1974 Guild M-75 - you're now mine

Phase Shifter

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I looked it over and have one question. The black wire that comes from the left to the phase shifter switch, is that connected to the middle left pole of the switch? It's under the gray wire in the picture.

It does look like I wired mine almost correctly. I did connect the ground to the upper left of the phase shifter instead of the lower right like yours but it's the same point electrically.

I'll do a better diagram soon so we can have it as a reference for others who bought modified guitar like mine.

Thanks again for the help!
 

Russian Guy

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To me it looks like it's connected to the lower left pole.

1-1.jpg


2.jpg
 

Phase Shifter

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The last picture looks like middle left. That is really the way it should work, I think.

If it was connected to the lower left, the pickups would work one way, then be completely disconnected the other way because the ground on the lower right would have no connection to the pickup wires. If it is wired that way, it would work as a cut out instead of a phase switch.

When you use that switch, does the down position give you a funky, nasal-type sound?
 

Phase Shifter

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Okay, here is a better wiring diagram. I wired the black wire from the bridge coil like I think it is supposed to be. Please double check to see if the black wire is connected to the middle pole.

guildstock.jpg
 

Phase Shifter

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The theory with the phase shifter switch is with the switch in the down position (looking at it the way it's configured here), the ground comes in, goes to the red wire via the contacts inside the switch, through the pup and out the black wire to the switch. The signal then goes through the switch, across the jumper from the bottom left to upper right, then to the volume pot.

If the switch is in the up position, the signal comes from the ground across the jumper from the bottom right to the upper left, through the black wire first, then through the pickup and out the red wire. It will then go across the closed contacts of the switch to the upper right pole and out to the volume pot.

So one switch setting enters the black wire first while the other enters the red wire first. If the pups are wired to work CCW, the phase switch would switch the bridge pup to CW, making them out of phase. From what I hear, it's a funky, nasal sound.

If the black wire is connected to the lower left, the pup will not be connected at all if the switch is in the up position. The signal would come in from the ground, jumper up to the lower left pole and stop since no wire would be connected to the middle left pole.
 

Zelja

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The phase switch basically swaps the plus & minus wires on the bridge pickup around. That's why your bridge pickup has 3 terminals on it & your neck only has 2. On the neck PU the minus wire is connected to the PU body & a single wire connects both gto ground. On the bridge there is a separate ground wire which is connected to the PU body only & then the 2 separate wires for the plus & minus of the PU are connected to the switch which chanes which ones goes to ground & which is used as the hot wire.

From my experience (so far sample of 1 only) in Guilds, when the phase switch is down & both pickups are selected, the pickups are out of phase with each other & provide a thinner sound than when the phase switch is in the up or normal in-phase position. The real fun starts to happen when you start backing off one of the volume knobs even just ever so slightly - you'll actually get a fuller sound & lots of different shades. Seems sort of counter-intuitive but remember when out of phase, the 2 PUs are cancelling a significant part of each others signals causing the thinner tone & less output. Once you drop the volume of one of the PUs there is actually less cancellation overall & hence a fuller sound.

If you are still reading after al this there is one more thing to try - select the bridge PU only & see if you can hear/feel any difference in the sound when you flick the phase switch, especially at some volume. It should sound more or less the same but I think one position sounds slightly fuller than the other. Which position depends on the amp you are playing (if the amp inverts the input signal or not - e.g. the normal channel of a blackface fender doesn't invert, the reverb channel does, Top Boost channel on a Vox doesn't invert, the normal channel does) & possibly also your position to the amp.

The easiest way to try this is to play a power chord into feedback in both positions One will feedback easier & at a fuller (lower) frequency. I think it has to do with the output coming out of the amp being in phase with the strings/initial signal & the acoustic reinforcement that occurs. Anyway, just my experience & thoughts - it would be good if someone else tries this to prove I'm not nuts (or at least not alone in being nuts). :)
 

Russian Guy

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Phase Shifter said:
If the black wire is connected to the lower left, the pup will not be connected at all if the switch is in the up position. The signal would come in from the ground, jumper up to the lower left pole and stop since no wire would be connected to the middle left pole.

Right you are, sir! Having studied the 2nd wiring scheme you posted I've noticed that if the black wire was connected to the lower left pole it'd be wrong.

Phase Shifter said:
Please double check to see if the black wire is connected to the middle pole.

I just did and you were right - the middle left pole. It's just so easy for a layman like me to get lost in that web of wires :lol:

P1040743.jpg


P1040745.jpg


You hit the nail on the head, the phase switch does give that nasal sound.

Zelja said:
If you are still reading after all this there is one more thing to try - select the bridge PU only & see if you can hear/feel any difference in the sound when you flick the phase switch, especially at some volume. It should sound more or less the same but I think one position sounds slightly fuller than the other. Which position depends on the amp you are playing (if the amp inverts the input signal or not - e.g. the normal channel of a blackface fender doesn't invert, the reverb channel does, Top Boost channel on a Vox doesn't invert, the normal channel does) & possibly also your position to the amp.

The easiest way to try this is to play a power chord into feedback in both positions One will feedback easier & at a fuller (lower) frequency. I think it has to do with the output coming out of the amp being in phase with the strings/initial signal & the acoustic reinforcement that occurs. Anyway, just my experience & thoughts - it would be good if someone else tries this to prove I'm not nuts (or at least not alone in being nuts). :)

Hey, Zelja. You're right - either we are both nuts or we're onto something. Back in 2011 when my only Guild was S-300AD I was trying to recreate or get as close to that single-coil tone when playing Good Times, Bad Times by Zep. It was the first song on their debut self-titled album. And back then Page didn't have his LPs yet so all those riffs were recorded on his Tele. So, I noticed that the best way to do that was the aforementioned method - switch to bridge pup and flick the phase switch down. It seemed to sound thinner and less angry-sounding. But then again the difference is so slight that you gotta literally listen the best you can to hear the difference.

I gotta try this more with M-75. Although I think I've tried it in the past months and since the body is so much thicker I could pick up the difference. Still gotta try it one more time.
 

Phase Shifter

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Glad we got those wires straightened out and I REALLY appreciate the pictures. I guessed with mine, copying the neck pickup to rewire the bridge. It's still not exactly how it came from the factory (250K bridge volume pot and .01 cap) but it sounds sweeter than any LP I have ever played. The pickups are smooth, even, and catch every sound from the strings. I even get the pick-bark like Moby Dick. Now I am searching for another M-75 instead of another Les Paul!

This one was a Christmas gift from my dad in 1981 and he hated rock music but saw I had so much talent he wanted to see what I would do. It means more to me than most things I own. My dad passed in 1983.

I would like to get another one to gig with though!
 

Russian Guy

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Glad to be of help :) And that's a sweet story about your dad buying you M-75. I too don't even want to own a Les Paul. This Guild is very sweet and I hate that I can not do it justice with my low playing skills.

They pop up occasionally but as with most vintage Guilds to find a bargain is a really difficult task. I'm on the constant hunt for a vintage S-100 and it kills me that I literally slept on a very clean model that went for paltry $890 with OHSC and it was cherry red.

I'm currently trying to raise the price down on one carved model that's on Ebay from outrageous $2000 (it's not mint, I'd say it's VG to EXC- and comes with a flimsy chipboard case). But since it's on consignment and the owner apparently doesn't want to sell it that bad they can't afford to go less than $1700.
 

Phase Shifter

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I daydream of finding one in a pawn shop, or on craigslist, or a yard sale. I'd buy 4 or 5 if I could find them cheap enough!
 

Phase Shifter

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I have never played an M-80. Is it the same with just the cut away? If it is, I'll take a few of them, too!
 

Russian Guy

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Phase Shifter said:
I have never played an M-80. Is it the same with just the cut away? If it is, I'll take a few of them, too!

For all practical purposes M-80 was a double-cut version of M-75 - as written by Hans in the Guild Guitar Book. Note that these were made only from 1975 to 1977. So these are even rarer than M-75s. Furthermore during that particular period Guild produced maple-topped M-75 and M-80.

Maple-capped M-75

P3240101.jpg


Maple-capped M-80

gal3.jpg


In the 80s there were two more incarnations of M-80 both of which don't share any similarities with their 70s counterpart.

1981 M-80

This one has no binding on the neck and the body.

1981cM-80.JPG


Whereas this one has got it all.
1982 M-80

1982aM-80.jpg


Both have maple tops and mahagony backs. The earlier 80's M-80 has got a 3-piece maple neck. I'd assume the later model has the same neck because the later incarnation just seems like a fancier version of the former.

The biggest difference of course is the pickups - the 80s M-80s (and that's a lot of 80s in one sentence :lol: ) have DiMarzio XR-7 pickups.

P.S. On Gbase there is both M-75 and 70s M-80 for sale from different guitar dealers and both are in $1600 ballpark.
 

Phase Shifter

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$1600 is not bad when you consider how much the Les Pauls from the time period are going for. I can't (don't want to) afford that price tag but I do buy lottery tickets every now and then, lol. I have 9 guitars so it might be difficult convincing my wife I just have to buy one that expensive. I think they will appreciate though over time, not that such appreciation really matters though. I will die owning mine!
 

Russian Guy

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I got mine for $1575 shipped all the way to Russia which alone costs about $175-200. And I got a pretty sweet deal considering that one with gold hardware sold on Ebay for $2200.

Phase Shifter said:
I have 9 guitars so it might be difficult convincing my wife I just have to buy one that expensive.

Preaching to the choir, sir. I have 4 guitars 1 of which is shipping out to St.-Petersburg tomorrow which leaves me with three. Although another Ovation of mine I think will also eventually go to pay for a future Guild.

That maple-capped M-75 above went for $1175 plus shipping off of ebay and it too was a good deal. I was thinking about it but the finish around the neck binding came off at some places and I didn't want to deal with that seeing that I'd probably feel it when playing. And the fact that it'd cost more to retouch has become the final deal-breaker.
 

Phase Shifter

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I know about that finish coming off around the neck binding. When I was much younger, some of mine was coming off. It looked better without the aged clear coat so I took a knife and scraped the clear off (I was 16 at the time and didn't know any better). Before I knew it, the binding popped off all the way from the nut to the 21st fret on the bottom of the neck. It's a real pain to play it like that but it still plays and sounds so nice! I need to find someone I can trust to replace that binding. I can imagine how good the neck would feel with the binding fixed.
 

Phase Shifter

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I cleaned up the digram some. Hopefully this will helps others. I could find no diagram anywhere online about the wiring of this guitar. I will add though, I think the phase shift switch wiring was wired differently by each Guild factory technician, sometimes the red and black and wires going out were swapped around. I can't see why mine would have been swapped around like it was by a technician after it was sold.
Anyway, here is what the inside of yours is wired like.
guildstock-1.jpg
 

Russian Guy

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Thanks for a great wiring diagram, Phaser! I've never seen one as detailed as yours is (click Save on hard drive-> Done).

I hope you find both M-75 & M-80 at reasonable prices :) And when you do post the pics :wink:
 

Phase Shifter

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Thanks!

I tried to even get the double hump correct on the pickups and arrange their poles correctly as well. I used MSPowerpoint and MSPaint.
 

Jett

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Phase Shifter said:
I cleaned up the digram some. Hopefully this will helps others. I could find no diagram anywhere online about the wiring of this guitar. I will add though, I think the phase shift switch wiring was wired differently by each Guild factory technician, sometimes the red and black and wires going out were swapped around. I can't see why mine would have been swapped around like it was by a technician after it was sold.
Anyway, here is what the inside of yours is wired like.
guildstock-1.jpg

Great diagram, just what I was looking for. I have a 77 M80-CS that I am restoring to stock and just picked up a pair of HB-1's. I have a question about the red wire on the bridge pickup going to the phase shift. Does the red wire connect to the center lug on the back of the pickup? Thanks.....
 
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