Dear All
As the title states i would like your advice on where (in this forum or anywhere on the internet) i could post for Guitar Amp tech help for my DRRI. Thank you in advance.
For those who would bother with the extra info read a brief description below:After reading on a hurry some advice on the internet ''I did something stupid'' . I tried to eliminate the popping sound that the vibrato foot switch was making when turning on and off on my modified DRRI by wrongly connecting a 220pf cap to the white and the grey wire of the vibrato/reverb foot-switch.
After that turned the amp on and quickly realized that:
- The vibrato effect stayed always on, no matter what (even when i removed the cap and disconnected the switch)
- The Power tubes started to glow bright red hot (something is going really bad)
I closed immediately the amp to prevent extra damage.The current state of the amp is:
- Power tubes get red hot when opening the standby switch
- Sounds comes from the amp normally (with the exception that Vibrato is always on)
- Reverb is working
- Controls are working
- No sign of burnt or damaged internal components(visual inspection)
The amp was biased properly components are all new (caps, transformers, pots, tubes, reverb tank, switches and sockets) and was working great up until now.
I have built some pedals and amps in the past and i know that you should never do something you are not sure or does not understand completely (especially in a hurry) but it seemed like a simple fix with not much risk at the time :'( :'( :'( and i feel really really bad that i damaged my favorite amp with my stupidity.
P.S. .The closest amp tech is located 400km away so i think i have to do it by my self. My soldering skills are up to the task but i don't have a deep understanding of of the amp circuit (just a basic understanding of how some components can affect the signal path).
EL34/Hoffman amp forum. Those guys will butter your bun and flip your pancakes at the same time.
I ll go and make a post right now. I will keep watching this one as well. Thanks for your reply it cheered me up a bit
I don't know much about amps, but this is the schematic of your amp?
https://www.thetubestore.com/lib/thetubestore/schematics/Fender/Fender-65-Deluxe-Reverb-Schematic.pdf
Looks like what you did was put a cap across the reverb signal and the vibrato oscillator. That seems like a poor idea! (sorry). Perhaps the cap was meant to go between the white wire and ground? Do you have a link to where you saw this info?
You are right. The cap was meant to go between the white wire and ground BUT i wrongly connected it there.
I thought that the cap was charged and released the charge as i was switching on and off and that it cooked some component in the vibrato section that had as a resault to have it always on. But the power tubes is a mystery for me
Looks like they are taking care of you over there! Good luck.
Quote from: HamSandwich on March 05, 2019, 06:29:41 PM
EL34/Hoffman amp forum. Those guys will butter your bun and flip your pancakes at the same time.
These guys not only did they butter my bun and flip my pancakes simultaneously...but they also solve the problem in a couple of replies after posting my voltage readings. Thanks a lot!!! ;D ;D ;D
For the record it was a burnt resistor (r69) that caused a problem in the bias voltage thus red plating the output tubes. On top of that you cant even hear the footswitch now.