Neurochrome 686 Mini Review

[AD Audio]

I was intrigued by reports of how good these Neurochrome modules are and also had a few requests to build some, so I thought it was time to try some out and evaluate the amps. The build was fairly straightforward and I used a chassis from Modushop who supply most of my cases. Tom the designer provides drawings for this chassis and suggests the large chassis shown in the accompanying photo.

The amp has a slow start module, and includes a sophisticated output protection system to protect your speakers. In practice, it turns on and off without a thump or buzz, with a small click as the relay clicks over. Construction is fully dual mono, and fully balanced with inputs by XLR. So far I’ve fed the amp with single ended source from my own brand ESS9038pro valve DAC, but I will try with a fully balanced source later.

Residual background noise is almost inaudible, even with my 96db sensitive JBLs, and sensitivity standard at 2v.

I’ve run the amp now for some 16 hours so it’s fair to start judging its sound quality. Overall, I’m very impressed. I should confess here I’m a valve man through and through, with 845, 805 and KT120 monoblocks in the house and studio. But I do get quite a lot of high end
Solid state gear through my workshop and also tried the Nord Class D amps a couple of years’ ago and have built Hypex-based amps for clients, but both of the latter left me cold.

This amp on the other hand is very musical. It’s neutral and revealing, but without robbing music of its soul. Bass is powerful and tuneful, and soundstage wide and deep. Higher frequencies are convincing, unlike IMO Class D amps that I’ve heard. It’s not going to make me sell any of my monoblocks but for anyone who has an aversion to valves, young children or mischievous pets this could be the amp for you. I would rate it above the large Krell or Mark Levinson amps if you want a comparison. Tom the designer makes a lot of the need for a lot of heatsinking but with my 90db and 96db sensitive speakers the heatsinks hardly rise above room temperature. [IMG][/IMG]