SOLVED Rodent problem

[Idroj]

Hi! And this is the 3rd and for now, last faulty pedal I build. A RAT that, now that I remember, I got from Tayda, pcb included. I built it, and similar to the Blue Breaker, I was able to enjoy it for a few seconds and then nothing.. I took it out of the enclosure, used this system that this youtube explained to narrow down if the problem is in the pcb board or the wiring, and it only worked for a moment, sounded amazing, but just for those few seconds. Now that I fixed 2 pedals this week with your all your help, and learning lots of things, I guess that a good place to start would be a good cleaning, right? I'll also have to try to unplug some pads and re-wire the 3PDT switch board...

Should I reflow anything else or just start the IPA toothbrush cleaning and put it all back together?

If I get to fix this one, after having fixed the other 2, this will be a HUGE VICTORY! Thanks everyone for taking the time to help out!

 

[Chas Grant]

The only mod you would have to do is moving the 30pF comp cap. On the LM308 it goes from pins 1 to 8. On the NE5534 it looks like it goes from 5 to 8. It looks like the NE5534 can get a faster slew rate than the LM308. You just have to lower the cap value from 30pF down to 0. At 0 it says its slew rate is 13. Just remove the 30pF cap and solder a ceramic cap on back of board between pins 5 and 8 of the IC

 

[perfboarder]

@Idroj Somehow the pict isnt load on my browser. That Mr Jack Orman. Info here, but i think its in amz-cd too.

@Chas Grant Thanks, will try for next build. Just trade my ContouRAT by @Chuck D. Bones with new Joyo American for my nephew. Thanks You Chuck.

 

[Idroj]

I received the LM308s in the mail today Will swap it on the soon and report!

 

[Idroj]

Sounds fantastic with the LM308s! I don't know exactly what changes but it improves in general. Sounds more "expensive" a little more body. The other chip sounds a little brittle compared to the 308. Nice! Thanks for the advice! Now I have a fat rat

 

[Chas Grant]

Sounds fantastic with the LM308s! I don't know exactly what changes but it improves in general. Sounds more "expensive" a little more body. The other chip sounds a little brittle compared to the 308. Nice! Thanks for the advice! Now I have a fat rat

I'm one of few who sees both sides of the old op amp debate. Some circuits sound the same no matter what op amp you put in it, while others sound better with certain op amps. The Rat is one that sounds better with an LM308N in it. I believe it has to do with the external compensation cap and it controlling the slew rate. I have also noticed some chips handle high gain circuits better than others, and the 308N handles the high gain of this circuit. What ever it is, the 308N definitely sounds better. I'm glad you like it.