retubing a combo amp. does it need to be re-biased?

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JimmyDoomsday

JimmyDoomsday

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i'm replacing the 4 6l6 power tubes (with tung-sol 6l6-g; 2 matches pairs) and 4 12ax7 preamp tubes (with 3 matched selection tung-sols and one svetlana) on a kustom '72 coupe combo amp. would this procedure necessitate a re-biasing? and if so, how would i go about doing that?

also, any other brands/combinations of tubes to recommend?
 
JimmyDoomsday":10i4nw08 said:
i'm replacing the 4 6l6 power tubes (with tung-sol 6l6-g; 2 matches pairs) and 4 12ax7 preamp tubes (with 3 matched selection tung-sols and one svetlana) on a kustom '72 coupe combo amp. would this procedure necessitate a re-biasing? and if so, how would i go about doing that?

also, any other brands/combinations of tubes to recommend?


Im not a tech, but I was told by many that any tube change should be followed by a correct bias.

More-so if you chage tube types or brands.

If you're sticking to the same exact tubes. Then maybe youd be ok without the bias. But to be safe I bias every single time I change a tube.

Cant advise how to on your amp, but some amps have an internal bias that you can do yourself with a screwdriver. BUT BE CAREFUL. You need a bias probe to test the voltages.

There are some online tutorials but if you do not have experience doing this or do not have a self biasing adjuster amp then Id call a tech.

It will save you money in the long run if you mess it up.
 
Normally yes, but the according to the manual, "The amp uses a mixed-bias system which is a combination of fixed and self-bias techniques to give the user the best of both worlds. The result is that the amp will control its own bias to a certain point, but without the typical reduction in power associated with normal self-biased amp designs."

So you're probably fine.
 
Try not to touch the glass on the tubes when you install them.
 
fredster":2bk9rs5w said:
Normally yes, but the according to the manual, "The amp uses a mixed-bias system which is a combination of fixed and self-bias techniques to give the user the best of both worlds. The result is that the amp will control its own bias to a certain point, but without the typical reduction in power associated with normal self-biased amp designs."

So you're probably fine.
The manual for the amp that was not mentioned? Very insightful.

Preamp tubes do not need biasing, power tubes do. If you're replacing any of your power tubes, your better off re-biasing the amp. You can find instruction to do this here:

http://eurotubes.com/euro-video.htm
 
chunktone":2pjetbcv said:
The manual for the amp that was not mentioned? Very insightful.

Preamp tubes do not need biasing, power tubes do. If you're replacing any of your power tubes, your better off re-biasing the amp. You can find instruction to do this here:

http://eurotubes.com/euro-video.htm

JimmyDoomsday":2pjetbcv said:
i'm replacing the 4 6l6 power tubes (with tung-sol 6l6-g; 2 matches pairs) and 4 12ax7 preamp tubes (with 3 matched selection tung-sols and one svetlana) on a kustom '72 coupe combo amp.
http://www.kustom.com/Content/KustomCou ... Manual.pdf
 
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