Aleph 30 the best choice of C1 C2 C3 on brian gt PCB

[tonimxp]

Greetings to all! Anyone have any suggestions for me before I mount the pcb? For example I'm thinking of replacing C4 with 15pF directly,so..i can save my time and i can not remove it all over again.
Are you agree with me?
Thanks in advance.

P.S. On the bottom Pcb as showed

First Wima 0.1uF + Ero 1860 0.01uf are in parallel with C2 220uF Silmic II

Second Wima 0.1uF is in parallel with C3 220uF Nikicon Muse

[boywonder]

Originally Posted by tonimxp

I'm thinking of replacing C4 with 15pF directly,so..i can save my time and i can not remove it all over again.
Are you agree with me?
Thanks in advance.

Toni: I'm no expert here, but on tube amps the feedback compensation cap (C4 in this case) is typically tuned/adjusted during testing to get a good square wave at 10Khz without overshoot/ringing. The final value can be somewhat hardware-dependent and can be sensitive to the specific output transformers chosen. Obviously, SS amps don't have output transformers, so like I said, I'm no SS expert.

If you want to play with the amount of feedback and change the feedback R, you need to re-check the 10Khz sq wave to see if the comp cap value is still correct.

Do you have a scope?

[tonimxp]

Originally Posted by boywonder

Toni: I'm no expert here, but on tube amps the feedback compensation cap (C4 in this case) is typically tuned/adjusted during testing to get a good square wave at 10Khz without overshoot/ringing. The final value can be somewhat hardware-dependent and can be sensitive to the specific output transformers chosen. Obviously, SS amps don't have output transformers, so like I said, I'm no SS expert.

If you want to play with the amount of feedback and change the feedback R, you need to re-check the 10Khz sq wave to see if the comp cap value is still correct.

Do you have a scope?

Hi!Bw i have just changed C4 with 15pF value,i think you're right, but I think by coarse analysis that 15pF should be ok, of course when I will try it i will make sure with the scope and signal generator, thanks anyway for the advice.

[tonimxp]

Hi to all!Today i have just start up my aleph 30. I think could be interesting some pictures.
Will be shown in order:
1) square wave test at 10 khz
2) supply voltages of one psu (my amp is a dual mono topology)
3) supply current of one psu (my amp is a dual mono topology)
4) control of the temperatures of the first cooling fin and then on the body of the MOSFET
5) check of the waveforms with tone at 10 kHz (I found 0.14 Vrms)and 100 kHz (I found 0.10 Vrms) sinusoidal,i think there is an attenuation of 3dB (Nelson says there should be about 1.5 dB).
6) I also detected a ripple voltage of 0.04 Vrms ( nelson says 0.3 Vrms but mine is a dual mono psu with uF 176000).
Do you have any suggestions for the frequency response slightly deficient on high?
Thanks in advance.

[tonimxp]

I remember you that i had changed C4 (10pF) with 15pF value for square wave test.
Any suggestions?
Thanks.

[Zen Mod]

leading edge/corner is rounded

try again with 10p

just for splittin' da hair sake

[Melon Head]

Just bloody listen to it you lunatic.
How perfect do you need that square wave?
Very nice work

[tonimxp]

Originally Posted by Zen Mod

leading edge/corner is rounded

try again with 10p

just for splittin' da hair sake

Hi Zen! Ok tomorrow i will try with 10 pF value

[tonimxp]

Originally Posted by Melon Head

Just bloody listen to it you lunatic.
How perfect do you need that square wave?
Very nice work

Hi melon Head and thanks for the compliments, nice to write with you

[boywonder]

Originally Posted by tonimxp

Hi Zen! Ok tomorrow i will try with 10 pF value

Please post a scope shot with the 10pf cap when you test......