My Rebel 30 has a odd problem , no ideas maybe you have one

thickwood

New member
Never had a problem on my 2011 Rebel 30 other than tubes or FX loop send return switching jacks needed exercising !

It started losing signal and slowly dropped the volume on channel 2 ?
Switched channels I had more volume but sound was different with less highs and midrange was weak but stronger bass ?
Then I tube tested every tube and checked jacks and switches and re-biased replacing the new Russian el84 tubes to Gold Lion el84 pair !
After bias was done I turned the controls and the volume came back only after rotating the bass control on Channel 1 ?
Next Channel 2 was working some what weak but slowly quit as the tubes got good and hot in 20 minutes !
Switched back to channel 1 and it began to get weaker sounding and a white noise hiss came on with no difference if guitar was plugged into the amp or not.

The guitar was directly in during bias and testing , but checking the FX loop no difference except it I removed only the return plug the hiss stopped !
Warming fully it gets worse and worse as it does not like running normal temperature ?

I do not like micro switch relays as the contacts are small , these are used on channel switching amps !
I had a Bugera 6160 that the signal became weak and distorted and repair shop could not find the problem but re-soldered some joints and I suspected the preamp signal was not getting cleanly to the phase inverter tube ?
That amp still is not right , but now and then it comes fully alive and like new but goes back to bad again !


All I have is questions , the new hiss showed up on day 2 of checking it out , usually a capacitor lets noise in but no caps looked swollen or problems during bias job !
I have 360 vdc on the power tube plates and set 40 milliamp DC on each per pair on both 6v6 and el84 tubes !

Any idea I can do myself please let me know ok , even if its weird or stupid sounding at this point !
I rotated a good 12ax7 after bias into 4 different preamp sockets with no change to normal !
I will replace the PI sovtek 12ax7lps tube as I have 3 balanced triode replacements for my amps !
 
It does seem like the signal is bad in the pots !
When I set the bias the sound came up stronger and better when I cut the bass up but still not near as good of a sound it had before ?
I will get to it after awhile .
Pots are a good start , hope I can access those ok ?
 
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