I may have missed something but I looked over the schematic and didn't find any obvious errors. Check the usual suspects and use a knife between your tracks and search for bad joints etc. I was tempted to try this one myself. But man it's a pretty dense layout. Anyone could make an error building a larger circuit like this. Best of luck. Keep us posted.
Went over the schematic and the vero and found a missing 220p cap from 18I to 18L. I also changed that 10k to a 68k while I was at it.
The bigger problem is I was wrong about which channel is the problem. It's the clean channel that is not working. As in at all. I unsoldered the dual gang and connected to two different 100k pots. The pot for the clean channel is doing absolutely nothing. Checked with an audio probe and the signal sounds great going into pin 5 of the TL074 but is very weak coming out of pin 7/into pin 3. Almost nothing comes out of pin 1. So that narrows things down. I can't look at the board/schematic anymore so taking a break for a while/maybe until tomorrow
So it turns out my TL074 was the problem. Put another one in and the pedal fired right up. Sounds great - especially with the drive at 9 o'clock. So the only changes needed from the way it is currently posted are adding a 220p cap from 18I to 18L and changing the 10k resistor at the input to 68k
Built this but there is barely any gain on the dirty channel. Will continue to troubleshoot but so far not finding any errors on my build
ReplyDeleteI may have missed something but I looked over the schematic and didn't find any obvious errors. Check the usual suspects and use a knife between your tracks and search for bad joints etc. I was tempted to try this one myself. But man it's a pretty dense layout. Anyone could make an error building a larger circuit like this. Best of luck. Keep us posted.
DeleteActually, the 10K on the input is listed as a 68K but I can't imagine that being the cause of your issue. Just recalled that anomaly.
DeleteWent over the schematic and the vero and found a missing 220p cap from 18I to 18L. I also changed that 10k to a 68k while I was at it.
DeleteThe bigger problem is I was wrong about which channel is the problem. It's the clean channel that is not working. As in at all. I unsoldered the dual gang and connected to two different 100k pots. The pot for the clean channel is doing absolutely nothing. Checked with an audio probe and the signal sounds great going into pin 5 of the TL074 but is very weak coming out of pin 7/into pin 3. Almost nothing comes out of pin 1. So that narrows things down. I can't look at the board/schematic anymore so taking a break for a while/maybe until tomorrow
So it turns out my TL074 was the problem. Put another one in and the pedal fired right up. Sounds great - especially with the drive at 9 o'clock. So the only changes needed from the way it is currently posted are adding a 220p cap from 18I to 18L and changing the 10k resistor at the input to 68k
ReplyDeleteBummer, did you use a socket or did you have to unsolder the TL074?
ReplyDeleteSocketed. I learned that lesson a few years ago. No IC goes in without a socket anymore
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