My NAP clone project

[neonixcool]

Good day
“Opium for people…”
Early NAP250 and NAP110 boards DIY
Julian Vereker boards design

 

[charly63]

Hello,
Nice work, its copy of original bords.

Regards
Ch

 

[neonixcool]

Hello,
Nice work, its copy of original bords.

Regards
Ch

Good day
Yes I draw this from original old boards
(Long long draw step by step )

 

[jpk]

You certainly need a test load, scope and signal generator [...] These checks are not rigorous, but offer some defence against gross problems. Defence against the dark arts anyone? Good luck.

So here are my scope shots (yellow = output, cyan = negative power rail, purple = positive power rail). I tried to follow your advice given in #9: I connected ~5m of NACA4 to the amp with an 8R high power resistor at the other end. BTW I used a cheap DDS signal generator: is that the reason we can see stairsteps in the sine wave?

noise (input shorted):

1kHz triangle (0.5V input):

1kHz sine (1.5V input):

1kHz square (clipping with 3.5V input):

 

[jpk]

More scope shots: I added a film cap across the dummy load and removed the NACA4.

20kHz square wave (0.5V input) into 8R and 1uF:

20kHz square wave (0.5V input) into 8R and 2uF:

20kHz square wave (clipping with 3.5V input) into 8R and 1uF:

1kHz square wave (clipping with 3.5V input) into 8R and 1uF:

So I hope my amp tested fine so far...?

 

[PigletsDad]

That all looks good. You are correct, the steps in the sine wave will be from the digital generation. This shows correct basic operation - to go further you need more specialised gear to measure distortion.

Yes, your amp tests fine. The clipping recovery shows a few microseconds of sticking, but that is expected and not important. Well done.

 

[jpk]

Thanks for the confirmation, I feel good now