output knob is straight forward. Rotate the output knob fully clock wise. Each knob has two set screws. Loosen both with your hex wrench so the knob will filly slide over the output

t-pad shaft. Align the white line with the last large dot in the fully clock wide position and tighten both set screws (Fig 72).

The gain knob is a little trickier if you have an older kit because of the adaptor and the Grayhill D shaft.

If you have a current kit with a 1/8” shaft knob, mounting is staright forward and you can skip the next part.

Start by rotating the Grayhill switch to the fully clockwise position. You may need to do his with a pair of needle nose pliers to get the necessary torque and grip. Your Grayhill shaft should resemble Fig 73.

Place the knob on your bench with the white line where it would be in the fully clockwise position. There is a set screw in the 8 o’clock position, loosen this set screw (Fig 74).

The set screw in Fig 75 is going to mount against the solid side of the adaptor. The second set screw is going to pass through the slot in the set screw and mount against the rounded side of the Grayhill shaft. Having the flat side of the Grayhill D shaft behind the solid side of the adaptor will allow the knob to mount evenly.

Fig. 72

Fig. 73

Fig. 75

Fig. 74

Page 32: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

28 | Lola Assembly Guide

Flip the knob over. Both set screws are loosened but the one we loosened in Fig 74 is in the 4 o’clock position. This is the screw that will mount against the solid edge. The other set screw is in the 11 o’clock position and will pass through the slot.

Place the adaptor in the shaft with the thicker end facing up. Make sure the adaptor is aligned so that the 4 o’clock screw will hit the solid adaptor edge and the 11 o’clock screw will pass through the slot. Tighten the 11 o’clock screw so it passes through the slot. Now tighten the 4 o’clock screw to set the adaptor in place. You’ll wand to place your finger on top of the shaft to keep it level. Because the thicker end was inserted facing up, the adaptor will stick out from the mounting hole. We want this, it will help the knob float off the faceplate a little and level it with the output knob.

With the adaptor securely in place, mounting the knob is fairly straight forward. Loosen the set screw that is trough the slot and place the knob over the shaft and align the white line with the 65 dB setting (Fig 76). Now you’ll only need to re-tighten the set screw that passes through the adaptor slot and secures the knob to the Grayhill shaft. It should now be located in the 1 o’clock position..

Lastly, step back and admire your work. You’re done!

Final TestingDepending on your level of expertise and available equipment, there is a wide variety of test you can run. I’ll guide you through a few basic test points.

Run the tests from the Testing The Main PCB sec-tion (page 19).

Feed a signal through Lola and adjust the input and output so you are getting +4dBu (1.25V) at output. You’ll need to figure out the best way to do this based on your available equipment. With a +4dBu output, your LED meter should light to the first orange LED in VU mode. Switch output to +1dBu (0.869V) output and the meter should light to fith LED in VU mode. With the same output level switch to PPM mode (0.869V = 1.25V Peak)and the meter should light to the first orange light (0dB).

Fig. 76

Fig. 77

Page 33: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

4 Appendix

Page 34: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located
Page 35: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

APPENDIX | A APPENDIX | A

5 Band Resistor Color Code Guide

Page 36: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

B | APPENDIXB | APPENDIX

Gain ResistorsValue Name QTY Value Name QTY3.9Ω R2 1 100Ω R8 1

Value Name QTY Value Name QTY6.2Ω R1,R3 2 160Ω R9 1

Value Name QTY Value Name QTY10Ω R4 1 300Ω R10 1

Value Name QTY Value Name QTY16.9Ω R5 1 620Ω R11 1

Value Name QTY Value Name QTY27Ω R6 1 1.2KΩ R12 1

Value Name QTY51Ω R7 1

Page 37: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

APPENDIX | C

Main PCB Resistors (10Ω - 33KΩ)Value Name QTY Value Name QTY10Ω R31,R32,R36,R37 4 2.2KΩ R29,R30,R34,R35 4

Value Name QTY Value Name QTY22Ω R22,R25 2 3.4KΩ R40,R41 2

Value Name QTY Value Name QTY39Ω R33,R38 2 6.8KΩ R16,R17 2

Value Name QTY Value Name QTY470Ω R15,R28 2 18KΩ R27 1

Value Name QTY Value Name QTY1KΩ R14,R39 2 33KΩ R23,R26 2

Page 38: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

D | APPENDIX

Main PCB Resistors (100KΩ - Inductors)Value Name QTY Value Name QTY100KΩ R18 1 3.3MΩ R20 1

Value Name QTY Value Name QTY330KΩ R19 1 4.7uH L1,L2 2

Value Name QTY1MΩ R21,R24 2

Page 39: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

APPENDIX | E

Main PCB Semi ConductorsValue Name QTY Value Name QTY

1N4004 D1-D6 6 2N3906 Q1 1

Value Name QTY Value Name QTYLM317 IC1 1 J201 Q2,Q3 2

Page 40: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

F | APPENDIX

Main PCB CapacitorsValue Name QTY Value Name QTY100pF C7,C9 2 47uF/25V C3-C6 4

Value Name QTY Value Name QTY680pF C2 1 47uF/50V C1 1

Value Name QTY0.1uF C10,C11 2

Page 41: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

APPENDIX | G

Meter PCB ResistorsValue Name QTY Value Name QTY10Ω R116,R117 2 1.4KΩ R112 1

Value Name QTY Value Name QTY240Ω R115 1 10KΩ R111 1

Value Name QTY Value Name QTY510Ω R110 1 100KΩ R101,R103,R104 7

R106-R109

Value Name QTY732Ω R114 1 Value Name QTY

200KΩ R102,R105,R113 3

Page 42: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

H | APPENDIX

Meter PCB Semi ConductorsValue Name QTY Value Name QTY1N914 D101-D104 4 TL072 IC103 1

Value Name QTY Value Name QTYLM3916N IC101 1 LM317 IC104 1

Value Name QTYTL071P IC102 1

Page 43: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

APPENDIX | i

Meter PCB CapacitorsValue Name QTY Value Name QTY

0.22uF C101,C102 2 3.3uF C106 1

Value Name QTY Value Name QTY0.47uF C105 1 47uF/25V C103,C104 2

Page 44: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

J | APPENDIX

Gain Resistor Detail

Page 45: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

APPENDIX | K

Meter Resistor Detail

Page 46: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

Controls and Switches: Mic Gain, Output Level, Phantom Power, Phase, Mic/Line, Di, Average and Peak Metering

Microphone Preamp Gain: 15.5dB to 65 dB (4.5dB stepped with output trim)

Microphone Mode Maximum Input Level: +13 dBu, balanced, < 1% THD

Line Mode Maximum Input Level: +25 dBu, balanced, < 1% THD

DI Input Maximum Input Level: -1 dBu, unbalanced, < 1% THD

THD + Noise : < 0.05% (1 kHz, 50 dB gain, +17 dBu output)

CMRR: > 90 dB (40 dB gain, 20 Hz to 20 kHz)

Maximum Output: +30 dBu balanced, 20-20 kHz, >1.6k ohms, <2% THD

Frequency Response: +/- 0.5dB 20 Hz – 20K Hz (-40dB, 1K input, 0dB output)

Current Draw: 130mA max

Microphone Input Impedance: 1.6K Ω, balanced line-to-line

Line Input Impedance: 10K Ω, balanced line-to-line

DI Input Impedance: 1MΩ, unbalanced line-to-ground

Output Impedance: 200Ω, balanced line-to-line

Metering: 10 Segment LED bar graph

Metering Scale: -20 to +3 VU (0 VU = +4 dBu)

Metering Modes: Average and Peak

Specifications

Page 47: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

100K

6.8K

6.8K

470

39R

39R

4.7

uH

4.7

uH

10R 10R10R10R

2.2

K2.2

K

2.2K 2.2K

100pF

100pF

GN

DG

ND

GN

D

1000uF

6.2R

GND GNDGNDGND

TQ

2-2

4V

TQ

2-2

4V

GN

D

LM

317

1K

TQ

2-2

4V

1K

GN

D

GND

2N

3906

330K

3.3

M

470R

TQ

2-2

4V

0.1uF 0.1uF

1M

1M

GN

D

GN

D

J201

J201

22R 33K

22R 33K

18K

680pF

16.9

R6.2

R

160R

1.2

K

100R

51R

620R

300R

27R

3.9

R

10R

3.4K 3.4K

GND

47uF

47uF

47uF47uF

47uF

R18

R17

R16

R15

R33

R38

L1

L2

R36 R37R32R31

R34R29

R30

R35

C7

C9

C8

R1

10

1

K1(IN

+)

2 4

3

97

8

10

1

K2(IN

-)

2 4

3

97

8

D5

D6

VI

31

VO

2

IC1

AD

JR

14

10

1

K3(Ø

)

24

3

97

8

D4

R39

1

2

3

5

4 6 7

8

9

Q1

R19

R20

R28

10

1

K4(D

I) 24

3

97

8

C11 C10

R21

R24

Q3

Q2

R22 R23

R25 R26

D2

S R T

J1

SN

RN

TN

R27

C2

OPT-R

OP

T-C

S4

P$12

P$P1

P$11

P$10

P$9

P$8

P$7

P$6

P$5

P$4

P$3

P$2

P$1

R5

R3

R9

R12

R8

R7

R11

R10

R6

R2

R4

R41 R40

C3C4C5 C6

C1

T2

EA

-1166-5

00

Bro

wn

Red

Gre

en

Blu

e

Purp

le

Gre

y

T1

EA

-10468

Bro

wn

Red

Ora

nge

Yello

w

Gre

y

Vio

let

White

Bla

ck

GN

D

GN

D

JH

-990

JH

-990

IN-H

I

IN-L

O

OU

T-H

I

OU

T-L

O

SW

3(L

INE

)SW

2(Ø

)

SW

1(+

48)

+16V

+48V

-16V

+16V

-16V

-16V

+16V

+16V

+16V

-16V

-16V

-16V

+16V

+16V

+16V

-16V

-16V

-16V

TL0

72

P

TL0

72

P

0.22uF

100K

20

0K

10

0K

10

0K

20

0K

10

K

1.4K

GN

D

GN

D

GN

D

GN

D

GN

D

GN

D

0.47uF

20

0K

10

0K

10

0K

51

0

TL0

71

P

10R

10R

GN

D

LM

31

7

100K

10

0K

GN

D

732R

24

0R

47

uF

47

uF

2.2

uF

0.22uF

10

K

10

K

10

K

10

K

10

K

10

K

8.2

K

8.2

K

8.2

K

3.4

K

LE

D1

1

V-

2

V+

3

DIV

LO

4

SIG

IN5

DIV

HI

6

RE

FO

UT

7

RE

FA

DJ

8

MO

DE

9L

ED

10

10

LE

D9

11

LE

D8

12

LE

D7

13

LE

D6

14

LE

D5

15

LE

D4

16

LE

D3

17

LE

D2

18

23

1

IC1

03

A

65

7

IC1

03

B

C101

R101

R1

02

R1

03

R1

04

R1

05

R111

R112

C105

R11

3

R1

07

R1

09

2

3 1

5

6 4S1

01

R11

0

5

1

23

6

8

IC1

02

7 4

R116 R117

AD

J

INO

UT

IC1

04

R108

R1

06

R114

R11

5

C1

04

C1

03

C1

06

C102

LM

39

16

N

IC1

01

+1

6V

-16

V+

16

V

-16

-8 -3 -1 +1

+3

+4

+5

+6

+7

+1

6V

XLR

OU

T +

XLR

OU

T -

Mai

n PC

B Sc

hem

atic

Met

er Sc

hem

atic

Page 48: Lola - Hairball Audiolibrary.hairballaudio.com/docs/LolaManual.pdf · 2 | Lola Assembly Guide LED Meter The Lola features a 10 segment integrated circuit controlled LED meter. Located

Hairball Audio, LLC • 6523 California Ave SW • PMB 291• Seattle, WA 98136 • www.hairballaudio.com