[moo55]

I have a 65 Twin RI. The sound of this amp is incredible! When I play at volume and thump the strings this amp is dead clear. I am amazed! When I play a chord or a note the signal is also dead clear. But, as the note or chord fades out when you hit a chord or note I noticed a distortion as the note (chord) diminishes in volume. Any thoughts woiuld be appreciated.
moo

 

[Soupbone]

1- check the cord and all connections.

2-Try another guitar, if the distortion is not there, change the pots in the original guitar, and install a new tone cap. Adjust the pick-ups as per spec.

3- change around the preamp tubes see if it clears up, get them tested and replace the bad one.(If as I suspect, the stock 1st tube is getting old change it for a good NOS one like a sylvania, youll be glad you did.)

4-Try a different speaker see if it goes away.

5-take it to a tech.

good luck wit ith.

 

[Kapo_Polenton]

1- possibly tubes being biased too "cold" but not likely if these are the same tubes. (output/power tubes I am talking about) Very possible the power tubes are on their way out.

2- You may have develloped "ghosting" due to the age of the filter caps. They might need to be changed. If they are 15 + years old, this can happen.

Take it to a tech if not comfortable with biasing or doing a filter cap job.. but try soupbone's suggestions first and then go down the list to consider these if need be.

 

[moo55]

THanks I will try your suggestions and let you know how it works.
moo

 

[Wild Bill]

THanks I will try your suggestions and let you know how it works.
moo

Absolutely I would have the bias checked. Fender tends to set the idle current kinda low at the factory. This means they are less likely to have a tube failure during warranty, when it's THEIR problem!

Also, bias should be checked and set with every change of output tubes! Someone may have changed tubes without re-setting the bias, making it a total crap shoot as to whether the setting is correct for the new tubes.

You may be hearing what is called "crossover distortion", caused by too low idling current from a wrong bias setting.

I don't have much confidence that anything besides actually taking measurements and doing real tech stuff will be positive but at least it will give you something to do and hey, even Al Bundy got lucky once in a while!:smile:

:food-smiley-004:

 

[Rong]

I would first eliminate the guitar from the list of suspects. Does it do the same thing with another guitar.

Next step check the tubes...swap around preamp tubes. No better look at the power tubes and biasing.