Modulus-86 build thread

OK, I'm more and more confident that for my near field setup the Modulus 86 will have plenty of power.

For near field, I'm confident the Modulus-86 will blow your ears. :)

The only thing I'm totally lost about is the power supplies. The Power86 + transformers would be 2x as much as a new SMPS300RE for me, is there any difference between the two either audiably or in usage?

The Modulus-86 performs as well on the SMPS300RE as it does on the Power-86 + transformer.

Does the amplifier make any pop/click noise at power on with either SMPS or Power 86?

When built according to the instructions with a differential input, there is no startup pop.

Through the years, a few people - maybe 1% of builders - have experienced a small startup pop in builds with RCA input. In those cases, the pop is very slight and can be further reduced by adding 10 kΩ across the RCA terminals. I have not heard of any such issues with Rev. 2.4.

Also, how is the 2.2 version of the Mod86 compared to 2.4? I could purchase a second hand 2.2 unit, were there any substantial improvements since then?

You'll find the revision history attached. The major rev from 1.x to 2.x offered substantial improvements. From 2.0 to 2.4, the improvements have been slight and the revisions mostly dealt with TI's decision to discontinue, bring back, and then ultimately discontinue the LME49710.

Rev. 2.4 uses the LME49720. All parts in the Modulus-86 Rev. 2.4 are in current production.

Tom
 

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Thanks, it seems I'll soon be a happy owner of 2 x Mod86 boards, bought from a fellow member here. My biggest confusion is actually the case.

I'm thinking about ordering a Mini Dissipante for 2 x Mod86 + 1 x SMPS300RE. What size is right for this?

More importantly, can you help me understand such super basic questions as:
- How do you mount the module in the case? Do you order Modushop to make metric screw holes in the bottom panel exactly where you want? Or you buy that inner baseplate with a grid of holes?
- Do the inner baseplate's grid of holes happen to line up with both the Mod86 and the SMPS300RE? Is this some kind of standard to put holes on a given grid in all kind of various audio PCBs, SMPS, Class D amps, chip amps, etc.?
- How do you attach the heatsinks to the side? Is there a screw hole in the Modushop case?
 
Thanks, it seems I'll soon be a happy owner of 2 x Mod86 boards, bought from a fellow member here. My biggest confusion is actually the case.

I'm thinking about ordering a Mini Dissipante for 2 x Mod86 + 1 x SMPS300RE. What size is right for this?

More importantly, can you help me understand such super basic questions as:
- How do you mount the module in the case? Do you order Modushop to make metric screw holes in the bottom panel exactly where you want? Or you buy that inner baseplate with a grid of holes?
- Do the inner baseplate's grid of holes happen to line up with both the Mod86 and the SMPS300RE? Is this some kind of standard to put holes on a given grid in all kind of various audio PCBs, SMPS, Class D amps, chip amps, etc.?
- How do you attach the heatsinks to the side? Is there a screw hole in the Modushop case?


This one would be adequate for a stereo build with the SMPS300RE:

Mini Dissipante 2U 250mm frontale 10mm ARGENTO coperchi in alluminio 2mm e retro 3mm

It is possible to integrate into a smaller chassis, but I personally prefer a bit of space inside the chassis. :)

I cannot comment on the grid-holes of the inner base plate an if it corresponds to any of the mounting holes of the PSU or amp modules.

Your last question - do you mean how to attach the heat-sink to the LM3886? You will have drill a hole in the heat-sink and tap it. The LM3886 has a hole in its center through which you can attach it to the HS; you can also use a "clip" that keeps the chip in contact with HS.
 
Tom I'm running 4x mod86p boards as a pair of bridged monoblock. Is it possible to rig them to run each chassis as a pair of parallel mod86p?

I'm not sure what you mean by "mod86p".

The Modulus-86 uses one LM3886. It's not really suitable for bridging.

The Parallel-86 uses the two halves of an LM4780 in parallel. The Modulus-286 is a further development of this design. If you run it on ±28-±30 V, you can bridge two Parallel-86 (or Modulus-286) for about 100 W into 8 Ω and a bit shy of 200 W into 4 Ω.

The Modulus-686 uses six LM3886es in a bridge-parallel configuration. If you max out the power supply to ±36 V, you'll get 240 W into 8 Ω and 360 W into 4 Ω.

If power is what you're after, the Modulus-686 is where it's at.

Tom
 
I recently changed to outputs on my Modulus-86 from RCA to differential and removed the ALPS pot that I had for volume control.



Now I need a preamp, any recommendations for a good one. I prefer differential outputs of course.
Less than $1000.



I have my eye on Schiit Freya.


Thanks everybody.
A Neurochrome 8x2 if you can find one, or get some of Tom's Universal buffer boards

That's would be my pick
 
Thanks, I'll keep looking at the Chinese eBay chassis as well.

For the layout what makes more sense to you? I made two drafts with SpeakON + XLR connectors. It's in the 250x250 ModuShop chassis.

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or

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If there are heat sinks on both sides, it will keep the chips cooler (and therefore better performance) if you use one heat sink per chip, rather than sharing one heat sink and not using the other one at all.
 
Really? I would have never thought of that. Tom wrote somewhere that the Chinese ones he bought had oil and terrible machinining / edges and he had to spend a weekend in the workshop just fixing those, and for this reason he prefers the ModuShop ones much more.

Yeah. The panels were soaked in cutting oil and the four posts connecting the corners hadn't been de-burred. The tolerances were OK and the chassis came together pretty nicely. I would say the surface finish was OK, but nothing spectacular. My chassis was the "BZ4309".

I do agree that the ModuShop brackets could be better. I would also like it if they'd use countersunk screws on the top and bottom panels and - even better - make take a little off the heat sink top/bottom to allow those panels to sit flush with the heat sink fins. I've forwarded that feedback to ModuShop, but it's up to them to act on it as they see fit.

For the layout what makes more sense to you? I made two drafts with SpeakON + XLR connectors. It's in the 250x250 ModuShop chassis.

Neither make sense to me. I would put one Modulus-86 on each heat sink and have the LM3886 as close to centre as possible. That said, you do want to keep the input of the Modulus-86 (including its connections) away from the rectifier on the SMPS as that rectifier emits a bunch of switching noise.

In the Modulus-286 Kit LE, I put the rectifier of the SMPS300 facing the rear panel. This was as far away as I could get it from the input sections of the Modulus-286 boards.

Tom