Reverb coil rewinding AWG

[Tom Phillips]

I have thought about rewinding reverb tank coils a few times but, after taking a close look at the way the coil bobbin is mounted on the lamination stack and then the assembly is riveted to the mounting bracket, I just don't see how you would get the thing apart. Is there something I'm missing that doesn't involve drilling out the rivet and disconnecting the springs?

[52 Bill]

Is there something I'm missing that doesn't involve drilling out the rivet and disconnecting the springs?

If you drill out the rivet that holds the laminated stack core, the core can be slid to the side and the coil can be removed from the core. In fact sometimes the stack can be pushed out from under the brass retainer without removing the rivet.

I've done them in the past, really just unwound the the coil and rewound it back on to fix a break. This was back in the days when the tanks were made in the US and cost more.

At one time, Fender would sell you the entire transducer assembly as a replacement part, so if the coil went open or if one of the end wires broke off you could just replace the entire end assembly for something like $5. Just order the input or the output and drill out one rivet and screw in the new one.

Back in those days the springs were not glued to the transducer ends, so you could just hook and unhook the springs. In fact a lot of time the only problem with a tank was that the springs would come unhooked from the ends and would end up rolling around in the case.

[Tom Phillips]

If you drill out the rivet that holds the laminated stack core, the core can be slid to the side and the coil can be removed from the core. In fact sometimes the stack can be pushed out from under the brass retainer without removing the rivet.

I've done them in the past, really just unwound the the coil and rewound it back on to fix a break. This was back in the days when the tanks were made in the US and cost more...

Thank Bill,
I have some old Gibbs tanks that I may try to fix some day.
Tom

[mhuss]

> I can get 42 & 43 AWG from Stu-Mac.
Just an observation, a spool of 43ga from StewMac will likely cost as much to ship to South Africa as a reverb tank, from, say, tubesandmore.

If it's a learning or fun project, that's one thing, but the economics look similar to me either way.

--mark

[epis]

Long time ago I was getting magnet wire for pickups from old cars ignition coils

[Tom Phillips]

It is an interesting idea to salvage magnet wire from other equipment. Especially since such a small amount would be needed for a reverb tank coil.

[diydidi]

> I can get 42 & 43 AWG from Stu-Mac.
Just an observation, a spool of 43ga from StewMac will likely cost as much to ship to South Africa as a reverb tank, from, say, tubesandmore.

If it's a learning or fun project, that's one thing, but the economics look similar to me either way.

--mark

Noted. but, I get quite a lot of faulty tanks round here.

[52 Bill]

I keep all of the old dead tanks that I replace and use them to scavenge parts from when I need to fix some old ones. I find that some players don't like the sound of the new tanks, some love the sound of the new tanks and some just don't care one way or the other.

If somebody wants the old one fixed or replaced, I'll do it. After awhile you can recognize the difference between the drive and the receive ends and you'll see that the coil bobbins are color coded based on their impedance.

Here in the US, the old Accutronics plant (Morley) will rebuild old tanks to whatever you need, as long as they still have the correct parts left from old stock.

[g1]

52Bill, do you replace the ferrite cores when their leads break? I understand the foam in their holders may have a big impact on the sound? Any tips or comments?

[Tom Phillips]

52Bill, do you replace the ferrite cores when their leads break? I understand the foam in their holders may have a big impact on the sound? Any tips or comments?

I one tried to replace a broken ferrite lead. I unsoldered the broken lead and pulled it out of the transducer assembly. The hot wire damaged the damping insert and that was the end of that experiment.
I'm also interested to learn any tips about repairing old reverb pans.

[52 Bill]

52Bill, do you replace the ferrite cores when their leads break? I understand the foam in their holders may have a big impact on the sound? Any tips or comments?

I did a few times when I was in a bind, used a very thin guitar string. The early tanks had the ferrite magnets press fit onto the end wires, so you could remove them. The newer ones were glued on and were impossible to deal with. What I did the most was to reuse the entire end assembly that was still good out of a dead tank. So sometimes the coil would need to be switched out or something, but with enough dead tanks you can build up a good stock of parts.

The foam inside the end tubes was supposed to be an important factor and was like a lot of other foam products, subject to aging. If you inspect an old tank you might find that the foam dampers have melted down into a tar like goo.

[J M Fahey]

> I can get 42 & 43 AWG from Stu-Mac.
Just an observation, a spool of 43ga from StewMac will likely cost as much to ship to South Africa as a reverb tank, from, say, tubesandmore.

If it's a learning or fun project, that's one thing, but the economics look similar to me either way.

--mark

True, but one wire spool is enough for 1000 to 5000 tanks, don't really know the spool weight but I assume we are talking about 1 pound ones.

FWIW diydidi might become the dead reverb guru for all of S.A. and a couple repairs might cover the investment.

It never hurts having some very thin wire around, at least as a sensitive and fast fuse

The ferrite cores are magnets, so essential to functioning, you can carefully heat them, ferrite, epoxy and wire all at the same time with a heat gun, at a certain temperature the epoxy crumbles and you can slide the wire out.
Do not use a flame, not even a Bic lighter, because the ferrite may crack.

Using a thin (.008) string is fine.

[diydidi]

just an update. Managed to get some 0,05mm wire. Looks to be the same thickness as used by Accutronics. Measures in at 8,6ohm/m.
Works a charm.

[mhuss]

I like happy endings. Thanks for letting us know how it turned out.

[J M Fahey]

> I can get 42 & 43 AWG from Stu-Mac.
Just an observation, a spool of 43ga from StewMac will likely cost as much to ship to South Africa as a reverb tank, from, say, tubesandmore.

If it's a learning or fun project, that's one thing, but the economics look similar to me either way.

--mark

Weeeellll, there´s a not so small difference: for the same price you can get a new tank and repair 1 amp, period, or get a wire spool (1 lb???) and be able to wind 100 or 200 pickups or about 1000 tank coils

Which will also become a job opportunity and an excellent investment: if you have what others do not, you may become *the* go-to guy for anybody local needing pickups rewound or reverb tanks rebuilt.
A true gold mine if you handle it well

FWIW guys here buy their Jensen C8/10R clones by me for U$ 40 instead of ordering them from USA at the same nominal price, because they will end paying 3X to 4X the price and sweat at the Customs office.
Besides U$40 buys here 2X or 3X what they buy in USA, measured in food/clothes/services/average cost of life, so count me as if I were charging U$80/120 ... a nice sum for a small simple speaker I can build 2 an hour or so .... I´m including manufacturing time in that, not just reconing.