+/- 12v regulated power supply review needed

[renfrow]

I've been in an apartment, away from all my heavy duty toys (table saw/drill press/etc.) and have been buying parts instead of building stuff. I'm probably going to be buying a house soon, so I thought I'd start putting together some building blocks. Using parts I already have, looking at data sheets and other plans online, here's what I've come up with for a +/- 12v regulated power supply. I think it would be more than ample for opamp based preamps. What do you think? I thought I'd get expert opinion before I applied solder to anything

Thanks!

Tom.

[luka]

Hi

I think it all looks good, no need to use MUR, 1N will do fine, I would use maybe 13 or 14 on secondary of trafo to really have good regulation even if primary in not that stable...

you could use even more simple design, with 7812 and 7912, what do you think?

[renfrow]

Originally posted by luka
Hi

I think it all looks good, no need to use MUR, 1N will do fine, I would use maybe 13 or 14 on secondary of trafo to really have good regulation even if primary in not that stable...

you could use even more simple design, with 7812 and 7912, what do you think?

The values shown are because that's what I have I bought the adjustable regulators because they were a good price, and I wouldn't have to worry about not having the right regulator (now all I have to worry about is the resistors ) I bought like 500 of the MUR for $14USD. Do you think maybe I should go with a lower voltage, 10 or 11? I have 10 of the dual 12v ($1/each) transformers, so wanted to start using them.

Thanks!

Tom.

[Eva]

You can go one step ahead and make it adjustable with two potentiometers. Sometimes you need 5V, 9V, 18V, etc... I did a similar supply many years ago allowing up to +/-24V output. It's a dirty PCB but I still use it.

[luka]

Originally posted by renfrow
I bought like 500 of the MUR for $14USD.

Huh that was cheap, wanna trade . you at this point coz you already have regulators, you "should" make them adjustable for any voltage, then you only make always the same board...

[Tahmid]

Hi,
Your circuit is fine, but with a centre tap, you could use a centre-tapped secondary as this will require only 4 diodes instead of 8. For +/- regulation, you could use 7812 and 7912. This would reduce overall parts count and make the circuit simpler.
Thanks.

[00940]

The lm317/337 are quite a bit better than the 7812/7912.

Just be careful how you lay things out on your pcb/protoboard. The sense ground of the lm317 should not contaminated by the charging current of the big caps.

I second the trimmers for a versatile supply. If you want to go for a fixed supply, you could also replace the bottom resistor for a zener+1n4148 (for rough tempco)