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Greetings from Cajah’s Mt ????…
Just finished assembling the Super Drive 70. Seems to be working ok- switching, controls, etc.- and effects are functioning as they should.
Problem is, there is a loud distorted hum, like you get from a poorly grounded guitar. I believe that this is the case here, I just don’t know where to start in running it down. I switched between a couple of different power supplies, so I don’t think that’s the problem. The hum is present even in bypass mode.
A little help would be much appreciated…
Double check the continuity of ground on all your cords.
After that, I’d continue troubleshooting by just plugging in the pedal to the amp and power up the pedal – no input cable or guitar to the pedal. Make sure there is no hum when the solo pedal is engaged or bypass. If it hums there, try a new cable between pedal and amp. If fresh cable doesn’t solve the hum (if it’s there), then there is an open ground somewhere in the pedal.
If no hum with just the pedal connected & powered, go ahead and plug in the guitar and check in both bypass and engaged modes. If hum, swap guitar cable. If it still hums, the problem exists with input wiring inside the pedal. Check the grounding continuity inside the pedal.
If all the pedal’s internal grounds exhibit continuity, the cables are known good, and the pedal still hums, teach the pedal the lyrics. 😉
More importantly, please let us know what find after checking the above.
Cables are good. Hum is ever present.
I’m not sure about the T-S connections on the I-O jacks. The picture of the full layout doesn’t clearly show (at least in my opinion and experience) which tab is which.????
It’s the only thing I’m not sure about otherwise as I have gone over everything several times and no joy.
Here’s a picture of the mess, (the honkin’ green caps are the only 220n’s I have on hand and checked out within spec since they were pulls).
Also, I did deviate from the wire colors slightly in that the (DC) Grounds on the switches are Black instead of White… as God intended ????…
For y’all’s entertainment…
I’m baaaack ????…
Welp, I chucked the dice and swapped the wires on the I-O jacks. This did help with a lot of the noise that was plaguing the box, but not all of it. Still, it’s an improvement! ????
Except, now the Fuzz section don’t work at all. ???? yeah… bummer, huh… ????. I will go back over everything, check for bad solder joints, stingers, gremlins, etc. Hopefully, it’s something simple… like me ????.
I don’t know if the pics that I included above will help, but, sing out if you see anything suspect.????
Another thing, the BOM called for 2N5089’s… those, I don’t got…
2N5088’s, I do got, so I used’em. Problem or no?
Also, is there any particular reason why I can’t seem to be able to get any of my 2n5457’s to bias correctly. I use the called-for trimpots, but I haven’t been able to get the voltage down past 7 volts or so… ever. This is flingin’ a damper on my choosing any builds that call for these chips in the future.
Thanks again for your support… ????
????STOP THE PRESSES!!!! HOLD THE PHONE!!!! ☎️
I done figgered it out!!! ???? ???????? (I know, I’m as surprised as you are ????…
Anyways, turns out that I made the rookie-est of mistakes…
I actually trusted the voltage output printed on the wall wart I was using. Yeah, I know… ????
Just because 9v DC 300mA is printed on the case… DON’T YOU BELIEVE IT!!!????
This lyin’ dawg of a transformer was putting out more like 15v!!! I don’t have to tell you how unhappy that made all those little components. ????
Dug out a known, reliable Digitech power supply, hooked it up, and now I have a truly kick-a$$ distortion machine! ????????????????
Another lesson learned (hopefully)… ????
Thanx, kind sir…
I admit that I’m of the “If all else fails, read the manual” school of mechanical endeavors with a minor in Hard Knocks, but, every once in a while, the blind squirrel makes out ok ????️????…
Maranatha
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