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Problem with uproar, at a loss :(

Started by Ang3lus, February 23, 2011, 01:02:39 PM

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Ang3lus

tried debugging for 2 days now, changes i made are

used bat41 instead of 1n34a
used c8 = 10n
c9 = 27n
tone knob = 10ka wired in reverse
switch for diode clipping = on/on spdt (could this be the cause for all my problems ?)


getting a really bassy sound and almost no gain at all.

tried changing diodes for 1n34a (after that changed to bat41)
tried changing ics (both)

missing a SPDT switch atm, so could this be the problem i'm getting almost no gain ? it's only a little bit distorted, volume seems ok, but almost no gain.

tried changing c8 and c9 to original and suggested values, but still remains the same

checked for bridges, it seems i have a bridge between ic chip number 2 (JRC4580) legs 1 & 2, also 6&7.

could those be the culprits ? I have no way to check cause i can't seem to remove the solder even with a solder sucker, it stays on the board and still gives me a connection between those legs, are they supposed to be bridged or is this my problem ?

all answers are appericiated

jkokura

So, the IC bridges aren't bridges, those are supposed to be there.

As for the cap changes, they could be a part of the problem, but they're probably having more to do with the bassiness more than the gain issue.

Not having a switch is probably your biggest gain problem. If you just don't have a switch in the spots, you won't get any clipping at all, which would result in very little or no gain. You need to either install a switch OR you need to use a jumper and connect one of the sides to the middle pads where the switch belongs. Until then, none of the diodes are connecting to ground and you won't get any distortion.

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals

Ang3lus

Thanks for the clarification.

I am using a SPDT on/on switch for the clipping, wired like in the photo, but still hardly any gain in both positions.

I got a DPDT on/on/on switch laying around, any chance i could wire it to suit ?

jkokura

You could use that switch but it won't fix the problem. Are you sure your switch is working right?

You've got a problem somewhere in your clipping section, but it could be as far back as the IC. I would start double checking the resistor values and try switching the ic. And also check you switch is working right. Also check the diodes are soldered correctly.

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals

Ang3lus

#4
could it be due to the fact i'm using color changing leds ? and not the painted leds ?


double chekced all values on everything + changed diodes to 1n60/1n270/1n34a, still i'm getting low gain with a really bassy sound. cap values are fine, changed ic also, any ideas ?

Ang3lus

came back after a few hours, for no reason, the pedal is ok now, except i get too much "woofiness", is there a way to fix that somehow ? sounds like there's a blanket over the pedal