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Home › Forums › Help/Technical Questions › bad stone phaser troubles
the deal:
found me a broken bad stone phase shifter and im thinking of repairing it.
1st:
its the version with the bizarre head graphic (v1 maybe. 1975), but unlike any photos found on the net theres a knob not a switch to control the ‘color’. is this the previous owners modification or is it a genuine thing? it doesn’t seem to alter the sound at all.
2nd:
i’ve replaced all the circuits and the pedal is somewhat functional. the effect sounds ok by it self but when i chain it with other effects there is a loud humming noise instead of the phasing when activated. is this a power supply related issue? and if so what kind of a supply do i need?
(currently using 9v 300mA minus on the center)
and 3rd:
thanks a million in advance for all of yous.
If I remember correctly that pedal requires an 18v supply. I can’t access my schematics at the moment so don’t do anything till you hear back.
Could you post some pics and pot codes?
Your pedal is likely a transitional unit using the earlier chassis and the later circuit, which was 9V.
The earlier units used a dual power supply (+9 and -9) so there wasn’t an adapter option.
If it’s using the old 1/8″ plug used on vintage units your adapter should be +9 with a positive tip. That might be your problem.
pot values / codes:
rate: 1377640 YL7989, mounted on the board
blend: 1377646 XM2148, mounted on the board
color: lin a 100k, not mounted
is there a schematic to be found?
thanks thanks thanks again
Yep, definitely a 2nd version board in a 1st version box.
Schematic here: http://filters.muziq.be/files/schematics/eh_badstone.gif
Anyone have a gutshot like the ones above for the v1 Bad Stone? I just had one palmed off on me that’s dead, and I’m trying to figure out whether I should keep it and try to fix it or return it to the seller.
It’s got one blown electrolytic and two loose wires before I can even start to think about what else might be wrong with it.
In fact, mine has three nasty looking trimmers soldered onto the board. Are they stock or has this idiot modded it?