Ok gurus, answer me this

[loudthud]

On the Tillman schematic mount just Q1, R1 and R2 in the guitar. Mount the rest in the amp and connect the two with a single coax.

[bob p]

I don't know why they didn't use DIN. Alembic has used DIN connectors for a long time. Alembic was responsible for the Dead's sound reinforcement during the "Wall of Sound" era. Additionally, Doug Irwin (the luthier who made Jerry's guitar) used to be at Alembic before he started making guitars on his own.

Maybe they wanted to maintain fall-back compatibility with standard guitar cables. I think that the Garcia guitars are wired so that if the FX cable isn't attached, the guitar can still work with a regular cable in the bottom jack. I don't think that having to carry special DIN cables would matter too much to the guys responsible for the Dead's sound system. It was a very complicated system that was constantly evolving and it had a full-time crew to maintain it. Maybe the fallback to a regular cable was there for the player ... so that he could use his guitar with a regular amp when he wanted to.

[R.G.]

Old Musicman preamps built around LM4250 draw nothing, battery can last several years.

Yep. Problem is, that the LM4250 is low power, but not particularly low distortion by today's standards or particularly low noise. That's one of the fundamental tradeoffs of low power and low noise. Tough to get low power, low noise and low complexity all at the same time.

On the Tillman schematic mount just Q1, R1 and R2 in the guitar. Mount the rest in the amp and connect the two with a single coax.

Yep. I think that was one of the ways Don used it. Still has the issue of DC running through the guitar cord. How much problem that is in practice depends on the quality of the connectors.

Here's a peek at what I did so far:

That circle is the diameter of a USA quarter. It's not quite fingernail size, but then it's discrete, not an even smaller opamp. A 3V lithium coin cell is just a hair smaller diameter than that. And it's using 0805 SMD parts. Equivalents as much as 1/4 the footprint are available. an opamp version would probably be smaller.

As I said, the tricks are all in the power side: getting power to it, conserving it if needed, and turning it on and off.

[daz]

I have another guitar that i like a lot but only on 10. No treble bleed or treble bleeed of any value and design helps, it just sounds like crap turned down. It's also the only guitar i can try this with w/o tearing it apart because it has rear loaded controls. So i'm going to put that tillman in it right after the pickups and see if i find big time value in doing this. If so, i will start looking for a transparent design to use in that and my thinline. If it doesn't seem really worthwhile i'll just move on. Thanks for all the replies in any case. I'll post back with my findings.

Yep. Problem is, that the LM4250 is low power, but not particularly low distortion by today's standards or particularly low noise. That's one of the fundamental tradeoffs of low power and low noise. Tough to get low power, low noise and low complexity all at the same time.


Yep. I think that was one of the ways Don used it. Still has the issue of DC running through the guitar cord. How much problem that is in practice depends on the quality of the connectors.

Here's a peek at what I did so far:

That circle is the diameter of a USA quarter. It's not quite fingernail size, but then it's discrete, not an even smaller opamp. A 3V lithium coin cell is just a hair smaller diameter than that. And it's using 0805 SMD parts. Equivalents as much as 1/4 the footprint are available. an opamp version would probably be smaller.

As I said, the tricks are all in the power side: getting power to it, conserving it if needed, and turning it on and off.

[rjb]

When the guitar's volume is all the way up, there is a resonance between the pickups inductance and the cable capacitance.

If I'm reading the OP right, he wants to maintain that resonance, at the same Q and freq as the original passive circuit produces with volume full up.
If I'm reading the various suggested schematics right, none of them do that. Yet.

[J M Fahey]

An unjustly forgotten or despised OpAmp which is perfect for this is TL062 and its family.
Basically the same as industry workhorse TL072 with 1/8 the current consumption and working down to +/-2V rails (or +4V single).

*Very* efficient, with +/-3V (2 button cells) it can put out 5VPP into a 10K load
It eats only 200uA per amplifier.
And FET input, so high impedance is easy

I use them a lot, in my Bass buffering and mixing a Piezo bridge pickup + a conventional magnetic, in my Son's Nylon strings Spanish guitars, in electret remote heads phantom powered on the far side of a parallel telephone cable, the works.

I even made a small 8 channel mixer, with XLR inputs, powered by a 9V battery, for street recording .... and the battery lasts a lot.
So much so, that the power LED drain is significant (compared to the active side) , so it's push-to-test only

EDIT: forgot the datasheet link http://www.ti.com/lit/ds/symlink/tl062.pdf

[R.G.]

If I'm reading the OP right, he wants to maintain that resonance, at the same Q and freq as the original passive circuit produces with volume full up.
If I'm reading the various suggested schematics right, none of them do that. Yet.

Actually, it's not a problem. What a (good) buffer does is re-power anything presented to its input without changing it. So let's assume that anything that can be produced by pickups and whatever else can be buffered and not deteriorate down a cable, which is what the buffer's job is.

What remains is to make the pickups think they're loaded and resonance-d, and Q-d just like the original passive circuit with volume full up. One way is to make a duplicate of the passive circuit with the volume full up, and buffer that.

That is kind of a pain because of the size of the parts and such, but some measurment and some math could return the set of Rs and Cs that, when stuck onto the output of the pickups, re-produce the resonance, Q and frequency response that the original tone-volume setup did, but only at that one magical setting. Identifying the components, impedances and frequency response curve of a black box with electrical terminals is (or was) a second year EE lab favorite.

That then gets buffered, and can be twiddled with after the buffer or not, as one sees fit.

Want the sound of pickups un-messed-with? Buffer them. Want the sound of pickups loaded? Load them so they're just right, then buffer them. Once again, I'm led back to the problems being making and powering a good buffer in a way acceptable to the guitar owner. I can be and often am wrong, but I don't see any huge issues with this version of the problem.

[frus]

Want the sound of pickups loaded? Load them so they're just right, then buffer them.

Will the parallel pickup combination still quack?

[R.G.]

Will the parallel pickup combination still quack?

We used to have a lot of apocrychal sayings. One of them was "Electrons don't have names." Meaning that one's just the same as another.

If parallel pickup combinations quack, and you arrange so when you switch them together they "see" an equivalent loading as they did before you buffered them, then they will quack the same as they did before. Pickups can't tell one resistor or capacitor, or electron, from another.

Granted, there may be some tricks involved to make sure that the switching in parallel, etc. preserves the magic loading, and that if there are two (or more!) magic loadings, they get switched properly too. And it is sometimes hard to know what "equivalent" means. But electrons don't know what resistor they're in. If parallel pickups quacked before the magic-load-and-buffer, they'll quack afterwards.

Notice that since the variable controls that have been replaced by fixed resistors in the hypothetical "magic load", the output volume and tone will only work on the buffered version, and will not have tonal changes which depended on reacting with the pickup's internal inductance, capacitance, etc. That is after all the point of all this - to remove the deleterious effects of the controls at some rotations.

[daz]

Tried it. Selector switch output to buffer, buffer out to vol pot. Results.....ehhh.....aside from that buffer's coloration, i heard no real improvement in the turned down tone. You guys can keep discussing and i'll keep watching the thread, but unless something sounds too good to pass up, i'm done with this stuff. I really think the original idea of this post is what i have to focus on....making these pickups better somehow or biting the boutique bullet.

[bob p]

> It's funny how we are caught by the two faces of the sins of the fathers and the conservatism of the guitar player.

The conservatism of the guitar player often means that people just like to stick with what works. Many guitar players are unwilling to accept change. That's in contrast with bass players, who tend to be more flexible and embrace change. I know it's a stereotype, but it's a stereotype because there's an element of truth in it.

[Leo_Gnardo]

Help me here. I'm sure there are things I haven't thought of.

That's quite a history!

Well here's one more but it didn't go either permanent or popular. Article I remember in Recording Engineer/Producer late 70's had Bruce Springsteen's guitar with a built-in buffer, 9V power supplied via ring terminal of a "stereo" quarter-inch plug. Needless to say, plugging or unplugging would result in a huge BANG. Probably spare guitars were left plugged in & 'noise-free' switching done by his guitar tech. I can imagine this system had occasional audio racket from imperfect contacts at either end of the cables.

I had a jaw-wag with Ian Waller (Wal Bass) in 1984 about "phantom powering" his instruments this way but we both decided it wasn't the thing to do.

Somewhere between then & now The Bruce went to Barden pickups on all his Tele's, and use of a wireless system with multiple transmitter/receivers on different frequencies. This I've seen up close & in person. Guitar tech still handles the switching.

Still no solution for daz...

[Leo_Gnardo]

An unjustly forgotten or despised OpAmp which is perfect for this is TL062 and its family.
Basically the same as industry workhorse TL072 with 1/8 the current consumption and working down to +/-2V rails (or +4V single).

Thanks for mentioning this Jose. TL061 used in MXR's MicroAmp, I've used many times (or home-made circuit copies) to offer buffering solutions to remedy loss of high frequencies due to long cable or low impedance loadings. For those who complain about the extra brightness brought on by MicroAmp's 5.6M input load, I change it to 1M & they get happy.

There's also the Alembic StratoBlaster, a very simple and effective 1 FET buffer with gain adjust from 0 to +6 dB. Can also load guitar with 1 Meg at StratoBlaster input to simulate typical input load in an amp.

I would apply either of these buffers AFTER all the guitar controls. That way all the typical RCL interactions still take place within the guitar & signal "sent down the pipe" with ability to drive any reasonable length cable. 100 ft, 30 meters, no problem.

FWIW daz I have one of those Fender "Seth Lover" HB pickups in bridge position of my mid 60's Guild Polara. Sounds just fine, but definitely different from other pickups possibly also due to CuNiFe magnet? I use it as a test guitar & everybody likes it.

[daz]

FWIW daz I have one of those Fender "Seth Lover" HB pickups in bridge position of my mid 60's Guild Polara. Sounds just fine, but definitely different from other pickups possibly also due to CuNiFe magnet? I use it as a test guitar & everybody likes it.

Must be an original eh? I'll tell ya, a *good* sounding one is a sound i honestly doubt more than a tiny fraction of players who love and understand fender sound wouldn't love. But as i said before, most of what is out there are reissues with the bar magnet and they have given it a bad rap. The character is there, but it's ruined by the horrible balance of wound strings to plain, bass to treble.

The old cunifes are great, but it's not due to the cunife. It's a combination of many things, but lollar and the creamery have designed replicas that supposedly sound almost exactly like them, some say better using threaded alnico instead of cunife. Cunife is no longer available at a viable cost so they use alnico.

By the way, not to confuse anyone, when Leo said "seth lover" he wasn't referring to the duncan seth lover HB pickup. He's referring to the fender wide range humbucker we discussed earlier which was designed by seth.

[Leo_Gnardo]

Must be an original eh? I'll tell ya, a *good* sounding one is a sound i honestly doubt more than a tiny fraction of players who love and understand fender sound wouldn't love. But as i said before, most of what is out there are reissues with the bar magnet and they have given it a bad rap. The character is there, but it's ruined by the horrible balance of wound strings to plain, bass to treble.

When they first came out these were such a change from the original Tele tone they got the thumbs down from just about everybody. But on their own, without any expectation of comparison to Tele or any other tone, they're perfectly capable pickups. @1977-8 I was monkeying around with the Guild Polara & I got assistance from a good local luthier who sold me a "wide-range" from his spares collection. Bless him, he figured out the optimum mounting position for it & also a DeArmond HB (commonly used by Guild) in the neck position. Since then I've given them beeswax dips to stop hi frequency squeeks. I'd already re-fin'd the neck in '76 removing all lacquer & applying tung oil to the point of refusal. I don't recommend this method unless you have a hell of a lot of patience, as it took YEARS for the tung to become non-sticky. Now it's smooth as a baby's bottom & everyone loves that neck. BTW the neck's mahogany - mm mm good!

By the way, not to confuse anyone, when Leo said "seth lover" he wasn't referring to the duncan seth lover HB pickup. He's referring to the fender wide range humbucker we discussed earlier which was designed by seth.

Kee-rect! 3 up n 3 down screws thru the cover. Have the bass version in my '68 Tele bass. The bass version has no top end to speak of, and local blues guys call it "The Slab." I can doll up the tone with a graphic EQ and there's some good tones to be found that way.