Tweed Champ Has No Top End

[ozspawn]

Help. I have a '64 Champ in mint condition that has a major tone problem: the treble has gone away, leaving only a dull and lifeless low to mid range tone. The tone is clean: there is no scratchiness, buzz or hum. There is just no top end.

I have replaced both the 12AX7 and the 6V6 tubes, with no change in tone. I have switched out the original CTS speaker for a new Kendrick, with no change in tone. I have even played the Champ through the speakers in a '70 Vibrolux Reverb (a Ragin' Cajun and a Copper Head), with no change in tone.

Does anyone have any ideas about what could cause the top end of the tone to go away?

Thanks.

[ozspawn]

Sorry, I forgot to mention that I just installed new caps, with no change in tone.

Thanks.

[abro163]

If a coupling cap is leaking DC it can do that

[brad347]

A cathode bypass cap that has gone open can also do that.

Of course, if it's an original tweed with the Astron paper-in-wax caps, those leak DC a lot, so the leaky coupling caps wouldn't be far behind on my list of things to check out.

[Blue Strat]

A '64 wouldn't be tweed, so...which is it?

Does the treble/tone control work at all?

[ozspawn]

Thanks for the suggestions, guys. I'm going to check out those caps right away. It sounds like a quick fix.

Blue Strat, you know your Fender amps. Which is it? Both. The '64 is a tweed amp covered in tolex. You know the story: Fender ran out of tweed in '64 so they used tolex. It has no tone controls, only a volume knob.

Thanks for your help guys. I'll let you know what happens.