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ARC Effects gamut

Started by LeroyP, September 21, 2015, 10:28:01 PM

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LeroyP

Hi All

I'm trying to build an ARC effects Gamut and it's not quite sounding right.

From all I've read it's just a Rangemaster clone (with the newer version having a charge pump).
So i read RG Keens excellent guide. Built it and biased it at 7 volts as per RG keen's doc, but it doesn't sound like the gamut. I even used PIO caps and all.

There are images on the web that show the insides. I can't id the transistor used (i'm using a AC128) and it seems to contain 5 resistors and a trim pot for the 68k bias resistor. The original design only has only 3 resistors (which would equate to 2 resistors and a trim pot). The resistors aren't for the charge pump because the older version doesn't have a charge pump but still has the extra resistors). I've even tried magnifying and sharpening the web images to try and work out the resistor colour codes but to no avail.

I've checked all over the web and can't find any schematics or layouts for it. I've checked other Rangmaster variants like the java boost etc.. and they all seem to be just a normal rangemasters with switchable/variable input caps.

Does anyone own one that they can check what's going on?
Does anyone know what the extra resistors are/do/values?

The Brett Kinnman YouTube demo sounds fantastic and i don't want to hand over $220 for a modified Rangemaster especially as I've already got the parts.

Thanks
Leroy