More VA the merrier?

[garbage]

Hi guys

Wanted to seek your opinion if allocating funds into a Gainclone project with emphasis on transformer VA a good idea?

Is more VA for the PSU section make for a better sounding Gainclone with a lower VA PSU? Any one has experiences to share?

Thanks.

[analog_sa]

IME, yes, higher VA generally sounds better.

Unfortunately there seems to be more to the sound than mere VA - one of my transformers is badly wound on a very old recycled EI core - and it sounds disproportionately better than all other transformers i have.

[garbage]

I was under the impression that a PSU with higher VA should help since the power supply caps used in a Gainclone is generally 1000uf or so.

Was thinking of getting the highest VA I can find with dual 18V secondaries for an future Gainclone project.

[tpenguin]

Originally posted by garbage
I was under the impression that a PSU with higher VA should help since the power supply caps used in a Gainclone is generally 1000uf or so.

Was thinking of getting the highest VA I can find with dual 18V secondaries for an future Gainclone project.

Really, there is no need to go to extremes in transformer VA ratings. I don't believe that it will make much of a difference. The only effect it would have is increasing the amount of current the amplifier can draw from the transformer's secondaries without overloading the transformer. Since a stereo gainclone draws very little current, this should be of little concern. I'm not sure if I understand what you meant about a transformer with a higher VA rating would help because of the low values of the filtering caps typically used. Increasing the current handling of a transformer will not make any difference here, unless the amp is current-starved to begin with, which will cause voltage sags. You can naturally use larger filtering caps if you so desire, but it would not be necessary.

As a general rule of thumb, I like to have a transformer that can supply about 25% more current than the amplifier should draw, just to have an extra safety margin, and to prevent it from getting hot. For a typically stereo gainclone, anything over 300VA would really be a waste money (unless you just happen to have one on hand or find a really good deal on one some place). I would certainly recommend a quality transformer, though, not just going after the cheapest you can find. However, I suggest spending more money on high-quality components, or maybe even a more elaborate CLC filtered and/or regulated power supply. In which case, you would need to slightly increase the voltage and the current capacity of the transformer to account for the innefficiencies involved.

[soundNERD]

Originally posted by garbage
I was under the impression that a PSU with higher VA should help since the power supply caps used in a Gainclone is generally 1000uf or so.

Was thinking of getting the highest VA I can find with dual 18V secondaries for an future Gainclone project.

1000 uf??? not at all true. some people who want no bass responce will use 1000uf. if you want a full range amp you should use something more like 5000uf on each rail. i think the more capacitance the less VA you need for the same power since between boom sounds the caps have time to recharge.

[garbage]

Thanks all for the response.

Guess I will go with say a 300VA transformer and play around with the caps for the power filtering for the first project.

[chris ma]

Originally posted by soundNERD



1000 uf??? not at all true. some people who want no bass responce will use 1000uf. if you want a full range amp you should use something more like 5000uf on each rail. i think the more capacitance the less VA you need for the same power since between boom sounds the caps have time to recharge.

I am using BrianGT GC-Kit which comes with 1000uf cap and the little amp provide all the bass I ever need. I like "No women no cry" too.
Regards,
Chris

[Circlotron]

1 VA per amplifier watt works just fine for domestic use with a normal class B amp. 10,000 uf per rail per chip for a gainclone is ok too, IME.

[pinkmouse]

My little monoblock driver testing amp based on a 3875 is also used to run background music in my workarea. It has a 50VA trafo, and goes plenty loud enough to hear through the rest of the house..

[uvodee]

transformers but

my set up with 2 18 v 1.2 A trannies per channels sounds the best (low volume ofcourse....)

when using the 200va trannies sound changes sometimes into harshness...


J-P