Old Fender reverb tanks

AlbertaGriff

Friend of Leo's
Joined
Mar 2, 2016
Posts
2,015
Location
Canada
Hey all, I've got a '66 Vibrolux Reverb that I had to replace the reverb tank in. I think I bought one of the MOD tanks. I haven't been thrilled with the reverb since. Even using a 12AU7, I find the reverb overwhelming before 3 on the dial.

Someone nearby is selling a reverb tank that appears to be from their '70s Twin Reverb. I assume it will be a reasonable match, but just wanted to make sure - will a tank from a 70s Twin be the correct size and impedance for a Vibrolux?

Thanks
 

cherryburst1

Tele-Meister
Joined
Aug 8, 2014
Posts
240
Location
Texas
Hey all, I've got a '66 Vibrolux Reverb that I had to replace the reverb tank in. I think I bought one of the MOD tanks. I haven't been thrilled with the reverb since. Even using a 12AU7, I find the reverb overwhelming before 3 on the dial.

Someone nearby is selling a reverb tank that appears to be from their '70s Twin Reverb. I assume it will be a reasonable match, but just wanted to make sure - will a tank from a 70s Twin be the correct size and impedance for a Vibrolux?

Thanks
Is it the level or sound quality you don't like?
 

cherryburst1

Tele-Meister
Joined
Aug 8, 2014
Posts
240
Location
Texas
That's the decay. Did you buy a 3 springer or long decay pan? They sell them for different decay times.
The long decays (usually 3 springers) are most popular with steel guitar players.
 

AlbertaGriff

Friend of Leo's
Joined
Mar 2, 2016
Posts
2,015
Location
Canada
That's the decay. Did you buy a 3 springer or long decay pan? They sell them for different decay times.
The long decays (usually 3 springers) are most popular with steel guitar players.

I'll have to take a peek and see. I thought I ordered the standard Fender replacement pan from MOD.
 

Dacious

Doctor of Teleocity
Joined
Mar 16, 2003
Posts
10,228
Location
Godzone
There's a plethora of different numbers.

It's important to match the decay time of the standard tank.
 

cherryburst1

Tele-Meister
Joined
Aug 8, 2014
Posts
240
Location
Texas
Should. Things to look for: Orientation of in/out jacks and whether the grounding on the pans are the same. If you find out what the accutronics number is, you can go the Belton website and search that pan number. It will tell you in/out impedance's, grounding scheme,etc...
If you know a good tech with real steady hands, he/she can re-tension the springs to adjust the decay time. I used to do this for steel guitar players while they played, listened and asked for tweaks until they were happy with the pan... Just a thought...
 

AlbertaGriff

Friend of Leo's
Joined
Mar 2, 2016
Posts
2,015
Location
Canada
Should. Things to look for: Orientation of in/out jacks and whether the grounding on the pans are the same. If you find out what the accutronics number is, you can go the Belton website and search that pan number. It will tell you in/out impedance's, grounding scheme,etc...
If you know a good tech with real steady hands, he/she can re-tension the springs to adjust the decay time. I used to do this for steel guitar players while they played, listened and asked for tweaks until they were happy with the pan... Just a thought...

I don't think that cost would be worth it in this case - the 70s Twin pan I am looking at purchasing is a cool $40 CAD.
 

The Ballzz

Friend of Leo's
Joined
Apr 11, 2016
Posts
2,066
Age
66
Location
Las Vegas, NV
I personally feel that the MOD tanks sound better than at least the ACCUTRONICS from late '80s onward. Have never swapped in a MOD in anything earlier than that. The difference in my '92-ish JTM30 was night & day.
Just My Take,
Gene
 

Buckaroo

Tele-Meister
Joined
Mar 22, 2012
Posts
303
Location
usa
A "new" reverb pan (aka tank) will not sound like an old one right away. It takes many hours of play time / use to "loosen up" a bit. It is mechanical and it moves. In some ways it is like breaking the moving parts of a speaker, or a new pair of stiff jeans.

Over the years, I can recall getting brand new tanks in the 1980's and putting them in 1960's era amps and the reverb sounds "new"...not like the 25 year old tank that came with the amp.

Further, newer tanks are not going to have the "exact" same parts / construction as the old originals. They may follow the original design, but the actual parts may be made by different vendors than the originals. So new tanks are going to sound a bit different due to that as well. Agree that matching the exact model number is a must...many specifications among the tanks exist.

The good news is that after the tank gets played awhile it will settle in and sound different than when you first put it in. It may never sound exactly like the old original, but most sound quite good after a time of usage...assuming you put the correct replacement model tank in the amp of course.

Good luck,
Buck
 
Last edited:

Wally

Telefied
Ad Free Member
Joined
Mar 17, 2003
Posts
40,769
Location
Lubbock, TX
I always solidify the inductors in their mounts…whether the tank is new or old, the inductors are likely to be loose. I want the springs to cause the reverb effect…not the inductors. The reverb signal is always improved when the inductors are solidified 8n their mounts.
 

schmee

Doctor of Teleocity
Silver Supporter
Joined
Jun 2, 2003
Posts
17,935
Location
northwest
Hey all, I've got a '66 Vibrolux Reverb that I had to replace the reverb tank in. I think I bought one of the MOD tanks. I haven't been thrilled with the reverb since. Even using a 12AU7, I find the reverb overwhelming before 3 on the dial.

Someone nearby is selling a reverb tank that appears to be from their '70s Twin Reverb. I assume it will be a reasonable match, but just wanted to make sure - will a tank from a 70s Twin be the correct size and impedance for a Vibrolux?

Thanks
Yes it will. But many old Fenders have strong reverb early on the dial. Are you sure the Mod is stronger?
There is also a modification to the pot that puts the reverb 0-5 over the 0-10 sweep for more control.
 

Jimy

TDPRI Member
Joined
Apr 15, 2013
Posts
65
Location
California
Totally agree with Buckaroo. A mod to consider is replacing the 100k linear taper Reverb pot with a 100k audio taper. This will make the reverb come on more gradually and you’ll have a useful sweep between about 2 and 7 on the knob. The tank will still be too much when full up, but you’ll have more control over the reverb on low to moderate settings.
 
Last edited:

Sea Devil

Friend of Leo's
Joined
Sep 23, 2006
Posts
3,153
Age
59
Location
Brooklyn, NY
I find that all MOD pans sound cavernous, more like a "Cathedral" reverb or an Ampeg "Echo" than the traditional Fender sound.

There's huge variation in most new and old pans with the notable exception of the MODs. They're consistent and widely available, so they're popular. The current production Belton and Accutronics pans are made side by side at the same facility, but are wired differently; they can sound the same, but different examples of the same brand can sound pretty different. There's no guarantee of anything more than a loose set of performance parameters with any of them.

That said, some of my favorites have been 60s and 70s Accutronics pans, and one came from a 1975 "Ultra-linear" Twin. Totally worth forty bucks; the best pans of that era are head and shoulders above current production.
 

Bowpickins

Tele-Meister
Joined
May 29, 2018
Posts
282
Age
21
Location
D/FW, TX.
I bought this one:

https://www.amplifiedparts.com/products/reverb-tank-mod-4ab3c1b-long-decay-2-spring

Which clearly says long decay.

So back to the main question though, would the 70s accutronics tank be fine in the 66 Vibrolux? I think so...

I had this same issue when I replaced the tank in my vintage Twin Reverb with a new MOD 4AB3C1B tank. The thing is, you're comparing a brand new tank/springs to a much older unit, so the new tank may sound more aggressive since the springs are much newer and haven't stretched out.

My solution was swapping it out for a medium decay MOD tank, which sounds much closer to my other older reverb units, but has the modern connections/reliability of a MOD tank. Here is the unit I used: https://www.amplifiedparts.com/products/reverb-tank-mod-4ab2c1b-medium-decay-2-spring
 

slider313

Tele-Afflicted
Joined
Jan 6, 2011
Posts
1,547
Location
NC
Before giving up on the tank, which is the correct replacement part, try a 12DW7/7247 in V4 which is your reverb recovery tube.
 

Wally

Telefied
Ad Free Member
Joined
Mar 17, 2003
Posts
40,769
Location
Lubbock, TX
I find that all MOD pans sound cavernous, more like a "Cathedral" reverb or an Ampeg "Echo" than the traditional Fender sound.

There's huge variation in most new and old pans with the notable exception of the MODs. They're consistent and widely available, so they're popular. The current production Belton and Accutronics pans are made side by side at the same facility, but are wired differently; they can sound the same, but different examples of the same brand can sound pretty different. There's no guarantee of anything more than a loose set of performance parameters with any of them.

That said, some of my favorites have been 60s and 70s Accutronics pans, and one came from a 1975 "Ultra-linear" Twin. Totally worth forty bucks; the best pans of that era are head and shoulders above current production.

Just to keep things straight,
Ultralinear Fenders were introduced in 1977.
 




Top