Octavia

[Jacob]

Hey guys,

I have a question about the Octavia.

Here is the schematic: http://fuzzcentral.ssguitar.com/octavia/octaviaschematic.gif
(The schem is the original version with positive ground)

My question is which side is the primary on the transformer? Is it the diode side or the other side?

Also, are power supply's the same as a battery, meaning with +9v and -9v? I want to try hooking up the DC jack backwards, so I can still use a standard power supply even though this circuit is positive ground.

Thanks,

Jacob

[Jacob]

Anyone?

Jacob

[Greybeard999]

Batteries don't supply +9v and -9v as this would be an 18 volt spread. It's +9v and 0v, zero being ground in most circuits. Your power supply's output is the same as a battery (maybe a few volts higher depending on load). Using a power supply to power positive ground pedals gets tricky, especially when more than one pedal is in use because what is ground on one pedal is positive 9v on another........... usually causing a short circuit.

I have had luck using a "battery replacement" type power supply, the ones with a battery snap attached in a positive ground pedal, and a separate standard power supply for the other pedals. Beyond this I don't have any experience with this.

[Jacob]

Okay, I built the circuit with the schematic above.

I used a board from tonepad.com, and reversed the polarity of all the elec caps and put in different transistors, so it would be positive-ground. After putting it all together, it doesn't work (as usual). I get no sound at all when it is engaged, though I found nothing wrong with the wiring, soldering or anything like that.

How can I check the transistors to make sure they are working?
I used all carbon comp resistors if that makes a difference. I put in the transistors in the same orientation as shown here: http://www.tonepad.com/getFile.asp?id=116, even though that is a negative-ground version. I matched the E, B, and C pins on the board to the ones on my transistors.

I have no idea what the problem is, so any help is appreciated.


Jacob

[diggum12]

You did use PNP transistors for q2 & q3 right?  Man all I can tell you is get a cheap meter like the Harbor Freight ones to test your transistors.  Always socket them too.  Swap them out and see if it's still happening.  Then build yourself and audio probe. 

[ppatchmods]

what type of power supply are you using? also, is there a diode(usually a 1n4001 or a zener) in the power path?

[Jacob]

I actually got it working. It doesn't work when the board is in place, but when I hold the board in a certain position it does work. I think that I might have broken a wire, or broken some of the strands in a wire.

Jacob

[Paul Marossy]

I actually got it working. It doesn't work when the board is in place, but when I hold the board in a certain position it does work. I think that I might have broken a wire, or broken some of the strands in a wire.

Jacob

Yeah, that sounds like a good possibility.

[Jacob]

Hey guys,

I'm just starting to fix this up. How would I hook up a battery to this since it's positive-ground?

Jacob

[Paul Marossy]

Check out a positive ground fuzz face schematic for help with this. Basically your positive terminal on the battery becomes ground. You have to make sure that you have the rest of the circuit is switched around so that it works properly. But that is no guarantee that it will work after you do all those things -- read the post by R.G. here: http://www.diystompboxes.com/smfforum/index.php?topic=44955.msg327858#msg327858

Good luck!

[Jacob]

Any of you guys know of someone I can send this Octavia to who might be able to fix it?

I couldn't find a broken wire, so I rewired the whole thing. It still doesn't work after that. I don't have the experience and knowledge to know where to check things and how to check things.

Jacob

[Paul Marossy]

I don't know of anyone. RG Keen says that converting positive ground circuits to negative ground doesn't always work. Maybe that's the case for your build?

[Jacob]

Well, mine is actually positive-ground.

Jacob

[Paul Marossy]

Well, mine is actually positive-ground.

Jacob

Oops... got it backwards. I think the same thing applies to converting a negative ground circuit to a positive ground circuit, it doesn't always work.

[Jacob]

Hey,

I'm still working on this off and on. I recently reversed the caps and power to make it negative ground. I put in two MPSA18 for Q2 and Q3, and I put a 2N6519TA in Q1. Since it still is not working, should I try different transistors? Is the 2N6519TA the right version of PNP transistor? I know the wiring is good and there are no solder bridges.

Jacob