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Topic: Deluxe Reverb Question |
Marty Broussard
From:
Broussard, Louisiana, USA
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Posted 26 Mar 2017 9:14 pm |
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If I want to cut down the power output on one can't I remove one of the tubes without harming anything ? If so, which tube? It's a Reissue model.
Thks
_________________
RETIRED
"Technique is really the elimination of the unnecessary..it is a constant effort to avoid any personal impediment or obstacle to achieve the smooth flow of energy and intent" Yehudi Menuhin |
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Tom Wolverton
From:
Carpinteria, CA
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Posted 26 Mar 2017 9:37 pm
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I do it with this speaker. Way easier.
_________________
To write with a broken pencil is pointless.
Last edited by Tom Wolverton on 27 Mar 2017 2:38 am; edited 1 time in total |
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Brad Sarno
From:
St. Louis, MO USA
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Posted 26 Mar 2017 10:00 pm
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Can't do it Marty.
It's a push/pull amp. Wouldn't work with half the amp gone. Do not try.
That works on amps with 4 power tubes when you pull 2 of them.
B |
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Marty Broussard
From:
Broussard, Louisiana, USA
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Posted 27 Mar 2017 7:37 am
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Thanks guys!!
_________________
RETIRED
"Technique is really the elimination of the unnecessary..it is a constant effort to avoid any personal impediment or obstacle to achieve the smooth flow of energy and intent" Yehudi Menuhin |
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Rick Contino
From:
Brattleboro, Vermont
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Michael Brebes
From:
Northridge CA
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Posted 28 Mar 2017 10:21 am
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You can cut the power in approximately half by attaching the screen grids to the plate. It should drop it down to about 10 watts. You could put in a switch to switch the screen grid to either the plate or the 470 ohm screen resistor. I believe Marshall does this in some of their newer amps. You would need a double-pull double-throw switch for the two tubes.
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Michael Brebes
Instrument/amp/ pickup repair
MSA D10 Classic/Rickenbacher B6/
Dickerson MOTS/Dobro D32 Hawaiian/
Goldtone Paul Beard Reso
Mesa Boogie Studio Pre/Hafler 3000
RP1/MPX100 |
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Steven Paris
From:
Los Angeles
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Posted 28 Mar 2017 10:17 pm
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| Michael Brebes wrote: |
| You can cut the power in approximately half by attaching the screen grids to the plate. It should drop it down to about 10 watts. You could put in a switch to switch the screen grid to either the plate or the 470 ohm screen resistor. I believe Marshall does this in some of their newer amps. You would need a double-pull double-throw switch for the two tubes. |
This makes no sense to me; the screen grids are not meant to handle as much current as the plates, which I guess would reduce the power handling capability of the tube. But I wouldn’t think that would limit the power output as much as it would shorten the life of the tubes. Please explain.
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Emmons & Peavey |
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Carl Mesrobian
From:
Salem, Massachusetts, USA
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Posted 29 Mar 2017 6:45 am
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If you are mic'ed, turn the volume down, and use the amp as personal monitor, and let the PA handle the front.
A lot depends on equipment location. It's my experience that amps should be close to any walls behind them, if a wall exists.
Or experiment with different tubes - lower mu preamp tube will send weaker signal to PI and output stages, and have more headroom. You can try weaker output tubes, too.
I'd be interested in hearing more about the screen grid and plate mods and what the outcome has been, as far as reliability, wear and tear, etc
I use an original 65 (?) Princeton Reverb on 3-4, mic'ed, and haven't looked back 
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--carl
"The better it gets, the fewer of us know it." Ray Brown |
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J Fletcher
From:
London,Ont,Canada
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Posted 29 Mar 2017 9:50 am
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Connecting the plates and screens together runs the tubes in triode mode. The idea has been around for a long time , I think the Simulclass Boogies use it.
I became aware of it in the late '80's , and tried it 2 or 3 times in different ways.
More linear operation of the tube , but reduced power. |
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ajm
From:
Los Angeles
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Posted 29 Mar 2017 10:09 am
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Since no one asked: Is there something that you are trying to accomplish, or reason why? Or did you hear this from someone and are just curious?
That said..........
In one of Gerald Weber's books on tube amps there is a discussion on this. I don't remember what the verdict was, but do remember the topic.
Also, the internet can be your friend. A creative search turned up this:
https://www.premierguitar.com/articles/20713-ask-amp-man-removing-output-tubes-to-reduce-power |
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Carl Mesrobian
From:
Salem, Massachusetts, USA
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Posted 29 Mar 2017 10:42 am
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| ajm wrote: |
Since no one asked: Is there something that you are trying to accomplish, or reason why? Or did you hear this from someone and are just curious?
That said..........
In one of Gerald Weber's books on tube amps there is a discussion on this. I don't remember what the verdict was, but do remember the topic.
Also, the internet can be your friend. A creative search turned up this:
https://www.premierguitar.com/articles/20713-ask-amp-man-removing-output-tubes-to-reduce-power |
Doesn't the volume or gain knob turn down the output??
_________________
--carl
"The better it gets, the fewer of us know it." Ray Brown |
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Steven Paris
From:
Los Angeles
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Posted 29 Mar 2017 10:02 pm
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| ajm wrote: |
| In one of Gerald Weber's books on tube amps there is a discussion on this. I don't remember what the verdict was, but do remember the topic. |
Hmmmm...I have three of the Weber books, but I can't locate the passage you are referring to. Do you recall which book, or anything else that might help to locate this discussion?
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Emmons & Peavey |
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Carl Mesrobian
From:
Salem, Massachusetts, USA
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Brint Hannay
From:
Maryland, USA
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Posted 30 Mar 2017 2:11 pm
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| Steven Paris wrote: |
| ajm wrote: |
| In one of Gerald Weber's books on tube amps there is a discussion on this. I don't remember what the verdict was, but do remember the topic. |
Hmmmm...I have three of the Weber books, but I can't locate the passage you are referring to. Do you recall which book, or anything else that might help to locate this discussion? |
I think the reference is probably to the question and answer that starts on page 203 of his first book, A Desktop Reference of Hip Vintage Guitar Amps. |
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