1457 wiring

[angelodp]

Ok, this gem is a 1457 Silvertone which dates to 1960. It has the original pickups and as you may know has the series setup. It also has the copper foil faraday box to shield it. Here is my question.

Can someone please explain this wiring and how it works, signal path and what the two caps do.

I am winding my own lipstick pickups and trying to get to this tone. I will use the stacked pots etc. Rather than simply copy the original I wan to fathom how this circuit works

BTW the tone part of the stacked pots are 100k

See below for corrected layout.

[JohnH]

it looks more like the rear pots are the tone pots?

gotta catch a train now...
j

[JohnH]

Yes definitely!
100k vol and 1M tone pots. Thats a credible arrangement with low imoedance pups. The low vol pot value keeps output impedance low when in series and the high tone pot value compensates by adding minimal further loading on the pickups. Each pup vol and tone is wired conventionally as a module, then the two resulting module groups are put in series between hot and ground. The one on the left is nearer ground.

This series arrangement allows each volume and tone pot to act only on its own pup and it works very well, much more controllably than normal parallel wiring. When i do series wiring on an lp thats basiclly how i like to do it too.

The switch is presumably an on off on to shunt one or other pup or neither in the mid position

J

[angelodp]

If I am running a version that has 1 master vol and 1 master tone ( no stacked pots ) with the lipstick pups....is it possible to successfully insert
a series/ parallel switch in the circuit, or am I back to the same issue of having the case tied to ground and it will produce noise ( like I have at the moment). How does the original manage the series connection and not have noise.... the original is dead quiet.

[sumgai]

I'm gonna take an exception here, in fact several of 'em.

First, the output jack is usually depicted with the sleeve as ground, yet here (the bottom-most lug or terminal) is shown as the 'hot' - not an auspicious beginning. Which goes to show why we use schematics in the first place, instead of drawings - they really do avoid errors of this kind.

Next, both pups show their red wires going to the Vol pot wipers. In a series connection, this will do one of two things when they're both on - either they'll hum, or they'll be out of phase with each other. Again, more concise information would be.... informative.

As I told newey earlier, I now stop at two "oopsies". Let's get past these shortcomings before we go any further, shall we?




sumgai

[JohnH]

Mr S
Good point about the jack.

But, for the rest of the wiring, my point is that the tone and vol labels should be swapped, and then it makes much more sence and is a good scheme. - hots then actually go to volume outer lugs.

J

[angelodp]

Ok, I am opening her up and will check exact wiring, back soon.

A

[newey]

I'm with John. The labels for the V and T are swapped on the diagram. The jack is also mis-depicted.

The switch shunts one pickup, or the other, out of the series chain, to ground in one direction and to the "hot" side in the other direction.

To trace the "series chain", start with the left-most pickup. Its blue wire is soldered to the back of a pot, to ground. Start the series chain here.

The signal then goes through the left-most coil, out the red wire to the V and T pots,

From there, via the gray wire from the wiper of the V pot to the other pot, and then via a black wire to the switch.

In the center "off" switch position, the red wire is thus connected to the blue wire from the right-side pickup, thence through that coil, out its red wire to its pots, and to "hot" output via the orange/yellow wires. This then completes the series chain.

I believe this scheme is similar to the series wiring on the Teisco "Tulip"- style guitars, we've had discussion of that in the past.

[angelodp]

Guys, sorry for the lousy graphic. It has several errors that I will correct in the morning. Jack and pots mislabeled for sure, but man this is one sweet sounding guitar. The 1457 that is.

I am thinking of going with the less expensive alpha 1m concentric pots and hanging a 120k in parallel to achieve the 100k value. Those pots are only 2.50 at AE. For a Dano DC30 build.

[JohnH]

Putting the 120k across a 1M will get around the 100k, but it wont do the main thing that the real 100k achieves, which is to keep the total series impedance low as you roll down volume on one pickup. The issue is loss of treble.

I get good results with very similar series wiring using 500k pots but with treble bleed on the volume pot. In your case s 2x500k pot would work, or if you want to more closely replicate the current tone, a 2 x250k also with treble bleeds. 500k would be a bit brighter

This will also help a solve s problem that I expect you may have. With the current wiring when you roll down the tone pots, does anything much happen unless you go almost all the wsy down? With 1M tone pot on a low impedance pickup i would expect not.

J

[angelodp]

Thanks for the additional input. Here is the corrected layout. In truth I do not use the tone knobs that often ( read at all ) on this guitar as the tones from the switch are just what I need. In that case will the cheaper stacked pots work out at max settings ( duplicate the original sound )?

BTW- switch is Carling SPDT on/off/on can be subbed with 2FC53 Carling, as the old phenolic back is no longer made.

[angelodp]

JohnH, so using the stacked 500k's with a treble bleed will work. What do you recommend for the treble bleed ( values? ). Would the .1caps in the harness need to be altered as well?

Cheers A

[JohnH]

New diagram is better, but I'm hoping the rear pots, now correctly labeled as tone pots, are the 1M ones (edit, now fixed, see A's next post below).

I can confirm the use of 500k pots for this circuit for series wiring, with treble bleed. I first used it in 2007 on my 'LP maximiser' which was built into an LP copy, I also have it on my Gibson, and it has been built several times by others into the HBD and JHJP designs.

The best values for treble bleed are likely to be, as for other guitars, 1nF in parallel with 150k. A set of those on both your volume pots between the hot outer and central lugs.

Just a comment on pot values and loading/tone. When you play at max volume and max treble tone, the extent to which the pickups natural top end is smoothed out is determined by the value of both the tone and volume pots as if they were in parallel, which they are except he tone pot is via the tone cap. At max tone, the value of the tone cap makes virtually no difference at all, whether it is a small value, a large value or a piece of wire. As you turn down the tone, the first stage is all about the increasing load on the pickup from the pot, and the effect of the cap does not become significant until about 6 and below.

So, in the base design, you have a 100k and a 1M, and that is effectively the same at max settings, as a 91k load across each pickup, and that is what controls the tones that you have. Its quite a low resistance, so quite a high load, but clearly it is a good sound with your guitar.

Strats, with single coils, have 250k for volume and tone - so by the same reasoning, that's effectively a 125k load at max. That's not much difference from your 91k, which is why I suggested that if you want to match the sound at max, then 2 x 250k pots would be the way to go.

With 2 x 500k, we have a 250k effective load per pickup. it will sound a bit edgier, and you might like it. However, to find very close to the same tone, you will turn the tone pots down, until they are around 110k, which will be at about 6 on the dial for a log pot.

BTW - you should use log pots.

Also, at max settings, if you don't want to use the knobs at all, your idea with the 120k resistor and 2x1M pots is OK.

So, for how you use the controls, the tone cap is not critical, but I would suggest you keep with the same value. That is a fairly large cap value at 0.1uF. I assume it was chosen to go with those pickups, but also, a high value is just right for turning down the tone of the neck pickup in a combination series mode.

Try this: both pickups on at full volume and tone, and wind down the neck tone. The bridge treble may start to come through more strongly as the neck is cut back to just bass. This effect becomes even more interesting with the 500k pots since you have more 'edginess' to play with.

cheers

John

[angelodp]

I adjusted the layout again and I do believe I finally have it correct. Very very interesting info and much appreciated.

Why the log pots?

A

[JohnH]

Nov 30, 2012 15:40:12 GMT -5 angelodp said:

Why the log pots?

A

Log pots dont change the overall range of volume or tone, but:

On a tone pot, most of the tonal change is in the last 20% of resistance, so a log pot will take this range and spread it out between 0 and 6 on the dial (10 = max), instead of just 0 to 2.

For volume pots - usually, its a matter of choice, if you want to make great changes in volume with a small turn down from 10 (such as to clean up a heavily overfriven amp), log is best. If you want to take a few db off a cleanish tone, lin is best.

Log pots are used in audio system volume controls, for reasons of hearing perception of increasing signal strength - but that has nothing to do with guitars IMO where we are starting at max and turning down.

But - for your scheme, log pots for another reason, if you use treble bleed. The action of the treble bleed, with its 150k resistor, reduces the steepness of the volume pot taper. So, a linear pot, which starts with a fairly slow volume decline from max, gets too flat. A log pot however, gets changed to something that is about half way to being linear - and it's a really good result, much better than a normal log taper IMO. Its still log-like, but not as steep, just right and perfect for series mixing.

Aside: Ive been working out some treble bleed values to go on my new Strat, with a 250k pot. Its looking like it will probably be 120k and 0.82nF. 150k and 1nF seem best with 500k pots.

John

[angelodp]

BTW - here is a loaner I opened up. Its a Korean re-issue mid 80's. Has the dual concentric etc. Tone is not comparable to my 59-60 1457 with the same circuit. I suspect magnets and wind to be the main issue - ( and wood and......)

[cnb]

This is really cool. You say it came copper shielded stock even way back then? Pretty cool.

Or did I misunderstand and you added that on your own?

[angelodp]

Yes, it is wrapped in a waxed paper ( inside ) copper foil (outside ) fold out box that is taped together. Farady box of sorts. These guitars are dead quiet. Tone... for miles.

[cwiegering]

I know that this thread is VERY old but I have the original 1457 wiring but my Toggle switch is busted.... and they dont have the original ones.... si I have the On-off-On that has that extra little tail on the oposite side.... the one they use in the reissues. I may sound like a fool but I have been unsuccesfull riging up the vintage layout with this new switch!....Help please

[ashcatlt]

Nov 7, 2016 11:51:03 GMT -5 cwiegering said:

I know that this thread is VERY old but I have the original 1457 wiring but my Toggle switch is busted.... and they dont have the original ones.... si I have the On-off-On that has that extra little tail on the oposite side.... the one they use in the reissues. I may sound like a fool but I have been unsuccesfull riging up the vintage layout with this new switch!....Help please

Got a meter? Use it to figure out what connects where when. And/or show us a picture or a link to your switch and maybe we can sort it out.

Going to a master V and T removes a whole bunch of the fun from this circuit. The original allows what we call "broadbucker" tones. By rolling down the tone of one of the pickups, its treble contribution is reduced, but some of the high end of the other pickup gets to bypass the inductance of the first, so it actually contributes more (and higher) treble.