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FDP Forum / Fender Amps: 1985 - Current / What is internal bias?



no hitch in my git along yet
Nov 14th, 2017 11:55 AM   Edit   Profile  

My 59 Bassman RI LTD literature says it has internal bias, meaning????? No bias adjustment is needed for a tube swap? Thanks.

Contributing Member

Lakeside, CA

Nov 14th, 2017 01:19 PM   Edit   Profile  

Bias adjustment is needed. The BMRI had no bias adjustment. The bias adjustment only applies to the 6L6 power tubes.


on the rhine

Nov 14th, 2017 02:39 PM   Edit   Profile  

Hi jtheissen!

The early Bassman-Reissues didn´t have bias-pot (internal bias), but I´m almost sure, they incorporated it when the amp was "re(v)amped" into the Bassman LTD.

It is a good idea to have your bias adjusted to the power-tubes you use - and that´s what your bias-pot is for.
The bias-setting determines how "hot" or "cold" your power-tubes work and it has an impact on the sound of your amp, as well as the life-span of your power-tubes.
If it´s set too cold, the tubes will last longer, but your tone may suffer, if it´s set too hot, your tubes may suffer - if it´s set WAY too hot, your tone may suffer, too ;-)

If you don´t want to be bothered with this - I think Fender offers replacement tubes that are selected to suit your amp, so you won´t need to re-bias.

cheers - C.



no hitch in my git along yet
Nov 14th, 2017 02:52 PM   Edit   Profile  

Thanks, fellas!

FDP Forum / Fender Amps: 1985 - Current / What is internal bias?

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