Need help with tubes....

[Juandetejas]

hello,

 

....my old band is firing up again after a three year hiatus, and I am getting my equipment together. I am not that much of a gear head, so I'm in a little over my head. Unfortunately, I sold my old Soldano 50 but I still have a 50w Laney Pro Tube which I have never gigged with. I pulled the old tubes out and there are (3) 12ax7 tubes and (2) 6550 tubes. My question is, can I use another tube in place of the 6550 (like EL 34) and would the amp have to be re-biased?

 

Another thing that confuses me.....when I pulled the old tubes out, I didnt notice the orientation they were in. I can now put them back in in any number of positions??? This doesn't seem right, but what do I know. I dont really have the $$ to take it to an amp tech (not until after we play a few gigs anyway) so any help would be appreciated. Thanks.

 

Juan

[greg apocalypse]

Another thing that confuses me.....when I pulled the old tubes out, I didnt notice the orientation they were in. I can now put them back in in any number of positions???

 

 

This could be trouble, from my understanding, your amp should be biased as all the tubes will be running differently, and this sort of thing can pretty much throw that all off.

 

 

good luck with the band though

[Juandetejas]

This could be trouble, from my understanding, your amp should be biased as all the tubes will be running differently, and this sort of thing can pretty much throw that all off. good luck with the band though

Thanks man...we all "buried the hatchet" and we are looking forward to getting out again.

[illini]

You will have to have the amp biased to put 6550's in it. It is a good idea to bias an amp after installing new output tubes as a rule anyway even if you are installing the same type.

 

As far as tube orientation goes, I have never seen this problem. There is usually a tab on the side of the output tubes so that you can only install them one way. The pre-amp tubes do not have a notch, but they usually only fit in the socket one way. I say usually, because I have never seen otherwise, but it seems you have.

[greg apocalypse]

You will have to have the amp biased to put 6550's in it. It is a good idea to bias an amp after installing new output tubes as a rule anyway even if you are installing the same type. As far as tube orientation goes, I have never seen this problem. There is usually a tab on the side of the output tubes so that you can only install them one way. The pre-amp tubes do not have a notch, but they usually only fit in the socket one way. I say usually, because I have never seen otherwise, but it seems you have.

 

 

I thought he ment like the order you put them in, like tube 1,2,3,4... I could be wrong, but I'm thinking this is how it's supposed to be

[Cibyl]

hello, ....my old band is firing up again after a three year hiatus, and I am getting my equipment together. I am not that much of a gear head, so I'm in a little over my head. Unfortunately, I sold my old Soldano 50 but I still have a 50w Laney Pro Tube which I have never gigged with. I pulled the old tubes out and there are (3) 12ax7 tubes and (2) 6550 tubes. My question is, can I use another tube in place of the 6550 (like EL 34) and would the amp have to be re-biased? Another thing that confuses me.....when I pulled the old tubes out, I didnt notice the orientation they were in. I can now put them back in in any number of positions??? This doesn't seem right, but what do I know. I dont really have the $$ to take it to an amp tech (not until after we play a few gigs anyway) so any help would be appreciated. Thanks. Juan

I thought that amp was suppose to run EL34's? Generally 6550's and EL34's are not interchangeable -- so if it was running 6550's you should stick with them. Oh,..and when it's re-tubed it will have to be biased.

[illini]

I thought he ment like the order you put them in, like tube 1,2,3,4... I could be wrong, but I'm thinking this is how it's supposed to be

 

 

Ya, I am sure you are right.

[Juandetejas]

You will have to have the amp biased to put 6550's in it. It is a good idea to bias an amp after installing new output tubes as a rule anyway even if you are installing the same type. As far as tube orientation goes, I have never seen this problem. There is usually a tab on the side of the output tubes so that you can only install them one way. The pre-amp tubes do not have a notch, but they usually only fit in the socket one way. I say usually, because I have never seen otherwise, but it seems you have.

 

 

 

The tubes that were in it are 6550, but I was considering using something else.

 

As far as the orientation, you are right, in the center of the tube socket there is a hole with a notch that I assume orients the tube. But the old tubes have nothing that would line up with that, just a tiny piece of the tube glass protruding from the center of the tube.

 

ok, I just examined them closer.....it appears the plastic 'locater' on the bottom of both tubes is missing (broken off very cleanly)

 

So, maybe I'll just pick up some new 6550's and hope for the best, but first I think I'll call a couple of amp guys to see what they would charge for a re-bias. Thanks for the help!

[illini]

It won't cost that much to have the new tubes biased, and you will be happier in the long run that you did. The amp will run at its full potential, and you will extend the life of the tube.