100W CFA with mosFET OPS

[dadod]

Here are schematics BOM and gerbers of the amp described in https://www.diyaudio.com/community/threads/200w-mosfet-cfa-amp.243481/page-75#post-6000469
Damir

R20 and R24 in the amp are there for overcurrent protection, but used value is a bit to high, better use 1.5k instead 6.8k.

 

[lineup]

Can you post an image of the schematic?

 

[dadod]

If you follow the above link it will direct you to the main thread with the schematics and all other needed information.

 

[dadod]

Here is the amp JPG schematic with new R20 and R24 values.

 

[lineup]

Thanks.
I like CFA Current Feedback Amps.

 

[dadod]

I would like to have some photos here if someone decides to built this amp.😉

 

[chat72]

One channel tested, bias and offset are good. Might be a while before I can finish both channels though.

 

[chat72]

Ok I have time before I'm away, here is a finished 100w CFA. Excellent sound, CFA is growing on me. Supply is unregulated +/-50vdc, bias is around 100mA, VAS current is a bit high at 10mA VAS trs are heating up and current through R5 R6 are around 2mA.

 

[dadod]

chat72,
VAS current could be to high if the red LEDs D11 and D12 are with too high forward voltage (could be up to 1.9V). I used HLMP-K150 red LEDs with about 1.7V.
BR Damir

 

[dadod]

Any news here abouth built this amp?
Damir

 

[Mas ArulTV]

hi dadot.
I'm having trouble getting vr 4k7 (R61).
Can it be replaced with vr 5k?

 

[dadod]

You can use 5k there, but strange that you can't find 4k7, it is most common value.
I see that you use different layout, actually I prefer to have output transistor in one line to keep them on the same temperature level.
Also I use N P N P configuration to get lower power supply loops influence.
Could you show your layout?
Damir

 

[Mas ArulTV]

i will install R61 with 5k.
thanks dadot.
happy with your fast response.
yes of course, i share the garber file.

 

[dadod]

I don't need your gerbers, just wanted to see the layout.

 

[Mas ArulTV]

yes i know you don't need garber file.
but with garber file you can see it in jlcpcb.
even the layout route.
but i will show it with jpg file.

 

[Mas ArulTV]

first, i was immediately impressed with the audio quality.
the guitar sound is classic.
i like your design damir.
thanks for sharing.

 

[dadod]

I am glad you liked it.