Guyatone pickups

[Mark Hammer]

The other day, I was working on what I gather is a Guyatone guitar I picked up a few years ago. I'm assuming it's a Guyatone, based on the very distinctive pickups found on a great many Guyatone guitars, including a lap steel I have that I know is a Guyatone by the nameplate on the headstock.

I had added a couple hundred extra turns on the bridge pickup to "heat it up", but the extra turns were a tad on the microphonic side so I needed to pot it. While it was apart, I snapped a pic, seen below. It has an interesting structure. You can see that it has a soft iron baseplate, whose "sides" bring the bottom pole of the bar magnet up at the sides. Tghe bent sides do not extend up as far as the top of the coil, the way they do on a classic gold foil. But, unlike some of the "economy" Strat pickups I have with a ceramic bar magnet on the bottom (and a Kent Armstrong I have as well), this magnet isn't simply glued to the bottom flatwork of the pickup. The bottom plate is used to extend the field outwards. The result is that, even though the stock unit has a DCR of around 2.7k, it's still pretty meaty-sounding. I should note that the shiny pickup cover is not ferromagnetic in the least.

I'm becoming more and more convinced that ferro-magnetic baseplates are where it's at.

[Antigua]

Do you have a way to measure the inductance?

[Mark Hammer]

I have an inductance range on my meter, but I wouldn't bet the farm on it.

[Antigua]

The walled, ferrous base plate probably increases the inductance by a good fraction. But I would bet that the eddy current attenuation caused by both the cover and the metal base probably have a lot to do with giving it a beefy tone. I felt the same way about the Burns TriSonics, and they too have a low inductance, very low Q.

[epizootics]

Thanks for the picture, it's always nice to see the guts of those old pickups. I assume that magnet is ceramic? Those designs seem to need a strong-ish magnetic field to balance out nicely.

[Freekmagnet]

My thanks to you for posting this as well. Seeing these old designs is really inspiring.

[freefrog]

Another thank you for this topic!

Albeit the coil is not bobbinless, I also understand that like an attempt to copy the Tri-sonic structure and I'd be grateful as well to know its measured DCR / inductance (some regular Tri-Sonic's that I've here read 6.7k /1.9H for three of them and 6.5H / 2.43H for one of them, for the record. It matches @ +/- 10% the values published online here and there, except for mini-Trisonics which are obviously different beasts).

Finally, as an hommage to the work done by someone else, I'd like to share this link: https://drowninginguitars.com/2012/0...-encyclopedia/

[Mark Hammer]

Wow! Thanks a batch for that. I probably have a number of those (well, a few....it's a LONG list at that site) in my to-repair-and-try-out bin. I have a copy of Dave Hunter's Guitar Pickup Handbook, but the vast majority of what's on the linked-to page is not included in his book.

The pickup I disassembled looks like the Crestwood pickup, but is half the listed DC resistance. I have a pickup that appears to be the same (at least cosmetically) to this one: https://drowninginguitars.files.word...heit-6-11k.jpg The coil was damages and I had no idea what sort of DCR I should aim for in rewinding it. Now I know, so thanks!