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Author
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Topic: Crappy reverb in Fender amp!!!... help!!
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Bob Carlucci
Member From: Candor, New York, USA
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posted 06 April 2006 09:32 AM
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I have a 1980 Fender 140 watt amp head... all tube, all hand wired Rivera designed amp... It has a 3 spring accutronics reverb tank and it should have KILLER verb,,, this is my second 140, the last one was GREAT and I should have kept it... The reverb was gorgeous.. this one is TERRIBLE...It has NO depth and is a nasty metallic "poing" with NO sustain.. almost like an old Silvertone.REAL bad... when I replace the tank with a two spring tank I have laying around, it improves a little but is still WAAYYY below Fender tube amp standards... lousy... I have tried a new reverb driver tube to no avail... can it be the little transformer?... any thing else I should try??.. I BOUGHT the damn amp for that great tube driven spring reverb, but ANY digital would be a huge up grade from this mess... HELP!!!!! bob
[This message was edited by Bob Carlucci on 06 April 2006 at 09:33 AM.] |
Bob Carlucci
Member From: Candor, New York, USA
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posted 06 April 2006 12:08 PM
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btw. there is a hum/buzz that gets louder as the reverb is increased... the RCA cables have been changed also...to no good result.... bob |
Russ Tkac
Member From: Waterford, Michigan, USA
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posted 06 April 2006 01:34 PM
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I don't know what the problem is Bob but I had a Fender Vibro-King that I sold because I couldn't get a good tube for the reverb. It sucked too.Russ |
Craig A Davidson
Member From: Wisconsin Rapids, Wisconsin USA
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posted 06 April 2006 04:33 PM
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Bob did you try replacing the tube for the verb? I have had to do this once or twice when mine sounded like it came from Sears. |
Donny Hinson
Member From: Balto., Md. U.S.A.
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posted 06 April 2006 04:38 PM
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Transformers either work or they don't, so it's not the transformer. Assuming the tube and the other tank you tried are good, there most be something wrong electrically. Did you try reversing the cables? The jacks could have been wired wrong at the factory, or someone else might have "worked" on it!If it's not the cables, it'll have to go to the shop for voltage checks and a circuit trace. |
Ken Fox
Member From: Ray City, GA USA
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posted 06 April 2006 05:30 PM
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What model is this amp? |
Robert Leaman
Member From: Murphy, North Carolina, USA
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posted 06 April 2006 06:47 PM
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Trsnsformers are NEITHER totally good nor totally bad and neither do they either work or not. Transformers can develop shorted turns that operate as a extra winding with a very low ratio and impedance. This changes the designed impedance ratios between the magnetically coupled windings. Also, it may cause early core saturation. If the transformer core is saturated, there is NO power transfer between any transformer windings. If sufficient power is transferred into the shorted turn winding, it may develop into an open winding which will make the transformer inoperable. |
Bob Carlucci
Member From: Candor, New York, USA
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posted 06 April 2006 08:38 PM
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Ken... Its a Fender 140.. made ONLY in 1980.. quite rare... all tube,wired, breadboards, etc.. channel switching...140 watts RMS.. same series as the Fender 75 amp,which came in a head version, 1x12 combo, and a 1x15 combo... the 75 might have lasted another year or so.Its not as rare as the 140, but these are NOT Fenders you see all that often.. They are terrific amps, and usually trouble free, but mine has several issues.. I got the schematic from Fender, it was in thier archives !... I'm about to dump it for whatever I can get... getting sick of this nonsense... one bad amp after another it seems.... bob
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Jim Sliff
Member From: Hermosa Beach California, USA
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posted 06 April 2006 11:28 PM
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Bob - check the filter caps and the resistors connecting them. If not a tube, that's usually the second-most common hum source in Fender amps. Note: "in". Outside sources also cause hum - but crappy reverb and hum in combination sounds like a dying cap to me.I'd do a cap job if it hasn't been done, and if that doesn't do it dump it. They were a short-run amp for good reason. |
Rick Johnson
Member From: Wheelwright, Ky USA
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posted 07 April 2006 05:03 AM
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Bob
I had a similar problem with Fender 30
with the Rivera circuit. The one I found
was a early 80's model and I bought it from
the store owner who originally purchased
it new and had retired and this was in
his attic, he told the the amp was screwed
up the day it came into his store and never
would work, I sent it to an amp tech friend
of mine and it turns out the channel switching circuit was miswired and it
could never had worked. The amp tech
ended up having to bypass the normal
channel and once he did that, things were
ok and the reverb started working too.------------------
Rick Johnson
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Marty Muse
Member From: Austin,Tx USA
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posted 09 April 2006 01:34 AM
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Bob-Another common problem you will find with older Fender amp reverbs is the RCA jacks on the amp. Many times you think there is a problem with your cables, the problem is in the jacks. I've been playing through old Twins for some time and have taken to just replace the RCA jacks as well as the cables. That may not fix your problem but it might be something to look at. If you replace the input and output tube to the reverb tank and the tank, and the cables and jacks you've eliminated 90% of the problem areas. Unfortunately, there's always that 10%. Bad bypass cap, bad resistor, etc. Relatively rare though. Good luck. Marty Muse |
Larry Robbins
Member From: Fort Edward, New York, USA
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posted 09 April 2006 04:20 AM
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Wow Bob,
A reply from Marty Muse! One of the best players( and amp techs) on the Planet!
Aint this Forum wonderful!! ------------------
SHO~BUDS,FENDER AMPS& GUITARS, TUT TAYLOR RESO'S "What a long, strange trip it's been"
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