Grateful Dead Music Forum

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 #119804  by redeyedjim
 Mon Oct 15, 2012 1:19 pm
I recently bought a pair of new/reissue MXR Custom Shop script phasers through AnalogMan: a CSP 026/handwired Phase 45 and CSP 105/hasndwired phase 90. Both were modified for true bypass, 9vdc power jack and an LED indicator. They're nice :D

The problem I have is that the phasers don’t work properly within the OBEL loop. Inside the loop, they sound very quiet and tinny, like the input signal was massively attenuated. Outisde the loop (i.e., in the cable run between the guitar and the amp) they sound fine. The signal also sounds fine when bypassed in the OBEL.

I have other phasers that sound fine within this loop: a vintage (script) MXR Phase 100, and a new EH Small Stone Nano. And no, I am not using all of these at once - they are for different projects.

Does anyone have any idea why the MXR Custom Shop phasers sound tinny and quiet when used within the OBEL, but fine when used outside of the OBEL?
 #119812  by Mosfed
 Mon Oct 15, 2012 5:31 pm
Don't know what to tell ya mate. I have a reissue script phase 90 with a led that sounds identical in or out of the loop (within reason of course).
 #119813  by redeyedjim
 Mon Oct 15, 2012 5:39 pm
Thanks - that actually helps, since it tells me that the custom shop phaers should work in an OBEL setup.

I've written to Analogman to see if he has any ideas. I sort of wonder if he could have inverted the phase of the signal when the effect is engaged (since he converted the effect to true bypass switching). It's just weird that it works outside of the OBEL but the signal is so quiet and obviously not correct within the OBEL.
 #119832  by redeyedjim
 Tue Oct 16, 2012 10:28 am
Update: I traced the problem to another pedal after the phasers, which apparently is not a true bypass despite being labeled as such. The root cause is with whatever this other pedal is doing with the signal; it has it's own buffer, which "works" but seems to kill the tone a bit at it stacks its lesser buffer on top of Mike's. When this pedal is set to use true bypass instead of its buffer, the signal falls to about 25%. It's weird, but at least I know where the culprit is.