Preamp or Power amp tube problem - tech question

[herrball]

OK Guys, tube tech question here......

On my DC-5 I am hearing a strange out of phase sound and an individual note fades out. ( right at the tail end of the note) I noticed recently doing some recording with my iso box and after switching to my main cabs, I did notice it there as well so it rules out the iso box and phase issues there.
I have new Ruby 6L6's in but have not changed the preamp tubes in the 2yrs that I've had the head and I bought it used so the tubes could be original. I just am concerned it may be more than tubes. need them either way but didn't know if a tranny could cause this type of problem.
BTW - it happens with both types of pups : EMG and passive pups.

Any thoughts would be appreciated

 

[Restless Rocks]

Go ahead and change those preamp tubes, particularly the Phase Inverter tube. Also make sure your pickups aren't too close to the strings on your guitar.

 

[herrball]

I'll be on the tube store site tonight. thanks.

Oh, and the pups height is good, I don't hear this problem with my other amps. they're EMG's so I don't need to set them so they are kissing the strings. ;-)

 

[herrball]

So my tubes from Doug just came in today. I changed V1 and V2 to new JJ ECC83S' and the phase inverter to a new Sovtek. The reverb tube was new as of a new reverb tank a yr ago and I kept V3,4.

Gotta tell ya, just changing v1/2 at the front end of the gain stage made a noticeable difference in harmonics, sustain and also brightened up the tone a bit. Kinda like new strings. ;-) I also could roll back the lead gain which I had been running at just a notch above 7 and pulled it back to 6. still the great sustain but notes were clearer.

Thanks for the help.