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Neurochrome Modulus-286: 65W (8Ω); 125W (4Ω) @ <-120dB THD Composite Amplifier Module

I open up for preorders of the Modulus-286 Kit on Monday November 26th, 9 AM MST (8 AM Pacific, 11 AM Eastern, 4 PM GMT). The first four kits will sell for $899. The next eight for $1099. Once those have sold, the price will settle at $1399.

The kit will include everything you need to put the amplifier together (except time, patience, tools, and solder). The kit includes:
  • Two Modulus-286 amplifier modules
  • One Connex SMPS300RE power supply custom made for this kit
  • Chassis with all holes cut and threaded and digitally printed front and rear panels
  • Mezzanine plate for power supply
  • Connectors, binding posts, mains IEC inlet
  • All necessary screws, nuts, washers, and chassis feet
  • Power ON indicator LED and series resistor
  • All wiring internal to the chassis
  • Detailed assembly instructions
The wiring harnesses will be preassembled, so all you have to do is to plug them in. This will especially help those who are a bit leery about mains wiring.

You can see the performance measurements on the Modulus-286 Kit Page: Modulus-286 Kit: Build your own high-end stereo amplifier.

Unlike the prototype build I showed earlier, the final version will feature a discreet (2.0 mm diameter) Power ON indicator on the front panel. It will also have the power switch moved to the rear panel. There is no power switch available that will fit in the front panel and survive the inrush current of the power supply. Sorry... It also cleans up the front panel considerably, which is nice.

Mark your calendars! 9 AM Monday! I've received quite a bit of interest in this kit, so don't dillydally too much if you intend to take advantage of the Early Adopter Deals.

Tom
 
IINM, Tom has used a 4 channel Mod86 build to drive his LX Minis? I guess at the end of the day, it’s a matter of how much dynamic headroom above your real world listening levels you deem necessary.
I must say that the 686 driving a pair if moderately sensitive MTMs this past August seemed to my ears to have a bottomless supply of dynamics and bass.
 
Any thoughts if 286 is suitable for the lxmini bass driver or should one go with the 686?

Chrisb said it well. It depends on how much headroom you prefer - and also on how loud you like to crank it.

My living room is relatively small and pretty live. So it doesn't take much power to get some SPL going. My listening position is a little over 2 m from the speakers. When I crank it, I reach 85-90 dB average SPL (I value my hearing). I find the 65 W of the Modulus-286 to be enough and the 40 W of the Modulus-86/186 to be not quite enough (harshness when I crank it). The Modulus-686, of course, drives the LXmini with ease. Mine are built with ±27 V supply (Mean Well RPS-400-27-C).

If your parameters are different, you'll need to adjust accordingly.

You don't have to build the Modulus-686 for the full 200+ W output power. You can make a safe-n-sane build by running it on ±27-28 V (130-140 W) or ±32 V (180 W). More options here: https://www.diyaudio.com/forums/ven...wer-amp-extremely-low-thd-49.html#post5443446

Tom
 
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BTW: I'll be offering the Modulus-286 Kit in both silver (clear anodized) and black front panel colours. I'll also have the power supply available in both 120 VAC and 230 VAC options. I just added these options to the product page: Modulus-286 Kit

Unfortunately, I don't have a picture of the chassis with the black front panel yet, so you'll have to visualize it for now. I should be able to show it off in about a week. I'm having a new set of front panels delivered from ModuShop that'll have the new Power ON indicator.

Tom
 
Thank you for your support and your order. I really appreciate it.

The $899 special sold in eight minutes! I still have a handful left at $1099. I'm updating the price manually and my website does allow for backorders, so if you happen to place a backorder before I update the price, you'll still get the $1099 deal.

Tom
 
The new front panels have arrived from ModuShop. They're pretty... Attached images show the final version of the chassis.

The ON indicator is a 5 mm LED countersunk into the front panel with a 2 mm hole on the front. The default LED will be a pretty HeNe Red (634 nm). If you'd rather have another colour, just use a different LED. Easy-peasy.

The chassis is available with both clear anodized and black anodized front panels.

I still have a couple left at the $1099 price point. I'll start a Facebook ad campaign on Monday. I suspect the kits that are left at the sale price will go pretty quickly once the campaign starts.

Manufacturing takes 3-4 weeks, so I expect the kits to start shipping just before the new year.

Tom
 

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Ugh! Due to a Christmas shutdown of the anodizing facility, the ship date for the chassis just pushed out to the third week of January. Sadly, this means I won't be able to ship until the end of January.

That said, I think the new chassis will be well worth the wait. The chassis will be anodized after all the machining is done, which means that all exposed holes and edges will be anodized (and dyed if applicable). This is normally something ModuShop charges extra for. This will make a big difference in appearance, especially for the black chassis where even the inside of the hole for the ON indicator will be coloured black.

Pardon the delay.

Tom
 
Congrats on another very good looking and good performing amplifer. Very nice implementation of the LM3886.

The title of the thread and your website says "THD < -120 dBc". I wonder where that specification comes from, I can't see it in any of the posted APx measurements. Care to explain?
 
Congrats on another very good looking and good performing amplifer. Very nice implementation of the LM3886.

Thank you.

The title of the thread and your website says "THD < -120 dBc". I wonder where that specification comes from, I can't see it in any of the posted APx measurements. Care to explain?

<-120 dBc was my best guess at the time I started the thread. I based this guess on the previous version of the MOD286 as well as measurements of the prototype MOD286 Rev. 2.0. I'll have the final number towards end of this coming week.

I'll rerun the measurements and fill in the spec table once the pro assembled boards come in. They should be here early this coming week.

The professionally assembled boards tend to perform much more consistently than hand-assembled boards, so I'll focus my efforts on measuring those rather than taking more measurements on the prototype.

Tom