Is 400VA enough for an Aleph30?

[tja]

it's better to use current sink (2A) as load- GUI and interpret are closer to human mind
in any case-thumb up for sim

Thanks, will try that next.

Take

 

[hifimaker]

Here's the simulation I was working with for my A30. What's the best way to determine the resistance of the capacitors for the simulation?

-David

 

[Zen Mod]

What's the best way to determine the resistance of the capacitors for the simulation?

-David

it's in fact educated guess-sollely depends on your exact caps.
for starters-you can load sample designs from PSU installation folder (program files-duncan....-PSU... by default) and just scale to your values of capacitance.

in fact -I think that this is covered in help

 

[tja]

Here's the simulation I was working with for my A30. What's the best way to determine the resistance of the capacitors for the simulation?

-David

I used the datasheets for BCcomponents 051 series snap in caps, at the bottom of page 4 there's the 40V table which includes ESR in mOhm at 100Hz.

BC components 051 series datasheet

Take

 

[Zen Mod]

I used the datasheets for BCcomponents 051 series snap in caps, at the bottom of page 4 there's the 40V table which includes ESR in mOhm at 100Hz.

BC components 051 series datasheet

Take

good 'nuff

 

[hifimaker]

I have Nippon Chemi-Con 22000mf 35v caps from the recent group buy. I looked up the datasheet on the manufacter's website and they have a column for the resistance data but it is not listed.

Just wondering if there was a way to measure it, or there are "typical" values for purposes of the simulation?

Thanks,

-David

 

[hifimaker]

Ok looking at the Bc components link above.... A very similar cap has a resistance of 28mOhms. If 2 caps are in parallel is the resistance halved to 14mOhms?

Thank you,

-David

 

[Tweeker]

Pretty much.

 

[jacco vermeulen]

Just wondering if there was a way to measure it

Bob Parker's ESR meter.

 

[Zen Mod]

esr meters usually works on 10 to 100KHz

nono........

 

[jacco vermeulen]

esr meters usually works on 10 to 100KHz

True, i should read the 100Hz line before posting. Bob's is 100KHz i believe.
ScuseMe.

 

[AR2]

I just finished my Aleph 30 with exact same transformers 22V 400VA made by Piltron. It works quite fine as is. Voltage is little bit below 31V with one channell, and 29V with two channels on one tansformer. I will be using two transformers, but just for testing purpose I first tested it with one trnnie only. So far works great and transformer doesn' worm up at all.
Sound is awsome!
I love these amps. My advice - build as with what you have and than see and measure.

 

[jh6you]

Interesting . . .

I am late. Anyhow, I understand that Aleph 30 has bias current of 1.6A per channel, i.e. 3.2A for both channels. And, the peak voltages from the secondary side (ac 22v) of the transformer are +/-31V, i.e. peak to peak voltage of 62V. Therefore, the VA is calculated 3.2x62=198VA to cover both channels. I think that using 400VA is enough as long as the current capacity of total psu caps is as large as possible.

Regards
jH

 

[AR2]

In my case 6 x 22,000 uF per channel, or 264,000 uF for both channnels.

 

[jh6you]

12 x 22,000uF, wow ! ! !
I think them enough to cover both the ripple voltage and the whole current boosted by the active Aleph current source. Why don't you save another transformer for one more A30?

The original A30 seems to use one transformer and total 12 x 10,000uF. I don't think that its transformer size would be bigger than 400VA. No? Then, I would think that Passlab is wasting their profit . . .

Regards
jH

 

[Andypairo]

Interesting . . .

I am late. Anyhow, I understand that Aleph 30 has bias current of 1.6A per channel, i.e. 3.2A for both channels. And, the peak voltages from the secondary side (ac 22v) of the transformer are +/-31V, i.e. peak to peak voltage of 62V. Therefore, the VA is calculated 3.2x62=198VA to cover both channels. I think that using 400VA is enough as long as the current capacity of total psu caps is as large as possible.

Regards
jH

Please remember that a large capacitance like the one needed will request huge current peaks that might saturate the core of the trafo it is not oversized enough, inducing mechanical vibrations and heat losses. I used a 500VA and I would suggest at least this as a "minimum" size for a stereo amplifier.

Andrea

 

[jh6you]

. . . a large capacitance like the one needed will request huge current peaks that might saturate the core of the trafo it is not oversized enough . . .

Well . . . the charge stored in each capacitor and the voltage between its terminals have a fixed ratio. The group of caps on + side and the other group of caps on - side would well co-operate, looking each other. Therefore, I would not worry about the core saturation with 400VA size.

Regards
jH