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Neurochrome Modulus-686 Build Underway

Mike Hanson

Mike Hanson

Trying to understand...
@paulski (not @James) mentioned that he really liked his Neurochrome Modulus-686. I'm between amp builds, so when I noticed that Neurochrome was based here in Canada, I couldn't resist the urge.

I received the package from them with everything appearing safe and sound. Here's my tentative layout:

0-Layout.jpg


I think this allows for enough space around the various connection points to make wiring a straightforward task.
  • As you can see, it's a dual mono, with a shared Neurochrome Intelligent Soft Start module and separate Power-686 boards. The input power will run straight along the bottom of the case to the ISS, with a pushbutton switch front-and-center to control it.
  • I'm using a Modushop Dissipante 3U/400mm case, so the heatsinks should handle it. My mains often drift as high as 125VAC, so I'm using 400VA 2x22VAC AnTek transformers, just in case. The transformers are stand-ins, as I wait for the AnTek (which might be a bit smaller).
  • I haven't decided yet whether to include thermal switches to shut off the amp at 65°C.
  • I considered using a single Guardian-686 module, but decided that It would be easier for the layout if I had the two smaller Guardian-86 boards.
  • Neutrik NC3FD-LX-B XLRs are on order, so I used RCAs to hold their spot.
  • These modules take balanced inputs, but I was hoping to include RCAs as well. After discussing it with Tom Christiansen of Neurochrome, I'll likely forego them, but that could change if I determine a "good" way to do it.
If you're wondering why there are so many connectors on the back panel, I prefer Neutrik powerCON and speakON. However, I have a friend who may eventually get the amp, and he wants an IEC C13 for the power and banana plugs for the speakers.

The last amp I built for him had a big DPDT rocker switch to toggle between power inputs, but this time I've decided to alternate by swapping the wires internally. It's fewer holes to cut, and fewer connections inline. Both the powerCON and IEC plugs use the same size Fast-on spades, so swapping two connectors is a simple task. The earths for both will be connected permanently to the chassis.

Any thoughts or concerns?
 
Last edited:
misterdog said:
I think you will not be disappointed with Tom's amp.
He is very helpful with any queries though his build manuals are as good as they get.
Click to expand...
Yes, I've been exceedingly pleased with my interactions with him so far, and the quality of his documentation. I'll be going through 4 sets this week, with all the various bits and bobs that I've received.
 
Mike Hanson said:
@James mentioned that he really liked his Neurochrome Modulus-686. I'm between amp builds, so when I noticed that Neurochrome was based here in Canada, I couldn't resist the urge.

I received the package from them with everything appearing safe and sound. Here's my tentative layout:

0-Layout.jpg


I think this allows for enough space around the various connection points to make wiring a straightforward task.
  • As you can see, it's a dual mono, with a shared Neurochrome Intelligent Soft Start module and separate Power-686 boards. The input power will run straight along the bottom of the case to the ISS, with a pushbutton switch front-and-center to control it.
  • I'm using a Modushop Dissipante 3U/400mm case, so the heatsinks should handle it. My mains often drift as high as 125VAC, so I'm using 400VA 2x22VAC AnTek transformers, just in case. The transformers are stand-ins, as I wait for the AnTek (which might be a bit smaller).
  • I haven't decided yet whether to include thermal switches to shut off the amp at 65°C.
  • I considered using a single Guardian-686 module, but decided that It would be easier for the layout if I had the two smaller Guardian-86 boards.
  • Neutrik NC3FD-LX-B XLRs are on order, so I used RCAs to hold their spot.
  • These modules take balanced inputs, but I was hoping to include RCAs as well. After discussing it with Tom Christiansen of Neurochrome, I'll likely forego them, but that could change if I determine a "good" way to do it.
If you're wondering why there are so many connectors on the back panel, I prefer Neutrik powerCON and speakON. However, I have a friend who may eventually get the amp, and he wants an IEC C13 for the power and banana plugs for the speakers.

The last amp I built for him had a big DPDT rocker switch to toggle between power inputs, but this time I've decided to alternate by swapping the wires internally. It's less holes to cut, and fewer connections inline. Both the powerCON and IEC plug use the same size Fast-on spades, so swapping two connectors is a simple task. The earths for both will be connected permanently to the chassis.

Any thoughts or concerns?
Click to expand...

How about making the finished amp available to forum members for review ? I was very tempted to build one myself many moons ago.
 
sq225917 said:
Mike, just daisy chain the rca off the xlrs, it's not like you're going to plug two sources in at once.
Click to expand...
From what I've learned, it's not quite that simple. Pins 1 & 3 need to be connected for it to work with the RCA, so I can't permanently hook that. I would need to use a DPDT switch to ensure that the RCA works properly when it's used, and vice versa.

Instead, I'll likely just create a pseudo-balanced cable, in case I need to hookup an RCA source.
 
Mike Hanson said:
@James mentioned that he really liked his Neurochrome Modulus-686. I'm between amp builds, so when I noticed that Neurochrome was based here in Canada, I couldn't resist the urge.
Click to expand...
I've never heard about Neurochrome, let alone own any. But I'm happy to take the credit. ;)

Actually, it was @paulski.

paulski said:
The Ergo IXs are remarkable and I still have mine. If they were all I had I’d be happy. But, they’re not a patch on the IIIRs although I’ll qualify that statement - my IIIRs never really reached anywhere near their potential until I changed to a Modulus 686 (Tom Christiansen - https://neurochrome.com/products/modulus-686) power amp and then they really came alive!
Click to expand...
 
$499 (£368 today) for each module, let alone the "usual overhead" of case + PSU. Hell of a thing to buy and build just because you're not doing anything else!

BugBear
 
I will be interested to read how it compares to your NCCs.

I don't think you need any extra thermal shutdowns. The LM3886 has plenty of protection built in.
 
Mike Hanson said:
From what I've learned, it's not quite that simple. Pins 1 & 3 need to be connected for it to work with the RCA, so I can't permanently hook that. I would need to use a DPDT switch to ensure that the RCA works properly when it's used, and vice versa.
instead, I'll likely just create a pseudo-balanced cable, in case I need to hookup an RCA source.
Click to expand...

Mike
Hot Pin 2 of the XLR connects to the signal of the RCA
Cold pin 3 of the XLR connects to the ground of the RCA
Pin 1 of the XLR connects to the Chassis earth
No need to connect pin 3 to 1
Alan
 
bugbear said:
$499 (£368 today) for each module, let alone the "usual overhead" of case + PSU. Hell of a thing to buy and build just because you're not doing anything else!
Click to expand...
Yeah I suppose. Something about it resonates with me. I can always sell it on if I don't like it.
 
Quite a bit different. Less noise, thd, imd, no turn on thump or turn off pop. No need to keep them switched on, pretty much load invariant. Whether you prefer neutral though is another matter.
 
sq225917 said:
Quite a bit different. Less noise, thd, imd, no turn on thump or turn off pop. No need to keep them switched on, pretty much load invariant. Whether you prefer neutral though is another matter.
Click to expand...
Yeah, it should be an interesting test. My Benchmark DAC2 is also exceedingly neutral, so that may be my thing.

I'm eventually going to go active, so this may be well suited in that configuration somewhere.
 
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