1st build: PCB, kit or assembled?

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Hey Tom, I've been reading all about your amps in your site. Design documents are really helpful. On Modulus 286 buy page it says "Ideally suited for multi-channel amplification" but on the circuit description page this is ommited ( only mono and stereo are explained). could you please elaborate on the multi-channel feature?

The Modulus-286 has two amplifiers per board. Thus for multi-channel amplification you'll need to assemble fewer boards if you buy the MOD286 than if you buy, say, the MOD86. That's all. This is handy if you're driving a multi-way speaker with active (line level) crossover, such as the Linkwitz LXmini, LX521, or Orion.

Tom
 
The Modulus-286 has two amplifiers per board. Thus for multi-channel amplification you'll need to assemble fewer boards if you buy the MOD286 than if you buy, say, the MOD86. That's all. This is handy if you're driving a multi-way speaker with active (line level) crossover, such as the Linkwitz LXmini, LX521, or Orion.

Tom
Understood, thank you
 
so IMHO you have only 3 choices (in alphabetical order):

  • Modulus 86 (balanced input)
  • My_Ref Fremen Edition (single ended)
  • Sympatico (full balanced)
Costs are pretty different, regarding perceived performace I never compared my design with the other two.

I would add another kit, GT-102(or 101) Stereo Power Amplifier Kit (GT-102K). Akitika Preamp and Power Amp Kits.
This guy(Dan Joffe) is very very good, customer service is A+[/QUOTE]

I agree. Dan very kindly agreed to sell me jsut the pcbs to save shipping costs and taxes for the UK for the full kit.

I orignally built it (GT101) a couple of years ago using my own grounding scheme becuase I thought there was a possibility of a ground loop when the inputs are connected with the standard scheme. The sound was OK, but nothing special.
I then rebuilt it as dual-mono with unregulated supplies. The sound was pretty much the same.
3rd attempt was using Dan's grounding scheme and the single regulated supply. I have to admit that this iteration sounded the best.
The Akitika was then decommissioned.

More recently I built an audiophile cost-no-object BOM version of the My-Ref FE. The sound was promising, but not quite to my taste. I then set about some system optimisations to get better synergy with the FE and finally got it sounding very good.

In the last few days I recommissioned the GT101 with a different physical layout and grounding very similar to (but not exactly the same as) Dan's scheme.
It would seem that either the GT101 is quite sensitive to layout and grounding, perhaps my system optimisation has helped, but the GT101 now sounds superb. It's interesting to note that my layout is more like the GT102 than the GT101 (I didn't realise there was a 102 until I read this thread today).

Ayway I have been listening to my GT101 "rev D" for the last 3 days and I don't feel any need to revert to the MyRef or my KT88 PP amp or any of my other DIY amps. That's a pretty good sign.

Conclusion: I can heartily recommend the GT102!
 
With my PCB you get a .pdf file with design documentation. The documentation includes a link to a project set up with Mouser Electronics. Click the link, order your parts, and a few days later a box of goodies show up on your doorstep. It's almost as easy as ordering a kit but saves me the work of stuffing little parts into little bags.

It does happen on occasion that a part is out of stock at Mouser. If you can't find a replacement, just toss me an email and I'll help out.

Mouser ships internationally with free shipping on orders over $100.

Tom
Hi Tom,

I'm nearly decided for 2x Modulus86. Main/only doubt now would be about the inductors. Is there anywhere else besides iwindcoils to get them? Asked for a quote long ago and didn't even get a reply. Don't want to spend that money and get the amp unfinished just for one piece.

Thank you
 
build with LM4702, it is a lot better than any LM3886 ...
few years ago I built this one: LM4702 kit (ask them via email)
for 45€ I got nice working kit (it is stereo) with original parts, mounting profile with screws is also here, and speaker protection is on board ... or alternatively you can try ebay but I am not sure about that (about original transistors in ebay kits) ...
 
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Hi Tom,

I'm nearly decided for 2x Modulus86. Main/only doubt now would be about the inductors. Is there anywhere else besides iwindcoils to get them? Asked for a quote long ago and didn't even get a reply. Don't want to spend that money and get the amp unfinished just for one piece.

Thank you

Hi

Toms Amps come with detailed assembly instructions, including how to wind the inductors. Trust me it is very very easy to do it yourself, even as a first timer.

Good choice btw.

SH
 
I'm nearly decided for 2x Modulus86. Main/only doubt now would be about the inductors. Is there anywhere else besides iwindcoils to get them? Asked for a quote long ago and didn't even get a reply. Don't want to spend that money and get the amp unfinished just for one piece.

Pardon the belated reply. I was on vacation with only limited internet access.

You'll need about 180 cm (6') of AWG18 (1.0 mm diameter) enamelled magnet wire to make the two inductors needed for a stereo pair. I bought a small spool of magnet wire on Amazon. You can get it elsewhere as well. In a pinch, regular 20 AWG solid core hookup wire would work too.
In the design doc, I provide all the instructions you need to make the inductors. I think it takes me about 15-20 minutes to make a pair of inductors and mount the power resistor inside them.

If you're willing to toss a few bucks in my Paypal account, I can also deliver the wire to you when you order your boards.

Tom
 
build with LM4702, it is a lot better than any LM3886 ...
few years ago I built this one: LM4702 kit (ask them via email)
for 45€ I got nice working kit (it is stereo) with original parts, mounting profile with screws is also here, and speaker protection is on board ... or alternatively you can try ebay but I am not sure about that (about original transistors in ebay kits) ...
-1(minus) !
You can't say that lm4702 is better than any lm3886 kit, maybe better than some bot not better than any...
 
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Pardon the belated reply. I was on vacation with only limited internet access.

You'll need about 180 cm (6') of AWG18 (1.0 mm diameter) enamelled magnet wire to make the two inductors needed for a stereo pair. I bought a small spool of magnet wire on Amazon. You can get it elsewhere as well. In a pinch, regular 20 AWG solid core hookup wire would work too.
In the design doc, I provide all the instructions you need to make the inductors. I think it takes me about 15-20 minutes to make a pair of inductors and mount the power resistor inside them.

If you're willing to toss a few bucks in my Paypal account, I can also deliver the wire to you when you order your boards.

Tom
awesome! thank you so much, i will surely contact you for that
 
-1(minus) !
You can't say that lm4702 is better than any lm3886 kit, maybe better than some bot not better than any...

sorry, but you have no idea ...
I built many LM3886 and LM4702 kits and many diy experiments with them, you can color it with opamp before but you never get perfect sound result, you can get good sound but not perfect ... even with LM4702 you have not perfect sound, but it is audibly class better like LM3886 ... and I am not talking about technical parameters, but about sound result ...
 
If you're willing to toss a few bucks in my Paypal account, I can also deliver the wire to you when you order your boards.

Tom

Hi Tom

How do we arrange that wire transaction on top of the mod's?

Also, is the power86 the best supply or smps would fit too? I intend to put the amp in an enclosure that also would have a source selector that might need some energy too

Thank you
 
Just email me. You can do that by going through the Contact Us form on my website ... or by adding @neurochrome.com to my username here. I'll invoice you directly for the boards + wire through Paypal.

The SMPS-86 is limited to 2.5 A on each output. That's plenty for a small desktop amp or a mono block driving efficient speakers. You'll get 28 W into 8 Ω (voltage limited) and about the same 28 W into 4 Ω (current limited) for such a mono block.
The Power-86 with a 2x22 VAC transformer (I can recommend a Hammond model for you that you can buy at Mouser) is ideal if you want to unleash all the power of the Modulus-86. You'll get 40 W into 8 Ω and 65 W into 4 Ω with that setup. One Power-86 is plenty for two Modulus-86 boards.

Tom
 
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