Some of these voltages looks odd. Pin 4 is ground so it should be 0v. Pin 5 is quite low, should be closer to 4v. Pin 1,2,3,6 and 7 should be closer to 4v as well. looks like a ground issue to me. Start of with check the jumper that runs between pin 4 of the op amp and and row C.
Also check the resistore After the diode at the voltage input. Sure you have 390 ohm? Maybe you have 390k?! In case, remove It and jumper It, it's not essential. Pin 8 must get the same input voltage.
I must have had a bad capacitor in there or something. I checked all my resistors, knifed it to shreds, etc. and ended up rebuilding it. My seconds attempt fired up right away!
Sounds great, but getting some weird behavior - with the 'Burn' (tone) pot at max, the signal completely cuts out. I've tried a couple of w20Ks and the behavior is the same. Any suggestions?
Tried three different ICs (one pulled from a working Screamer build), and the resistors measure spot on (470r and 15k) - no difference. Going to try a B20k next (since I tried all my W20ks).
So, no B or C25k on hand - so I put back the W20k (measured at 19.75k or thereabouts) and put a 47r resistor inline with lug 3 - seems to solve the problem with the tone at max. I could arc it over cols 13 & 14 for now...
Build this one and sounds awesome :) I didn't bother with the correct taper for the tone pot - after playing for a bit I realized it was going to be always dimed, so I just ditched it ahah. It's a fat and loud tubescreamer :) Thanks for the layout
Built this one. Sounds frickin awesome. Its hellishly loud and aggressive, a nice, even more in your face tubescreamer. Perfect for both your sludge and tighter riffing needs.
But is it sounds so aggressive like the demos on youtube? It's a soft clipping with LED overdrive circuit style, but in the demo it sounds so dirty even at low gain setting, and almost fuzzy at high gain setting.
I built one some time ago. It's aggressive. I hate screamers but love this. The Burn control is the secret sauce. Make sure you use the proper taper. It doesn't sound like a tube screamer to my ears. Even if it technically is. It's much more "amp like". (I was just messing with mine a couple days ago after not playing it for a long time). Love Black Arts....especially the Pharaoh.
Initial build was a failure but the 2nd time was a charm (still working on my soldering skills). Fuzzier than a tube screamer but tighter than a fuzz. Great pedal! Thanks for uploading!
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ReplyDeleteson of screamer!?
ReplyDeleteYes it is, with some values changes, i took this info on Pedalpcb forum and matched with google's pics.
DeleteI built this one up and triple checked everything. I'm getting a very gated distortion out of this one.
ReplyDeleteHave you meassured your voltages? These could give an indication of the issue....
DeletePower supply: 8.82v
DeletePin1: 3.12v
Pin2: 3.3v
Pin3: 3.13V
Pin4: 1.01v
Pin5: 1.25v
Pin6: 6.6v
Some of these voltages looks odd. Pin 4 is ground so it should be 0v. Pin 5 is quite low, should be closer to 4v. Pin 1,2,3,6 and 7 should be closer to 4v as well. looks like a ground issue to me. Start of with check the jumper that runs between pin 4 of the op amp and and row C.
DeleteSorry, my computer sent before I was done typing up my previous post and it had some errors in my info. I'll check the grounds out later today.
DeletePower: 8.8v
Pin1: 3.12v
pin2: 3.3v
pin3: 3.13v
pin4: 0.1v
pin5: 1.01v
pin6: 1.25v
pin7: 1.43v
pin8: 6.6v
Low voltages there...I would doublecheck the values of the two 10k resistors right to the op amp. They regulate the voltage reference for the op amp.
DeleteAlso check the resistore After the diode at the voltage input. Sure you have 390 ohm? Maybe you have 390k?! In case, remove It and jumper It, it's not essential. Pin 8 must get the same input voltage.
DeleteI must have had a bad capacitor in there or something. I checked all my resistors, knifed it to shreds, etc. and ended up rebuilding it. My seconds attempt fired up right away!
DeleteI built it and it works great👍
ReplyDeleteDone mine too
ReplyDeletehttps://ibb.co/7xD6wPn
https://ibb.co/s3nsJk0
Another winner enclosre!
DeleteSounds great, but getting some weird behavior - with the 'Burn' (tone) pot at max, the signal completely cuts out. I've tried a couple of w20Ks and the behavior is the same. Any suggestions?
ReplyDeleteHmm, not sure. You could try an another IC and double check the value of the 470ohm eesistor connecting to the wiper of the tone control.
DeleteTried three different ICs (one pulled from a working Screamer build), and the resistors measure spot on (470r and 15k) - no difference. Going to try a B20k next (since I tried all my W20ks).
DeleteYeah my 20kw pots do the same thing I give got them from tayda
ReplyDeleteThis is wierd. Do you gyus have any 25k pots to try out?
ReplyDeleteMy 20kW pot worked fine, it is an Alpha, not from Tayda, though...
Yeah but not any W taper I'll try a B taper when I get back home from work..I liked the response of the b20k taper better
ReplyDeleteMy W20s are from Small Bear. Will try a B20 and B25 and report back.
ReplyDeleteI tried b25k and it works and doesn't cut the signal but the sweep is garbage
ReplyDeleteSo, no B or C25k on hand - so I put back the W20k (measured at 19.75k or thereabouts) and put a 47r resistor inline with lug 3 - seems to solve the problem with the tone at max. I could arc it over cols 13 & 14 for now...
ReplyDeleteI tried another 20kw pot and it works fine
ReplyDeleteGood!
DeleteIt seems like this one is quite sensetive to the tolerance of the 20kW pot...
Build this one and sounds awesome :) I didn't bother with the correct taper for the tone pot - after playing for a bit I realized it was going to be always dimed, so I just ditched it ahah. It's a fat and loud tubescreamer :) Thanks for the layout
ReplyDeleteBuilt this one. Sounds frickin awesome. Its hellishly loud and aggressive, a nice, even more in your face tubescreamer. Perfect for both your sludge and tighter riffing needs.
ReplyDeleteBut is it sounds so aggressive like the demos on youtube?
ReplyDeleteIt's a soft clipping with LED overdrive circuit style, but in the demo it sounds so dirty even at low gain setting, and almost fuzzy at high gain setting.
I built one some time ago. It's aggressive. I hate screamers but love this. The Burn control is the secret sauce. Make sure you use the proper taper. It doesn't sound like a tube screamer to my ears. Even if it technically is. It's much more "amp like". (I was just messing with mine a couple days ago after not playing it for a long time). Love Black Arts....especially the Pharaoh.
ReplyDeleteThanks, maybe I'll put it on my breadboard.
DeleteInitial build was a failure but the 2nd time was a charm (still working on my soldering skills). Fuzzier than a tube screamer but tighter than a fuzz. Great pedal! Thanks for uploading!
ReplyDelete