Switching Power Supply for Gainclone

[Rarkov]

Hi,
I'm trying to design a switching power supply for some gainclones. I don't have room in the chassis for an xformer (about 8cm x 10cm x 3cm at a guess) and I don't want a seperate bopx for a PSU. Whilst I was sat with orcad playing around, I thought I might as well ask in case someone else has done one before...

Another thought was an AC wall adapter; has anyone tried one with a Gainclone before?

Thanks,

Gaz

[Optical]

I am currently investigating modifying a PC power supply, there is an article in silicon chip magazine (october 2003?) on how to modify them to 13.5V, and it gives details on how teh psu's work..
I dont really see what is stopping you making it a higher voltage by winding a few extra turns onto the transformer and using a voltage divider to take the output back to 12V for the voltage sensor if anyone knows what i mean..

i imagine the output caps will need to be replaced with higher voltage low ESR ones too.. but other than that??

these psu's are a dime a dozen, ive got a few now and plan on pulling them to bits this week for a play around..

[analog_sa]

I have listened to computer power supplies in audio circuits and find the resultant sound to be awful. I have also listened to Chord amps powered by smps and they're absolutely divine for solid state. Obviously good sound from smps is possible but likely not easy.

[Magura]

According to Circlotron whos making SMPS's for living, its not worth the trouble. If you can mod a computer supply to fit the bill, then its at least fairly cheap and not too time consuming.



Magura

[jackinnj]

if you do your homework you should be able to put together a switcher without enormous difficulty -- an audio amplifier isn't a job for a computer supply off-line switcher -- they aren't up to the task of handling wide swings in load -- this has been reported on some of the ham radio newsgroups where folks had tried to use switchers for CW (code) -- the response time just isn't great.

delve into some of the manufacturer's application notes -- you will find some good ideas for low noise switching supplies at www.linear.com under the LT1533 and its associated gate drivers (Application Note 70) -- if you are going to use a push-pull topology you can use the "plug-n-chug" spreadhseet linked here: http://www.tech-diy.com/smps.htm

oh, it really helps to have a scope...

[Rarkov]

OK, thanks guys...

I think I'm just going to use bigger heatsinks & a linear PSU
The Gainclone monoblocks will still be tiny though!

Thanks,
Gaz

[Colin]

I was also wondering about a switched psu for the Gainclone. Russ Andrews here in the UK is offering switched psu as an upgrade for Naim preamps - but stresses that he had to audition about 30 to find a good one!

Russ Andrews


Not sure if the supply could be adjusted for the GC.

Colin

[Optical]

What do big PA amps usually use as their psu's?
i always thought those big amps used switching psu's..
there must be some good practicle alternative to using a transformer...