• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

Review and Measurements of Neurochrome Modulus-286 Amp

tomchr

Technical Expert
Technical Expert
Manufacturer
Joined
Nov 5, 2018
Messages
239
Likes
659
Location
Calgary, Canada
#81
Obviously the chassis is a non-trivial component of the cost. Tom, you're using the Mini Dissipante 3U 300x330, right? If so, note the base price is $179, so over half the cost Tom quoted above is for custom machining. You can save a lot by doing the machining yourself, or, just go with less machining.
Correct. 3U 300x330 for the Modulus-686 on ±27 V rails. 2U 200x230 for the Modulus-286 on ±36 V rails.

I modify all panels except the top, which drives up the cost, especially at QTY = 1. You could easily drill the holes in the bottom plate and front panel of the MOD286 chassis yourself, provided that you have access to a drill press or drill stand and can drill to a certain depth without punching through the panel. If you have ModuShop do the work, I recommend getting them to machine the rear panel and heat sinks. Most people have trouble with the larger cutouts for the XLR and speakON connectors and with cutting the threads in the heat sinks.

I haven't looked, but I'd be willing to bet you could get an even cheaper case from China (ebay/aliexpress).
I have. I built my first Modulus-86 amp (four channels powered by Power-86 and an Antek AS-3222 power transformer) in a "BZ4309" chassis from eBay. The chassis arrived coated in cutting fluid (oil) and reeked to high heaven from it. Some of the holes were not de-burred. I wasn't impressed. Once cleaned up, the chassis worked just fine. I still had to machine all the holes I needed, which took the better part of a weekend.
A few months later, I found ModuShop and went "aww...." for $20 more than the eBay chassis, I could have had something that would have been of much better quality. Oh, well.

Cheaper still would be to simply buy the required heatsinks, then build a wooden chassis around those (somewhere on diyAudio someone did that with a Mod86 build).
True that. ModuShop will sell you the heat sinks too. I bet they'll cut threads in them before they ship if you throw a little money at them.

If you have all the tooling and know what you're doing. Otherwise you'll likely spend hundreds on tools, mess it up and have to fork out for more casework to replace the stuff you ruined! :D:D:D
Well, there is that. That's in fact why I decided to offer a kit. The chassis is a significant challenge for many. The drawback of having me do the work for you is that I don't work for free...

[...]I want my amps to be 300mm wide by 420mm deep, but unfortunately heatsinks will add another 80-100mm to the width.
Heatsink USA is your friend there. You can always get the heat sinks anodized after machining. Black heat sinks are more efficient (closer to black body radiators).

Another option is to build a pair of dual monos, if the heat cannot be managed. I wonder if anyone has shared their mono 686 build images with you?
I've given a list of posts with build pictures in Post #1 of the Modulus-686 vendor thread on DIY Audio. I'm pretty sure there's a mono build among them.

Tom
 

tomchr

Technical Expert
Technical Expert
Manufacturer
Joined
Nov 5, 2018
Messages
239
Likes
659
Location
Calgary, Canada
#82
BTW: The Modulus-286 chassis arrived Wednesday night and shipping boxes today. I'll start shipping the Modulus-286 Kits on Monday. Yeehaw!

In case you're wondering, this is what 25 chassis look like when they come in via FedEx. I chose to pick them up at the FedEx location as I couldn't be home to receive them Wednesday and didn't want them left on my front lawn. Good thing I drive a hatchback. :)

Tom
 

Attachments

maty

Major Contributor
Joined
Dec 12, 2017
Messages
1,411
Likes
567
Location
Tarragona (Spain)
#83
The great diyer Pinnocchio has made a Modulus-686 with two Connex SMPS800 (with other caps).

The [Connex] SMPS800 that you had suggested. I recapped them completely since only the output caps were of good quality. The cheap Chinese caps were still working properly but for the long run, it is better to use quality caps.

Cresnet uses only quality caps in his designs. All the SMPS I got from him had reputable brands. I still have a few of his SMPS but they are higher voltage and are reserved for other projects.

Pictures (you need to be registered):

https://www.diyaudio.com/forums/ven...omposite-power-amp-extremely-low-thd-103.html

Improved by me:

Modulus-686-Connex-SMPS800-inside.jpg


Bigger case and... more distance between SMPS and the Mod-686 boards. You know, a great diyer.
 
Last edited:
Joined
Feb 11, 2019
Messages
1
Likes
0
#84
Thanks Maty!

I didn't know about this forum. I'll look around, I'm sure there's plenty of interesting stuff here!

Do
 

maty

Major Contributor
Joined
Dec 12, 2017
Messages
1,411
Likes
567
Location
Tarragona (Spain)
#85
You know I am a fan after I verified the excellence of your choice in the expensive Big Mundorf capacitors in your USSA-5 class A amplifier in the prototype of my DC & Ripple Blocker.

I have been reading the forum for years without participating until very recently.
 

tomchr

Technical Expert
Technical Expert
Manufacturer
Joined
Nov 5, 2018
Messages
239
Likes
659
Location
Calgary, Canada
#87
Improved by me:
Bigger case and... more distance between SMPS and the Mod-686 boards. You know, a great diyer.
I'm curious what you base your "improvements" on. Opinion or science?

Attached shows my Modulus-686 build. It's powered by a pair of Mean Well RPS-400-27-C power supplies controlled by my Mean Well Control board. I'm not able to measure any detrimental effects of having the power supplies within 15-20 mm of the Modulus-686 boards.

Do's build looks excellent to me. I'm sure it'll perform well.

Tom
 

Attachments

W2S

Active Member
Joined
Dec 30, 2018
Messages
150
Likes
89
#88
Lovely Looking Amp

Love the Board layout looks superb

You just need to add a clear top to show off that beautiful Work :eek:
 

maty

Major Contributor
Joined
Dec 12, 2017
Messages
1,411
Likes
567
Location
Tarragona (Spain)
#89
I'm curious what you base your "improvements" on. Opinion or science?
If the Modulus-286 has very good measurements and it is presumed that, why worsen them in a channel because you did not want to buy a slightly wider case or add few small 1 mm steel sheets to isolate the PSU?



Mean Well RPS-400-27-C

https://www.tme.eu/es/details/rps-400-27-c/fuentes-de-alimentacion-abiertas/mean-well/

[PDF] https://eu.mouser.com/datasheet/2/260/RPS-400-SPEC-1131384.pdf



Connex SMPS800RE

https://www.audiophonics.fr/en/smps-power-supply/smps800re-power-supply-module-800w-60v-p-6950.html

 
Last edited:

jtwrace

Senior Member
Joined
May 31, 2017
Messages
301
Likes
123
Location
Orlando, FL
#90
@maty

Since you're on multiple forums adding your feedback, can you discuss what qualifications you have to suggest to someone like @tomchr what he should do? His background in electrical engineering is quite extensive. If you haven't seen it, take a look here.
 

tomchr

Technical Expert
Technical Expert
Manufacturer
Joined
Nov 5, 2018
Messages
239
Likes
659
Location
Calgary, Canada
#91
If the Modulus-286 has very good measurements and it is presumed that, why worsen them in a channel because you did not want to buy a slightly wider case or add few small 1 mm steel sheets to isolate the PSU?
1) I wanted a compact amp for two reasons: a) lower cost and b) because I thought it would make a really cool and marketable kit. This has been discussed ad nauseam earlier in this thread, so I'm quite puzzled that you still bring it up.
2) A 1 mm steel sheet would do nothing to isolate the PSU. A 1 mm µ-metal sheet might work. However, machining µ-metal is a challenge. None of my manufacturers use it.
3) Adding 1 mm of anything to the current design will not happen as there isn't 1 mm to spare. As I'm sure you know, you need at least 6.3 mm of space between any high-voltage point and the rest of the circuitry/chassis for safety. I am not willing to compromise safety to chase down 2 µV of mains hum.
4) The difference in mains hum between channels is a few µV. That's a couple of orders of magnitude below audible.

Of course, these are facts. And you should never let facts get in the way of a good opinion... :)

If you don't like the performance of the Modulus-286 Kit, you're free to buy the Modulus-286 modules by themselves and build your own amp using whichever chassis and power supply you prefer. Show off your awesome design skills.

Tom
 

tomchr

Technical Expert
Technical Expert
Manufacturer
Joined
Nov 5, 2018
Messages
239
Likes
659
Location
Calgary, Canada
#92
@maty

Since you're on multiple forums adding your feedback, can you discuss what qualifications you have to suggest to someone like @tomchr what he should do? His background in electrical engineering is quite extensive. If you haven't seen it, take a look here.
I'm curious too. And @maty, you didn't actually answer my question about whether you base your "recommendations" on opinion or science. The pictures of the Mean Well RPS-400 and Connex SMPS800RE (neither of which will fit in the Modulus-286 Kit) did nothing to address that question. Would you like to give it another try?

Tom
 

maty

Major Contributor
Joined
Dec 12, 2017
Messages
1,411
Likes
567
Location
Tarragona (Spain)
#93
I think there is no point in discussing more. I have only discussed the width of the case.

As for the images, it was to illustrate.
 

maty

Major Contributor
Joined
Dec 12, 2017
Messages
1,411
Likes
567
Location
Tarragona (Spain)
#94
In a bigger case you can joy with shield and distance. 1 mm galvanized steel sheet works if there are distance.

[ Updated Mumetal attenuation ]

Of course, 3 mm galvanized steel sheet (12 dB) is better and u-metal (60 dB 30 dB, per layer) much better to shield (in a case or wrapping it) a transformer.

Audio Transformers, by Bill Whitlock

[PDF] http://www.jensen-transformers.com/wp-content/uploads/2014/09/Audio-Transformers-Chapter.pdf

Page 9

[ The effectiveness of magnetic shielding is generally rated in dB. The transformer is placed in an external magnetic field of known strength, generally at 60 Hz. Its output without and with the shield is then compared. For example, a housing of 1/8" thick cast-iron reduces pickup by about 12 dB and a Mumetal can by about 30 dB. Where low-level transformers operate near strong magnetic fields, several progressively smaller shield cans can be nested around the transformer. Two or three Mumetal cans can provide 60 dB and 90 dB of shielding respectively. In very strong fields, because high-permeability materials might saturate, an iron or steel outer can is sometimes used. ]

With this case width, bad solutions.
 
Last edited:

jtwrace

Senior Member
Joined
May 31, 2017
Messages
301
Likes
123
Location
Orlando, FL
#95
@maty

So you won't answer my above question?
 

BYRTT

Active Member
Patreon Donor
Joined
Nov 2, 2018
Messages
168
Likes
183
Location
Denmark (Jutland)
#96
@maty

Shure it looks you mean the best and the creative thinking plus visual ideas and examples are of a logic that probably should give a improvement, then again expect discussions when actual suggested implementation is not backed up by real numbers because as seen here at ASR site many excellent/executed looking units can fall apart staring into a AP or other gear quality check point even it looks like be a best practice build or ears tell about a pleasing good sound. Guess passion is mostly whats your posts is about and good enough input but also when @tomchr let his amp in actual implementaion be benchmarked here its great because those are the real numbers to expect for that particular implementation, not to speak of will guess @Pinnocchio down the road document either for himself or public sharing if that nice looking implementation holds water in real numbers quality check.
 

maty

Major Contributor
Joined
Dec 12, 2017
Messages
1,411
Likes
567
Location
Tarragona (Spain)
#97
A simil. One buys an expensive car but decides to save on the upholstery of the seats. Some will look good and others will not. I am one of the seconds, that is the question.

If the difference in cost is small/very small, the decision is more incomprehensible to me.
 

BYRTT

Active Member
Patreon Donor
Joined
Nov 2, 2018
Messages
168
Likes
183
Location
Denmark (Jutland)
#98
Good enough example @maty :) think problem is in audio world even implementation looks good by eye or best practice its not always honored the expected 100% when unit or system is bencmarked.
 

jtwrace

Senior Member
Joined
May 31, 2017
Messages
301
Likes
123
Location
Orlando, FL
#99
@maty
By blatantly ignoring a simple question, you lose any credibility.
 
Top Bottom