Dude, I'm afraid to even look at a capacitor!Originally Posted by jim p
If it comes down to modifying the circuitry the way you describe, then I'll take it to someone like you that knows what an ohm is.
Dude, I'm afraid to even look at a capacitor!Originally Posted by jim p
If it comes down to modifying the circuitry the way you describe, then I'll take it to someone like you that knows what an ohm is.
See my photos at: micknewton.smugmug.com
Where the he..............hec is DR. TUNG:
"I love being alive and I will be the best man I possibly can. I will take love wherever I find it and offer it to whoever will take it... seek knowledge from those wiser and teach those who wish to learn from me."
"Develop your talent, man, and leave the world something. Records are really gifts from people. To think that an artist would love you enough to share his music with anyone is a beautiful thing."
Duane Skydog Allman
You come to a point in your life when you really don't care what people think about you, you just care what you think about yourself." - Evel Knievel
Well thought it might help. On the chance changing a tube could have an effect changing V3 may have an effect. This is used as a cathode follower for the clean signal to the reverb and the output. If its cathode impedance was higher then normal it could cause a problem like this. Hope this helps.Originally Posted by Mick
Okay, I tried swapping out all of the preamp tubes, one at a time.
No joy...
I'm about 99.999% positive that it's not a microphonic preamp tube causing the feedback.
So, I pulled out the reverb tank...
...but I didn't see any obvious problem with the tank, like a loose wire, broken spring, or whatever. So I cleaned the RCA connectors where the cable goes into the tank, then put it back in the amp.
I still have nasty feedback when the reverb is turned up.
Could the reverb transformer be causing the feedback? Is there some way to test it to see if it's within specs?
What should I try next?
See my photos at: micknewton.smugmug.com
I think Jim P gave a fair evaluation of his prognosis after perusing the schematic of the amph. I would suggest taking it to an amph tech to confirm (or disprove) his theory as to the cause of the feedback.
Guitars
Wilburn Versatare, '52 FrankenTele(Fender licensed parts), Fender USA Roadhouse Strat, Fender USA Standard B-bender Telecaster, Agile AL 3000 w/ WCR pickups, Ibanez MIJ V300 Acoustic, Squier Precision Bass,
Amps
Ceriatone Overtone Special, Musicman 212 Sixty-Five, Fender Blues Jr., Peavey Classic 30, Fender Super Reverb, Traynor YCV-40 WR Anniversary w/ matching 1x12 ext. cab, Epiphone SoCal 50w head w/ matching 4x12 cab (Lady Luck speakers), Avatar 2x12 semi-open back cab w/ Celestion speakers
Pedals
Digitech Bad Monkey, Digitech Jamman, DVM's ZYS, Goodrich volume pedal
Pay someone that knows what they're doing to fix it, eh? That's quite a concept you got there!Originally Posted by oldguy
Nawt yet... Methinks I'll try to verify that all the existing components are within specs before I throw in the towel.
I checked the tubes.
! checked the tank.
What's next? Maybe pull the chassis and have a look inside? How do I do that without electrocution? How do you drain capacitors safely? Lick the ends?
See my photos at: micknewton.smugmug.com
Some prednisolone for your tongue
No other idea than the tubes, the tank and the tech - sorry.