Hi all, kinda new here. I've spent most of the last couple of year's on upright and moving into electric bass some. I just bought a SVT classic w/ 4x10 HLF cabinet at a local pawn shop. It plays and sounds good compared to other bass amps in the store. The head is made in St. Louis and the Cab in China, I think. All the controls function, lights etc. One of the 6550 tubes has a "burned" spot on the inside of the tube glass, so I'm guessing it is blown. Various Mfg.'s replacement tubes are readily available. What is the best brand and do I need to go ahead and replace all the tubes (6) 6550's, (2) 12AU&'s, and (1) 12AX7 or just replace the one? Any help or advice is greatly appreciated! Thanks. I'll be playing a Fender American Standard Precision V through it and mostly Americana type music.
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Re-Tubing an Ampeg SVT Classic
- Thread starter meddings
- Start date
Don't jump to the conclusion that your tube is burned out- many tubes will get that exact discoloration you described after being played for a few years. If it sounds good, then the tubes are most likely fine. If you're looking to replace your power tubes anyway, make sure you get a matched set. There are at least 45 thousand threads on here where people voice their tube preferences.
If it is a white cloudy looking discoloration, you have a problem. Otherwise, as Hodgy said tubes get discolored with use. If it seems to work it should be fine.
Yea.....most tubes have a metallic discoloration to them. If you can see the tube element inside glowing when the amp is on, your tube is just fine. If you want to get into the "tube race", by all means go ahead and spend hundreds of dollars getting all the tubes to optimize your equipment and sound. And then try more tubes. Have fun!
In another perspective, you can just replace tubes as they burn out or they cause you a problem with the performance of the amp. I burned out a power tube and I simply replaced it ($25) and re-biased the amp.
In another perspective, you can just replace tubes as they burn out or they cause you a problem with the performance of the amp. I burned out a power tube and I simply replaced it ($25) and re-biased the amp.
If the tube is white inside and you cant see it glowing at all then you probably should replace it. Or have a tech look at the amp.
The power tubes are all you should have to replace most likely. My svt (from around 1990) still has the original 12au7's in the power section.
The power tubes are all you should have to replace most likely. My svt (from around 1990) still has the original 12au7's in the power section.
Remember that the new outputs will need to have the bias set to suit them. They are not plug and play.
White and cloudy could mean an air leak. A tech can test the tube in the amp. Chances are they will find that it isn't working. The SVT will continue to work with one power tube shut down. It just isn't good to operate it that way as the other two good ones will be strained and it will shorten their life. Your new set will fix that.
