Is 400VA enough for an Aleph30?

[hifimaker]

I bought 2 Antek 22v+22v 400VA trafo's on Ebay. Can I get away with just using one for a stereo Aleph30 or do I need both? Will 400va limit the amps performance?

I guess I'm asking, how much transformer is needed here?

Thank you,

-David

 

[Zen Mod]

www.passlabs.com

www.passdiy.com


download all what you can

save all and anything you can

read with a smile

 

[MikeW]

You can use it. It may have a little more mechanical hum and get a little warmer than using two.

 

[mpopovics]

I would recommend to use both.

And also recommend Nelson's article on Power supplies

 

[hifimaker]

Thanks for the guidance and suggestions. I'll use both of them.

-David

 

[Nelson Pass]

I would, if only for the ability to avoid ground loops by having
separate grounds for the two channels.

 

[MikeW]

TWO?

I would, if only for the ability to avoid ground loops by having
separate grounds for the two channels.

Do you use two in your amps or one with separate secondaries (4 sets for a 2 channel) ?

 

[motzu']

The thread just hooked my attention.

I currently own the same type of transformer 2x22V 400VA but I never thought to try use them in an Aleph 30/Aleph 3, because I knew that voltage was supposed to be 25V DC .That if I read correctly the manual

Anyone so kind to advise ?

From my point of view 22x1.41=~31 V

Too much for Aleph3 but slightly less for Aleph 5

Am I so lucky to find some use for those babies ?

Thank you

 

[Zen Mod]

close enough for both
go to duncan's and download PSU designer,try with diff approaches- C bank,CLC , CRC and you'll see that you can build both with these donuts.
btw 1,41 is not valid for A class

 

[Zen Mod]

http://www.duncanamps.com/

 

[tja]

close enough for both
go to duncan's and download PSU designer,try with diff approaches- C bank,CLC , CRC and you'll see that you can build both with these donuts.
btw 1,41 is not valid for A class

I'm looking to build a PS for an Aleph 30 and playing around with duncan's PSU Designer II too. I could just use an 18V transformer and some caps, but if I get a 22V one and use CRC, ripple would be substantially less. Also I'm struggling with the question what value to use for the load. Anybody got a hint?

Take

[EDIT]Punctuation[/EDIT]

 

[Zen Mod]

first hint-you can unwound and also add some (additional ) wounds to donut-very easilly;

second hint-for current consumtion just read service manual for exact aleph and you'll know ;

R is still equall to U/I

 

[tja]

From the Aleph 30 manual:

"The amplifier draws about 200 watts from the wall at all times"

so 100W/ch with rail-to-rail 50V means bias is 2A, so load for one secondary is 25V/2A is 12,5 Ohm.

Correct?


Take

 

[Zen Mod]

From the Aleph 30 manual:

"The amplifier draws about 200 watts from the wall at all times"

so 100W/ch with rail-to-rail 50V means bias is 2A, so load for one secondary is 25V/2A is 12,5 Ohm.

Correct?


Take

yup


read and re-read help in PSU designer;

it helps a lot

 

[Mark A. Gulbrandsen]

first hint-you can unwound and also add some (additional ) wounds to donut-very easilly;

Choky, Thats not always as easy as it soulds. Many Toroids with dual secondaries have the secondaries wound one on top of the other in a bifilar manner. On those you'd have to unwind at least the one secondary to get at the other to add or take away turns.



On the Aleph I would go for both trannies. Thgose Anatek trannies are actually pretty darn good for the $$!! I've had absolutely no mechanical hum from the two pairs I've used building KSA-50's. I would reccomend them to anyone to use unless they were after the best..... Then Plitron ......

Mark

 

[Tweeker]

I dont think a 400VA 22 VAC toroid will be a problem either, if the rails are higher than you like, just add a little more R into a CRC filter.

 

[motzu']

Seems that i'm too idiot or too uneducated to play with the program.

@choky - could you be so kind to post a .psu file for this particular problem ? I can learn easier if I see the solution

From 22 VAC to not exceed 25 VDC .... I was unable to find out how to do it , and worse, still I'm too newbie to know how to interprete those graphs

This is it....


2'nd stupid question .Why is not valid ~1.41 for class A . Because of the high constant current needed by the amp ? The cap's are not 'charged' enough ?

BR

 

[tja]

Here's my model for a CRC PSU for the Aleph 30 with a 22V transformer.

Take

 

[Zen Mod]

Choky, Thats not always as easy as it soulds. Many Toroids with dual secondaries have the secondaries wound one on top of the other in a bifilar manner. On those you'd have to unwind at least the one secondary to get at the other to add or take away turns.

......

Mark

agree,my man; but-that is not always case (anyway I can tnk ya in name of original poster for additional info ) ;
in case of adding several turns-it's not matter in which manner are wounded secondaries -you just add few turns and connect it in phase with adequate original windings

but-in casewhen two secondaries are wounded in bifillar manner and you need to unwound some turns.........PITA of work......

 

[Zen Mod]

Here's my model for a CRC PSU for the Aleph 30 with a 22V transformer.

Take

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