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ELTIM high-end AMPLIFIER modules Available from 25th of July 2018, can be ordered updated July 13th, 2018

PA-3886 Amplifier modules More than once we are asked to develop an ELTIM way built module based on the very nice performing / cost effective LM3886 IC from Texas Instruments. More and more experience that the cheap crap one can find all over the internet have way to small tracks, poor parts, etc. Due to these technical mishaps this IC will and cannot not perform as is could do. We made boards not limiting the LM3886 specifications at all.

With around 80Wrms @ 8 ohms this most easy to build and to use module will fit for a lot of projects like small stereo amplifiers and active speaker systems. Also a very nice project for starters (schools!) actually. In order to make a true difference compared to about all on Internet available cheap modules, we use the ORIGINAL Texas Instruments IC and a double sided board, providing space for even 4mm tracks to the IC and at the same time have a ground separation of the input- and output currents as recommended by TI.

As an environmental friendly company, we use the LM3886T, RoHS compliant and Lead-free. It is capable of delivering 7A of audio currents. Also, this one has a metal back side, allowing more heat to flow into a heatsink. On the cheap Internet modules with 15um single layer copper and at the same time a track width of only 1 – 1,5mm, the power supply and speaker tracks can handle only around 1-2A. Despite the fact that with our DOUBLE LAYER copper of 35um we need 2,2mm for the 7A of current the IC is capable of, we made them 4mm wide and where possible even wider, since a dynamic current is something else than a constant current. Our tracks are capable of feeding 12A+. Close to the IC we go some smaller, but added short tracks on the other side there. Despite the fact that a double sided PCB costs more, we believe this IC deserves it and give it the ELTIM design/sound signature where this nice and cost effective IC truly can show what it is capable of.

Prototype model. Final model is slightly different, some small parts only!

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WARNING: Since this project could attract beginning electronics DIY’ers, we give following warnings. Please note that an ORIGINAL Texas Instrument type + quality PCB cost more than the Alibaba/Ebay modules as complete modules, so something must be wrong, isn’t it? And as always, there is! To start with: ONLY the T version is RoHS compliant and lead free as EU-rules demand….. So, as you can read in this RoHs statement it is not even permitted for businesses to sell other versions into the EU. None of the ones we found use TI-originals and most probably are even counterfeited products as there are so many on today’s market. Type “counterfeit” in Google! IC’s, transistors, capacitors, etc. are “restamped” and “copied” on daily bases. We use the originals, and so meeting specs, with a metal back plate (-T), conducting heat way better, so better (and as the docs state) performance. Original plastic ones deliver around 40-50W@8ohms, the ones we use with metal back plate can do 80Wrms, but then it really NEEDS this metal plate, otherwise the thermal protection comes in action! The copy plastic ones can deliver 30W max. if you are lucky! Other specs????

Lots of these modules also use other fake or overstock (aged) components, f.e. re-stamped capacitors (f.e. 35V becomes 50V overnight…). To old (overstock) electrolytic capacitors are useless! That’s why they blow up! There is a lot of stuff like this on the Ebay/Alibaba markets! Since we are a professional company you can rely that we supply decent and actual material and buy from professional, respected companies. If you experience a problem, we are there for you! +31 595 491748 info@eltim.eu By now (summer 2018) we delivered lots of ELTIM modules and DIY kits, no complaints or faults whatsoever so far.

Remember, the Power Supply is part of the chain. Cheap SMPS’s show poor dynamics and bad high frequency behaviour due to their relatively high and increasing impedance with frequency. Result: poor bass and screaming highs !

As always: if the price looks too nice, there most probably is something wrong ! Deep in your mind you know.

How we do it First of all: some people are complaining that we need so many words in order to tell about our work. Unfortunately they believe it’s one of our marketing tools. But, we are technicians, no marketers! We write in an “electronics magazine” style on purpose to help newcomers learn about electronics too. So, here we go.

The TI datasheet strongly recommends to keep the speaker track as thick and as short as possible and as far away from the input circuitry, so WE did. Also, we kept the input ground apart from the output ground. The speaker ground goes directly to the power Supply capacitors and the central ground connection. The input ground also leads directly to this centre ground pin, so not affected by speaker currents. Both use large surface area’s at both sides ground planes, so about 70% of both sides is actually grounded. Ringing, “motorboating” and oscillation effects will not occur in (any of) our designs.

As also recommended by the TI datasheet, we use an output coil, so capacitive loads will be accepted more easy. We wound this coil around a 10R/5W Mundorf MOX resistor, which is also recommended.

In the cheap Internet modules you’ll find the cheapest input capacitor one can find and so, acting as a filter already. With us, you can mount a serious MKP version, f.e. Mundorf MCap400. There are multiple holes for all kinds of dimensions, 15/22,5/27,5/41mm pitch versions. Max width is 19mm. Ready built modules and kits are delivered with a nice MKP Panasonic ECWFW-2,2uF/450V, pitch 15mm.

By using the extra INdc tab, you could bypass this input capacitor. In that case, be sure that the input signal is dc free! You could also use this INdc while using a large, external mounted (mostly large) High-End capacitor. As it always should be, RF interference from outside is blocked by an RC network in the input circuit and the gain of the IC is limited beyond the audio range by the TI listed circuit, avoiding oscillations and other mishaps.

As in about all our designs, we use 1% MOX resistors of course. In some of our top models we even use 0,1%.

Unlike others, we don’t attempt to push all on the smallest board possible, mostly even a cheap single layer version with only 12 or 15um copper. As with our other audio modules we gave tracks and components the space they truly require on a DOUBLE layer board. We use 2x 35um copper in order to let the LM3886 perform at best!

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The PCB’s come from a respected EU manufacturer, with a solder mask and printed parts locations/values. You need a 60W iron at least to solder due to the heat exchange with the board, despite the fact that we partly isolated the solder pads from the larger area on purpose. Parts will become less hot while soldering this way. Also NO (China) pollution and no people doing the job about for free for you. We would be ashamed.

As it should be done always (increasing GSM, 4G, Wifi, etc.), the input is filtered by an RC network (1k/470p). The gain and bandwidth of the IC is limited beyond the audio range by the TI listed circuit, avoiding oscillations and other mishaps. Unfortunately, we found out that more simple solutions tend to show oscillation and “motorboating” effects!

We added a INdc input, where you can bypass the input capacitor. Use this input if you are sure your audio signal is free of dc or mount a high quality (mostly large) capacitor here as shown in the picture below. With OUR modules it makes sense.

We use a symmetrical power supply instead of a single one where an audio degrading output capacitor is required. Instead, you’ll find the recommended output coil. Now also capacitive loads as many speakers tend to show can be powered.

Output power We see all kinds of output data on the internet, mostly just by copying each other. The data there is just general information, so specified for the least performing types. Basically it’s the data of the ORIGINAL plastic versions. Copies perform even less power. This copying, mostly by non-technicians only reading the first page of a datasheet, results in incorrect or incomplete info. Better is to study the TI datasheet completely, which may be believed to be true data.

The Texas Instruments LM3886 datasheet shows us following graph at page 14:

This graph shows what an ORIGINAL T-version (with metal back plate) can perform. We use this one !

0,1% distortion is a very acceptable figure, not even noticed by many people. Probably not even by you.

So, it’s not 40Wrms @ 8 ohms as we read everywhere, but 80W instead, which is quite some difference (3dB in sound). But then the PCB must be designed properly with wide tracks, etc. as we do. You can’t lead 7A (IC specs.) of dynamic current over a 1mm wide (or even smaller) track and expect to get a dynamic, rich sound. We don’t understand this, since everybody agrees that a speaker cable has to be as thick as possible……. And fed by a tiny track? Weakest chain! Our calculations show that you need at least 4mm tracks with a

thickness of 35um of copper as we do. Safe side calcs. The internet’s use most probably only 15um.

Also, you need to cool the IC properly with sufficient cooling surface. The IC datasheet helps you out.

In most cases the heatsink is grounded; in that case use a thermal pad and a NYLON mounting bolt for fixing. Unfortunately this gives a small thermal resistance, but is still way better than while using plastic versions. With our modules and kits we supply both a high quality thermal pad (Silpad 400) and a nylon M3 bolt.

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Mute function In their datasheet TI recommends to connect pin 8 (MT) via a resistor and a switch to V- for (de)activating the mute circuit, which is most unpractical, due to the fact that the switch is connected to V-, mostly around -35V. In that case some extra electronics would be required to come to TTL/CMOS level resp. ground. After studying the internal schematics and some controlling measurements on our prototype, we found a way better solution. We mounted a 39k resistor directly from pin 8 to V-, causing a current out of pin 8 from 0,42-0,85mA, depending supply voltage. Due to this the amp is active (Gain 0dB), see graph below.

With this fixed mounted connection to V- by a resistor, the MT line of the IC is at a potential of around -2,7V, where the base of the internal mute transistor is at ground level, so conducting > sound. By connecting this MT line to ground now, the internal transistor will lead no current since the BE part of it is below 0,5V and so the circuit is in mute mode, that’s it ! Now you can use a switch to ground or an active circuit via f.e. a processor system. Any voltage higher than aprox. -2V will activate the mute function. Due to the internal diodes, this can even be a quite high voltage. The MT pin on our boards take hardly any current (diodes/transistor blocked), so can be driven by any circuit.

Since the gain could be controlled as well by draining more or less current (to V- !) from the MT pin, you could even use it as electronic volume control -) Sinking around 0,05mA or less gives a gain of around -93dB, while 0,35mA or more sets the gain at 0dB, see graph above. So, in a range of 0,3mA, you can control the gain from 0 to -93dB. Sink this current to V- ! You could use a variable resistor of 500k in series with a 39k resistor, connected to MT and V-. This comes in place of our 39k resistor, so cut this one off the board or put the potmeter in series with it. Please note that we did NOT try this ourselves and it is not meant to function this way!

By mounting a some larger capacitor from MT to V+, the amplifier’s sound will fade in slowly after the power is switched on. While uncharged it will connect MT to V+ first. Then it’s charged by the 39k resistor causing the voltage on MT dropping. After passing around -1V at the – pole (=MT), the sound comes in faded. Since the MT line will reach -2,7V, connect the – pole of the cap to MT ! The voltage of the cap needs to be V+ + 3V at least. You could mount it on the marked PCB position. Try f.e. 10uF/50V. Power Supply An impulse rich current draining device as these amplifier modules require a Power Supply capable of delivering this. Most Switched Mode Power Supplies (SMPS) CANNOT perform this and are meant to feed quite constant currents! Also, they mostly contain lots of the switching frequency on the power rails and even worse, the impedance rises with load frequency, together resulting in poor bass and screaming highs. With the cheap internet modules, the PCB design is that simple (insufficient to lead 8A of dynamic power), that you most probably won’t notice the difference, but with ours you do, sorry to say.

They about all also use a single voltage power supply, causing an IC output swing around half the supply voltage. Due to this, there is a high value capacitor required in order to keep this V+/2 voltage away from the speaker. This value must be that large, that only electrolytic, polarity sensitive capacitors can be used. However, these are meant for power supplies, NOT for leading AC currents. They form another audio filter in the circuit, especially resulting in poor small signal details, bad phase (3D) response, “fluffy” bass, etc. Since it is a misused component in the audio path, it sucks up a part of the output power as well. Also, half the time the polarity is wrong as well, shortening the lifespan of this component (= device) dramatically! Imagine what we see: people buy fantastic capacitors for their speaker crossovers, preceded by a plane electrolytic capacitor in value of €2,00-3,00 leading the same signal……. We don’t understand this at all.

Unlike others, we use a symmetrical power supply, where the IC output swings around ground level and so, NO output capacitor is required. Since there is none, it doesn’t age and doesn’t mess up the audio signal, nor sucking up power. The capacitors you see on our boards are part of the Power Supply chain! Also due to the missing output capacitor, our modules will surprise you with very nice, honest and powerful sound.

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ELTIM PA-3886, module without Power Supply:

ELTIM PA-3886, 100x65mm

Scale 1 : 1 Connect a symmetrical Power Supply, +/-40Vdc max. This module is meant to connect to a decent (so, preferable not a cheap SMPS!) power supply with sufficient capacity on board. We have some in our program. Most SMPS supplies have RF on the power lines, which can cause a deterioration in audio quality or worse: oscillation of the amplifier! We did all possible to prevent this, but it still is possible if the added power is of poor quality and/or contains significant high frequency content.

This ELTIM PA-3886 PCB requires about all energy from an external Power Supply, but fits 2x Ø16/18mm or 2x2 Ø12,5mm electrolytic capacitors to bring some extra energy reserve closer to the IC. If you mount some, use quality caps like NICHICON Fine Gold ! You will be rewarded with better sound. Low ESR capacitors like these only make sense while mounting them close to the load with thick/wide tracks as we do. Unlike the cheap internet modules, we use serious AND Audio Grade capacitors on our ready built modules with sufficient capacity and a long life span to do the job properly. Furthermore we added 220nF MKP capacitors close to the supply connections in order to keep RF outside and increasing high frequency quality. We also added some extra capacitors over the power rails, as close to the IC as possible, a 100n and a 22u type as recommended in the TI datasheet, not seen anywhere else.

Since we mostly build all our modules on demand you can ask in the comment line of the order form for other types of electrolytic capacitors. We will respond with an offer to you. We can supply about any type. While building it as a kit you could mount up to 2x 2200uF/50V actually, but they are way higher and Ø18mm, but fit. As always, in DIY kits we leave out the Power Capacitors, since many want to use their own preferenced caps. So, if you want them from us anyway, order the capacitors you like, matching your requirements/wallet.

We always try to get some more out of a specific module design. Since we also hobby (for over 40 years now), we mostly can and do think as many do, meaning that we try to make our modules as useful as possible. In this case, with these small modules we also found a nice extra, without any extra costs. You can sandwich-mount this one, even on top of our version with its own Power Supply as shown at the next pages. Mount it on top of a PA-3886ps module, using some distance holders. Three straight copper leads form the power lines of a full pack. On the PA-3886ps version and the extra capacitor “booster pack” PS-BOOSTER there are holes exactly at the same location, so the copper rods are easy to mount. With this sandwich possibility, you become a solid pack for stereo, parallel, bridged, 2- or 3-way active setups, etc., all fed by just a single transformer, connected to the PA-3886ps module, but 8A (±300W output) max. We also see a function where multiple PA-3886 units are connected to a PA-3886ps, for multichannel purposes like home theatre systems or for shopping malls, etc. as improved replacement of 70/100V systems. In that case, also mount at least one PS-BOOSTER. See our example at the last page of this document. If all carry the same signal, feed it to only one and add a small copper rod just below the input capacitors, similar as the Power Supply rods we mention below ! All INac lines are connected then. Mount the jumper! This line even goes through any type of PS-BOOSTER module at the same PCB location.

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ELTIM PA-3886ps, module with an integrated linear Power Supply:

100x100mm with on board Power Supply

Scale 1:1 Just connect a transformer, 2x25Vac max. This module is technically similar to the basic one, except for a full functioning linear, symmetrical Power Supply with quality secondary fuse holders, a rectifier + small caps around it and required larger capacitors. These capacitors can be Ø25/30mm, so indeed serious ones (f.e. 4700uF/50V) can be mounted. Instead, you could mount 2x2 Ø18mm or 2x3 Ø16mm types, mostly more cost effective. You can even use (very) long Ø18mm ones (f.e. 2200uF/50V), even if a PA-3886 is mounted on top, see the red line marking. If you prefer multiple small caps (Nichicon Fine Gold is fantastic), mount 2x7 Ø10mm electrolytic capacitors. Here only small values fit, insufficient for 80W bass output. For low power or tweeters only or assisted by our PS-BOOSTER module! In that case its best to use capacitors of the same “family” in both modules.

In order to complete this module in a working power amplifier, you only need to connect a (quality), regular transformer. The transformer secondary windings are connected to P1/N1 and P2/N2. Max. 2x25Vac. Fuse them as listed with the transformer data. Since even these are part of the chain, we use good quality fuse holders, not the cheap basic ones. Fuse the primary side of the transformer accordingly !

The V+, GND, V- and input signal can be fed to a sandwich mounted unit by 1,5mm² solid copper rods. So, f.e. you can mount one or more of our PA-3886 modules on top of it, fed by the same, single transformer. For even better performance you could connect a PS-BOOSTER module with extra power supply capacity in the same way. We recommend to use this one where three or more amplifier modules are sandwiched this way. Also with this module the INac line can be fed through to the other sandwiched modules. Mount the jumper!

A pair of these (exactly) fit in a MODU Galaxy 230mm wide, 40mm high cabinet, see the example at one of the next pages. Depth depends on the space the transformer and possibly other electronics would take. Want it even more compact? A pair also (exactly) fit top mounted in a 124mm wide Galaxy cabinet. We also show an example of this below.

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PS-BOOSTER Booster module For continuous high power of three or more amplifier modules, the total PS capacitance of the amplifier module(s) could become a bit short. Also, if one PA-3886ps and a PA-3886 module both are at continuous high power, it could use some help. In order to solve this issue, we also developed a PS-BOOSTER “booster” module in the size of a PA-3886ps, where only extra Power Supply capacitors are mounted in order to match the probably required extra power reserve in a multichannel setup or continuous high power levels. Some examples are at the last pages of this document.

Just mount a PS-BOOSTER in the pack as mentioned above, the three power supply copper rods follow the same route (three red circles in the middle). You can connect them anywhere in the pack, but best is in the middle of the two most current draining modules. We even thought of the common ACin line while using multiple PA-3886 modules; for this there is just a hole at the right middle, marked ACin. In that case you have to sacrifice two capacitors (left and right), only if you used Ø25mm ones. In fact, while using it this way, the 3-pole screw terminal is not used. You could even connect two chassis mounted large capacitors there. They need to be connected with thick wires, so we used a connector with 7,5mm spacing here. While connecting a pair of these babies there will be enough power reserve at all times.

If we build these modules for you, also here we use quality, long life, audio grade parts from NEW stock.

PS-BOOSTER, scale 1:1, 100x100mm

This extra capacitor board fits following capacitors:

2x15 Ø16mm radial caps (f.e. 1000uF/50V), pitch 7,5mm or 2x5 Ø25mm radial caps (pitch 10mm) + 2x2 MKP (pitch 15mm).

Besides working as a “booster” capacitor bank for our PA-3886 and PA-4766 amplifiers, this board can also be used as extra capacitance in existing systems where appears to be lack of sufficient power reserve capacitance. Connect it with the 3-pole screw terminal (7,5mm pitched) with as thick wire as possible to the existing equipment. This connector can also be used to feed other electronics if it is in a sandwiched pack with the mentioned 3-rod setup. This connector is unused then by our setups.

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Following products are available from our webshop and dealers: Ready built and tested basic modules:

PA-3886 ST with 2x 1000uF/50V Panasonic FC capacitors Height 27mm PA-3886 LP with 2x2 680uF/50V Panasonic FR capacitors Height 32mm PA-3886 FG with 2x2 330uF/50V Nichicon Fine Gold capacitors Height 23mm

Ready built and tested modules with Power Supply parts: PA-3886ps ST with 2x2 2200uF/50V Panasonic FC capacitors Height 38mm PA-3886ps LP with 2x3 1000uF/50V Panasonic FR capacitors Height 28mm PA-3886ps FG with 2x7* 100uF/50V Nichicon Fine Gold capacitors Height 22mm PA-3886ps HQ with 2x 4700uF/50V NICHICON LGU capacitors Height 32mm PA-3886ps RQ with 2x 4700uF/40V Mundorf MLGO capacitors Height 33mm

Ready built and tested “Booster” modules: PS-BOOSTER LP with 2x9 1000uF/50V Panasonic FR capacitors Height 27mm PS-BOOSTER FG with 2x9 470uF/50V Nichicon Fine Gold capacitors Height 27mm PS-BOOSTER FG+ with 2x9 1000uF/50V Nichicon Fine Gold capacitors Height 34mm PS-BOOSTER HQ with 2x2 4700uF/50V NICHICON LKS capacitors Height 27mm PS-BOOSTER RQ with 2x2 4700uF/40V Mundorf MLGO capacitors Height 32mm

* NOTE: The 2x7 FG version is short of Power Supply capacitance for driving woofers. Recommended for low power or driving tweeters/mids in multiways or assisted by a PS-BOOSTER module. On request, we can assemble any combination of the above as a multichannel combination. Just mention this in the comment line of the order form. We do this free of extra charge for now! Note that we use “overvoltaged” types, resulting in way longer lifespan than while using 35V versions “on toes”.

DIY kits: PA-3886 kit with all parts, except power supply capacitors. PA-3886ps kit with all parts, except power supply capacitors and trafo. PS-BOOSTER kit basically just the required PCB and 3-pole connector, so NO caps.

Instructions and wiring diagrams can be found on our website.

Please note that pricing (margin) of DIY kits doesn’t allow us to give technical help at any time! In the case you are not able connecting a ready built module

or (assembling) a DIY kit, we can help you at € 60,-/hour charge. Just send back and write the problem you face with it. Don’t forget to mention your name and address.

This project is now in production phase, so you can order it already !

For us it was encouraging to find as many combinations as possible with these tiny modules. We did NOT attempt to make them as cheap as possible but as good and multifunctional instead.

We have an increasing number of audio related modules, also available for dealers. Inquire here. Other electronic parts

Besides our amplifier- and Power Supply modules/kits we also have a numerous number of quality parts in our

webshop, all together around 12000 items. Drive units, Gramophone cartridges and styli, capacitors,

coils, resistors, power transistors, nice electronics cabinets, connectors, cable, damping material, etc.

These designs are copyrighted by ELTIM audio BV, Louis Timmers 2018 ©

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PA-3886 models

Depth of all models: 65mm

Scale 1 : 1

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PA-3886ps models

Only recommended to drive mids/tweeters or i.c.w. PS-BOOSTER module and/or serious power supply.

Depth of all models: 100mm Scale 1 : 1

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PS-BOOSTER models

Depth of all models: 100mm Scale 1 : 1

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Example of sandwiched amplifier modules

Example of two Amplifier modules and a “booster” module in the middle. Three copper rods just behind the screw connectors provide the power from the PA-3886ps (or PA-4766ps) module to all other modules. You just need to connect a suitable transformer to the PA-3886ps. In the same way you could interconnect all INac lines just below the input caps.

Bottom one is f.e. a PA-3886ps for the woofer (80W/4ohms), upper a PA-4766 2-channel (50W each/8ohms) for midrange and tweeter forming an active driven 3-way speaker setup. Just connect a transformer. With this one there will be way enough sound in any living room. A (DSP?) active driven/filtered speaker sounds louder than passive somehow! You would need over 200W in a passive system for similar sound level. You can combine as many modules as you like in a random mix of PA-3886 and PA-4766 modules. You only need ONE with a Power Supply while using the connecting rods! It can supply enough power (up to 400W, assisted with a PS-BOOSTER module) or use versions without on board PS and connect an external Power Supply. Note that so far, a linear Power Supply “sounds” much cleaner/more natural than an SMPS!

Do NOT attempt to interconnect INdc lines on PA-3886(ps)’s, this will lead to severe problems (f.e. DC at the outputs).

Any combination of our PA-4766 and PA-3886 modules is possible, BUT keep in mind that the lowest voltage supply capacitors decide the max. allowed supply voltages !

Mount them on a back panel heatsink in your active driven loudspeaker! The IC sticks out 2mm in order to allow an airflow between the heatsink and the PCB/IC. This improves thermal stability and max. sound level compared to modules where the PCB is mounted against the heatsink > no airflow/more heat. Also, our double sided PCB provides extra cooling. Together with the metal back plated IC, it can finally be used to its limit of 80Wrms, but COOL IT !

Multichannel (up to 40 channels) setups fit in f.e. MODU Dissipante 3U cabinets, where the module packs are mounted vertical. As an alternative you could use MODU Slimline 3U cabinets for low power purposes. Both also in 19” models.

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Smartphone/Monoblock power amplifier example with:

- 1x or 2x PA-3886ps Power amplifier, 2x 60Wrms @ 8ohms (80W/4ohms)

>100W/8ohms as bridged Monoblock - Toroidal transformer 120VA/2x25V (just fits) - MODU Galaxy cabinet, 124x230x40/80mm

Just connect your smartphone/tablet and enjoy powerful, quality sound. For this, you need two PA-3886(ps) modules. Mount some 15-47ohms resistors (as earpiece dummies) over the input connector as load for the smartphone output for better sound, especially at higher frequencies. You device wants to “see” a load! Monoblock Have some fun and build the probably smallest true analogue MONOBLOCK in bridged mode! Enjoy the uncompressed and powerful sound. Use a single module in a 40mm cabinet, or a dual in bridged mode in a 80mm high MODU Galaxy cabinet as shown at right. Feed them directly with a balanced signal, but better use one of our buffer input modules in order to do it as it should be done.

With a single module it could make 50Wrms/8ohms, 65W/4ohms while using a 2x25V /80VA transformer. This one just fits in height (36mm)!

While using a 80mm high cabinet and two modules as shown at right, there could be 80W/8ohms or way over 100W/8ohms (only) with a 2x22V/160VA transformer in bridged mode. This size just fits (around 92x58mm).

Cooling For optimal airflow we let the IC stick out 2mm. Since this Galaxy cabinet has an internal width of 104mm, at both sides of the PCB is a 2mm gap and air can flow from under the PCB.

More cooling > less heat > better performance.

Not by coincidence, while fitting two modules upside down AND reversed (one IC to each flank) on top of each other we come to 104mm, being exactly the internal width of this cabinet. See example at the right. We even took the height of capacitors in mind, just

Fitting with a space of about 5mm in between.

Power interconnection Also not by coincidence, the power rods are exactly in the middle of the PCB’s. So while mounted as shown, the +, GND and – power solder holes are above each other. By mounting one module upside down AND mounted against the other side as shown at right, the power lines are even above each other with the same polarity, so no line crossings. At the same time there is max. cooling since each IC has its own cooling surface. This also works with 2x PA-3886 modules ! (Not) surprisingly, the width is 104mm then, exactly the internal width of the MODU Galaxy 124mm wide cabinet.

Even while using 2x ps versions (because of more capacity available), just connect the trafo to one of them and use the three copper rods to connect them! This will fork fine as well, while both capacitor banks are paralleled by the rods.

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Integrated amplifier example with:

- PRE 230 preamplifier, 3 inputs, 2 outputs, independent Power Supply - 2x PA-3886ps Power amplifiers, 2x 60Wrms @ 8ohms / 2x 80W @ 4ohms

- Toroidal transformer 120VA/2x25V - MODU Galaxy cabinet, 230x280x80mm

For optimal channel separation, use ps types for both channels. Both PA-3886ps modules are interconnected under the boards by short wires to solder pads (blue lines) if only one transformer is used. Select the module quality you prefer. For even better channel separation use 2x 80VA transformers instead of one and connect to each PA-3886ps.

While using only one transformer you can mount an ALPS potentiometer on the PRE-230 preamplifier module and lead a 6mm rod through the front panel and mount a volume knob.

With two transformers, the increased quality could be improved even more by use of one of our VCA volume control modules. In that case you only need some (DC) wires to a single (linear) potentiometer or change volume by SPI data.

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Multichannel setup example:

As a sound quality improving alternative of 100V PA systems in f.e. exhibition halls, shopping malls, fun parks, etc., multichannel setups can be made with our PA-3886 modules. Connect every speaker separately to an output and adjust the levels. Max. 20x 60W/8ohms (80W/4ohms)……

Here about the max. number of channels possible : 20x in a MODU Dissipante 400mm deep, 120mm high cabinet. This one provides way enough cooling for constant (professional) use in f.e. exhibition halls, shopping malls, fun parks, etc. With 20x 80W/4ohms = 1600W there will be enough sound….. In the middle a PA-3886ps with integrated power supply (400W max.). Just beneath it a PS-BOOSTER module with extra supply capacitors. All the others are PA-3886 models. For all, select the quality you want. For >400W of power per side, use a separate Power Supply! In order to “feed” them right, use our line or balanced buffer input modules. You could random mix with our PA-4766 range for even more channels as well.

You could build it yourself, but we can do this for you as we can with all our modules. For this we have a separate website with some examples: www.eltimaudio.com

Just contact us and explain wat you require. We’ll respond with an offer.