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Big single or two smaller transformers for power amps?

JimmyB

pfm Member
What are the thoughts, pros and cons, around using either a single large transformer e.g. 500VA 30-0-30 and running both channels from a separate 30V output on this as opposed to 'full' mono two smaller single transformers e.g. 200VA 15-0-15 run as single 30V rail?

Both would provide enough current headroom so is there an advantage? No regulators before any amp stages is the plan, so essentially a NAP180 type build.
 
Just meaning the transformers themselves, wording a bit off up there. Basically just what's the feeling for...one big weighty thing running the amp or fully mono with smaller transformers. Everything upstream just as needed to give the Dc to the amp boards or does it not really matter?
 
Just meaning the transformers themselves, wording a bit off up there. Basically just what's the feeling for...one big weighty thing running the amp or fully mono with smaller transformers. Everything upstream just as needed to give the Dc to the amp boards or does it not really matter?

If you drive both channels at full steam, it makes no difference. If one channel temporarily needs more power than the other, one big transformer can supply more power to that channel than a smaller "mono" transformer could.
 
Still need more information really...
Separate transformers or dual secondaries can sometimes help when trying to optimise the grounding/earth returns and voltage rails layout. Not much in it generally though.
 
If it's really mono blocks in one chassis for for two, better earthing options

It is, in a nutshell, just that. I'm trying to find a use for a rather large (just checked and it's 600VA!) transformer I was given as it just seems overkill for my slowly progressing Hicap build and also wondered if I should try to shoe-horn it into my NAP160.

Sounds like it's just keep calm and carry on with it in the Hiccup and leave the dual tranny 160 alone.

I do need to look harder at my grounding arrangements though for both. I've been a bit lazy here and probably better tidying that up instead.
 
Dual mono always seems like a simple choice, easy to make and make better. Earthing is always tricky, especially with modest psrr circuits and single or dual layer boards.
 
Yes, earthing has always been a grey area for me in builds and I'm pretty sure it's never been ideal. Lot's to learn.
 
Works great in the bpbp, but not really the same as keeping your signal and power ground separate with the lowest loop area as applicable to any amp.
 
I enjoyed the hifisonix article on wiring power amplifiers to avoid earth problems and noise.
Probably should be in the reference section.
Who manages that?
Cheers Andy.
 


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