From powe–(at)–wdc.com Mon Jul 29 10:38:23 CDT 1996
Article: 19657 of alt.guitar.amps
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From: O’Connor
Subject: Re: Tube Rectifier Replacement For Fender Amps
Date: Mon, 29 Jul 1996 05:40:14 -0700
Organization: London Power http://www.wwdc.com/~power/
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William R Rodrick wrote:
if, for example, the amp in question is a Fender with a 6V6
> output stage, replacing the tube rectifier with solid state rectifiers is
> liable to fry the 6V6(s) because of the resulting increase in plate voltage;
> Fender already runs them way over spec to begin with.
>
> Bill
Contrary to popular belief, Fender never operated 6V6s beyond their
ratings. Most people are familiar with the 360V anode rating of the 6V6,
but this is an old style rating called a “Design center value”. This is
a rating that has a built in allowance for variations in tube
manufacturing, AND, it tries to anticipate variations in the application
circuit.
Later, the rating system was revamped to list “Design maximum values”,
where only the production variations were accounted for. The low 360V
plate voltage then magically soared well above 400V with no actual change
to the tube itself. The same was true for the 5881.
With respect to the solid-state rectifier sub question: As long as the
bias level is properly proportioned for the higher anode voltage, then
6V6s are happy to work at B+ values above 420V.
Note that the 6V6 was used in early TVs as a horizontal driver subject to
1,200V at a 15% duty cycle. Don’t try this with an EL84!
Tinker carefully!
Kevin O’Connor
From Teleologis–(at)–orry.NoEmail Mon Jul 29 10:38:42 CDT 1996
Article: 19660 of alt.guitar.amps
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From: Teleologist
Newsgroups: alt.guitar.amps
Subject: Re: Tube Rectifier Replacement For Fender Amps
Date: Mon, 29 Jul 1996 06:58:38 -0500
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O’Connor wrote:
>
> William R Rodrick wrote:
> if, for example, the amp in question is a Fender with a 6V6
> > output stage, replacing the tube rectifier with solid state rectifiers is
> > liable to fry the 6V6(s) because of the resulting increase in plate voltage;
> > Fender already runs them way over spec to begin with.
> >
> > Bill
> Contrary to popular belief, Fender never operated 6V6s beyond their
> ratings. Most people are familiar with the 360V anode rating of the 6V6,
> but this is an old style rating called a “Design center value”. This is
> a rating that has a built in allowance for variations in tube
> manufacturing, AND, it tries to anticipate variations in the application
> circuit.
>
> Later, the rating system was revamped to list “Design maximum values”,
> where only the production variations were accounted for. The low 360V
> plate voltage then magically soared well above 400V with no actual change
> to the tube itself. The same was true for the 5881.
>
> With respect to the solid-state rectifier sub question: As long as the
> bias level is properly proportioned for the higher anode voltage, then
> 6V6s are happy to work at B+ values above 420V.
>
The dissipation rating for 6V6GTs also goes up to 14W from 12W.
Re 6V6s, SS plug ins, & 420+V, for posterity you probably need to add:
Don’t try this at home with Sovtek 6V6GTs 🙂
