100W Ultimate Fidelity Amplifier

Follow up from post #10533 regarding ax14 PCB Gerber file from parsi post #10405, I've built them and they work.

Bias is quite stable, it moves up a bit, offset is stable at 16-17mv. I did not match any transistor but I choose from the same cut tape.

Here is the pictures.
 

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Follow up from post #10533 regarding ax14 PCB Gerber file from parsi post #10405, I've built them and they work.

Bias is quite stable, it moves up a bit, offset is stable at 16-17mv. I did not match any transistor but I choose from the same cut tape.

Here is the pictures.

Hi Chat72,
Congratulations on your successful build :)
Have you made any changes to the original schematics other than the inclusion of additional pair? Also please share us your listening experience.

If I recollected it right, the offset would be <=10mv, that's what Mr Mile mentioned somewhere in the forum.

Thank you.
Sha
 
Hi Chat72,
Congratulations on your successful build :)
Have you made any changes to the original schematics other than the inclusion of additional pair? Also please share us your listening experience.

If I recollected it right, the offset would be <=10mv, that's what Mr Mile mentioned somewhere in the forum.

Thank you.
Sha

Here is the list of change,
Bc546/556 for bc547/557
A1220/c2690 for 340/350
Mje15034/15035 for 1837/4793
Mjl3281/1302 for 1943/5200

Offset is on the high side, actually one channel is around 6mv another is 17mv, but no problem so far, no hiss or hum.

For the sound, high is very good comparable to class A amp, bass is not as deep as I would like it to be. I will change the main filter cap and see what happen. Now I'm using panasonic I plan to change to Nippon chemical.

Regards,
C.S.
 
Follow up from post #10533 regarding ax14 PCB Gerber file from parsi post #10405, I've built them and they work.

Bias is quite stable, it moves up a bit, offset is stable at 16-17mv. I did not match any transistor but I choose from the same cut tape.

Here is the pictures.

Very neatly done indeed and nice layout of modules with a good sized heatsink. Congratulations!
I see that you also use a protection PCB and a soft start. Whats the thickness of Aluminium angle?

Regards
Prasi

P.S. For a trial (at your own risk:D), you could bypass the protection circuitry and see if it sounds any different. My observation is that relays can sometimes mess with S.Q. This is only an opinion, you can ignore it completely.
 
Sir, There are so many models of Apex amplifiers with different varients. I am totally confused as to to which is better in terms of distortion sound quality and commonly used parts. Will our experts recommend one updated schematic and its layout so that I can start building the same for my home.

Thanks