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#1 2014-03-25 04:54:08

oldsoul
Member
From: Long Island, NY
Registered: 2014-03-16
Posts: 12

VT-40 Reverb

I ordered a replacement reverb from Fliptops and I am a little confused. The tank in mine has the code 4FB2D1C. The Fliptops one is 4FB3A1B. I'm a bit concerned about the longer decay time and confused about the mounting. The unit I have looks right but the spec of a C type says vertical mounting but the one I received states horizontal.

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#2 2014-03-26 00:53:28

hangman
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From: Seattle Washington
Registered: 2006-09-03
Posts: 1848

Re: VT-40 Reverb

you must have the older version of the vt-40 where the controls are on the top side of the amp. 

the reverb tank in that one doesn't mount the same as the later vt-40 which had the same chassis as the v2. 
so the tank is incorrect for your vt-40.    finding the correct one will likely prove difficult however,   you might try buying a vinyl fender style reverb bag,  screwing a piece of thick cardboard or thin piece of plywood on to the open side of the tank, and maybe a thin bit of foam to the other side... then putting the tank on the bottom of the cabinet.

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#3 2014-03-26 15:52:36

oldsoul
Member
From: Long Island, NY
Registered: 2014-03-16
Posts: 12

Re: VT-40 Reverb

My VT-40 is the model with distortion on ch1. The controls face forward not on top.

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#4 2014-03-28 04:40:55

oldsoul
Member
From: Long Island, NY
Registered: 2014-03-16
Posts: 12

Re: VT-40 Reverb

And after install I am getting no reverb. Any ideas? The old reverb worked it just had a broken spring.

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#5 2014-03-29 10:24:49

hangman
Banned
From: Seattle Washington
Registered: 2006-09-03
Posts: 1848

Re: VT-40 Reverb

and the tank mounts on the lid of the chassis?   your tank should be horizontal mount.   if you plug the tank in and get no reverb,  do you at least get the sound of the springs?   can you turn the reverb to 1 or 2 and then agitate the amp and get the sound of the springs to come through? you sure you got the input and output wires to the correct terminals?

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#6 2014-04-01 18:58:18

oldsoul
Member
From: Long Island, NY
Registered: 2014-03-16
Posts: 12

Re: VT-40 Reverb

I moved the amp around and rattled the springs and that caused a reverb to echo. I plugged a jack into the footswitch jack and that triggered the reverb to work when playing a Fender Rhodes through it. It does seem very weak and sounds like it's perhaps on the verge of feeding back. Like their is some sort of weird harmonic reverberating. Could this be caps, or the 6cg7 tube?

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#7 2014-04-02 00:57:23

hangman
Banned
From: Seattle Washington
Registered: 2006-09-03
Posts: 1848

Re: VT-40 Reverb

hmm,   the reverb should be pretty thick.   there are some issues with this circuit oscillating.   I certainly struggled with some of that in my Vt-22

I think the big thing is to figure out why it is weak first.   the feeding back bit will be solved to some degree if you no longer need to turn it up so much.

6cg7 is the driver.... but hard to say if that is indeed the problem.   certainly give it a shot.

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#8 2014-04-02 17:13:56

oldsoul
Member
From: Long Island, NY
Registered: 2014-03-16
Posts: 12

Re: VT-40 Reverb

I tested the tubes and they all test strong. I've only replaced the electrolytics caps.

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#9 2014-04-02 20:27:15

hangman
Banned
From: Seattle Washington
Registered: 2006-09-03
Posts: 1848

Re: VT-40 Reverb

if you can  rattle the amp or reverb tank and get a good loud crash on the amp,  the problem is likely with the driver stage.  perhaps the .47uf capacitors has gone bad? 

no harm in swapping those out.  its not like working on a blackface fender where the caps are worth something.  ampeg never really used valuable capacitors.

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#10 2014-04-02 20:28:00

hangman
Banned
From: Seattle Washington
Registered: 2006-09-03
Posts: 1848

Re: VT-40 Reverb

if you can test the resistors in that circuit too,  I've seen a fairly high number of resistors go open in these. usually in the mid eq circuit but.... who knows?

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#11 2014-04-05 20:46:35

oldsoul
Member
From: Long Island, NY
Registered: 2014-03-16
Posts: 12

Re: VT-40 Reverb

Thanks! Thats exactly what I'm looking into and ordering some parts. Many box caps and tropical fish in there. I'm actually trying to find a .47 that will fit.C9 going to the input i a tight fit. The Orange Drop I have is huge.

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#12 2014-04-08 00:11:06

hangman
Banned
From: Seattle Washington
Registered: 2006-09-03
Posts: 1848

Re: VT-40 Reverb

the mallory or Illinois tubular film caps will fit.

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