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Topic: Fender Deluxe Reverb tone issue |
Mike Taylor
From:
Wetumpka, AL
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Posted 28 Sep 2009 10:55 am |
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I'm having trouble with my Fender Deluxe reverb amp that I believe is due to a bad tube; but wanted to run it by the forum quorum before I begin changing tubes. Here's whats going on. With the reverb control at zero, the amp has a great tone; but as you turn up the reverb control, not only does reverb come into the mix; but there is a decided change in tone -- mainly treble to my hearing. I believe this is the reverb tube going/gone bad -- thoughts???
Thanks
Mike |
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Keith Hilton
From:
248 Laurel Road Ozark, Missouri 65721
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Posted 28 Sep 2009 7:15 pm
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| Mike I want to buy one of those amps. If you want to sell it, like it is, let me know? |
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Mike Taylor
From:
Wetumpka, AL
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Posted 28 Sep 2009 8:04 pm
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Keith.. It took me 10 years to find one of these -- not a reissue of coure. this one is even more unique in that it is an export model with a built in transformer where the typical extra power plug is!! It sounds great -- other than when you turn up the reverb..
Whaddya think? Is it the tube going bad on me???
Mike |
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Marc Jenkins
From:
Victoria, British Columbia, Canada
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Posted 28 Sep 2009 9:34 pm
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| Changing the reverb driver is the easiest thing you can do, so start there. If it has no effect, you know the problem lies elsewhere in the circuit. It's that simple. |
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Ken Fox
From:
Nashville GA USA
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Posted 29 Sep 2009 7:10 am
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V3, the 12AT7 (ECC81) is the reverb driver It drives the reverb transformer that then drives the tank.
After the tank it is recovered and mixed with the dry signal at V4, 12AX7 (7025, ECC83).
I would not hesitate to change the 25uf/25volt cap on V4! It can cause a lot of issues and is a good idea if that is an original cap |
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Jim Sliff
From:
Lawndale California, USA
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Posted 29 Sep 2009 9:00 pm
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What Mark and Ken said.
IMO any tube amp owner should have at least one spare set of every tube in the amp (of course, most tube amp owners don't use specific brands/models/types in their amps, they just use what was in it when they bought it or run to GC and buy "tubes" - usually Groove Tubes, and stick them in without a second thought (and change power tubes without biasing on fixed-bias amps).
You can not only fix problems with spare tubes, you can change the character of the amp.
But in this case the first thing to do is try a tube swap - and if you have no spares (shame!  ) pull the first preamp tube (V1) and put it in the V4 socket (your amp will run fine with no tube in V1 - it's the preamp tube for the "normal" channel nobody uses...). If that's not it, put the 12AX7 you pulled from V4 in the driver socket - the one next to the power tubes - and try the 12AT7 driver tube in the V3 socket (the 12AX7 won't hurt a thing as a driver - it provides more gain, which some people like - but in this case you're just doing it to test things).
If that doesn't solve it, it's off to the tech for the cap change Ken recommended - if that's not it there are several other possibilities, including the reverb driver transformer.
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No chops, but great tone
1930's/40's Rickenbacher/Rickenbacker 6&8 string lap steels
1921 Weissenborn Style 2; Hilo&Schireson hollownecks
Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
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