big muff from positive ground to negative?

[nikosrf]

So i did the big muff pi V2 http://www.kitrae.net/music/big_muff_guts.html#WiringDiagrams and it worked. The only problem is when i have the guitars' volume off, the BMp  gives a sound like a mike feedback. In addition i don;t want to have problems with my other negative ground pedals, so  tried to make it a negative ground.
I changed the transistors, the voltage and some caps like the schematic shows, but it didn't work.

Has anyone made it? Any ideas?

[armdnrdy]

I'll say what the other people that have viewed this thread are thinking.

With all of the verified negative ground Big Muff schematics, layouts, and projects available on the net.....why don't you start fresh and build one of those?

[nikosrf]

The changes i made were according to verified schematic...

[R.G.]

So i did the big muff pi V2 http://www.kitrae.net/music/big_muff_guts.html#WiringDiagrams and it worked. The only problem is when i have the guitars' volume off, the BMp  gives a sound like a mike feedback.

It's oscillating depending on the impedance it sees at its input. This is a common problem, and is likely to be caused by ground-trace wiring or other mistakes. It could also be a lack of power bypassing inside the pedal. This makes wiring/routing issues worse.

In addition i don;t want to have problems with my other negative ground pedals, so  tried to make it a negative ground.
I changed the transistors, the voltage and some caps like the schematic shows, but it didn't work.

Read and follow "Debugging thread: what to do when it doesn't work". It's likely that there is some minor mistake in the conversion. If the conversion was done correctly, it would work.

Has anyone made it? Any ideas?

Many, many people have made many, many variants of the BMP. Probably many, many people have made the same component and/or wiring mistakes. The best idea is to follow the debugging process rather than easter-egging for ideas.

One of the most common posts here is "I've just built the Belchfire Megablaster. I did all the construction perfectly and verified it N times. But it still doesn't work. What could possibly be wrong?"

This is usually followed a few posts later by "Oh... I can't believe I did that and couldn't see the mistake."

The changes i made were according to verified schematic...

[nikosrf]

Thanks R.G.  ll try to debug..  :-)

[R.G.]

Actually, reading and following the procedures in the debugging thread are helpful way beyond just trying to debug. They expose things you'd miss otherwise because you're forced to measure and note things that you would otherwise miss.