i've built a Pearl octaver clone but i have some problems and i really could use some help
First of all the upper octave does not exist...when i max the upper octave pot i only hear normal signal coming through
But the most important problem with my build is that along with clean signal , normal or octaved, i hear a distorted signal in the background. I can still hear it with all the volumes down...
i've checked layout ,wiring 3 times but everything seems ok
I'd check the bias voltages on the IC's for the distorting thing.
Have you adjusted the trimer for the uper octave, the sweet spot is when you get the lowest volume.
What layout did you use?
/Krister
8.9 on pin4 of tl074s
4.44 (vg)
i already checked them and swaped ics but the problem remains
i tried removing ics one at a time and i found out that when i removed the 2 ics giving signal to pin 6 of one of the 4013s there was no distortion (and ofcourse no octave effect)
Ok, what fets are you using?
I got 2SK30 for the octave downs in mine, and a LM324 is feeding the 4013:s, dont know if that matters but......
Did you check that "vg" voltage on each IC?
/Krister
i used all j201 and checked for pin compatibility for the layout
for ics i used tl 074 but also lm324 and got the same result
vg measured the same on all ics
damn can't debug it
any help guys?
Quote from: changes on October 23, 2007, 01:22:57 PM
8.9 on pin4 of tl074s
4.44 (vg)
i already checked them and swaped ics but the problem remains
i tried removing ics one at a time and i found out that when i removed the 2 ics giving signal to pin 6 of one of the 4013s there was no distortion (and ofcourse no octave effect)
So you did not use the layout I made? I used a single LM324 feeding the 4013:s.
Just one idea, check the grounds of the unused pins of the 4013:s, compare to the schematic at gaussmarkovs site http://gaussmarkov.net/wordpress/circuits/octaver-clone/ (http://gaussmarkov.net/wordpress/circuits/octaver-clone/)
I'm just guessing but an inproper grounding here could be an issue.
An oscilloscope could be helpfull in debuging it.
/Krister
Any solution? I see this is an old thread... I used the layout by gaussmarkov, foud here httpgaussmarkov.networdpresscircuitsoctaver-clone
I have exactly the same problem. For ICs I used 3x LM324, 1x TL072, and 2x HEF4013BT.
Also, I've tried many different Jfets, started w J201, then 2n5457, 2n5952.... The only time I got no dist in background was when I used BF245c, but the signal was very weak (low volume)...
After a while, I "solved" the problem ;D. The bass bleed was gone when I installed the new pots (the old ones were probably pretty pretty bad), and the hiss was gone when I plugged in the battery. I use regulated power supply, but anyway, there was a little bit of hiss. Now, I remember that I had a similar problem with the FTM few years back...
OC7 is in my pedalboard now, and it rocks as hell ;D
Regards,
Marko