Amp technician Patrick McKeever offers a few thoughts on those mysterious tubes.
Most serious guitarists today prefer to use tube amps. People have long struggled to explain just why they sound so much richer and expressive than solid state amps, but to most ears they just do. But tubes need to be replaced like the oil and filter in your car. How often? Chicago Amp Works’ Patrick Mckeever tackles that question below.
Heat and vibration are what wear tubes. If you rehearse or gig several times per week, you can expect about a year max before the power tubes become noticeably rattly/microphonic and or sluggish and dull sounding. The pre-amp tubes generally last about twice as long and can be changed every other time the power tubes are changed.
Some players are not as picky about tone or rattles but should know that waiting too long to replace power tubes can be costly because when a power tube shorts, it can damage other components like resistors and output transformers.
Back in the day when the best tubes were made here in the USA, tubes could easily last for several years with little noticeable change in tone or reliability. But even the best of todays tubes will rarely last more than a year or two with heavy use. Pretty good motivation for a yearly “Amp Check”!
Chicago Amp Works stocks a wide variety of high quality J/J preamp and power tubes. If you need something different, just let us know and we’ll get ’em. Groove Tubes, Mullard, Tung-Sol, Electro-Harmonix, Sovtek… you name it.
Hi Patrick i have a bugara 1990amp head with 4- 5881 tubes i wou lihe to have you change them with up grade matched tubes also re bias
Roy,
Bring it on in. Pat just did the same with another Bugara that turned out great!
Hey Patrick,I have the jcm slash model 2555 head,the sound fades in and out,I replaced the tubes a couple years ago,I pulled them out,to check them out,reinstalled,powered it up and a fuse blew,then noticed one of the tubes broke,I would like to have you look at it.I was also wondering if a mod is possible for that amp.thanks in advance.
Patrick,
I have Fender DRRI. When I purchased it two years ago, it would crackle and pop once it warmed up. GC said it was bad pre-amp tubes. So they gave three brand new ones. It’s still made the noise. Took it to the store, and the tech there could nt get it to make the noise, of course that never happens ;-( anyway, I took the V1 out and went right down the line, and it’s not the tubes. Could it be a loose solder, or bad circuit? Thanks
Does the volume control affect the crackling or does it stay consistent? That information can help us track where in the circuit the problem lies. Ultimately it could be a connection problem like a cold solder joint, or it could be a bad small component like a resistor ( though likely not a larger one like a transformer.) Presuming we can get the sound to happen here, we shouldn’t have trouble finding it on the oscilloscope. If you’re in Chicago, bring it by any time. If you’re not local, feel free to ship it here. Remove the tubes and pack separately if you do that!
Hey Pat!
Quick question. I got my hands on a Soldano Hot Rod 50, single channel version. In shipping sadly the tubes were shattered and upon replacing them noticed the OLD power tubes had 16.5 written on them. Guessing thats what the owner had them biased at, seems a bit cold. Would that impact sound greatly? Thinking of bringing her by for a once over anyway. THANKS.
Sorry to take so long in seeing your comment/question. I’d recommend emailing Pat directly at info@chicagoampworks.com if you’re still wondering about this amp. He’d be happy to help!