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Tube Amp Common Mistakes
- Thread starter mydog213
- Start date
Also, sometimes, the center alignment pin will break off and stay stuck in the socket. Like the 2nd tube from the right in this pic.
Pull the tubes up slowly and make sure that pin is coming up with it, or put a little dot with a marker/whiteout or something to make sure you put it back in the right way. Get the wrong pins in the wrong holes and you're in for a very expensive repair.
Pull the tubes up slowly and make sure that pin is coming up with it, or put a little dot with a marker/whiteout or something to make sure you put it back in the right way. Get the wrong pins in the wrong holes and you're in for a very expensive repair.
grinx said:
Not an old wives tale. You can see where finger prints are. Lightbulbs are more susceptible to this damage. You'd see them brown in that spot and then fail.
Anyway for what we pay for these what does it hurt to grab with a soft cloth?
My tube tech uses a rubber gripper designed for the purpose.
http://www.ampeg.com/pdf/SVT-2PRO.PDF
I cooked my SVT-2pro a bit by running it at 8ohms. I now know that Ampegs aren't really fond of 8ohm loads.
But you know, this user manual never really says NOT to do it. I suppose it is implied because it makes mention of 2ohm operation and 4ohm operation, but not 8ohm operation. The only time it mentions 8ohms is when telling you how many cabs to use to make a 2ohm load.
I'm not saying that it's Ampeg's fault. But i have noticed other manufactures be very specific in their manuals about what kind of impedances to use or not use. GK comes to mind. And it may be on me again because coming up in the 90s- most of the amps I came into contact with were solid state and big thing to worry about was not going BELOW a certain impedance. I didn't know there were amps that had a maximum impedance they could handle.
So to stay on topic with this thread-
Always make sure you don't go ABOVE the recommended impedance. and check for sure REGARDLESS of the ambiguity of the manual. good luck!
I cooked my SVT-2pro a bit by running it at 8ohms. I now know that Ampegs aren't really fond of 8ohm loads.
But you know, this user manual never really says NOT to do it. I suppose it is implied because it makes mention of 2ohm operation and 4ohm operation, but not 8ohm operation. The only time it mentions 8ohms is when telling you how many cabs to use to make a 2ohm load.
I'm not saying that it's Ampeg's fault. But i have noticed other manufactures be very specific in their manuals about what kind of impedances to use or not use. GK comes to mind. And it may be on me again because coming up in the 90s- most of the amps I came into contact with were solid state and big thing to worry about was not going BELOW a certain impedance. I didn't know there were amps that had a maximum impedance they could handle.
So to stay on topic with this thread-
Always make sure you don't go ABOVE the recommended impedance. and check for sure REGARDLESS of the ambiguity of the manual. good luck!
They sell Invalid Link Removed that allow you to safely keep using 8-pin tubes with broken locator pins. Unfortunately, the adaptor costs more than some tubes.
I'm not sure if this is old wives' tale as well, but...
I was always told to set the amp to standby for a couple minutes before shutting off the power. So, whenever I finish a gig, the first thing I do is put the amp on standby while I pack up and unload everything else. My amp and cabs are the last things to come off the stage.
I was always told to set the amp to standby for a couple minutes before shutting off the power. So, whenever I finish a gig, the first thing I do is put the amp on standby while I pack up and unload everything else. My amp and cabs are the last things to come off the stage.
don't bother with that, just turn the amp straight off leaving the standby on, this drains the voltage
Mr. Foxen
Commercial User
I remember jamming with a buddy of mine outdoors in near-freezing temps.....his tube amp seemed more comfortable than us
but ALWAYS give a tube amp proper warm up and cool down times... especially when dealing with cold temperatures or wild temperature swings like going from your cold car to the stage, or from the stage to your cold car. We once played a show in january where a guy in the other band walked offstage with his tube amp and loaded directly out to his car and as he came out the door it sounded like firecrackers as all his tubes straight up exploded!
I've heard people who claim to be techs (I wouldn't know) say they have noticed improved tube life with warm-up and cool-down procedures. Especially in extremes (Sub zero night in a trailer for hours - taken out of a cool case and powered on full in a hot room within a few minutes... apparently bad).
Seems to make sense (all glass is stressed with rapid changes in temperature).
Seems to make sense (all glass is stressed with rapid changes in temperature).
Mr. Foxen
Commercial User
The most important thing to remember about tube amps is,
Always lift with your knees, Not your back!
And get one of these
Link Removed
Always lift with your knees, Not your back!
And get one of these
Link Removed
Although that's maybe 4 cents worth of plastic there, $10 isn't too awful bad. Probably stick with my marker though.
Absolutely. Aviation engineers designing engines etc. can testify to that. The type of metal and the conditions limit lifespan.
If you're running vintage tube amps, letting the tubes cool down prevents you (okay, me) from burning your hand or arm on hot tubes as you wrap the supply cord and tuck it inside the amp. Every night.
According to the 6550A tube data sheet, there are six of these in the SVT, the hottest temperature on the glass bulb when the tube is operating, is 250 degrees C or 482 degrees F.
That's a lot of heat.
That's a lot of heat.
If you don't like the sound of your properly performing tube amp, don't replace the power tubes and think it will sound better. Even replacing preamp tubes in a crappy sounding (to you) amp may make it sound different... But IME, a different kind of crappy.
I replace tubes when they die, begin to sound bad or go microphonic. Not just because they are dusty of I have an extra $300-400 lying around.
My 1936 Gibson tube amp still has a few original tubes. They can last a long time if treated properly.
Wives tale question..... Does using a padding layer between amp and cab (gramma pad, sorbothane balls, etc) actually cut vibrations and extend tube life?
I replace tubes when they die, begin to sound bad or go microphonic. Not just because they are dusty of I have an extra $300-400 lying around.
My 1936 Gibson tube amp still has a few original tubes. They can last a long time if treated properly.
Wives tale question..... Does using a padding layer between amp and cab (gramma pad, sorbothane balls, etc) actually cut vibrations and extend tube life?
Mr. Foxen
Commercial User
Using a decently made cab that doesn't vibrate the head is a better call. But not vibrating the head full of glowing hot metal is definitely beneficial.
Just because tubes have sockets doesn't mean they are the main thing to replace, anything more than 15 years old is due an electrolytic cap replacing, valves may well still be fine.
