General Guitar Gadgets Rangemaster Positive Negative Help

Started by mattpas, April 02, 2008, 01:01:32 PM

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mattpas

I am building a General Guitar Gadgets Rangemaster and am going to use the OC44 from Small Bear.
I have searches through the forums and am still confused.
Which layout is the best to follow.
It will always be powered with batteries.
So should I build the PNP Positive Ground or PNP Negative Ground?

R.G.

Do yourself a favor. If it will always be powered with batteries, do not even consider negative ground. Do it positive ground.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

rossowj

Quote from: R.G. on April 02, 2008, 02:08:04 PM
Do yourself a favor. If it will always be powered with batteries, do not even consider negative ground. Do it positive ground.

why?

petemoore

  For one, the track record. Experiences of noise, oscillation, other 'intractable' [fixable by conversion to 'normal' PS scheme] problems.
 
Convention creates following, following creates convention.

rossowj

not to hijack the thread or anything but...

so if youre powering the neg RM with a psu you wont have these issues?

petemoore

so if youre powering the neg RM with a psu you wont have these issues?.
  Nope, but I know what my power supply is, and that I have a -gnd. RM, and that tested against the almightily quiet and 'very DC like' [ripple free] battery, no discernable difference were found, mileage varies.
  RG's Spyder article...put an independant, regulated, floating 9VDC source as PS for the RM, then compare that to a battery noise-wise, should be about the same.
  Other than that I've noticed differences worth noting using various daisy chains and adapters to power other pedals and the RM, with RM being about finickey [concerning PS ripple on DC] as any of them.
Convention creates following, following creates convention.

gigimarga

If you want to have ground you can build it using a germanium NPN instead of the PNP, inverting the electrolytic capacitors too.
I've done that for me, using an AC127, and it sounds very good.
I don't hear any difference from another one that i've built using a germanium PNP (an OC76, if i'm remebering well...).
But, if you're sure that you will always power it by a battery, listen to the R.G.'s advice: positive ground :)