Help Troubleshooting GGG 6-Band EQ

Started by studiostud, June 10, 2009, 12:16:29 AM

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studiostud

Hey guys,

I finished populating and wiring a 6-band EQ from GGG and I'm having trouble getting it to work.  Currently there is no sound exiting the PCB.  I've poked around with an audio probe and here are some of the results:

1) the signal gets weaker across the first 100K resistor after the input.

2) The signal is present at pin6 of IC1 (TL074) and present at Pin7.  Once it leaves Pin7, it's split in parallel between the 250k trim and a 10k resistor.  Once it hits that 10k resistor, the signal drops dead.  I've swapped out the resistor 4 or 5 times with no change.  What else should I be looking at.  Could it be a problem with the TL074?  Are those ICs pretty susceptible to heat damage? The reason I ask is because I didn't have any 14-pin sockets so I soldered them directly to the PCB.  I'm pretty quick though so I can't see it being a problem unless those chips have a reputation for being overly heat sensitive. 

Any other ideas?



Builds Completed: Big Muff. Fuzz Face. Tube Screamer. Rat. Crash Sync. Harmonic Jerkulator. 6-band EQ. Rebote 2.5. Tremulus Lune. Small Stone. Small Clone. Microamp. LPB-2. Green Ringer. Red Ranger. Orange Squeezer. SansAmp. MXR Headphone Amp. Bass Fuzz.

studiostud

let's give this a good ol' bump to start the day! :icon_rolleyes:
Builds Completed: Big Muff. Fuzz Face. Tube Screamer. Rat. Crash Sync. Harmonic Jerkulator. 6-band EQ. Rebote 2.5. Tremulus Lune. Small Stone. Small Clone. Microamp. LPB-2. Green Ringer. Red Ranger. Orange Squeezer. SansAmp. MXR Headphone Amp. Bass Fuzz.

kvb

heat can definitely be a problem

gotta' use sockets

I even fried a chip that was in the socket (because I forgot to take it out) while I was making some changes.