Problems with my Fender Blues Deluxe

[JShape]

What's up guys? I've been having some issues with my 94' Fender Blues Deluxe I wonder if some of you could give me some insight on. I'm no expert by any stretch, but I have some basic generic knowledge of tube amps, just as far as how they work and what makes them sound so sweet.

I typically run the amp on the clean channel with the volume knob turned about halfway up, with my guitar running through a variety of light overdrive and other effects pedals that boost the signal slightly. I would estimate that this pushes the amp to use about 30 of its 40 watt maximum output. After the amp's been pushed for a little while, it gives a nice warm natural overdrive from the tubes that sounds wonderful.

However, recently I've had a problem with it cutting out on me. It happened the first time towards the end of about a 4 hour practice, and another time towards the end of about a 3 hour set. When this happens, the signal completely vanishes and I can't get any sound whatsoever. Both times I took the amp home, switched it on the next day, and it worked perfectly. I'm wondering if anyone else has had this problem, and if this is simply being caused by the tubes or something else in the power amp over-heating. If so, can this be prevented by simply placing a fan behind the amp. Could it be time to change the tubes? Or is this the warning sign of an imminent, more serious problem?

I realize the only way to know for sure would probably be to have a tech have a look at it, but I just thought I would get some opinions here first. Thanks for the help guys, and God bless!

[Bob Womack]

Sounds like you have a thermal problem. Of course, there first answer to all tube amp power problems is to replace the tubes and see if the problem goes away. Start with the power tubes and go to the preamp tubes next. From there, it could be a myriad of little things: bad circuit board traces or solder joints that have finally cooked to the point of failing, a circuitboard mounted jack flexing a trace or connection, components that have failed and exhibit their problems thermally. I can point you to a site that addresses many of the causes of intermittancies, but in another Fender product, the Hot Rod Deluxe. They aren't exactly the same, but you could pick through and see what you can see. That site is THE UNOFFICIAL HOT ROD DELUXE OWNER'S GUIDE.

If you have never worked inside a tube amp, please understand that there are voltages and amperages inside there that can EASILY kill you. Read up on the precautions to take and methods to bleed the power caps before attempting any repairs. We like you alive.

Bob

[JimLin]

I had a similar problem with my Blues deluxe. I'd be playing along and it would cut out (usually in the middle of a gig). Turned out with my amp, The input jack was the culprit. It was made of plastic and easily strips (several friends had similar problems). I believe Fender is STILL uses plastics jack. My amp had 2 inputs (low/high) one worked fine and the other required replacement -- cost $40 ten or so years ago.

I also had a similar problem with a Peavey Delta Blues amp ... the sound volume would drop/disappear after playing several hours. After several trips to the amp tech, they sent it back to Peavey. It worked for a while and then the problem started up again. Long after I sold the amp a Tech told me others had similar problems and he found it was linked to the use of the effects loop ... and you didn't have to be plugged in to the loop when the problem would arise. Hmmm

Anyway ... good luck.

PS. Bob ... that's a great link ... thanks!

[D. Churchland]

Check the fuse, sometimes it get's a little worn and needs to be replaced. I've had to do that a few times with several amps that my customers brought back and that was usually the problem.