supro in bridge pickup

[johnnydr]

Hi, I've been a member for a while, but I think this is my first post. I've picked up lots of great info here, thanks. Anyway, I just got a supro pocket bass at a junk store. It has one of their in the bridge pickups. Anyone know how these work? Mine works fine, I like the sound, but I'm not sure how it works. I haven't unstrung it yet to take a look, and I'm not even sure if I will be able to tell once I do that. It looks like there are 2 poles coming down from the top part of the bridge, where the strings bear. Are they magnets going into a coil in the bottom part of the bridge? I am imagining the magnets vibrating from the string vibration and inducing a current from the coil. I hope I explained this well enough. I will probably sell the Supro, I got it really cheap. But I was thinking a pickup like that might work well on a mando bass I was thinking about building. Thanks, Johnny

[Peter Naglitsch]

No first hand info on this but a quick google reveals that it is a piezo pickup embedded in the bridge and there is a balance control between piezo and magnetic neck pickup

[johnnydr]

Thanks for the reply. When I search piezo pickups I see they were invented in 1969, so I don't think that is what these are. I'll be taking the strings off the bass today so I can clean it up, and if possible I'll take pics and post.

[johnnydr]

having trouble loading pics, but there are 2 thin rod magnets attached to the top portion of the bridge, they insert into two small coils inside the bottom portion of the bridge.

[Peter Naglitsch]

having trouble loading pics, but there are 2 thin rod magnets attached to the top portion of the bridge, they insert into two small coils inside the bottom portion of the bridge.

Now we really need pics!

[David Schwab]

Now we really need pics!

Daily Guitar Repair: What I believe is a 1965 Supro Martinique, with a pickup problem


Interesting pickup idea! Kind of like the Ampeg "mystery pickup" without the steel diaphragm.

[jonson]

There is a patent for this.

[big_teee]

There is a patent for this.

That is cool! If I read it correctly?
So I guess by magetizing the bridge, the bridge would need to be 1010, 1018, or similar steel?

[David Schwab]

That is cool! If I read it correctly?
So I guess by magetizing the bridge, the bridge would need to be 1010, 1018, or similar steel?

There are two rod magnets sticking down in the coils that move with the bridge.

[johnnydr]

David, thanks for the pics, that one looks just like mine, except mine is notched for bass strings. I'm making myself a baritone guitar right now, I think I'll try to make a pickup somewhat like this for it.

[Peter Naglitsch]

Realy interesting. I would have thought that either the magnets of the coils would have needed to be mounted somwhat flexible (introducing more movement) to produce a decent output.

@ Johnnydr: How is the bridge pickup output compared to the more traditional pickup output in tems of pure volume?

[jonson]

Everything I ever read about the pocket basses with their short 25 inch scale rated them as one of the best basses for recording. That is if you like bottom end tone. Seeing as nine out of ten I pick up either my eb3 or eb2 as I like short scale and bottom end then gonna have to clone one of these to find out.

[David King]

There was an acoustic guitar pickup back in the day that used a moving magnet inside a fixed coil. When you think of how highly evolved stereo record needles/cartridges were back in the day I bet we have everything we need to get absolutely killer sound out of a small interface. Of course it might take and RIAA preamp to really get the bass out.

[David Schwab]

Of course it might take and RIAA preamp to really get the bass out.

No, it should be full range. The RIAA curve was used to reduce bass while cutting the record so the grooves wouldn't be too wide. Then the preamp restored the original tone by boosting the lows.

That's one of the things that cracks me up when people say vinyl is more accurate. It was never an accurate representation of the master tapes. It's been compressed and EQd on the way to the cutting machine. It's just a sound we were all familiar with.

[David King]

David, the IRAA curve was also used to reduce surface noise by accentuating the treble when cutting the groove and then reducing the same about to restore the original sound. Not that different from Dolby B on cassette tape. Granted the whole concept is somewhat flawed but it worked well for what it was intended to do and the musicality is there. I'll take late '70s vinyl any day over early '80s CDs.

I used to run my bass through an old tube Eico RIAA phono preamp to boost the bass. It was fun for dub and I was saying it tongue in cheek. Sorry if the humor evaded your detectors.