Neurochrome Modulus 686 Monoblock Amplifiers. Apr 2024 I heard a pair of these at a local HiFi meeting and fell in love with them. Sound familiar? It should, it was when I heard them hooked up to a pair of Canton CT-1000 Speakers. There was definitely great synergy in this pairing, enough to make me want to own both items. Neurochrome is the Brand owned by designer Tom Christiansen, who is based in Canada. His products are available to the DIY community as a bag of parts, assembled modules, or for the less capable, as fully built products. I could have ordered modules, a case and built them myself, but a chap called Joe Henry in the UK advertises Neurochrome Amps (and other kits) he will build for you. The pair I initially heard were built by Joe, construction was to a very high standard and at a very reasonable price. It made sense to order ready made Amps from Joe. The Modulus 686 is a class AB amplifier, each unit uses six LM3886es configured as a Bridge-Parallel power amplifier. Each 500VA power supply in my build, outputs +/- 34V and will deliver aprox 350w into my Canton 4ohm Speakers (220w into 8ohm). Standard gain is 26dB (x20 Lin) with 2.0V sensitivity. The following are pictures of my amplifiers, while under construction. With this build, a group of four hefty capacitors are used in each power supply, totaling 188,000uF in each amp. Each toroidal transformer is 500VA. Speaker protection circuitry is included in this build, but no soft start module, its not needed. I never get any kind of noise when powering up/down. My units going through a final soak test. The Amps are a fully differential balanced design, with just an XLR input, a pair of binding posts and a mains input socket on each rear panel. The front is even simpler, with just an illuminated on/off push button switch. And here they are after collection, I need to make a pair of speaker stands now, so they can sit under each speaker. This is R19, a surface mount resistor of 1kohm value used to set the amplifier gain. I removed it from each of the Amps. Removing this resistor reduces the Amplifiers gain to 20dB (x10 Lin) with a sensitivity of 4.0V. This gives a better overall gain structure, while lowering the Amps already low noise floor, even further. It's a recommended upgrade by the Amplifiers designer, Tom Christiansen, when your not concerned about complying with THX gain requirements, which I'm not. Its a fiddly thing to remove, but it's a free upgrade. I found it gave an even clearer window into the music. In my set up, the lower mids and upper bass became fuller and richer. I'm guessing this is because my Pass Labs Pre Amp, is now contributing more toward the total gain and its character is having more effect on the sound. This really is a cracking amplifier/speaker set up and my end game.