Hi there fellow music lovers. I've got an old Fender Deluxe Reverb at 100watts. It's a tube amp and for the most part it works flawlessly, however there's a problem with it that I just don't understand. Sometimes when I play the volume cuts out, sometimes right away and sometimes a little slower and the only way I can get it back to normal is either turn it off and then back on or kind of shock it by turning the volume way up and hitting the strings a bit. The cutting out of the volume is often accompanied by a strange noise I can only describe as sounding almost like frying something in a frying pan. This problem occurs seemingly at random, and naturally every time I've asked someone to take a look at it they couldn't reproduce it.
Anyone have a clue? I love the amp and I really want to use it for band practice, but this weird problem will completely ruin a song when it happens. I'll be extremely grateful for any help I can get.
There are several possibilities, but one thing that will do exactly what you describe and is enormously frustrating is if the amp is oscillating at an ultrasonic or radio frequency. It's fairly easy to identify this if you have an oscilloscope, but if you don't have one it'll make you tear your hair out trying to figure it out. It's often a tube-related problem, so replacing tubes, swapping tubes around from position to position (in the case of same-type tubes) or even unplugging, cleaning sockets with a spray cleaner like Caig Deoxit and reinserting them will sometimes fix it.
By tube-related, I don't mean that the tubes are dead. Often "tube problems" are really tube contact problems, so the socket cleaning procedure is the first thing to try whenever your amp's not right. Lots of times problems that are solved by tube replacement were really fixed because pulling out a tube and plugging one in scraped out the oxide and dirt in the socket contacts. I use lots of old pull-out used tubes, and don't bother to test them first. They nearly always work fine.
Pots are bad for similarly getting dirty and cutting out. Older pots could have cleaner sprayed in them, be worked vigorously back and forth, and be restored for a while. New pots are sealed, and this won't work. They have to be replaced.
Jacks often get loose and intermittently cut out, too.
Don't even get me started about instrument cables. They cause more aggravation than anything in an amp.
"A cheerful heart is good medicine."
Thanks for the quick reply! I'm a complete idiot when it comes to the technical aspect of amps though, and I'm not quite sure what you mean by the amp oscillating. Would you recommend me to try and pull out and clean the tubes myself or should I get someone more knowledgeable to do it for me? She's a real beauty and I would hate to lose her by screwing something up. Also I'm unfamiliar with what you refer to as "pots" and "jacks" since my first language isn't english and they're probably called something else in my native tongue.
Well, I am in no way knowledgeable about electronics and amps like Ricochet, but this sounds almost exactly like a problem I've had with my Marshall DSL401. The volume will slowly fade out. Sometimes it comes back in a minute or so, sometimes not. I can turn the amp off and then on again and the volume will return. Sometimes it would work fine for hours, sometimes the volume would cut out after a few minutes.
In the case of my amp it was caused by overheating due to the EL84 power tubes that get very hot. The bridge rectifier nearby would overheat and apparently this was the cause of my volume going out. I actually found a site addressing this very problem with my particular amp.
http://www.piller.at/music/index.php?target=dsl201/index.html
I had the amp serviced about a year and a half ago and it was working flawlessly until the Riverside jam. I left the amp running for several hours and it was very hot (90+ degrees) outside. When I went to play my amp, no sound at all. Man, I was super frustrated.
Didn't feel like paying $170 for service again, so just this week I opened up the amp and went over all the solders myself. Like I said, I am no techie, but I fumble around a bit, just enough to be dangerous. Anyway, I found a few solders that looked very bad, very dull. I went over about 50 solders that didn't look so good. Put the amp back together and so far it works great. I also bought a fan I am going to install in the amp this weekend, exactly like the one shown at that site.
I have no idea if your problem is similar, but the volume cutting out is just like my amp. My amp does not make any funny noises at all when the volume returns, so maybe it is a tube problem like Ricochet said.
You might search around on sites like I did and find someone who has had this problem. That is how I found the site that addressed my amp's problem. It is a great amp when it works. :D
If you know something better than Rock and Roll, I'd like to hear it - Jerry Lee Lewis
Pots are short for potentiameters which are your volume/tone knobs. Those are the contacts Ric is talking about. the jack is the hole on the amp you plug your cable into.
"It's all about stickin it to the man!"
It's a long way to the top if you want to rock n roll!
And oscillating is the amplifier "ringing," rather like the feedback that you hear when the speaker output comes back into a mic or the guitar pickups, but happens internally and at higher frequencies that you usually can't hear. Draws off power that would go to amplifying sound. Every amplifier can turn into an oscillator under the wrong conditions. Happens way more often than most folks realize.
As for removing and replacing tubes, it's simple. The small tubes have 9 pins in the base with a gap in the circle for alignment. They pull straight out, and as long as the gap in the pins is aligned with the gap in the hole, they push straight back in. The big tubes have a plastic pin in the center of the base with a key on the side that has to rotate to align before the pins can push into place. Really, it's no harder than replacing a light bulb. The small tubes usually have a metal shield over them that may have to be pushed in, twisted slightly counterclockwise to release it before turning it off. Some of these shields just pull straight off. Don't force anything, be gentle.
"A cheerful heart is good medicine."
Thanks for the help and quick replies guys. It's strange that no music store "tech" I talked to before had any idea what my problem might be. I'll try what has been suggested, hopefully it will work. If it doesn't I'll probably pay for getting it serviced and hope that magically solves my problem.
Hmmm,
Frying noises and volume drop.
I suspect after replacing tubes and cleaning pots I would suspect that you might have some capacitors beginning to go bad.
Also, see if you have a 5U4 tube in the amp, this means that you have tube rectification, I usually don't have problems with these. But if you don't, you might have solid state rectification with diodes, when these get hot, they might start to break down and quit working. This is probabily what was going on with Wes' amp.
They are neither hard or expensive to replace.
A quick and dirty way to check if you are having problems with a microphonic tube is to turn on the amp, no guitar jacked in, and tap (Lightly!) each tube and see if one makes more noise than the others, this might let you know where a problem is. Tap with a pencil or, better yet, a chopstick to prevent getting shocked.
And as usuall, BE CAREFUL! There be very much lightning inside any tube amp, no matter how big or small. (250V to 500V!) Even unplugged, the caps in the amp will store this power for a surprising amount of time.
If you are not sure what you are doing, take it to a qualified amp tech!
When I die, I want to go peacefully in my sleep like my grandfather, not screaming......
like the passengers in his car.
Well cleaning the tubes didn't help, at first I thought it did because it worked beautifully during 2 long jams together with a drummer at near max volume. It screamed, it wailed, it sounded simply wonderful but nearing the end of the second jam it finally gave up. The volume once again became really low but this time accompanied by a burning smell (!) and a slightly distorted noise, and turning it off and back on did nothing. I haven't had the opportunity to test it again to see if it will spring back to life once it has cooled down but the burning smell makes me doubtful it will. So I suppose my only option now is turning it in for a service? I'm thinking it deserves one seeing how old it is and I don't know if the previous owners ever took good care of it.
Burning smells are bad. Take it to the tech.
"A cheerful heart is good medicine."
2nd to what Racetruck was saying.
Those CAPS can keep and hold enough juice in them to kill you....yeah, KILL YOU!!
Be very careful when poking around in the guts of one of those things.
Research is what I'm doing when I don't know what I'm doing. - Wernher Von Braun (1912-1977)
Listen to Ricochet, if electronics make odd smells when they are used then something is very wrong.
Steve-0
I brought it in today for repair and a full and well deserved service. The guy said it was probably just a busted tube and I will most likely have it back again in a week or so. Hopefully it will sound even better than before then. Thanks for the help guys, I'll keep you updated. :)
I hope it does turn out simple, inexpensive and well! :D
"A cheerful heart is good medicine."
Just heard from the tech and it's safe to say I'm feeling pretty relieved right now. According to him my amp was in excellent shape despite its age and the only thing wrong with it that he could see was that two tubes were on the breaking point. So if all goes well I'll have it back in a few work days (the time it takes for the new tubes to arrive) and will only have to pay a modest fee for 1 hours work and 2 replacement tubes. :D
