Unknown class D module - could serve for DIY amplifier?

[RitchieBitchie]

Dear ASR community,

First of all, this is a TERRIFIC forum/community!
After I discovered this site several months ago, I am visiting daily and reading diverse topics and of course the fantastic reviews.

Indeed, this is my first entry. So 'Hello' to all!

Struggling to decide for a new stereo setup to step up from my vintage Denon PMA-480R due to just too much variety on the market, I was wondering about a DIY using hypex modules or Sylph-like. It so happened that I just got a semi-broken PA amplifier with 2x250W class D modules.
Big question here: can I use those modules for an DIY amp and are these actually 'good'?

It is hard to find info about these modules; also happened to be designed by the company.
Here, the links to the device and the data sheet: https://www.gm-elektronik.swiss/en/bo-cd-250-2-ev-digital-class-d-dual-amplifier-2-x-250-watts/

https://www.gm-elektronik.swiss/wp-content/uploads/ds_BO-CD-XXX-2.-EV_05_en.pdf

I was surprised and wondering about the 'minimum impedance' of 40 ohm stated in the data sheet.
Attached, some photos of the PCBs. I removed also the cooling plate on the amp chips to identify those, but seems impossible (there are 4).

Anyone might have some leads to what modules these could be and if they might serve for an DIY HiFi amp purpose?

Cheers,
Richy

 

[NTK]

Welcome to ASR!

It seems that your amp modules are designed for 100 V (PA) speaker systems. Below are a few links explaining what they are.

Understanding 70v / 100v line Loudspeaker Tappings

HowToAV and AVIXA audio expert Chuck Espinoza discusses loudspeaker tappings for 70v / 100v line loudspeakers.

cie-group.com

https://www.lowellmfg.com/wp-content/uploads/What-is-a-25V-70V-or-100V-Speaker-System.pdf

Constant-voltage speaker system - Wikipedia

en.wikipedia.org

 

[RitchieBitchie]

Hi NTK,

Thanks for your quick and very informative answer.
I see; learned something new. ;-)

So... these modules are useless for the envisioned finality. Pity.

Cheers,
Richy

 

[TimoLux]

fosi audio amplifier board can also be used as a DIY. like: https://fosiaudio.com/search?type=product&options[prefix]=last&q=board

 

[Remk]

Hi NTK,

Thanks for your quick and very informative answer.
I see; learned something new. ;-)

So... these modules are useless for the envisioned finality. Pity.

Cheers,
Richy

There not useless.
Look's likes they use the transformers for the 100V output.
If so, those transformers would be 4 or 8 ohm to 100V. Just make extra speaker terminals on the back and connect those where the transformers connect(the thick wires).

Rem.

 

[tomchr]

The Edcor EA300 distribution transformer could be the ticket: https://edcorusa.com/collections/sp...-bidirectional-audio-distribution-transformer
Only trouble is that they're $120/each and you'll need two for a stereo amp. You could likely find a different Class D module for less. TI makes a pretty nice one. There's also Purifi and Hypex.

Tom