Teach me about Supro lap steel pickups

[Mark Hammer]

A buddy has offered me a lovely old mother-of-toilet-seat Supro lap steel, with one of those over-and-under pickups that look like a wide-range humbucker from the top. I gather it functions like a horseshoe, though maybe not exactly.

He says the unit is dead, though I have no information as to whether the deadness lies in the pickup itself, or something preventing the pickup from sending out its signal.

I'm open to any collected wisdom, or links, you may have on the nature of the pickup, in case I have to rewind it. At the very least, what should I expect to find?

[David King]

Magnut might know something about Supro lap steels. He's studied the guitar ones pretty extensively.

[Lollar Jason]

You probably know I have been making repros of those for 6 or 8 years and was the only one doing so until about a week ago, the bobbins are really funky. The holes that the pole pieces run through are made of really small paper tube or straws so they will crush on each end from wire pressure. One way to deal with that is to soak the paper core with super glue to harden it and after it dries put a piece of the correct size dowel or steel rod in each end hole. Better yet make a clamp caul with a couple pieces of acrylic so you have a caul on top and bottom of each bobbin and run machine screws through each outside pole hole and screw it fairly tight- this will keep the thin paper flatwork top and bottom from warping completely, thats how I rewind, usually I just replace the entire bobbin with ones I make which are way better. The interconnect is made from some stranded fender hookup wire- take on strand out from the bundle- youll see when you open the pickup.The tape surrounding the coils is to keep the bare wire interconnects from shorting out the pickup to the steel case
Both wound same direction- they are hooked together so they humcancel but both magnets have to be facing the same polarity so one coil is out of phase with the other. If one magnet is flipped the wrong way so one is north and one is south youll get some strings dropping out in volume- very common problem. another problem is the student models only had a magnet on one side and they used a painted wood block on the other- doesnt work very good, they really need two magnets. 44 gauge wire 5000 turns per coil. Be careful taking the coil cover plate off- the tabs can break if bent too hard or two many times then youll have to make another cover plate.

[rjb]

Be careful taking the coil cover plate off- the tabs can break if bent too hard or two many times then youll have to make another cover plate.

Does anyone know if the tabs can be annealed to make them less brittle?
I don't own a Supro- but do have other pickup cover plates held by tabs.

[Mark Hammer]

Thanks for that Jason. Much appreciated. Unfortunately, I made the mistake of doing a Google image search for "caul" instead of "clamp caul". Lemme tell ya, a VERY different set of pics!

[Magnut]

Thanks David, I saw this but waited as I figured Jason would chime in. He knows much more than I in regard to the Laps. I do love those Supros though...

[Lollar Jason]

Ha! Never occurred to me Mark!

[ScottA]

(edit) ...another problem is the student models only had a magnet on one side and they used a painted wood block on the other- doesnt work very good, they really need two magnets.

I just got done doing a Floyd tribute, and I borrowed the keyboard player's (also a guitar player, very versatile guy, actually) old National Waikiki model.

As I was learning how to play it, I noticed some output imbalance, with the high E especially suffering.

I took it apart and realized that the "magnet" serving the high side was not very strong. I tried to recharge it with some Neos and it didn't work. It does have a slight charge, but I'm assuming it's just slightly magnetized steel. It's not painted wood, it's cast, but it's got a slightly different shape and surface morphology than the magnet.

At first I just swapped them out, and put the working magnet on the high side, as I was playing mostly on those strings for these songs. It was still compromised, though.

Jason was kind enough to sell me two replacement magnets for it, and that thing cranks now. Jason's mags are a little stronger than the one original magnet.

Here's a little clip of it in action:

https://www.facebook.com/claire.lawi...7564879065112/

[fieldwrangler]

Sounded like a fun clip to hear, but I keep getting a "sorry, expired or you're just not worthy" kindof prompt when I try to access it...

[Lollar Jason]

Thats the problem with the original magnets- not consistent at all- seen it happen on these supros and rick horseshoes where the magnets were almost dead and wouldnt take a charge. A real shame with a horseshoe!Its either inconsistent material or with shoes it can be that it wasnt hardened properly

[ScottA]

Sounded like a fun clip to hear, but I keep getting a "sorry, expired or you're just not worthy" kind of prompt when I try to access it...

Try this one it's on the band's FB page so everyone should be able to see it. The one above was on my wife's page. Worst case, if you like the band page you should be able to see it.

https://www.facebook.com/14046934279...3034988209065/

This is actually the first show on 9/18. The one I linked to above was the second show on 9/25.

The building was actually cleared at the end of this clip, that's what's going on. I guess the fog set off the fire alarms, lol.

I'm kind of torn on which is better. I think overall my intonation was better the second night (I was hearing myself on stage much better which is critical), but there were a couple of more obvious clams...