'50 wiring ("old gibson" style)

[Marco Pancaldi]

This is a fashion of last years.
I understand that the only difference between "modern" and "old" wiring is the "routing" point to tone pot and capacitor: in the modern the signal is tapped from the "input" lug on the volume pot, in the '50 wiring the signal is tapped from the "output" lug. I read fantastic notes on the web about this: the guitar don't have treble loss when you roll off the volume, the tone is better...

I think that:
1 - with all maxed the difference is non existant
2 - with the tone even slightly rolled off all you obtain is to have a dramatic interaction with volume setting (you need to change the tone every time you make a volume correction)
3 - with tone maxed maybe the treble loss due to lowering the volume pot is a little less evident, but there are better ways (es: RC "treble bleed" networks) to compensate this without devastate the tone pot response.

The technical reasons are so simple that I can't believe "expert" on the web are writing pages about it. Sometimes I suspect they write but never tried that in person.

Or maybe I'm completely wrong and missing something, please correct me in case.

Thanks
m.

[Leo_Gnardo]

Well there may be more to it than that BUT I can tell you a Sommatone I just looked at last week had NO circuit board, just a couple of tie strips and some circuitry built right atop tube sockets, very old-fashioned style, and it's one of the best sounding amps I've heard in a while. The gigantic OT may have had something to do with it too. It was a Roaring 40, with 4 EL84s. Gorgeous fat tone, nice sense of compression, just awesomely good. Wonder whose transformers Somma uses.

[pdf64]

Leo, I think the OP was referring to guitar tone/vol control arrangements, rather than amps.
Thanks for the report on the Sommatone though, not heard of them before.
The website says mercury magnetics transformers http://www.sommatone.com/roaring-20-40.html

Marco, yes, my experience and conclusion is the same a yours.
The '50s wiring' does have another advantage (for me) that you didn't mention - with the volume turned down some, the tone control becomes rather ineffective, so set to eg 3 there's still plenty of brightness. That allows for a nice rhythm tone/light overdrive setting. Then turn the volume up for the lead break and the tone control setting of 3 has much more effect and rolls off some treble, resulting in a fat lead tone.
Yes, treble bypass caps on the volume control can have a similar effect but personally I've never got along with any arrangement of that which I've tried, whereas the 50s wiring (due to the above) seems the best compromise for me.
Pete

[LtKojak]

I'm missing something, please correct me in case.

You're missing that '50s wiring can be done in two ways: the traditional way, where there's an interaction of both volume and tone controls, or "independent volume", where there's no interaction so it behaves like "modern wiring", just without suffering from the treble loss caused by the volume pots.

Marco, do you play guitar, and if you do, do you use the volume and/or tone controls?

[pdf64]

That sounds interesting, please could you give more detail eg schematic or link to a web resource?

[Mick Bailey]

I'd like to see that too. I've examined quite a few wiring arrangements in Pspice but never found one where volume didn't affect the tone. Just the fact that there's a pot involved suggests a variable filter to some degree. The problem with independent volumes is the varying S/N ratio, especially in electrically noisy environments. I've wired quite a few guitars this way but most have ended up going back to stock. For me I'd rather have the control and put up with the noise.

[frus]

I like treble bleed WAY better

[Mike Sulzer]

I'd like to see that too. I've examined quite a few wiring arrangements in Pspice but never found one where volume didn't affect the tone. .

So this is why you wind less wire on the pickups to lower the inductance about a factor of ten and use 25K pots. The first thing this passive guitar should go to is a low noise preamp. You can use a cap across each pickup to set the resonant frequency and then use a traditional tone control (with appropriate values for pot and cap), but I prefer to replace it with switched caps.

[Mick Bailey]

I was considering existing pickups in commercial guitars that are already wound. I use preamps a lot - just fitted two this week and they'll stand 10k pots - but it's difficult to convince people of the benefits. I also built a guitar a few weeks ago with a rotary switch to select fixed value caps (have you been reading my diary?) and like it a lot. A difficult 'sell' to the customer, but he's really happy with the result.

[Jim Shine]

I am surprised few are toying around with pot values. The old potentiometers had crazy sloppy tolerances compared to todays. Like +/- 20%. Today they are consistently tighter.

[Leo_Gnardo]

Leo, I think the OP was referring to guitar tone/vol control arrangements, rather than amps.

OOPS quite right... (put embarrassed smiley thing here) . Failed to notice it's under pickup makers. D'OH! My bad...

Now I'm gonna shut up & pay attention, maybe learn something.

"mi 'scuzza!"

[soundmasterg]

To the OP, have you ever tried the 50's wiring yourself?

For me it makes a huge difference and sounds way better. Without it humbuckers sound muddy and undefined. no matter the pickup.

Greg

[Steve A.]

To the OP, have you ever tried the 50's wiring yourself?

For me it makes a huge difference and sounds way better. Without it humbuckers sound muddy and undefined. no matter the pickup.

Greg

Agreed! There was a discussion of this here in 2011 as I recall. As the OP surmises, with the volume and tone controls dimed there should be no difference (although some people swear they do.) Since it is usually such an easy modification (ES335-ers excluded!) I suggest that anyone wondering about it give it a shot. I've been meaning to hook up a double-pole switch to be able to A/B the actual difference in real time but I'm already a believer and I have rewired many of my guitars like that (with the tone control connected to the output of the volume control.)

You're missing that '50s wiring can be done in two ways: the traditional way, where there's an interaction of both volume and tone controls, or "independent volume", where there's no interaction so it behaves like "modern wiring", just without suffering from the treble loss caused by the volume pots.

"50's wiring" was the term that Bruce Collins' brother used when he first posted the idea to the Seymour Duncan forum maybe 15 years ago and it refers to having the tone control pot connected to the output of the volume control and not the input, i.e., to the wiper and not to the CW terminal.

What you bring up is a different but equally important issue which I call "jazz guitar wiring" mainly since it is not recommended for high gain guitar. With this wiring the hot leads from the pickups are connected to the wipers of the volume pots and the output jack or selector switch takes the signal from the CW terminal of the pot. With this arrangement you have full range of blend positions between all bridge and all neck. (With modern guitars if you turn down the bridge volume control it mutes the neck pickup.) I have converted many of my guitars to this wiring but there is one disadvantage- with both 500k pots set to 0 the output signal is not completely shunted to ground so the signal is still there but connected to ground with a 250k resistance.

The Fender Jazz Bass is wired in a similar fashion:



Thanks!

Steve Ahola

P.S. I moved thread from Pickup Makers to Guitar Tech. BTW before I tried 50's wiring I usually added a 180pF treble bleed cap to volume controls which would retain highs at low volumes but it wasn't 100% natural. A good example of this is the Tele which uses a .001uF treble bleed cap for a very specific purpose- as you turn the volume down Leo & Co. intended for the sound to get brighter.

If you look at the wiring diagrams for steel guitars in the 40's and 50's you'll find that most of them used the 50's wiring.

[freefrog]

This is a fashion of last years.
I understand that the only difference between "modern" and "old" wiring is the "routing" point to tone pot and capacitor: in the modern the signal is tapped from the "input" lug on the volume pot, in the '50 wiring the signal is tapped from the "output" lug. I read fantastic notes on the web about this: the guitar don't have treble loss when you roll off the volume, the tone is better...

I think that:
1 - with all maxed the difference is non existant
2 - with the tone even slightly rolled off all you obtain is to have a dramatic interaction with volume setting (you need to change the tone every time you make a volume correction)
3 - with tone maxed maybe the treble loss due to lowering the volume pot is a little less evident, but there are better ways (es: RC "treble bleed" networks) to compensate this without devastate the tone pot response.

The technical reasons are so simple that I can't believe "expert" on the web are writing pages about it. Sometimes I suspect they write but never tried that in person.

Or maybe I'm completely wrong and missing something, please correct me in case.

Thanks
m.

Hello,

1) I'm not an expert.

2) 50 wiring has been no less than a revelation for me. Finally, I could actually use the vol & tone controls of my LP on stage!

3) I've tried several recipes of treble bleed with various PU's. No one sounded as "natural" as 50 wiring, at least with HB's and P90 PU's. I've kept a treble bleed in several of my guitars, but only with hot PU's (DiMarzio, Bill Lawrence).


I post below a screenshot showing the frequency response of a PAF replica under various settings. One can clearly see how 50 wiring shifts the resonant peak towards the upper frequencies... A treble bleed will do that only if the cap used has a value calculated to "answer" to the capacitance of the cable used, AFAIK.

[Marco Pancaldi]

Happy to see lot of opinions - even more different from mine. I evidently was (half) wrong.

to pdf64: I made a test after your advice, and it works as you suggest. I think you gave the best explanation of '50 wiring pros.
to LtKojak: I play, and I use controls a lot. Often I don't like stock wirings and cap values so I experiment with R and C to vary frequencies and pots response.
to soundmasterg: I tried the '50 wiring in the past, but was rejected from the abrupt change in response between "full volume" and "attenuated volume" settings (more on this below).

After your posts, I tested with more attention the '50 wiring (or simply: "tone control attached to volume pot out") and the "independent volume" wiring, here my observations (I used a new Gibson SG with 300K lin volumes and 500K log tones, 10-46 roundwound new strings):

- differences between '50 and modern are evident only when attenuation is about 6dB or more (volume pot on 7 or 8 if log, 5 on my SG);
- with '50W you can obtain a less heavy tone and keep presence while rolling off tone pot (I noted a sort of "hi-pass" response with tone pot on 5). But with tone below 3, the guitar is dead (filter too close). No resonance between tone capacitor is possible except with volume level on max (and here the '50W behaviour is not different from the modernW). The tone circuit is clearly interactive with volume pot position. (probably due to series resistance introduced in attenuation positions).
- the "independent" volume pot arrangement is intresting and has a different volume and presence response (due to the variable load presented to the PU instead of a straight voltage divider function) but I found no differences between "traditional" and "independent" for the tone behaviour (the important thing is where you tap the tone control, input or output from volume pot).

My conclusions:
- the '50W has its uses (and can be optimized, in case, to operate at best).
- if you like to use the tone completely rolled off to obtain near-wha resonances, and more in general you prefer to have constant response from the tone control (into the limits of a passive, Hi-Z circuit) not dipendent from volume pot setting, the '50 wiring is not for you: here the tone is totally dependent from volume setting.
- for my guitars, I keep to prefer a traditional tone arrangement, with RC compensation network on volume pot lugs, fixed or variable (using the free lug on teh tone pot).

Thanks all!
m.