- This topic has 6 replies, 3 voices, and was last updated 5 years, 6 months ago by
.
-
Posts
-
I’ve replaced the 4k7 resistor and reflowed multiple times. The signal is good from input thru IC pins 1,2 and 3 and C6 up to one side of R8, but nothing on the other. Some faint signal on IC pin 7 and R11….here’s the voltages and pics:
IC Pin – voltage: 1=4.69, 2=4.69, 3=4.26, 4=0, 5=4.67, 6=4.66, 7=4.66, 8=9.33
I agree. That would kill the gain from that opamp stage.
Thanks much for the input!!! I’ll rectify that….
That fixed it.
Thanks to Billy and Wilkie for your help. I feel a bit silly as I looked at that resistor multiple times and could swear that was a 220k….oh well, lesson learned — take a picture and zoom in to inspect your populated resistors!!
Just for info Greg, you may already know this but with less resistance you increase negative feedback and decrease the op amps gain factor in this case x 1000
220K would be gain 46
220R would be 0.046
And that would obviously affect what’s going back via the negative feedback loop from output pin 7 to – input pin 6 and throw it all out
I’ve told this one before, I’ve built 100s of pedals yet still managed to put not 1 but 3 incorrect resistors in a delay build, checked multiple times but still took a while to find them
We all do it………
Many times, at least yours was only 1 colour band out
Helpful and encouraging info there – I appreciate your enthusiasm to share, Thanks!
- You must be logged in to reply to this topic.