JAZZ CHORUS 55 / bad sound

[snowtiger]

Hello,

A few years ago, the sound of my JC55 became sometimes very distorted and ultra compressed, and at all, it was like an amplifier with 2 or 3 watts...

The amp was repaired but after a few months, the problem came back. I didn't received any explanation about which problem was involved.

I didn't use this amplifier during one year or two. The problem was away, and then once again it happened again.

At the beginning I had only some variations with the output level, and after an ultra compressed sound (a sound that you can not use to play with).

Do you think that this is a big problem or not? A new amplifier like a Cube 60 or a Peavey don't cost too much, so sometimes the price of the repair is so big that you can almost afford a new amp.

If I choose to give the amplifier to a technician, which are the points that I must keep in mind ?

Thank you for your aguments.

[drewl]

Sounds like an intermittant problem that may never have been fixed in the first place.
Possibly something in the signal chain breaking down, preventing the signal to pass or component failure, or more commonly a bad/poor connection somewhere.
I know it sounds silly, but have you tried "tapping" the amp? or hitting it slightly?
These amps were built pretty well, and if fixed properly could last a lifetime.

[DanJ]

I agree with drewl, give the amp a little tap when it goes out, see if anything changes. If you are going to bring it in for repair, you will be able to let the tech know what exactly it is doing. If it works ok for a while, then goes intermittant after it warms up, and tapping on it makes it act differently, it's a pretty easy fix and should be much cheaper than buying a new amp. Yes it does sound silly, but there is a lot to be said for "percussive maintenance".

On the other hand, those cube amps are pretty cool for the money!!!!

HTH,

DanJ

[Enzo]

Don't tap on it, ball up your fist and whack the top hard. If it won't handle that whack, it won't handle travelling to the gig either. If yuo want to be official, use a rubber mallet.

If the amp reacts to that, then something is loose. SOlder connection, jack contact, wire connecter, whatever. Turn the reverb down, THAT will make a lot of noise if you don't.

When it happens, take a spare cord and plug one end into the effects send jack, and then plug the other end right back into the effects return jack. If this restores the sound, then the return jack needs service. If there is a preamp out and powr amp in pair of jacks, try the same thing there.

As to what to tell the technician, since I are one, make sure to tell him it is an internittant problem, and be prepared to discuss how often it does it. I get things in that don't act up for two days and feel pretty good about it, only to have it crap out on day four. If the guy says it "don't work," then two days ought to tell me it does, but if he says "Once in a while it drops the volume," then I know to be parient.

Don't worry about what the technician did or didn't do last time, the tech is working on whatever the problem is NOW. A good technician never assumes any evidence from a previous tech is correct or complete. As experienced and as skilled as I may consider myself to be, if someone else works on something after me, I don't expect them to take my voltage readings or other assurances without question.

[snowtiger]

Thank you for the answers.

I will remember all of your recommandations.

Pat.

[jefbet]

I have the same problem with my jc120 first the volume went down some times wen i turn it on and some times it sounden good then i took it for repaird an the volume problem was fixt but it enden up soundin with a lot of bass and if i play true the bass pickup (neck) of my guitar it sounds badly distorded. i am guesing that the tech tath fixe it didnt replace the parts with the apropiate ones,, what you guys think????

sorry for the speling im need more practice with my english ...