7 replies to this topic

[Brathering]

So, after find out that the noise in my last efx-circuit comes from the "wally-test-psu" I use for prototyping it's time to build one by myself.

Searching the web for a while, it's look like the simplest solution is to go the voltage-regulator-route like this:

tonepad-pedalpower.pdf


So, before I start building I want to ask, any experience with LM317 based PSUs here?
Better solutions known!?



thanks in advance
alex

[Hawkeye]

Hi Alex,

The LM317 works great (if you want "uneven" voltages, because you can adjust it with resistors or pots)! (I use one to bring down the voltage for my FPV video goggles from 11-12V to 6.5V).
For "standard" voltages, e.g. exact 9V you can also use the 78XX (here 7809) Regulator, they are also very easy to use, you just need two small capactitors with each one and are ready to go...

Bye,
Peter

[jojjelito]

Hi,
The issue with the LM 317/337 is that they require more external components, but: they have lower ripple than the fixed voltage regulators. If you're really picky this is what you want

Edited by jojjelito, 01 July 2012 - 15:07.

[m00dawg]

I love building PSUs so going the DIY route here will be fun and get you what you want. But, if you would rather spending time building something else, you could simply by a linear regulated PSU like this one. I think that is the exact one I use for my sammichFM and modded NES in fact.

[Brathering]

@Hawkeye:
I see, I should have make it more clear, the question was not about LMxxxx in general, that should we all know from our midiboxes, it is more about specific PSUs with the 317 and diodes for (bridge-)rectifying as in the PSU linked above - but thanks anyhow! :-)


@jojjelito:
Yeah, that's the point why choose this one! ,-)


@m00dawg:
I've several 08-15-wallys here, all with the same problem.
It seems that some switch-mode-circuit is present in all of them, okay for a midibox but absolutly not for (guitar-)effects without additional filtering.
I've learn it the-hard-way a few days ago! *lol*

Edited by Brathering, 01 July 2012 - 22:22.

[m00dawg]

@m00dawg:
I've several 08-15-wallys here, all with the same problem.
It seems that some switch-mode-circuit is present in all of them, okay for a midibox but absolutly not for (guitar-)effects without additional filtering.
I've learn it the-hard-way a few days ago! *lol*

Thus my suggestion to use a linear PSU like the one I linked to which is not a switch-mode (but is a wall-wart).

[Brathering]

It was just an idea about the switch-mode because several wallys (stable, unstable, transformer, switchmode) fail in the efx-circuit, with a 9V-bat everything is fine.
Before I buy a wally like mentioned by you I think I'll go the diy-route and be shure that it work as it should, but thanks for ya reply! :-)

[m00dawg]

It was just an idea about the switch-mode because several wallys (stable, unstable, transformer, switchmode) fail in the efx-circuit, with a 9V-bat everything is fine.
Before I buy a wally like mentioned by you I think I'll go the diy-route and be shure that it work as it should, but thanks for ya reply! :-)

No worries. I like building PSUs myself - always a fun route to go! Just wanted to point out there does exist and off the shelf solution should that not pan out or you wanted to spend time building something else.