Review and Measurements of Neurochrome Modulus-286 Amp

[restorer-john]

They're not tamper-proof, actually. The tamper-proof Torx has a nib in the middle that requires a corresponding hole in the screwdriver.

Yes, the pic made them look like the tamper proof variety- sure looked like the nib to me

 

[tomchr]

Yes, the pic made them look like the tamper proof variety- sure looked like the nib to me

Eagle-eye! Nah... It's just the light reflecting off the bottom of the screw head.

Thanks for your comments regarding the use of grommets and such. A lot of thought did go into the mezzanine plate to ensure that the amp will function reliably for years and to ensure that all safety distances are met.

Tom

 

[tomchr]

This is the sort of thing that really makes this website worthwhile. This process of testing and in some ways collaborating with these objectivist oriented small companies is going to reshape the stereo "audiophile" industry in the right direction.

I absolutely agree. I think audio/audiophile has dug itself into a pretty big hole with the whole "gotta hear to believe" mantra. Murtlewood speaker cable stands anyone? I hope to be able to contribute to a culture change in the field so we get closer to applied science rather than marketing babble.

Tom, if you can get to the point where you can mass produce this stuff and get the prices down you will have a really big customer base.

I think I'll stay at least a little bit boutiquey. I don't want to compromise on the quality just so I can make it into a big box store. It would be nice to grow to the point where I can start to reap the benefits of scale, though. It would be nice to get to the point where a production run of 100 or 250 becomes feasible.

Tom

 

[Blumlein 88]

They do not though. You can see the response graph I posted from AP above. I have measured the same.

That is the same graph I posted, but that isn't what AP is calling an AES17 filter. The one below is though this is specified for DACs which is where I think the miscommunication is coming from.

 

[amirm]

That is the same graph I posted, but that isn't what AP is calling an AES17 filter. The one below is though this is specified for DACs which is where I think the miscommunication is coming from.

View attachment 20866

Yes they are two different things. One is a filter option to cut out the out of band noise for DACs which is what you show above. The other is meant for switching amplifiers and hence, its cut off is well above 100 kHz.

What they both share is the specified in-band response (essentially flat response to the stated limit). The internal AES filter is unable to cope with the switching noise of amplifiers due to their high voltage/slew rate.

 

[invaderzim]

I absolutely agree. I think audio/audiophile has dug itself into a pretty big hole with the whole "gotta hear to believe" mantra. Murtlewood speaker cable stands anyone? I hope to be able to contribute to a culture change in the field so we get closer to applied science rather than marketing babble. <snip>

It will be a slow battle and the sides seem to be getting more and more divided but there is always hope. I thought the LM3886DR would be cold and lifeless since it wasn't designed with emotion But it is very enjoyable and full sounding. I can only imagine how much better it will sound with Noise Harvesters plugged into the same outlet.... Couldn't resist.

 

[jackenhack]

I am actually tempted to go the other way around and standardizing at 10 watts.

Haha! Yeah, it would probably be more accurate when showing the performance.

 

[Headphonaholic]

I absolutely agree. I think audio/audiophile has dug itself into a pretty big hole with the whole "gotta hear to believe" mantra. Murtlewood speaker cable stands anyone? I hope to be able to contribute to a culture change in the field so we get closer to applied science rather than marketing babble.


I think I'll stay at least a little bit boutiquey. I don't want to compromise on the quality just so I can make it into a big box store. It would be nice to grow to the point where I can start to reap the benefits of scale, though. It would be nice to get to the point where a production run of 100 or 250 becomes feasible.

Tom

You are a very smart and admirable person, the world needs more people like you. As a programmer and perfectionist, I totally appreciate your care and attention to detail. That level of passion I think has a hope to change this world.

Definitely stay a bit boutique, it separates you from the rest of the crowd. I think it will also allow you to do what you think is right instead of chasing everyone to the bottom as @March Audio puts it.

I don't actually need any more amps but I want to buy your headphone amp because I know how much you put into it. If it weren't for the fact that I want to get into electrostats I would probably do it, but it may have to wait until my wallet can allow it.

 

[maty]

Well, putting the audio electronics so close to a SMPS is a bad decision a priori.

Those manufactured by Hypex emit very little interference and still keep more distance than those used here from Connex.

Nothing between MOD286 kit and the Connex SMPS.

Improved by me:

To compare:

Apollon, with Hypex NC500 modules and SMPS1200:

The LE case is too small. Better the others 27 Mod-286 LE poweramps with bigger cases.

 

[maty]

Btw, some years ago, Jean-Marc Plantefève used two Connex SMPS500R with his Buzzquito [MOSFET] amp.

[French] http://jm.plantefeve.pagesperso-orange.fr/prat.html

[PDF, French] http://jm.plantefeve.pagesperso-orange.fr/solide.pdf

 

[yummy]

this neurochrome is kinda famous in DIY kit world, for their LM3886

 

[Killingbeans]

Well, putting the audio electronics so close to a SMPS is a bad decision a priori.

Nothing between MOD286 kit and the Connex SMPS.

The LE case is too small. Better the others 27 Mod-286 LE poweramps with bigger cases.

Well, the man already explained that it's a compromise he made consciously:

The difference in mains hum between channels is due to inductive coupling between the SMPS and the amplifier. The rectifier in the SMPS will couple into sensitive nodes. I oriented the SMPS to minimize this coupling, but one channel will always be closer to the rectifier than the other. That's the price you pay in a compact design like that. Like you, I decided not to worry too much about the hum, as it is well below audible.

 

[maty]

It is to ship by end of this month and costs $1,299.

Extra cost of a slightly wider case? Very little compared to the final cost I think.

 

[Killingbeans]

Am I talking to a wall? There's no need to do a Don Quixote.

 

[maty]

$25 -$50 / $1,300 = 2% - 4% more.

If he has time to rectify (if he does not have the 28 cases), the advice is relevant. Sligtly wider.

 

[Killingbeans]

I give up...

 

[Ralf Stocker]

Building a small PreAmp with 0.0001% THD+N is very easy. A Poweramp that has to prove itself in the wild is very difficult. As the material of the jacks plays a role or the transformer manufacturer. N.B. never ever build audio stuff with switched mode supplies!

 

[Killingbeans]

N.B. never ever build audio stuff with switched mode supplies!

Because of THD+N, or because of reliability?

The first is (as far as I can tell) not an issue in a well designed amp. The latter, maybe not quite up to snuff yet... but it's getting close.

 

[tomchr]

Because of THD+N, or because of reliability?

Probably because of personal belief/opinion. That'd be my guess.

The first is (as far as I can tell) not an issue in a well designed amp.

I have designed both line level (DIFF PRE 8x2, HP-1) circuits and power amps with SMPSes. All circuits show stellar performance, so clearly it is possible to design high-end audio using SMPSes.

That said, consumer psychology experiments show that males (who tend to be the ones buying audio gear) associate heavier products with better quality, so maybe there's a psychological argument for transformer-based supplies.

Tom

 

[tomchr]

Well, the man already explained that it's a compromise he made consciously:

Exactly. I saw the small chassis at Burning Amp and instantly fell in love with the challenge of stuffing a Modulus-286 and power supply into that chassis.

Engineering is all about balancing compromises and the Modulus-286 Kit is a good example of that. If you prefer different compromises, there's nothing that stops you from buying a chassis and a pair of Modulus-286 modules and implementing your own design. You will find, however, that the cost of the chassis, power supply, Modulus-286 modules, and sundry items necessary to complete such a build exceed the $1299 I charge for the Kit. The chassis alone is about $350/each + shipping at QTY 1 as I have ModuShop modify all panels except the top panel.

Tom