Dumb question about new tube installation.....

[moronmountain]

So I bought a matched quad of KT88's from the Tubestore. I got my last set from them as well, and the new ones have the same rating number for their "perfect pair" system. Anywho, does the tubestore "pre burn in" their tubes, or do I need to leave my amp on for a day or???????

 

[Inquisitor]

I remember reading somewhere that they do on a technical system, but its been a while since Ive needed new ones and they have changed the site since I last used it. Ive always let em burn for a while when I get them new (and sometimes after Ive been using them overnight )

 

[charveldan]

Foolish not to get them biased for $40 bucks, specially with monster sized tubes like 88's.

Get a bias.

Have no idea about TS practices.

 

[Anonymous]

what amp do you have? can you bias yourself? tubes/amps generally drift in bias over time.

 

[moronmountain]

what amp do you have? can you bias yourself? tubes/amps generally drift in bias over time.

VHT/Fryette Ultra Lead. The way I understand it is that the tubes' bias drift, not the amps? At any rate, the amp has something else going on. Even with all new tubes, including replacing each pre-amp tube one at a time, the amp is still loosing volume after only playing on the lead channel for more than a few seconds at more than bedroom level volume. It's gonna have to go see someone. And it's not going back to the last guy who told me it only had a bad power tube, and there were no other issues. I know for sure at least the V1 was bad and the V4 was getting noisy.

 

[Shark Diver]

And it's not going back to the last guy who told me it only had a bad power tube, and there were no other issues. I know for sure at least the V1 was bad and the V4 was getting noisy.

If it was just a tube why did the last guy not fix it? Then he would know whether that was really the problem.

It's like a doctor giving you antibiotics. They don't really know what's wrong, antibiotics just normally cover 99% of it. Tubes are the same way.

 

[moronmountain]

And it's not going back to the last guy who told me it only had a bad power tube, and there were no other issues. I know for sure at least the V1 was bad and the V4 was getting noisy.

If it was just a tube why did the last guy not fix it? Then he would know whether that was really the problem.

It's like a doctor giving you antibiotics. They don't really know what's wrong, antibiotics just normally cover 99% of it. Tubes are the same way.

Becuase he wanted to charge me $500 for "premium Sovtek" KT88's, and would only do it if I let him "redo" every single solder joint in the entire amp, and he was really weird. I had to say no.....

 

[Shark Diver]

And it's not going back to the last guy who told me it only had a bad power tube, and there were no other issues. I know for sure at least the V1 was bad and the V4 was getting noisy.

If it was just a tube why did the last guy not fix it? Then he would know whether that was really the problem.

It's like a doctor giving you antibiotics. They don't really know what's wrong, antibiotics just normally cover 99% of it. Tubes are the same way.

Becuase he wanted to charge me $500 for "premium Sovtek" KT88's, and would only do it if I let him "redo" every single solder joint in the entire amp, and he was really weird. I had to say no.....

I never understand how guys like that stay in business. He obviously wasn't listening to what you wanted, or didn't care.

 

[Anonymous]

what amp do you have? can you bias yourself? tubes/amps generally drift in bias over time.

VHT/Fryette Ultra Lead. The way I understand it is that the tubes' bias drift, not the amps? At any rate, the amp has something else going on. Even with all new tubes, including replacing each pre-amp tube one at a time, the amp is still loosing volume after only playing on the lead channel for more than a few seconds at more than bedroom level volume. It's gonna have to go see someone. And it's not going back to the last guy who told me it only had a bad power tube, and there were no other issues. I know for sure at least the V1 was bad and the V4 was getting noisy.

bias can drift in time if the amps components drift, ie, bias resistor. also, if it's a trim post bias, it can vibrate to either direction believe it or not.

generally though, output tubes drift.

which preamp tubes you running?

v3 in your UL is a cathode follower slot. be sure you're NOT using an EH or tung sol in that slot...those tubes in a cathode follower position can die fast.

 

[moronmountain]

what amp do you have? can you bias yourself? tubes/amps generally drift in bias over time.

VHT/Fryette Ultra Lead. The way I understand it is that the tubes' bias drift, not the amps? At any rate, the amp has something else going on. Even with all new tubes, including replacing each pre-amp tube one at a time, the amp is still loosing volume after only playing on the lead channel for more than a few seconds at more than bedroom level volume. It's gonna have to go see someone. And it's not going back to the last guy who told me it only had a bad power tube, and there were no other issues. I know for sure at least the V1 was bad and the V4 was getting noisy.

bias can drift in time if the amps components drift, ie, bias resistor. also, if it's a trim post bias, it can vibrate to either direction believe it or not.

generally though, output tubes drift.

which preamp tubes you running?

v3 in your UL is a cathode follower slot. be sure you're NOT using an EH or tung sol in that slot...those tubes in a cathode follower position can die fast.

I originally had the following in there, just as factory recommended. V1 Sovtek LPS, V2-V5 all Chinese. I just replaced them with the following, still all factory recommended. V1 Tungsol balanced triodes, V2-V4 all Chinese select, and V5 Chinese select/balanced triodes. And I of course I had new Sovtek KT88's in there as well. The amp was quieter, punchier, gainier, and better than it has ever sounded for about a minute, until I tried to SLIGHTLY push it at all on the lead channel for about 30 seconds, then it did the volume loss thing again. I'm gonna assume there is is something in there getting hot???

 

[Anonymous]

could be that

could be a loose tube socket

too many variables at this point to diagnose from a desktop my friend....sorry.

 

[C1-ocaster]

what amp do you have? can you bias yourself? tubes/amps generally drift in bias over time.

VHT/Fryette Ultra Lead. The way I understand it is that the tubes' bias drift, not the amps? At any rate, the amp has something else going on. Even with all new tubes, including replacing each pre-amp tube one at a time, the amp is still loosing volume after only playing on the lead channel for more than a few seconds at more than bedroom level volume. It's gonna have to go see someone. And it's not going back to the last guy who told me it only had a bad power tube, and there were no other issues. I know for sure at least the V1 was bad and the V4 was getting noisy.

bias can drift in time if the amps components drift, ie, bias resistor. also, if it's a trim post bias, it can vibrate to either direction believe it or not.

generally though, output tubes drift.

which preamp tubes you running?

v3 in your UL is a cathode follower slot. be sure you're NOT using an EH or tung sol in that slot...those tubes in a cathode follower position can die fast.

I originally had the following in there, just as factory recommended. V1 Sovtek LPS, V2-V5 all Chinese. I just replaced them with the following, still all factory recommended. V1 Tungsol balanced triodes, V2-V4 all Chinese select, and V5 Chinese select/balanced triodes. And I of course I had new Sovtek KT88's in there as well. The amp was quieter, punchier, gainier, and better than it has ever sounded for about a minute, until I tried to SLIGHTLY push it at all on the lead channel for about 30 seconds, then it did the volume loss thing again. I'm gonna assume there is is something in there getting hot???

Not that I know what the problem could be, but just a reminder, even new tubes can be bad.
Try rolling some around, and if you have the older power tubes, maybe try them one at a time.
Who knows, could be a bad tube.
Cheap try though.

 

[moronmountain]

what amp do you have? can you bias yourself? tubes/amps generally drift in bias over time.

VHT/Fryette Ultra Lead. The way I understand it is that the tubes' bias drift, not the amps? At any rate, the amp has something else going on. Even with all new tubes, including replacing each pre-amp tube one at a time, the amp is still loosing volume after only playing on the lead channel for more than a few seconds at more than bedroom level volume. It's gonna have to go see someone. And it's not going back to the last guy who told me it only had a bad power tube, and there were no other issues. I know for sure at least the V1 was bad and the V4 was getting noisy.

bias can drift in time if the amps components drift, ie, bias resistor. also, if it's a trim post bias, it can vibrate to either direction believe it or not.

generally though, output tubes drift.

which preamp tubes you running?

v3 in your UL is a cathode follower slot. be sure you're NOT using an EH or tung sol in that slot...those tubes in a cathode follower position can die fast.

I originally had the following in there, just as factory recommended. V1 Sovtek LPS, V2-V5 all Chinese. I just replaced them with the following, still all factory recommended. V1 Tungsol balanced triodes, V2-V4 all Chinese select, and V5 Chinese select/balanced triodes. And I of course I had new Sovtek KT88's in there as well. The amp was quieter, punchier, gainier, and better than it has ever sounded for about a minute, until I tried to SLIGHTLY push it at all on the lead channel for about 30 seconds, then it did the volume loss thing again. I'm gonna assume there is is something in there getting hot???

Not that I know what the problem could be, but just a reminder, even new tubes can be bad.
Try rolling some around, and if you have the older power tubes, maybe try them one at a time.
Who knows, could be a bad tube.
Cheap try though.

Yeah I've pretty much decided to ship it to SDF, and have them give it a once over. I love this amp too much to keep messing with it.

 

[cardinal]

Try tensioning the tube sockets?

 

[moronmountain]

Try tensioning the tube sockets?

Heh if that requires me to risk getting shocked and/or take the board of the chasis, the I'm not inclined to do that lol!

 

[H3000]

Try tensioning the tube sockets?

Heh if that requires me to risk getting shocked and/or take the board of the chasis, the I'm not inclined to do that lol!

if you retension the sockets without draining the caps you can DEFINITELY get a shock that will stop yout heart and if no one is around to administer CPR to restart your heart then you WILL die