Brian May Red special Series/Parallel

[newey]

In the above diagram, the switches at the bottom are for in/out of phase, right?

Yes.

Which way is in phase if the toggle is flipped up? I know that connects the middle and bottom wires.

Assuming all pickups are the same make/model, blue -to-blue, red-to-red is in phase as shown on the diagram. Your colors may vary (and probably do).

Absolute phase doesn't matter here, though- it is only the relative phase of one pickup vis-a-vis another that we care about.

Only 2 phase switches are necessary to obtain all the possible OOP combos of 3 pickups. The third switch is really just overkill.

For the on/off switches at the top of the diagram, are the off and on labels to designate that they're on/off switches,

Yes.

or the actual switching, ie, on at the bottom (toggle up) and off at the top (toggle down)?

And yes.

On the parallel/series switch, same question. Is toggle up for series and toggle down for parallel?

I think so, but it's too late to trace out the wiring on that and I'm going to bed!

Of course, if the positions of Up and Down aren't as one desires, the switch can usually be rotated, assuming the wires are long enough. Probably won't work with the 4P behemoth, though.

[katillac]

Yeah, that's the down side to this. I'm planning to make this all as tidy as possible. I even bought solid-core wire to go between switches, where flexibility should never be an issue, provided I get it right the first time. That's why I'm trying to make sure I have it all lined up right before I even start soldering.

I already cut a little extra out of the pocket (Strat knockoff) before I restained the body. It originally had the typical Strat setup - S/S/S, 1 vol, 2 tone, etc. I had to cut the pup cavity to a swimming pool route, and I recently cut a little extra to the switch side to allow for spacing things out the way I want.

Thanks for the help so far! I'm looking forward to learning more as I go. That's the only way I can do things.

[JohnH]

The labels shown above the switches indicate the switch lever positions, but note that since this was drawn as a mod to a Red Special, the dpdt's are drawn as slide switches instead of toggle switches, so the on-off positions would be reversed if it was wired up with toggles. The 4 pole is drawn as a toggle however.

Here's an interesting cultural difference across the pond, with regards to switches:

Americans expect 'on' to be up, while Brits expect it to be down. This occurs on light switches, and is also evident if you compare the power switch on a Fender amp to that of a Marshall.

John

[sumgai]

Aug 7, 2011 3:26:00 GMT -5 JohnH said:

Here's an interesting cultural difference across the pond, with regards to switches:

Americans expect 'on' to be up, while Brits expect it to be down. This occurs on light switches, and is also evident if you compare the power switch on a Fender amp to that of a Marshall.

And the reason for that is that Americans have paid more attention to ergonomics. A person who is in distress mode and is critically desparate to turn something off will invariably slap at the switch in a downward motion. Making them fumble with a second attempt at slapping upwards is considered unsafe.

And in America, at least, most Marshalls have their switches set to operate correctly, albeit in the last decade or so that's been slowly reverting to the British way. I attribute that more to economics than anything else. (Why stock to kinds of switch, etc.)

Maybe if we installed Aussie-made mirrors, we might all be able to flick switches in the same direction..... ;D

HTH



sumgai

[katillac]

I thought about going with slide switches, but I decided it would be easier for switching on the fly. I'm pretty good with my Dremel, so doing the rectangular holes for the slide buttons wouldn't be too difficult, though.

I was unaware of the opposite switching in the UK. I could understand it being that way for Aussies and Kiwis, as they're upside-down.

[JFrankParnell]

Aug 7, 2011 13:13:46 GMT -5 sumgai said:

And in America, at least, most Marshalls have their switches set to operate correctly, albeit in the last decade or so that's been slowly reverting to the British way. I attribute that more to economics than anything else. (Why stock to kinds of switch, etc.)

Hmm... I wonder which is more expensive, "up-on" or "down-on" switches?

[sumgai]

Aug 7, 2011 22:42:54 GMT -5 JFrankParnell said:

Aug 7, 2011 13:13:46 GMT -5 sumgai said:

I attribute that more to economics than anything else. (Why stock to kinds of switch, etc.)

Hmm... I wonder which is more expensive, "up-on" or "down-on" switches?

It's not so much the cost of each switch, comparatively speaking, it's more the matter of "yet another" line item in the inventory. Keeping track, making sure that the installer picks up the correct part to put into the amp (matching the destination with the part number), all of that adds up. Or more correctly speaking, all of that subtracts from the bottom line.

HTH



sumgai

[cavinyagi]

Hi all,

New to the forum but been stalking a while as its so helpful!

Decided a while back to have a little bit of fun and mod a spare Yamaha Pacifica and i thought i'd add this functionality to it.

Ive wired it up and its mostly working however i have a couple of dead zones and i cant get my head round where the problem is.

I've missed out the middle phase switch in my design (for a total of six
switches)

The dead spots are:

In Par
B on, M on, N on (Or any combo as long as bridge is on)
NP - in or out / BP in

If i turn the bridge phase to out everything works

In Ser:
B on / M on / N on
NP - in or out / BP in

Only the bridge work, the neck and middle pickups make no sound

Same as above but turning the BP to out and none of the pickups work

Turn the bridge off and the middle and neck work fine

I know its a lot to ask but if this makes sense to anyone could they explain it to me thanks lol. Ive spent a few hours already looking about but can't seem to find whats going wrong myself.

Thanks in advance!

[JohnH]

Welcome to GN2. There's not enough there to tell with certainty what is happening, but a wild guess would be that on your bridge pickup, maybe at the phase switch or at a wire connected to it, one lug is grounded when it shouldnt be. Something like that would explain those symptoms. In parallel mode, one end of the bridge does get grounded but if the hot side is also grounded there would be no sound, but flicking the phase switch could appear to fix that. In series mode, the bridge pickup is nearer to hot than M and N, so a wrongful ground to the bridge will bypass N and M.

Such shorts could be just a whisker of wire, or a lug thats too close to shielding and touching.

If it does not get resolved, then photos might help, and tests with a multimeter measuring resistance. A cheap digital one is fine, set all knobs to max and measure across the guitar output. Check every combination of switch settings. This will tell if each setting has the correct resistance of a few k (based on the pickups selected), or zero (a short circuit) or a high value (pots only, pickups disconnected)

cheers

john

[cavinyagi]

Thanks for the help john

Yeah i was guessing it was a case of something being grounded but didnt understand why.

I do already have a multimeeter here (cheapo one lol)

What resistance setting should i put it on and what should i expect to see with the switch changes?

[JohnH]

If your meter is like mine, it probably will have Ohms settings for 200, 2000. 20k, 200k and 2000k?

The right values for working settings are probably on the 20k setting, and it will depend on your pickups. Lets say your pickups measure 6k on their own, then approximately, you would measure as follows:

3 in para 2k (ie, one pickup x 1/3)
2 in para 3k
one pickup 6k
2 in series 12k
3 in series 18k

Actual correct readings would be a a few % less due to the volume control. If you find very low readings due to a short circuit, then step down the ranges, and on the 200 Ohm range, you might read a few ohms.

If you have disconnected settings, with which you will only read the volume pot resistance, they will be off the scale, unless you set to 2000k.

If there is any doubt as to which pickups are active, tapping he poles with a screwdriver while plugged in will check which.

John

[cavinyagi]

Ok doki so this is what we get:
Meter in 20k mode

In Para:
Phase set to In (working way)

Only Bridge - 11.8
B+M - 3.8
M+N - 2.8
All 3 - 2.3

Phase set to Out on bridge only
Only Bridge - 0.01 (set at 200 - 15.1)
B+M - 0.01 (same as above at 200)
M+N - 2.8
All 3 - 0.01 (same as above at 200)

In Para
Phase set to In

Only Bridge - 11.8
B+M - 11.8
M+N - 11.3
All 3 - 11.8

Phase set to out

Only Bridge - 0.02 (set at 200 10.5)
B+M - 0.02 (same as above at 200)
M+N - 11.27
All 3 - 0.02 (same as above at 200)

So guess this means i have a short somewhere lol. Whats the best way to track it down with the meter? (im a bit of a newbie with these things! lol)

[JohnH]

Are the second set of readings actually in series rather than parallel?
Do you have a really hot bridge pickup at about 11.8k, and M and N pups at about 5.5 to 6k?
Please set just one pickup on at a time, in series and parallel.

So far, it seems like a short, in the area that I thought before around the bridge wiring, but you may not be able to isolate it just with the meter - youll have to look for it physically

J

[cavinyagi]

Sorry yes they were just noticed the typo.

also can't believe i missed ind readings. Its the stock pickups in a 112 so i have no idea what they are etc at the mo. Ill do a quick google after this post.

In Par:
B-11.8
M-5.76
N-5.67

Ser:
B-11.7
M-5.77
N-5.67

I dont know if i mentioned it before hand but its a HSS set up hence the hotter bridge pickup

I keep looking around the switch but nothings popping out. Im very tempted to desolder the whole switch and try again

Anything i could check while im doing that?

[JohnH]

OK, your readings all check out with it being the bridge wiring. maybe remove the bridge pup and its phase switch completely and redothat wiring, leaving the B on/off switch, the other pups and the 4 pole switch

With B out of circuit, the other para settings should work fine, whether B is switched on or off. In series, with B on, you should get high resistance and no sound, and working normally with B off

[cavinyagi]

yup bang on what you said

While i was taking the wires out i checked the resistance over the 2 centre poles (aka just the bridge pup) with the switch in both positions and it checks out fine.

Im about to start rewiring it and im gonna check the centre poles after each solder

Hopefully if the ground starts again ill spot it lol

[cavinyagi]

Well luck is not on my side it seems!

I've now rewired the switch 2 times yet each time it results the same.

I'm not sure if this'll help but i noticed when i swap the + and - from the pickups the direction of the toggle changes for working and non working

Could that mean anything or should that happen? lol

I may just end up emmiting the bridge phase switch as well if i can't solve this. I intend to update the pickups in future and will prob add a coil split switch in instead (was going to add it in as well if i could fix this lol)

[newey]

Since JohnH has started this troubleshooting with you, I'll let him continue to take the lead, so I'll wait to see what John says.

But you've rewired it three times and had the same results each time. The odds that you could reproduce the same fault condition three times in a row become vanishingly small!

At this point (and if you haven't checked it with your meter yet), my suspicions would be a dodgy switch with an internal short. Testing of the switch should ideally be done with it completely de-wired to be sure it's good.

Or, just go ahead and replace it with a known good one, if you have spare switches.

[JohnH]

Here's another theory, consistent with everything else so far:

What exactly is the wiring coming from the bridge pickup?. Being a humbucker, does it have a grounded back plate and could that be permanently connected to the usual grounded coil wire? This would be all fine in a simple wiring but would cause these exact problems with phased or series wiring.

If so, need to seperate the pickup back plate/case ground from the coil wires, if possible.

Got any photos?
J

[cavinyagi]

Thanks for the advice newey - i did double check the switches as i had worries there too

The prize goes to john though. Just very carefully peeled back the back plate and there is indeed a connection to the ground here. With my DIY shielding in place this would be casuing the problem.

Heres my question. I know i can trim the cable off the sides of the back plate and conect them and problem solved but while im in here can i add a split/tap to the other side?

Can i just use normal equipement wire like ive used in the guitar or do i need something different?

[newey]

Heres my question. I know i can trim the cable off the sides of the back plate and connect them and problem solved but while im in here can i add a split/tap to the other side?

This can potentially be done, but it may not be as easy as dewiring the plate. It depends on the type of humbucker you have.

You have to find the "series junction" between the two coils, separate the wires, and then solder leads to each wire.

The wires are usually very fine, and difficult to work with. Often, if some form of potting, wax or plastic, has been used, it may be impossible to get to the connection without de-potting them. De-potting is doable with wax potting, but if the coils are epoxy'd, forget it.

Our friend wolf, who runs www.1728.org, has a more complete description of the process here:

www.1728.org/guitar1a.htm

There is risk of destroying the pickup in the process, so I'd advise caution before attempting this.

Unless the pickup is some super-duper something or other that you just have to have installed in this guitar, it's usually easier to just buy a 4-wire humbucker as a replacement. And, if you factor your time and frustration level into the equation, it may be "cheaper", too.

[cavinyagi]

thans again newey

Ive managed to get the humbucker rewired just bypassing the connection to the plate but there was some work involved. I wont even attempt to add the split.

Everything seems to work perfect now and i was almost scot free untill i tired to put the assembled plate back in the guitar. Mustve moved the output cable the wrong way and i now have a snapped lugg off the volume pot

Theres still a little metal left, can i just as a temp fix tack the output wires to that untill i buy a new pot?

[JohnH]

That sounds promising, and hopefully it will all work, once the coil wires are completely separate from grounding to the back plate. I’d probably still ground that plate though, using a separate wire, though I suppose it’s not essential if you have also shielded the cavity.

On the coil split – I’ve opened up two sets of humbuckers and converted them, haven’t lost one yet, though it is a bit delicate as newey describes. It involves peeling off the outer wrapping that goes around both coils, to reveal the separately wrapped coils and the soldered connection between coils. On mine, this is not the very fine winding wire, but an insulated stranded wire, ok to work on but don’t pull!

If that does not appeal, ignore the following:

If you do tackle the wiring addition, the coil cut would be a good idea, if you are up for having one more switch to control it. The B pickup, once split down to one coil would probably be a good match for the other coils, according to the resistance readings.

You could rewire it for full four-conductor wiring, which is not too hard to do and you could have series/parallel and single coil wiring. Or you could just add one further wire joined to where the two coils are currently joined to each other, inside the pickup. This would allow splitting the humbucker to single coil. Personally, I’d say that would be enough on this design, controlled by one more two-position switch.

Normally on coil cutting, the centre connection of a humbucker is connected to ground, but in this case, for the same reasons as caused the previous problem, you must connect it to one of the other coil ends (but see below), not directly to ground.

You could just pick one of the main pickup wires and wire the centre connection to it, but there’s a few ways to be cleverer than that without adding complication. I suggest wiring your new centre-tap connection, via a switch, to one of the output wires from the bridge phase switch. Pick which of these positions to wire it to so that it cuts to a coil that is humcancelling with your middle pickup (just test it wired up with some amp volume, listening for minimum low frequency mains hum). The B phase switch will control which coil it cuts to. Flick the B phase switch and it will cut to the other B coil. On its own, this coil will sound a bit different to the other, and combined with the M coil, you will still have a hum cancelling combo, this time with out of phase sound.

Now switch off M and switch on N. This will likely be non humcancelling because N will probably have been reverse wound compared to M, But if you flick both N and B phase switches, the sound will still be in phase but hum will be cancelled. Put N back to normal phase and B reverse phase and you will have a hum cancelling out of phase combo.

All of that is easier to do than it is to describe!

John

[cavinyagi]

are you a mind reader john? lol

Actually a selectable split was exactly what i was wanting for the next mod. I'm going to wait untill i upgrade the pickups though as i'll be replacing the scratchplate with one i can drill the holes for the switchs and pots myself etc.

The idea i had was to use the wiring system in this pdf, first diagram on the 2nd page then take the ground and hot to the input of the phase switch. (i would attach the shield cable, if the pickup had one, to the ground directly)

www.bartolini.net/instructions/pickups/passive/switching/Switch_Wiring_DualCoil_Pickups4_cond.pdf

I've not had time to check if this would cause any issue like we just had yet, do you think that would also work? I'd prefer this way of doing it only as it puts all the humbucker options into one switch

In your system with the split switch off does the phase switch still work as normal?

One more question, i know its very subjective but, do you have any reccomendations for pickups for this guitar? (HSS set up). I'll be playing mainly bog standard rock with a little either side (little heavier, little lighter) mostly dist/od/fuzzed up lol.

Thanks so much for the help so far its been amazing!

[JohnH]

That scheme will work fine, so long as you keep the bare shield wire seperate, as you describe.

In my suggestion, the phase switches still all work as normal - even in single coil mode the bridge phase switch is still reversing phase while also moving to the other coil.

When there are lots of similar possibilities, some of which are humcancelling and some not, I like to try to suppress the non-humcancelling combos if possible.

On pickups, I dont know enough to recommend a set, Im sure others can advise.

John

[cavinyagi]

ah right i see what you mean - yeah prob a good idea

Little update on the guitar - got it all back together and finally put some strings on it and just plugged it straight into the amp. Sounds great, i knew there was a reason i picked up a pacifica to use as a base.

I noticed in Seires that adding the other pickups doesn't make a massive difference. I assume this is due to the hotter output of the humbucker? Could i combat this when upgrading by getting hotter SC pickups?

[JohnH]

dc resistance is strictly speaking, a poor indication of pickup 'hotness', but it probably illustrates in this case that your bridge pickup is indeed quite powerfull. You could get something similar, on the basis that cutting to a single coil will bring it down, or you could go for a more 'vintage' Hb, of 7 to 8 k - and the addition of the other single coils in series could build it up if needed. I wouldnt personally seek to get even hotter single coils than you have, since then the series settings could get rather over blown and muddy. (lower windings have a clearer brighter tone)

If you are looking to get new pups, but not spend a heap, Guitarfetish in the US is very good, and lots of folk here use them. They ship worldwide quite efficiently. They sell own-brand designs in most pickup styles.

John

[cavinyagi]

Thanks for the guitarfetish shout John

I can get 3 GF branded pickups delivered to me in the uk for about the price of aone"decent brand name" pickup so i think thats a great option. Might go for the vintage type pickups, they sound like they're just the sound im after

[nichstp]

Sorry to bring up a dead thread but this is SO CLOSE to how I want my guitar wired.

Instead of on/off switches, I want on/off/half volume (DPDT on/on/on) switches and I want to have three 250k pots: volume, tone (standard high cut), tone (low/bass cut).

I found a circuitry diagram for the switch but Im finding it hard to read compared to yours, because of that I don't know how to integrate it into your design.

guitarnuts2.proboards.com/post/92050

All the best,

Nic

Dec 26, 2009 20:32:23 GMT -5 JohnH said:

OK, I think this might do it:



(EDIT: diagram amended 05/01/2010 in response to errors noted in following posts)

I'd be interested to know what value pots are used and if they are linear or log- but what ever is there now will work fine. Another mod I often do is to add a 220k resistor and 1nF cap, in paralle from hot to centre lug on the volume pot, to preserve treble as you reduce volume. There's no need to add this unless you wish to however, and I haven't shown it here.

The thick red and green wires indicate hot and ground connections - just for guidance, but any thickness of wire is fine.

I've checked it a few ways, no guarantees (the scheme is proven. but the diagram is new of course) but it is hopefully ready to go. So good luck! Sound clips, photos, build reports, comments etc, if possible, will be much appreciated, as will questions!

cheers
John

[JohnH]

Hi nic and welcome to GN2

The pots sound to be easy, since they are all master controls after the switching. They'll be based on PTB wiring, see this thread:

guitarnuts2.proboards.com/thread/7172/bass-cut-ptb-system

For the switching, the current dpdt switches are fully occupied, even if made as on-on-on. So you'd need to use 4pole on-on-on's, which are available as toggles. On each one, two poles (eg 1 and 3) are wired as in the BM diagram and the other two do the volume change.

4pdt on on on switches, in the middle position, tend to have the centre lugs connecting down-up-down-up, hence the basic on off switching from tbe diagram is using poles 1 and 3.

I hope that is at least a clue!

There's a few more stages to working it out. I suggest the volume switching should be such as to completely bypass the 1/2 volume circuits when they are off. Also, note that in mixing in series and parallel, the effects of the volume switchjng will vary. Ie if one is full on and another is at reduced volume, the relative mix will vary between series and parallel.