+/- Power supply

[rosshenning]

I'm wanting to take a stab at doing a stripboard layout of a pedal circuit, and I am a bit confused with the power requirements on the circuit in question as it has a split requirement needing +9V and -9V.  I'm wondering how this would be accomplished with a regular pedalboard power supply providing 9VDC?  Any suggestions would be appreciated.  See the circuit in question here: http://www.6v6power.ru/inf/Wah_AutoWah/MU-TRON%20III%20Auto-Wah.jpg

Also, is there a piece of specialized software lvlark uses for his layouts, or it just an drawing program?  If I get this to work, I'd be happy to share, and I would like it to use the established standards.

[tjdracz]

Hi there. You need a charge pump to output booth +/- 9v. Something simple like this will do:
http://www.sabrotone.com/wp-content/uploads/2011/01/Charge-pump.gif
For layouts, we use DIYLC. Mark uses version 2 and Miro works with version 3. Both can be found here: http://diy-fever.com/software/diylc/
IMO, v2 makes much nicer layouts

[IvIark]

There's a negative voltage inverter layout here:
http://tagboardeffects.blogspot.co.uk/2012/05/negative-voltage-inverter.html

[rosshenning]

Awesome...I figured there had to be something like this available, and I've used the 7660S before in the Katana boost circuit, so I have a few on hand.  Thanks for the info!

[rosshenning]

Appreciate it!

[Freppo]

I have a question regarding voltage inverters.
Is it possible to use two or more voltage inverters together for more avaliable current?
I have a circuit (guess which one.. :)) that draws alot.. about +/- 30ma (60ma total)
And I would like to use it with a 15v/5A single supply that I already have
I'm going to box it together with the Tiny Giant amp
Or would I be better off building a dedicated supply?

cheers / Freppo
ps. Sorry to hijack the thread

[IvIark]

Yes you can.  Or use an LT1054 which can handle up to 100mA

[Freppo]

Thanks!
I will report back on the Tiny Giant build later today

/ Freppo

[IvIark]

I wouldn't use it with the Tiny Giant though.  The amp has a quiescent current of up to 120mA, and that will obviously increase when the amp is being used, and I don't even know what it's likely to go up to.  It's too much unless you use a bank of the charge pump IC's I reckon.

[Freppo]

Yes, but I'm powering the tiny Giant directly from a 15v/5A power supply (an old toshiba laptop supply) and I want to use the same supply for the Subsommander Guitar Synth, so that what I will use the voltage inverter for since it requires a dual supply. I read that the Tiny Giant draws just under 1A in use, so there should still be plenty of juice left for the Subsommander. I will use a 12v regulator + a TL1054 for the negative voltage for that. Should be ok I hope..

I'm not having any luck with the Tiny Giant build though.. :/ I check my build and your layout against the schematic a bunch of times and I can't find any faults, so I'm suspecting I got a bad poweramp chip.. The regulator part is working as it should and puts out 11,6v. I get sound, but it sounds distorted/buzzy.. sounds more like a synth then a guitar.. I will probably build it up again and change the layout alittle bit, just to make more room for the chips, since there is not enough room for the heatsinks. I never thought I'd say so, but your layout is just alittle bit too small :P

cheers
/ Fredrik

[IvIark]

Aah right I see.  I ignored you mentioning negative voltage and thought you were using it as a charge pump for the supply with you mentioning the little giant.

If it's not working check the pins of the amp IC.  I couldn't get a clear pic of the pins showing the numbering and the datasheet is fairly useless because it's 2D, so you can see the 4 shorter and 3 longer pins, but because the diagram had no depth you couldn't tell which row of pins would be closer to you, so the orientation is unclear.

[Freppo]

I think your pinout is correct, can't see how it could be any other way. I put it up on a breadboard just now  and used another chip but I still have the same problem.. I get sound, but it's distorted, not very loud and very noisy.   I think I better read the Tiny Giant amp thread though and see if anyone else experience the same problem. Maybe it's my powersupply or there is some error in the schematic.