8 output 9V psu (yes another one)

[Fender3D]

..I don't think Fender3D uses a huge transformer like that...

I hook this http://www.musikding.de/product_info.ph ... 94b55b6376


I don't feel the need for a fuse either, the adapter should be protected already,

anyway @ Zokk:
the fuse should block the max current needed and/or the max current available, whichever occours first.
The bridge rectifier is rated 1A too here.

[Zokk]

I opted for LM317LZ since none of my pedals draw more than 100mA

I just was referring to that.
But sure 800 mA seems a bit overrated. You can adapt to whatever maximum rate your power transformer is up to, since the main goal of such a fuse is to protect this component (and ideally the lm317s before they burn). The ideal solution being a fuse for each output, and an additionnal one in front of the power transformer, but this takes quite a lot of room.

ok that makes sense. But there seems to be another option for a full protection. I was told to use triacs to do that, but it's also very complicated for me.
I've found a very good info about that, but it's on a french only website:
http://www.sonelec-musique.com/electron ... triac.html

And anyway in most of cases the fuse on the mains should do the job I think.

@ Fender3D, yep that ac adapter should have its internal protection.

[MicMicMan]

I don't feel the need for a fuse either, the adapter should be protected already,

Unfortunately I've opened several times my DC adapters, and even in AC transformers like the one you linked, and I never saw any kind of protection such as triac, polyswitch, fuses, etc. Not even varistors. Even the expensive Eventide "9V" DC adapters are just a transformer, a diode bridge and a capacitor. I'm not saying the one you linked does not include any kind of protection, I just don't know. But that's something I've never seen yet.
Maybe the BOSS PSA adapter is an exception, since I know it to be quite well filtered (I never opened it).

(the sonelec website is an incredible ressource, yes... I'm quite glad to be a native french speaker )

[Fender3D]

You're both right Zock and mic
but triac protection is before the trafo.

I'm worry about fitting a trafo into a 1590B or BB or whatever,
I feel it's dangerous even while protected...
(you know the math: pedals = modern music = beer (or other) then beer (or other) + 220Vac = )



PS
many adapters have a thermal protection disconnecting the mains

[Zokk]

Hey I've seen a mistake in the files I've posted previously, that's not a big deal but the PSU won't work without this mod if you decide to keep the LED resistors onboard (check the LM317 datasheet to see why ).
On the old layout you'll see I've put the LED resistors to ground instead of the 9V rail
I've seen that when building my second psu, where I couldn't wire the LEDs close to the outputs and solder the resistors directly onto the positive pin of the LEDs... sorry for that.



Here is the update, also changed the LED resistors value with 820 ohm to limit power sucking to 8mA per LED:

[aquataur]

I don´t see a schematic, folks. Am I missing something?
Thanks,

-helmut

[Fender3D]

I don´t see a schematic, folks. Am I missing something?
Thanks,

-helmut

A simple rectifier, with a filter and a regulator, multiplied by the outputs needed shouldn't be a concern, expecially if you'd willing to build it yourself.
Said that, go to http://www.electronics-lab.com/articles/LM317/ , calculate your needed voltage and multiply the schem. shown there

[Zokk]

You're right Fender3D, this psu is very simple, everything is in the LM317 datasheet. But there are many schematics online (as I said in the first post I've taken bits of the Ken Stone CGS66 psu). I've also added a 1uF cap to each output to get more stable voltage... very minor mods added to the datasheet schematic.

It is also important to know that R1 should be very low (some datasheet say less than 1K, but the ideal value is around 200ohms).

[coldcraft]

I'm working on a PCB for the Weber transformer. I'm keeping it documented at madbean's forum, and I will probably finish the project in September.

http://www.madbeanpedals.com/forum/inde ... pic=956.45

[Zokk]

If I read correctly this Weber transformer outputs 11V?
If so it won't be enough for the LM317's... but as you may know the 317 are far more clean than the 78XX.
I wish I could have found the same type of transfo with toroidal design and 12V secondaries.

[coldcraft]

If I read correctly this Weber transformer outputs 11V?
If so it won't be enough for the LM317's... but as you may know the 317 are far more clean than the 78XX.
I wish I could have found the same type of transfo with toroidal design and 12V secondaries.

11V AC (RMS) would rectify to ~14.5V DC

Xvrms*sqrt(2) - Yvdrop=XvDC

Although, I did not know about the 317 being "cleaner" than 78XX. Is that in terms of noise on the output or output voltage drift or what?

[Zokk]

The LM317 has very low noise and the regulation is very precise, in some application it will definetely make the difference (high gain/impedance circuits for example). I'm still a noob so I cannot develop on the subject really.
I know the 78/79 are very common because they imply one or two component less than in a LM3XX circuit, they have lower specs (more noise and ripple) and are more expensive than the LM series...

Maybe someone here have the real knowledge to tell you what are really the differences in technical terms.

edit: do you know the trick to have alternate voltages from a fixed regulator?
I've read something which told to use zener diodes with 78XX, for example if you have a 7805 and you want 9V output, then you'll add a 3,9V zener which will give you: 5V + 3,9V = 8,9V... that could be cool for your design if you want to add the "dying battery" option on some outputs.

[Ice-9]

Here's my 3D modules for KiCad http://www.wizardinside.it/foto/schemi/modules3d.zip.
Still missing some capacitors and PCB jack sockets... I'll add them whenever I'll find the time to draw 'em..

Thanks for these, they work perfect in Diptraces 3D PCB view, very grateful especially for the 3PDT footswitch.

[Fender3D]

Thanks for these, they work perfect in Diptraces 3D PCB view, very grateful especially for the 3PDT footswitch.

You welcome