Fender Dual Showman - grid resistors

zoork_1

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While restoring/modding my Dual Showman, a tech recommended me to try out 82 ohm screen grids resistors instead of the 470 ohms. I've tried to figure out the pros et cons, but I don't get it (right). Anyone who knows? Thanks in advance.
 

ARandall

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Why not ask the tech, given that he's got not only a specific value to advise on but that its different to the stock value by a large amount.
 

zoork_1

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Thanks, I asked the tech, but didn't understand him fully.
Then another one warned me to go below 470 ohm (std AB763 value).
Hence my question...
 

ARandall

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Maybe ask the tech to explain it more simply then - or with reference to what you might expect to hear. There is no reason why any explanation here should be any more understandable than what you got from him - especially given we have no idea why you didn't understand in the first place.

Your second sentence makes little sense as is - did the second tech warn you not to go below 470ohm
 

zoork_1

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Ok, let me put it like this...

Q: What are the pros (if any) and cons of using 82 Ω screen resistors instead of 470 Ω screen resistors?

Background: one tech said go for it, another tech said going below 470 Ω is a no-no.

Rationale: I don't want to take unnecessary risks with my amp.

BTW, if there is any interest I'll upload some sound clips later on w. my R9, vintage PAF's, 2x15 JBL D130 and the now AB763 D Showman... :cool:
 

strayedstrater

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I'm not an amp guru, so this is just what I read on a Google search.

Some people raise the grid resistors to 1000 Ω. Apparently to be able to use tubes like EL34/6CA7.

I didn't find a single recommendation to lower the grid resistors, with several people specifically saying not to go below 470 Ω.
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This is primarily a guitar forum, with a general discussion amp sub-forum.

The Marshall forum is a sister site of this forum. It has a sub-forum called "the workbench" where actual amp techs hang out. They know a ton of theory, gladly talk about Fenders, and could tell you the why's and wherefore's of grid resistors.

There are Fender-specific forums with gurus who would have already answered your questions. They aren't affiliated with this site so I don't know if I should mention them.
 

strayedstrater

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Separate post in case the mods want to delete it -- TDPRI has people who know everything about Fender amps.

Moe's Tavern 2.0 has some of the remnants of the FDP and they can answer your questions.
 

zoork_1

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Thanks for your efforts and for pointing out a direction...
 

el84ster

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Here’s my 2 cents as an amp/tube gear tech for 20 years:
My only guess is that an amp will often sound better with no screen resistors. But…the tube not be as stable. Plenty of old amps ran and tun just fine with no screen reissitors, but yes it is an extra bit of protection for your tubes.

So my guess is that he was suggesting improving the tone while still offering a bit of protection.
The tech that said ‘no way’ is probably thinking like many techs do: about reliability only.
 

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