Announcement

Collapse
No announcement yet.

Fender UL Twin low volume distortion.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Fender UL Twin low volume distortion.

    Fender UL Twin, was converted to blackface but owner decided he preferred the UL cleanliness. Re-mantled back to specs, voltages perfect (to the 10th!) master volume replaced etc,etc. At low volume there is distortion, either channel. Figuring it's the power stage, changed 6l6's, P.I. voltages great, screen 492v, anode 493v, drawing 35mA per tube...did keep the 100 ohm resistors for the 6.3v instead of the hum control pot...any ideas why there is low volume distortion.??

  • #2
    Did you play the amp through different set of speakers? Rubbing voice coils sound much worse at low levels.

    What does the distortion look like? Trace a signbal through teh amp and see where this distortion adds itself in.
    Education is what you're left with after you have forgotten what you have learned.

    Comment


    • #3
      Thanks Enzo, yes I tried different speakers and the same...I've been miraculously fixing alot of amps by ear and just simple test equipment, I don't have a scope...however, I did find a broken leg on the opto, and I changed the .1's off the PI tube, yet to test at higher volumes but it seems to have reclaimed it's sterile clean sound...I've converted several silverfaces with MV's to blackface, this is the first UL amp I converted and it sounded great but the owner decided he wanted that UL sound...the reversal was quite a challenge due to the schematic...I recall someone commented whoever drafted the schematic must have been on acid...

      Comment

      Working...
      X