Stringmaster pickups

Tim Whitlock · From: Colorado, USA

I had sold my '56 Stringmaster in 2001 and last week I bought it back. As you can see from the photo it has been used hard. It sounds magnificent except the middle neck is out of phase with the other two. It sounds like a transistor radio when I play the middle neck. It was not that way when I previously owned it. I checked the wiring and it looks correct and unmolested. I did replace the .05 cap but otherwise I don't think anything has been touched beyond spray cleaning the switches.

Could the out of phase sound be simply due to deterioration of the pickup over time?

Dave Mudgett · From: Central Pennsylvania and Gallatin, Tennessee

When you say it is 'out of phase' with the other two, do you mean that it's thin when the middle and one of the other two are on, or is it just that it's thin sounding when switched on by itself? Very different scenarios.

If it's only thin when switched on with one of the other pickups also switched on, then that might be a phasing issue.

But if it's thin when switched on by itself, that that is not a phasing issue. One thing that can happen is if a pickup's windings open up - break, giving essentially infinite resistance to the coil. Then what you hear is essentially what is passing through the capacitance of the coil. Since a largely pure capacitive circuit is a high pass filter, all you get is the high frequencies, leading to the thin sound. The cutoff frequency of that filter depends on the exact impedance parameters of the circuit - which at this point is almost purely capacitance and inductance.

Pickup coils can break for many reasons - e.g, rough handling, breakdown of the wire from age, corrosion in the coil itself, breakdown of the bobbin, and so on. So measure the resistance of the pickup coil. If it's way higher than the typical rated resistance, like more than 1 Meg Ohm or completely off the scale at the highest resistance setting, than that's definitely an issue.

If the coil is broken, sometimes it can be repaired by unwinding the wire until you hit the break. Failing that, the solution is to rewind the coil.

Tim Whitlock · From: Colorado, USA

Thanks for your very informed reply Dave! The middle neck sounds thin by itself or in combination. I say it sounds "out of phase" because it has that slightly lower output, thin midrangy sound like a Les Paul that has been wired out of phase.

My meter is down so I'll order a new one and see what the resistance looks like.

Bruce Derr · From: Lee, New Hampshire, USA

Dave explained it perfectly. I'll just add that if you're adventurous, have good eyesight (a magnifier helps), and can solder, you might take a close look at the pickup where the coil wires are terminated. If the break is there, it might be fixable.

I've had this happen to me twice recently, on a Carpsteel pickup and a Tonealigner. I was able to fix the Tonealigner. On the Carpsteel pickup I found the break but couldn't manage to make the repair.

If you find the break (you might have to carefully peel back the tape covering the winding a little), keep in mind that the wire is enameled and needs to be scraped with a knife before it'll take solder. I usually solder a short piece of insulated #30 wire to the loose end so I have something a little more substantial to work with.

I have performed similar repairs on transformers, a reverb tank coil (the coil itself, not the flying leads), and the like. It's fussy work and there's certainly some luck involved when it succeeds.

K Maul · From: Hadley, NY/Hobe Sound, FL

If you need that pickup fixed I recommend Jerry Sentell. He could also make you a new one, which he's done for me, as well as fixing Fender Boxcar and Trap pickups.https://www.sentellpickups.net/
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KEVIN MAUL: Airline, Beard, Clinesmith, Donner, Evans, Excel, Fender, Fluger, GFI, Gibson, Hilton, Ibanez, Justice, K+K, Live Strings, MOYO, National, Oahu, Peterson, Quilter, Rickenbacher, Sho~Bud, Supro, TC, Ultimate, VHT, Williams, X-otic, Yamaha, ZKing.

Bob Hoffnar · From: Austin, Tx

Before you mess around with the pickup check for cold solder joints. One way to do that is to check the ohms with a multi meter on the contact points before the solder joint. A cold solder joint is a very common reason for your issues. You can also just resolder the pickup if you donâ€™t have a meter. (Multi meters are pretty cheap BTW)

Oh yea, also check your pickup selector switches if your multi meter says the pickup is fine.
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Bob

Jerry Erickson · From: Atlanta,IL 61723

As Bob said, check your pickups. Disconnect the hot lead and test the pickup with your meter. I have an Epiphone Electar Zephyr that I thought had both pickups with open windings. I removed one to send it in for a rewind and put a meter on it to check it. It read around 6.5K ohms, not the megaohm reading I was expecting to see. I replaced the wiring harness and all is good now. The original switch and pots had a whitish powder on them, probably in them as well. The harness was giving me the false reading with my ohmmeter when the pickups were still attached to the harness.

Tim Whitlock · From: Colorado, USA

I checked all the pickups. All read 7.7k - 8k ohms except for the middle bridge pickup which read 330k! Sending it off to the very capable Mr. Nick Fryer for repairs.

Thanks to all for the advice!

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