Carvin M22 wiring: 3-wire + shield type

[carvinm22s]

HELP!



I need help wiring an old 22 pole Carvin M22. It's the old 3-Wire + Shield pickup (white, black, red, and shield. I have seen the Carvin wiring sheet where they show FOUR wires!)

Only one of these (at the bridge). Neck is an old Epiphone humbucker (two wire: hot + grnd).



This is a homemade guitar. This has two volume, two tone, one 3-position toggle.

It works, BUT........ 

Almost no diff b/w bridge, neck, or both, when switching between the HBs.

Sounds like I have tone turned down on both. Soft, almost muffled.

Neck is a tad cleaner; bridge is a little more distorted (like old Dimarzios)........Think Big Muff sound, but on both pups.

I will admit: sustain is excellent!

But, switching to bridge does NOT "brighten up". No high end at all.


I had these Carvins in a Guild S100 and the worked fine...but the luthier who put my Guild pups back in that S100 did NOT make note of the M22 wiring.

So, I am lost.

[newey]

Sorry, I had to move your thread from the "Schematics" section.

Hello and Welcome to G-Nutz2!

If there is no difference in sound, it seems as if both pickups are not functioning. You can tap each one with a screwdriver to check. That's the first thing to check.

[cynical1]

Jun 20, 2015 9:57:23 GMT -5 carvinm22s said:

HELP!



I need help wiring an old 22 pole Carvin M22. It's the old 3-Wire + Shield pickup (white, black, red, and shield. I have seen the Carvin wiring sheet where they show FOUR wires!)

According to Carvin:

PICKUP WIRING:

All Carvin 22 series pickups have three wires plus a bare shield wire. The shield wire always goes to ground. The white wire only gets used if you want dual-to-single coil switching. If you don’t want to use this feature, then tape the white wire back. The black and red wires are to be used for standard humbucking operation. Solder red to hot and black to ground. If your guitar sounds out of phase with both pickups on, reverse the red and black wires of one pickup.

Do you have a diagram of how you wired the guitar?

Happy Trails -

Cynical1

[carvinm22s]

Diagram: no. I could try to describe though.

By the way: before I go any further, I disconnected the red (had used red as hot as per Carvin wiring instructions) and taped it back. I then connected the white to hot. Why? 
On one of them (after they came out of Guild) the white was bare, the black & red soldered together.

So now:

Black to ground

Red taped off

White to hot

Shield to ground

This 'brightened" the M22 up a bit, but still not as bright as it was when in the Guild. Probably because I now only have one coil hot?
IOW: less "muffled", a tad brighter, but not going to shred anyone's ears with high-end treble.

So, am wondering if I have a neck pup at the bridge. Have read in some sites that there IS a difference.

Here goes attempt at describing; remember that this was wired back in about 1980 whilest still in High School. Dont remember exactly, but I GUESS it was taken directly out of the Epiphone that was sacrificed and dropped into this homemade with no changes:

>Neck Pick-up = Epiphone 2 wire HB
>Hot to Neck Volume Pot (NV)
**Note: the way this is wired, the RIGHT POST is being used as hot (looking down on pot)
>Ground to pot 

Bridge Pickup = Carvin M22 3-wire+shield
>Shield to Br Volume Pot (BV) {note: right post = hot)
>Black to ground
>Red taped off (was hot before)
>White to hot at BV

Toggle = 3 position
>left post to NV center post
>right post to BV center post
>center post to Plug Jack hot, and ground on this wire to plug jack grnd......
NOTE: this wire is shielded. So, wire to center post on toggle and hot post on Plug Jack; shield to ground on toggle, ground on Plug Jack.

THE POTS:

Neck Volume-to-Neck tone
>NV hot (RIGHT) post to Neck Tone (NT) LEFT post
>NV pot ground to NT pot ground

Bridge Vol-to-Bridge Tone
>BV hot to BT LEFT post
> BV pot ground to BT pot ground

NOTE: one post on each Volume Pot is bent back and soldered to the pot.

TONE POTS
>NT Cap soldered to pot ground and CENTER post
>BT cap ditto
>Each Toned pot is then grounded to Plug jack Ground.


I am sure that this is all wrong; please get me straight!
And thanks for the advice.

[carvinm22s]

By the way:

Also have a wire running from bridge to ground.
This wire is soldered to the NV pot.

And, entire cavity is shielded with copper tape.

[newey]

This 'brightened" the M22 up a bit, but still not as bright as it was when in the Guild. Probably because I now only have one coil hot?

That's one possible explanation, and all the more reason that you should test the pickups as I described. Rewiring things willy-nilly without knowing the problem does not seem a likely route to success . . .

First, please describe what output there is in all switch positions, by tapping the coils while plugged into an amp. If only one coil of a HB is operating, you will still hear a bit of a thump out of the inactive coil, by virtue of its proximity to the active one. But an active coil should be much louder when tested this way.

More involved testing will require a multimeter:

guitarnuts2.proboards.com/thread/3194/discerning-lp-type-resistances

Using this method, we can usually discern whether you have two coils or one operating.

[carvinm22s]

Tapping with screwdriver:

Switch to Neck Position, just the Epiphone HB, as you'd expect
Switch to Bridge Position, South or "closest to neck" poles sound a bit louder than north poles.
Switch in center: ditto, with Epi HB also sounding off.

I guess this is what I should expect by taping off red and using white as hot, eh?

On Carvin board they reiterated: RED is hot, white should be taped off if not used.

UNLESS I have the M22 Bridge pup at the Neck position (not sure if ca1980 M22s were different or not b/w Bridge & Neck pups), maybe this thing was wired with the white when it was in the Guild & I never really heard them as I should have?

 

[carvinm22s]

Sorry.
This should read:

"...Switch to Bridge Position, South or "closest to neck BRIDGE" poles sound a bit louder than north poles...."

[newey]

Your testing seems to indicate, as suspected, that only one bridge coil is operational. And, given that we seem to have definitive info from Carvin that indicates that the wiring is backwards, I'd say that you should change it accordingly. But, you indicated that you still had problems even when wired like that . . .

This is a 3-wire HB. (The bare wire is just a shield, it does not carry signal.) You have a + wire (red, apparently), a - wire, and a wire (apparently white) to split the coils. Use a switch to ground that wire, you'll get the one coil; use a switch to connect it to the + and you'll get the opposite coil.

A 4-wire HB (more common nowadays than your 3-wire style) allows for each coil to be wired independently; your 3-wire set up does not. You can only use it to split the coils (or not). You can't do series/parallel between the HB coils, for example.

When you had it wired before, it sounded as if the 2 pickups were wired Out-of-phase with each other, from your description. This can easily occur (50% chance) with different pickup manufacturers. But you can test for proper phasing using the "Screwdriver pull-off test" (in the "References" section) to check for proper phasing before wiring.

[carvinm22s]

Thx much!
Think I read that the remedy for phase issue was to reverse the black & red. 

I honestly think that it was never connected this way before (think it was always wired with white), and I never got the full appreciation for the over-sized magnets.

I checked both pups with a meter, btw. From Carvin site:

PICKUP       TYPE                          CONDUCTORS DC         RESISTANCE (ohms)         MAGNET             POSITION

M22N          Dual Coil Humbucker     2+tap+shield                8.4K                             ALNICO 5            Neck

M22V          Dual Coil Humbucker     2+tap+shield                7.3K                             ALNICO 5            Neck

M22T          Dual Coil Humbucker     2+tap+shield                13.3K                            ALNICO 5            Bridge

M22SD        Dual Coil Humbucker     2+tap+shield                13.9K                           ALNICO 5            Bridge

[SD (bridge), T (bridge), V (neck) and N (neck) models]


Both of mine tested to 11.58 ohms using red & black leads, 5.8 using white & black leads.

[carvinm22s]

It gets better.

I taped off the tap (white) and reversed the red and black (black to hot; red to ground).

I get the same Bridge sound I originally had (no real high end), and neck pup sounds "normal".
But.............

If i switch to middle i get a "thinner", out-of-phase" sound.
And get this: if I back off on either volume the middle position sound gets louder!

I have a jazzy/heavy neck, heavy almost over-driven bridge (without high end), and Strat-like middle (but only if either volume is on "10").

Maybe it's time to replace the inerds and get new tones, volumes, & switch

[newey]

Both of mine tested to 11.58 ohms using red & black leads, 5.8 using white & black leads.

That sounds about right, assuming the pickups were disconnected from pots, etc when tested. White to red should give you a similar reading, approx 5.8

Your pickups are now definitely OOP in the center position, so the wires need to be switched back again. That's why I advised doing some testing first . . .

The problems with your pots are mysterious, although weird things happen if you fry the pots too much with a soldering iron. They should be tested with a multimeter. The switch itself is unlikely to be a problem, sounds as if it's working fine.

Start by swapping the red/black to reverse the phase back, and report back what you get.

[cynical1]

Granted, I've only been glancing at this thread, but I've got a C22 in a guitar, and RED is HOT, BLACK is NOTHOT, and the white wire is for splitting the coils.

HTC1

[carvinm22s]

Will do. I suspect the pots, too

[carvinm22s]

By the way, I need to clarify:

When we built this thing (ca1981) we took a piece of 1.5" solid mahogany for the body and routered it out. 
We stole the hardware (pups, neck, bridge, pots, etc etc) from an old Epiphone. 

the pup leads were too short, so we patched in a wire from pots to pup leads, and it worked for years.

it then sat neglected for many more years.

I tore it down and, after getting my S100 Guild back to original, decided to put the Carvin M22s in this. The neck M22 would not fit, so I took the Epi neck pup and am using (it has a lower profile).

the wiring from the pots are all the same: no changes. I have not soldered or re-soldered the pots. And I am still using those wire extensions.

So, frying the pots is likely not the problem.

[carvinm22s]

I might add, though not correct, the sound is growing on me. I turn the bass down on my Crate GFX-15 and it actually sounds ok.
And if I want a "strat-ish" sound I simply move to the center and turn the volume pot (either one) to 10......

Yes, it's F'd up, but all-in-all not too bad. Lemme play it a while then will wire back to non-OOP.

Thx!!

PS anyone know where I can find a Flying-V style neck? You know, with the arrow-head headstock??


 

[cynical1]

Hey, Pete Green's guitar was wired wrong...but everyone drooled over his tone...

eBay would be my first stop looking for a neck. Make sure you match the scale and neck pocket on the body with whatever neck you find.

HTC1