How to do Single center tap/bridge regulated supplies?


2002-11-29 5:41 am
Hi all,

I have a broken amp with a good preamp section and I want to replace the amp section with a gainclone.
It has a huge tranny with +/-40AC and only one center tap. This gives +/- 55V DC output. Is there any good circuit to drop the voltage down to below 35V?
Note I don't want to take apart the tranny to get 2 CT.

I had looked at Pedja site (Thanks Pedja for the info) and there is a nice discrete circuit. But I don't know if it will work with single bridge +/- supplies.



2002-11-29 5:41 am
Thank you, guys. I only know the basic electronics, so a switch mode is a bit out of the question.

The secondaries are 94Vct (1A), 74Vct (3.75A) and 15Vct (1A). The 15Vct is for the preamp section.

I wanted to use the LM3875 with +/-35V.
Guess I will use the LM3886 with +/-45V. Now that's only a 10v drop.

Can anybody tell me if Pedja discrete supply work with some modification. thanks.
Hypex modules can theoretically run on 42v

ABS Max continuous voltage for general audio amplifier applications:
LM3886TF, 37v
LM3875T, 40v
LM1875, 31v
And, at slightly beyond this point you can use fans and/or add about 4 ohms resistance in series with the speaker output.

These maximum voltages aren't something to do on purpose, but rather. . . just a note on "where" that "too far" might be.

Also, too-high voltage necessitates higher powered input or higher gain setting, and at some point either can be a mess.

Hey, is that 15v a single (15v AC) or is it a 15vct (as in 15+15 AC)?