Don’t worry, this pic of a pure unmolested ’70s Guild HB-1 in mint condition with its unused ring, perfect springs and screws is not the pickup I dismantled. Doing that would make me a monster.
For this discussion I have sourced a Guild HB-1 that’s had its cover removed and came to me in an inoperable state. If worse comes to worse, then I lost a few bucks buying a broken pickup but I documented its autopsy for science. That’s what this is; this is science.
People removed the covers because they didn’t like the tone and were trying to get rid of parasitic capacitance. That, or they thought it would look cool with the cover off. Looking dumb in the pursuit of tone is good. Looking dumb in the pursuit of looking cool is dumb. So sayeth GAD.
Upon unwinding the black tape I was greeted with a liberal application of yellow tape, this appearing to be more like electrical tape in look and feel. If you thought the pickup looked great with the cover off, well then surely you must appreciate the fisherman’s raincoat yellow of the new tape. I mean, come on, that right there would look killer in a bright pink ’80s shred machine, don’t you think?
The problem with the pickup turned out to be one of those tiny wires being broken. I decided to detach them all and proceed with the teardown. As we’ll soon see, this proved to be a mistake.
With all of the yellow tape carefully removed, I then got a tiny screwdriver and pulled the two screws holding the slug bobbin in place. With those screws loose enough the bobbin pulled right up leaving the center four slugs while the outer two remained stuck in the bobbin. With the bobbin screws loosened on both coils I was then able to slide the bar magnet out. Note that you do not need to pull the tape or take the bobbins off if you want to swap the magnets, though I’ve never heard of anyone doing a magnet swap on a Guild HB1.
One of the things that’s always been a mystery for me is the type of magnet in these pickups. Having one in-hand and dissasembled, I set about figuring out how to tell what type of magnet it was.
The magnet in an HB-1 is most certainly not ceramic because those tend to be black while Alnico magnets tend to look like metal. This one looks like metal, so I’m going with Alnico since vintage guitar bar magnets are usually Alnico.
Within this chart are two columns entitled Gauss (under residual induction) and Oersteds (under Coercive Force). Gauss is a well known measure of magnetism and Oersteds are the unit used to measure how strong the pull of a magnet is which, yes, is a different thing. What I wanted to measure was Oersteds, and to do it I needed a Gauss meter. Those wacky scientists and their oddly named toys are always good for a laugh.
Armed with my chart from the magnet people, I could see that an Alnico 2 magnet generally reads 560 Oersteds while an Alnico 5 magnet reads 640 which means…
Unfortunately I broke the inbound lead wire on one of the bobbins when I dismantled it so I was unable to measure the resistance of each one individually. That means I don’t know if they’re wound differently from each other which kind of sucks because it might be part of the magic. I’ll have to be on the lookout for another vintage HB1 to
torture and dissect analyze. Since the pickup was broken when I started I couldn’t get a measurement of the entire thing, either. This is why I’m not a scientist.
Even though my science was a miserable failure, I figured I’d post this article anyway because who wouldn’t want to see torn-apart gut pics of a Guild HB1 pickup? I know I would if I were you.
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8 thoughts on “Guild HB-1 Pickup Teardown”
GAD please tell us the AWG of the wire used in the pickup coils, the bobbin and slug measurements etc. this will provide other potentially important properties of the pickup. BTW I think this is very important for the 100’s of us not so lucky to have scored a set of HB1’s. In medicine they say “the dead shall teach the living.” this is certainly the case here.
Thanks in advance
Your weakness as a scientist is certainly compensated for by your strength in writing and photography. The documentation of the HB1 sacrifice will certainly save the life other pickups as the potentially homicidal curiosity of likely pickup sadists could be abated.
Some time in the 1980’s, I took the cover off one of the pickups of my S-300 (just out of curiosity). My view of it’s appearance was pretty much the same as yours; the colour of the bobbins is just wrong and those square slugs look a little odd. To be honest, I always liked the look and sound of these pickups, with covers on, too much to seriously consider using them with the covers off.
Do not be sorry for the broken wire of the coil that you could not measure – it was probably broken to begin with – the two coils are in series – and if one is kaputt you can not measure total impedance either.
And when you find that second dead pup – you can play dr Canavero – join them to live happily ever after.
Good reading – Nuuska
Can you tell me the correct/recommended pickup height for Guild HB1 pickups?
I don’t recall ever seeing a published document, but that doesn’t mean that one doesn’t exist. Like all pickups, I just adjust them to where they sound best.
Have you ever removed the cover from a new HB-1?