Sorry - more questions !! Biasing ??

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pedro
Posts: 312
Joined: Tue Jan 31, 2006 9:45 pm
Location: Leeds, United Kingdom

Sorry - more questions !! Biasing ??

Post by pedro »

Where are people biasing their output tubes

Ive got 435v on the plates of my TAD STR 6L6GCs and wondered how hot my tubes should be running ?

Havent fited 1ohm cathide resistors yet - just wondering.

Thanks
Pete
mlp-mx6
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Location: NW Atlanta

Re: Sorry - more questions !! Biasing ??

Post by mlp-mx6 »

Around 35ma +/-3 is usually good. Judge by ear once you're in that ballpark.
pedro
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Location: Leeds, United Kingdom

Re: Sorry - more questions !! Biasing ??

Post by pedro »

thanks for the tip mlp
have a good week
Pete
pedro
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Re: Sorry - more questions !! Biasing ??

Post by pedro »

jsut fitted cathode power resistors both measured 1.2ohms - getting 40mv so reckon I'm already at 33ma per tube or so.
groovtubin
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Joined: Tue Feb 07, 2006 4:52 am

Re: Sorry - more questions !! Biasing ??

Post by groovtubin »

pedro wrote:Where are people biasing their output tubes

Ive got 435v on the plates of my TAD STR 6L6GCs and wondered how hot my tubes should be running ?

Havent fited 1ohm cathide resistors yet - just wondering.

Thanks
Pete
Last edited by groovtubin on Tue Apr 25, 2006 5:36 pm, edited 1 time in total.
oldmacman
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Joined: Fri Jan 20, 2006 12:39 am
Location: Austin, TX

Re: Sorry - more questions !! Biasing ??

Post by oldmacman »

Wait a minute...

70% of 25W is 17.5 W.

17.5W / 460V (about what you might see in an ODS) = about 38 mA max bias current.

Let your ears tell you what's right, but use that number as a safe upper limit. Depends what kind of 6L6 you have in there too.
groovtubin
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Joined: Tue Feb 07, 2006 4:52 am

Re: Sorry - more questions !! Biasing ??

Post by groovtubin »

oldmacman wrote:Wait a minute...

70% of 25W is 17.5 W.

17.5W / 460V (about what you might see in an ODS) = about 38 mA max bias current.

Let your ears tell you what's right, but use that number as a safe upper limit. Depends what kind of 6L6 you have in there too.
thanks macman!! did that off top of my head, sorry guys!!
jim
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Funkalicousgroove
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Re: Sorry - more questions !! Biasing ??

Post by Funkalicousgroove »

A 6L6 is a 30W tube Fellas
Owner/Solder Jockey Bludotone Amp Works
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