In my experience using resistors (CRC) in series with the powersupply will degrade the bass performance and dynamics. I have not tried CLC, but I suspect the same with an inductor in series with the supply.
On the other hand it gives good ripple/noise figures....
Also (my opinion), one larger cap (47.000uF) will sound better than 2x25.000uF in parallel. Also, in my opinion too much C is as bad as too little. Enough is when there is no audioble hum....thats it.
Therefore I will use the following PSU to my Aleph 3/30 version:
-1000VA 2x18VAC EI transformer
-One 47.000uF/40V per supply half
Does this seems to little? Has anybody tried this combo?
What is the positive and negative PSRR in the Aleph 3/30 circuit? My guestimates says -70dB on the negative and -75dB on the positive....
I am not a expert but i just finish my aleph overkill :-)
68000uF +1.2mH +68000uF +1.2mH +68000uF
1.2mH internal ohm=0,15 ohm
and with the results a ok not topend aleph3 power would be:
1- 2x 21 vac not 2x18 to get +/- 25 volt one solution would
be to boost the 18 to 21 with a 24vac with center tap 10A
wired like a stepup transfo to boost the input 240vac to
250 or 260vac it s not ideal for noise but possible
2-my bridge are 2 x 35A 400v
3-just 47000uF too low for me 2x 47000uF ok or CLC better
maybe more infos will be helpful
1-my overkill aleph 3 supply is for 2 channels and you ?
2-with output = +/- 24.9 v and 3.6 amp test resistor load
ripple with CLCLC : on cap1=500mV
cap3=not measureable with my scope
3-i don t change my design but cap3 is overkill
i hope it s help you to take a good decision :-)
I am not looking for overkill, just right will do nicely ;-)
Have you tried with "just" 47.000uF? And can you describe the changes in the different solutions?
On other class A amps (not Pass) I have found lack of punch in the bass with resistors in the psu.....
with just one 68000uF all others cap and inductor disconnect
vout go from 24.9 to 26v
iout test go from 3.6 to 3.75A
the ripple is 500mV
maybe around 700mV with 47000uF
if you are afraid for the sound go to with just one 47000uF
and reserve space in your casing for 2 more caps
for aleph 3 from Mr.Pass document there is just one cap(4 x 22000uF)
for +v and another 88000uF for -v for 2 channels
No, just wondering if someone actually tried where the limit "too small" is....and also "too large" (sound wise, not calculated).
700mV on the supply will give 125-221uV ripple related noice on the output I don't think this will be a problem noisewise...and given the dynamic reduction with a series element, that will be my first version.
sorry to bother you with my calculs :-)
maybe start another thread
No, it is interesting to know different veiwpoints :)
I am looking for different methods to adjust the Aleph performance.....and the powerpupply is an naturel start.
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