Reverb Tank bobbins - good question for Juan?

[nickb]

Does anyone know a good source of bobbins for reverb tanks?

I know JMF was making his own tanks at one time and I thought he might have some insight. Although knowing him, he probably designed and built his own injection moulding machine from scratch

Cheers!

[Enzo]

Yu plan to go into production or do you just want a project? If you only need a few, take them off some dead reverb pans.

[J M Fahey]

Not the injection machine, but had the dies made for the half height plastic bobbins.

The cores were made out of standard , bought over the counter stacked E laminations, the smallest size, what was used for transistor radio audio driver transformers, the E are 19mm wide, center leg 1/3 that, about 1/4" .

The regular bobbin would be as high as the center leg, because transformers fill the windows, a friend of mine had been making his own reverbs (the best Industrialization policy in the World is having high Tariff, so imported stuff is *expensive* and it pays to invest on dies and machinery to make your own) out of regular cores and bobbins , but results were poor because cylinder magnets were really outside the shortest magnetic field.

Hammond, Gibbs, Accutronics, Piezo (brand) and such stamped special laminations, (just look at any commercial reverb), my typical lateral thinking answer was to make a shorter bobbin so it used half of the available window and magnets could sit at the proper height.

Here's a couple dusty rusty leftovers, today I don't have the stamina (nor the $$$$$$ motivation) to make more, the problem being the hollow cylinder magnets, I have the ferrite dust pressing dies but minimum order would be 5000 or 10000 magnets, so when I need one, I make it real quick using aftermarket Piezo disks.

The "mechanical" side (springs, floating frame/chassis, terminals, etc.) are relatively child's play because I'm setup to cut, bend and punch my own chassis.

















The basic idea behind being able to make stuff in small scale and not investing/wasting millions of dollars is to find whatever commercial product uses some die or machine or process which might help me and is readily available for other purpose.

I dont care about "the other" finished product but what part of its manufacturing process can do something I need.

I already said that my speaker frames are made in a car parts factory who makes aftermarket parts for FIAT / SEVEL / Renault , the basic frame is a conical blind stamping which is an intermediate step of making car wheels/hubcaps and the holes are punched with the die used for a hole in the door frame where the window glass rising "machine" (a threaded "worm" ) fits.

It was the perfect size for 10" frames, but for the 12"ones I used the same (non other available for free) and had to punch 7 holes (instead of the customary 4 a Celestion or Eminence frame uses) to have adequate "breathing" space.

It allows me to order small 50/100 frame runs, only problem is waiting maybe 1 month, sometimes even 3 months until they have to use a certain punch/stamp die.
No big deal for me, I use around 20 speakers a month on average.

[nickb]

Yu plan to go into production or do you just want a project? If you only need a few, take them off some dead reverb pans.

I was thinking about resuscitating dead pans so wanted a small float of spare bobbins. That was my back up plan if I could not find a source. Often you can see the broken wire and it's easy and at other times the coil requires replacing (or rewinding).

[nickb]

Thanks for taking the time to take and post those images, Juan.

I wasn't considering any production type arrangement but I always enjoy reading and learn from your problem-solving abilities. I think I've found someone who can make me a small run. I'll have to see what the price comes up as.

The actual bore is 3.5 x 1.75mm - much smaller than any off the shelf bobbin I've found so far.

[J M Fahey]

OK, that's a custom bobbin, probably not even used on transformers.

Where will your supplier get the empty plastic bobbins?
Unless he's the Korean OEM supplier, that is.

In your case, I'd disassemble all dead bobbins, pull wire (not unwinding but cutting most of it to save time) , and rewind all them in a single session, only way to make it $$$$$ worth.

The pickup winding guys might give you a suggestion or two about winding fine wire.

[nickb]

OK, that's a custom bobbin, probably not even used on transformers.

Where will your supplier get the empty plastic bobbins?
Unless he's the Korean OEM supplier, that is.

In your case, I'd disassemble all dead bobbins, pull wire (not unwinding but cutting most of it to save time) , and rewind all them in a single session, only way to make it $$$$$ worth.

The pickup winding guys might give you a suggestion or two about winding fine wire.

Yes, it's a custom. I just wanted some empty bobbin. I do have a coil winding machine although I never used anything thinner than 0.14mm (36 awg -ish). No doubt that will be a whole fun exercise in itself but the p/u guys are welcome to chip in.

Hmmm, a 3D printer might work.

[Enzo]

I had a luthier client once who needed a connector for some amp pedal, and lacking one, he carved one from a block of maple and made pins of thick piano wire stock. I had to applaud his ingenuity, even at the cost of losing my sale of a $4 plug. On the other hand, unless this is a dear project, really, how many hours labr goes into fixing one reverb pan like this? And costs at your labor rate?

[nickb]

I had a luthier client once who needed a connector for some amp pedal, and lacking one, he carved one from a block of maple and made pins of thick piano wire stock. I had to applaud his ingenuity, even at the cost of losing my sale of a $4 plug. On the other hand, unless this is a dear project, really, how many hours labr goes into fixing one reverb pan like this? And costs at your labor rate?

Point well taken. There is a little more to this than simply repairs that means it makes more economic sense that is might otherwise seem.

Thanks guys.

[Mick Bailey]

I repair reverb tanks wherever possible (just done a couple this week). In the UK they're nowhere near as cheap as in the US. For me the economics come down to getting a repair done there and then, or ordering and waiting around for parts. Parts cost knocks down the profitability on a job due to the ceiling price that I can place on any particular repair. Buying a new tank means money going into someone else's pocket.

[Enzo]

While I am selling off my shop now, when I was in operation, I kept a 4EB, an 8EB, and a 4AB pan in stock. When I used one, I'd then order a replacement.

[nickb]

While I am selling off my shop now, when I was in operation, I kept a 4EB, an 8EB, and a 4AB pan in stock. When I used one, I'd then order a replacement.

That covers about 90% of amps. I also carry 9EBx, 9ABx and also medium and long delay versions. That reminds me. Mick B - if you need some tanks at a decent price PM me and I may be able to help.