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Finished A Neurochrome Modulus-86 Amplifier

jwdevos

Member
Joined
Jan 4, 2024
Messages
8
Likes
17
Hello ASR,

DIY products from Neurochrome are known around here but perhaps not as much as they deserve. From my own experience, reasons to use Neurochrome products include: great information and support, easy to build and implement, easy to achieve ultra high performance. I can't think of a better way if you want to build a good amplifier that will last you a long time.

Last week I finished my first Neurochrome Modulus-86 amplifier. The chassis was designed by Modushop. They customized it (drilling, threading, printing) via some CAD drawings that I made with QCAD. Modushop is great to deal with, fast and friendly service and good products.
The guts include an Intelligent Soft Start (ISS) from Neurochrome. The soft start provides LED connections for standby and power-on and for a standby switch. I didn't use it, but you can also implement a 12 V trigger with the ISS.
Besides the ISS, I also have speaker protection modules from Neurochrome. I like that there's no relay which could get welded shut if I manage to melt my power amp.
The PSU is a Connex SMPS300REh, pretty nice for this purpose.
The power amp boards are the Neurochrome Modulus-86 boards. I bought the kit which includes all components. The PCB's are great to work with. I cleaned the flux after soldering.

This is the third power amp chassis that I built. Still some lessons learned, but it's getting there. I like experementing with different ideas to see if I can eventually grow to professional results.

A year ago, my system consisted of a pair of Mission M74i floorstanders + B1 buffer (preamp) + LM3886DR (power amp) + logitech bluetooth unit. The bluetooth unit recently got replaced with a fanless HTPC (Windows with Roon) and an SMSL D-6s DAC (with volume control, so the DAC goes straight to a power amp). I also moved from Spotify to Tidal HiFi Plus. With the source updated to the current decennium, all high quality and high performance, the power amp deserved some love, hence the Mod-86. The speakers are still pretty good (subjectively, got no clue otherwise).
With placing the Mod-86 in my system, I've also connected a Wiim Pro Plus instead of the PC + DAC. I want to get into PEQ (never done it before). The Wiim is a bit behind the SMSL DAC but in the same league. I wanted to test it anyway, to loan to friends together with future amps I'll build. The app is nicely integrated with support for a whole bunch of stuff. Eventually I want PEQ measured with Acourate and implemented with CamillaDSP. The Wiim together with the iPhone app House Curve are my first EQ and DSP training wheels.
To be honest, I just like listening to music. If you'd cast a spell so I couldn't upgrade the system I had last year anymore, I could live with that. Upgrading the source was a night and day difference though, it really struck me and everyone who's heard it, still with the LM3886 in the system. With the Mod-86 connected, I got more of the same improvement as when I upgraded the source. Everything just cleans up so much. A whole lot of separation between instruments, and bass much more tightly controlled. The Mod-86 deserves a whole lot more listening time than I've put in at this moment, so I'll share a more detailed experiences later on.

Below are some attached photos. You can view some of the measurements (don't have gear for SINAD yet, won't ever have something that measures 120 dB or more probably). With short plugs connected, I got ~.3 and ~.5 mV DC offset on the output. The PSU voltage I used (±36 V) allows for 60 watt at 8 ohm (instead of the regulur 40 watt with ±40 V). Note that Neurochrome does not recommend operating the Modulus-86 in this way. With a signal generator, I tested to 50 watt for 15 minutes per channel. Note that the RMS voltage on the generator is double what the amp input sees, because of a 50 ohm terminator on the BNC cable. The max temp got up to around 70 degrees C. No clipping visible on the scope.

Kind regards,
Jaap de Vos
 

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groovybassist

Active Member
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Joined
Dec 11, 2020
Messages
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Location
Wendell, NC
Nice build! Tom’s stuff is the real deal - enjoy the amp.
 
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