I don't hate spring reverbs.....

[Axtman]

I just don't want them living in my neighborhood, going to my church or dating my daughter.

But seriously folks, it seems like every third amp I get in for repair has a broken reverb tank. Luckily they are an easy fix.

[glebert]

i have been meaning to post a question about fixing reverb tanks. Do you have a way to reattach springs? i hadn't found a method, but am not sure I looked that hard. Seems like half of the amps I buy (junkers) have no tank or a broken tank, and that isn't even the problem that they are being junked for. Even a $20 tank is expensive on an amp that you hope to sell for $120.

Greg

[Axtman]

Here is how you repair a reverb tank.

1. Remove old tank from amp.
2. Throw old tank in trash.
3. Buy new reverb tank.
4. Install new reverb tank.

Unless it is a simple fix like resoldering broken wire, reverb tanks are really hard, if not impossible, to repair. Luckily they are widely available and relatively cheap. That said I once had to order a reverb tank from Germany (Tube Amp Doctor) because Carvin stopped using spring reverb tanks and instead went to digital reverbs. No US distributor had a replacement tank.

[Mick Bailey]

I repair reverb tanks all the time and there's pretty much nothing that can't be fixed unless the tank has been run over by a truck. Parts can be swapped with other tanks, transducer coils removed, springs changed, bobbins rewound to fix them, alter impedance or increase the output voltage. Grounding changed, etc.

If a spring is broken near the attachment point it's usually sealed with epoxy and the bond can be broken with a soldering iron and forceps. If the suspension wire is broken it needs desoldering from the brass tube, taking real care to minimize heat damage. A spring that's broken midway can have the free ends bent over in a little hook and a bead of epoxy to secure. I usually desolder the spring assembly and fit one from a junk tray if the suspension wire is broken. A reverb tray is not a precision instrument.

[Axtman]

Mick,

Usually where I find that they break is the fine wire that holds the magnet in place in the transducer. I don't know of anyway to repair that fine wire, plus new reverb tanks are inexpensive.

If you were close to me I would send you a whole pile of broken reverb tanks.

[52 Bill]

Usually where I find that they break is the fine wire that holds the magnet in place in the transducer. I don't know of anyway to repair that fine wire, plus new reverb tanks are inexpensive.

In a pinch, I've replaced the spring hook wire with a really thin guitar string.

I don't recommend fixing them anymore, as every part has been epoxied together and getting the ferrite magnet off of the original wire is pretty much impossible to do without breaking it. Fender used to sell just the transducer end assemblies so that you could repair the tanks with a bad hook or coil, but those days are long gone.

Even though the new tanks sound full and lush and make for more natural sounds similar to digital reverbs, I still prefer the bright, sproingy sounds of the vintage tanks. I guess it's just what I've heard all of my life and what I've come to expect from a spring reverb.

[Mick Bailey]

To get the ferrite magnet off I use a high-current 1.5v power supply across the wire. Just a quick touch to get the wire hot enough to pull the magnet off but not destroy the magnetism. Then use electro-brassed high-tensile steel wire to replace it. This is used as the strain relief in telephone drop-cables (from pole to house).

I do a lot of restoration work on vintage amps and keeping the original tray is important. Plus, with most modern trays I can fix one quicker than ordering one and waiting for it to arrive.

[g1]

What do you do about the rubber or foam damping material in the housing the ferrite wire goes in?

[nevetslab]

I repair reverb tanks all the time and there's pretty much nothing that can't be fixed unless the tank has been run over by a truck. Parts can be swapped with other tanks, transducer coils removed, springs changed, bobbins rewound to fix them, alter impedance or increase the output voltage. Grounding changed, etc.

If a spring is broken near the attachment point it's usually sealed with epoxy and the bond can be broken with a soldering iron and forceps. If the suspension wire is broken it needs desoldering from the brass tube, taking real care to minimize heat damage. A spring that's broken midway can have the free ends bent over in a little hook and a bead of epoxy to secure. I usually desolder the spring assembly and fit one from a junk tray if the suspension wire is broken. A reverb tray is not a precision instrument.

I am very intrigued by this procedure. I've never made any attempts to repair or remove the actual reverb springs. I'd love to see how that is done. I still have a pile of broken Accutronics reverb tanks that are missing the long springs. I normally pull that tank out and replace it with a new one when it hits that stage in life. Repairing the broken wires from either the RCA connectors or the mating push-on connector, or a broken tack-solder after the IDC connectors have been eliminated is what I normally have to deal with every week.

Now I'm going to have to educate myself in this next phase of reverb tank repairs. Is there some circular insulator or centering part on the inside of the brass tube that centers the spring termination? I certainly have enough broken tanks to cobble some back together if this is an easy repair.

[Mick Bailey]

What do you do about the rubber or foam damping material in the housing the ferrite wire goes in?

I have some silicone tubing that does for some, and use silicone putty for others. To make silicone putty use a small amount of clear bathroom silicone and stir in unscented talcum powder until it's a stiff paste. Let it set to a kneadable consistency and it can be used to make all kinds of formed rubber components. It's insulating, heat resistant, flexible and tough - much tougher than just silicone. I use it to make moulded ear plugs, missing rubber components and casting moulds for resin.

[g1]

Thanks Mick.
How much do you put into the housing, and I guess you run the wire through before it sets up?

[Mick Bailey]

Yes - just poke the putty in with the shank of a small drill bit and pass the wire through. The desoldered end can be a little rough and sometimes its better to poke a thin guitar string through, let the putty set overnight and then do the final assembly. Still tricky to feed that suspension wire through even if the damper is not being replaced.