Changeing tubes in Yamaha T-50 head?

[Ibanez_st50]

Hey guy's can anyone help me? I need to change the tubes in my yamaha t-50 amp and I'm not real sure if I can without damageing it? It has 2 6L6 gc power tubes and 7 12AX7's. I play pretty heavy stuff but not really the drop tuned stuff? 1. which tubes would give some good results ie,ruby,groove; I really want it to sound like soldano and yamaha wanted plenty of gain and great tone. 2. can I replace the tubes or should I pay a tech to do it,will it sound the same no matter? Right now I'm running through the effects loop if I plug straight into it it sounds thin then cuts off for a couple of seconds after it gets hot from driving it hard,then back on. going thru the loop I haven't had this problem I run my digitech rpx-400 thru it and it rocks but I know it's just a matter of time before it goes out or hurts something?
Any Help? Many Thanks Jeff

[Lake Placid Blues]

Re: Changeing tubes in Yamaha T-50 head?

1) You should replace the output tubes with 6L6 type tubes. Exactly which ones depends how much money you want to spend. NOS type will cost more than 100USD, but the winged C 6L6GC is a good current production tube for a lot less dough. The JJ 6L6 is popular current production choice as well.

2) You should probably have a tech do it. I don't know how the T-50 is biased. Several modern amps don't have adjustable bias. I recall playing through a T50 once several years ago. As I recall it had Sovtec tubes in it. A new set of tubes should cause a noticable sonic improvement if the tubes are fairly worn down.

A tech can also identify which 12AX7 tubes should be replaced along with the output tubes. All or most of them, or perhaps just a few may need replacement.

Cutting out can be worn out tubes, but it can also be caused by the PCB getting hot, or other things. Thin sound when plugging into the main input is not right. You need to have a tech diagnose the problem. It could be any number of things. It will sound better once a tech fixxes the problem.

[Marcel]

Re: Changeing tubes in Yamaha T-50 head?

Right now I'm running through the effects loop if I plug straight into it it sounds thin then cuts off for a couple of seconds after it gets hot from driving it hard,then back on.

Sound like something is wrong!! Maybe you better wanna bring the amp to a tech!
Maybe just a pre amp tube is dead but not sure....
As said before if you want to change the power amp tubes your amp have to be biased.
But you can change pre tubes on your own and you can use any 12AX7.

[Ibanez_st50]

Re: Changeing tubes in Yamaha T-50 head?

Hey guy's thank you for the help!!!!! You Just confirmed my thoughts on the problem. I knew you guys would know for sure Thanks Again Jeff