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Topic: Stringmaster volume between necks |
Ed Baker
From:
Connecticut, USA
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Posted 2 May 2019 5:17 am |
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Hello all,
I have a 1954 Stringmaster dual 8, 26" scale, that I've been restoring for a while.
The volume between necks is dramatically different. The top neck is much stronger than the lower neck.
The blend knob works fine on the upper neck. But, the lower neck's neck pickup doesn't seem to respond at all.
I've got both necks strung with a new set of John Pearse #7650 strings.
All of the pickup to string distances are about 1/8 to 1/3 inches.
Does anyone have a wiring diagram for this?
Any suggestions for testing the dead pickup without major disassembly would be welcome.
Thanks
Ed Baker
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Tommy Martin Young
From:
Sacramento-California, USA
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Posted 2 May 2019 6:01 am
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(Edited to remove wrong wiring diagram)
One way to test pickup with multimeter set to 20k ohms
- Plug in to lap steel, make sure volume is on
- probes per the pic (you can hold probes to jack)
- I tested this same guitar on a hot day and got a reading of 7.01k
- this is just for testing to see if the pickup is live and only an approximation of actual output
_________________
The One & Lonely Tommy Young
"Now is the time for drinking;
now the time to beat the earth with unfettered foot."
-Quintus Horatius Flaccus (65-8 B.C.)
Last edited by Tommy Martin Young on 2 May 2019 8:12 am; edited 1 time in total |
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Ed Baker
From:
Connecticut, USA
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Posted 2 May 2019 6:46 am
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Thanks for replying, Tom
I don't think that schematic matches up with what I've got.
The old Stringmaster has only two knobs. The schematic you found has three. And, the schematic seems to be for a single neck guitar. There aren't any neck selector switches on it.
The neck selector slide switches on the Stringmaster are 'on' when down toward the player. They allow selecting either neck or both.
I wanted to see how the wiring from the selector switches to the volume and blend knobs was done.
It seems hard to find a diagram just 'googling' around. Thanks for your reply though. |
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Brad Davis
From:
Texas, USA
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Posted 2 May 2019 6:59 am
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You are correct, that is the wrong wiring diagram for this guitar. That is a diagram for the later "Mark II" revision guitars. 1953-55 long necks have a different circuit. Please see here for my ramblings and postings about all the stringmaster diagrams I could find. The best diagram for this guitar is probably the one from Forrest White's book.
https://bb.steelguitarforum.com/viewtopic.php?p=2650415 |
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Fred Treece
From:
California, USA
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Posted 2 May 2019 7:14 am
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The knobs are volume and blend, not volume and tone, like in the diagram in Brad’s link?
No broken wires from the pickups or pots? |
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Bill Sinclair
From:
Waynesboro, PA, USA
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Posted 2 May 2019 8:38 am
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| I'll bet you have an open pickup winding on the lower neck. Sometimes they will still function due to capacitive coupling but sound weak and thin. I purchased some early stringmaster parts guitars a while back and five out of the seven pickups were open. Tom Brantley did a great job of rewinding them for me. The Seymour Duncan and other reissue Stringmaster pickups will not work on your long scale guitar (too big). Try the method that Tom Young illustrated to check the pickup resistance of one neck against the other and let us know what you find. |
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Ed Baker
From:
Connecticut, USA
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Posted 2 May 2019 9:42 am
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I was afraid what Bill just said about an open winding.
I guess I'll just have to take everything apart, and test it with a multi-meter.
That link to the "Stringmaster Project" started by Brad Davis on 7/12/2017 is terrific. Thanks for pointing me to it.
BTW, I used to use a steel tuning fork held a 1/4 inch or so above the pickup on standard guitars to test them. That gave a good indication of output compared to just tapping with a screwdriver. You can also check the tone controls with that method.
Do you remember how much the rewinding cost? |
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Bill Sinclair
From:
Waynesboro, PA, USA
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Posted 2 May 2019 10:16 am
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Ed,
Before you take everything apart, check the resistance with a guitar cable like Tom shows above. Volume all the way up, one neck at a time. Since the neck and bridge pickups should be wired in series, I'd expect something around 10K or so with just the good neck turned on and something higher or an open circuit on the weak neck. (I'm just guessing here since I don't have one wired up.) Let us know what you find before we assume it's an open winding. |
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Ed Baker
From:
Connecticut, USA
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Posted 2 May 2019 12:52 pm
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The upper neck reads 3.4K ohms at the lead cord with both volume and blend turned up maximum.
The lower neck is open.
I know that number is extremely low. But, I checked my ohm meter across a couple of volume pots. The pots were rated at 250K ohm and read out correctly. |
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Bill Sinclair
From:
Waynesboro, PA, USA
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Posted 2 May 2019 1:39 pm
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| Ed Baker wrote: |
The upper neck reads 3.4K ohms at the lead cord with both volume and blend turned up maximum.
The lower neck is open.
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I may have been mistaken about the pickups being in series. Glancing at the diagram in Brad's linked thread, it looks like when the neck switch is thrown they might be in parallel through the tone (balance) pot until the pot is turned all the way up and the bass pickup is fully bypassed. I need to study it a little closer. 3.4K may be about right. The loose single pickup I just measured reads a little over 6K. Does the lower neck measure open with the tone control at both extremes?
I think Tom Brantley charged me $80 for the Carvin pickup he rewound for me last month. That may be his going price now. Contact him through his website once you know how many you may need. |
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Jeff Mead
From:
London, England
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Posted 2 May 2019 2:26 pm
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I see that one of the necks has no strings on it. That would make it much quieter than the other  |
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Ed Baker
From:
Connecticut, USA
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Posted 2 May 2019 2:58 pm
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That was just a photo from long ago when I started cleaning it up. Both necks are strung with a new set of John Pearse C6th strings now.
To say this guitar has "patina" is being waaaay to kind. I'm not too surprised that it has issues.
I just wanted to have a Stringmaster and it turned up on Craig's List  |
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Roy McKinney
From:
Ontario, OR
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Posted 2 May 2019 3:16 pm
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| Check the grounding on your pickup. On my T3, the grounds are made by a screw in the wood. No ground no output! |
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Bill Sinclair
From:
Waynesboro, PA, USA
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Posted 2 May 2019 4:11 pm
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| Good point, Roy. The grounding on a lot of Stringmasters is a piece of wire stapled to the wood and the staple is supposed to touch the switch plate to ground it when it is screwed down. |
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Brad Davis
From:
Texas, USA
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Posted 2 May 2019 8:32 pm
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| Probably not a culprit but there is also a flimsy bridge ground for each neck on these. A thin piece of wire running from the top right screw under the bridge pickup surround to underneath the bridge plate. Generally they are a little blackened or rusted and pressed hard into the wood and paint with age - it's difficult to tell sometimes if they are even making good contact any longer but I've never messed with one other than making sure it is still in place on the rare occasion that one came loose. |
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Erv Niehaus
From:
Litchfield, MN, USA
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Posted 3 May 2019 8:44 am
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The pickups are wired in sort of a humbucker fashion, in opposite directions.
The tone control lets you dial one pickup in or out, I forget which one.
Erv |
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Chris Clem
From:
California, USA
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Posted 3 May 2019 9:46 am
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Hi Ed,
If you think you have bad pickup the (surefire) way to check it is with an Ohm meter right at the eyelets on each pickup coil.Write them down,they should all read fairly close to each other.If one is way off from the others then you'll know for sure......Chris |
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