When changed ASAT wiring from Broadcaster to ASAT Classic?

[yowhatsshakin]

Hi folks,

In the description of a 1994 ASAT Special on his web site, Greg Gagliano makes this intriguing statement: "However, the BBE-made ASAT and ASAT Special had a different circuit from the pre-BBE ASAT. The BBE-era ASATs used the pre-BBE ASAT Classic circuit."

What constitutes that difference? The Broadcaster, and later the ASAT, has CTS 250k Audio Taper potentiometers, 200pF disk capacitor on the volume, and 6.8kΩ resistor with .100μF cap on the tone. The ASAT Special still has the 200pF disk capacitor on the volume, but the 6.8kΩ resistor has been removed and the cap now has a value of .022μF. Note that this is identical to the pre-BBE ASAT Classic wiring (as documented e.g. in my George's ASAT Classic Signature w/Leo Fender Fine-Tuner Vibrato post). (Note: the ASAT Classic model also had a 6.8kΩ resistor on the tone when it was introduced but it was quickly removed to improve the sound of that model.)

But when exactly did this change take place?

My mid-1989 flamed maple ASAT still has the Broadcaster wiring:


As expected, my late-1993 ASAT Special has the pre-BBE ASAT Classic wiring:


So with the 1989 still having the Broadcaster wiring and the 1993 ASAT Special the ASAT Classic wiring, I got intrigued by the aforementioned question.

Although Will Ray's first ASAT likely was assembled in 1992, it still uses a wiring harness with CTS pots dating back to 1990 (as do the date stamps) and does not have the resistor and the lower cap value.


What I call the ASAT Signature '500', an employee guitar from April 1991 does not have a resitor either:


In hopes of finally resolving it, I took possession yesterday of a beautiful 1991 ASAT Signature w/Dual-Fumcrum Vibrato from one of the members of the Michigan Mafia (as they were affectionately known on the old Forum). Given Greg's remark as when a transition might have happened, I had fully expected that it would still have the Broadcaster wiring. I was completely wrong:


This leads me to believe the transition to ASAT Classic wiring happened well before BBE took over G&L. I can totally understand it from a production standpoint where using the same wiring harness for both ASAT and ASAT Classic makes things a lot easier.

BTW, later on BBE changed that .022μF cap to .047μF, I think because the pups were wound hotter. At least, I find this value on my (pre-2002) ASAT Custom:


Would love to know whether anybody has additional information. Maybe you have a 1990 ASAT and want to take a peek underneath the control plate.

- Jos

[Katefan]

Hey Jos,

Nice detective work… I don't have a photo of Char's control plate assay but I do in fact know that she has both the resistor and the green cap. Body dates I believe off the top of my head are '89 neck and '90 body but you can check in the registry as for the specific dates.



Here's the what the wiring on my control plate of my ASAT Classic 'Prototype" looked like when I got it… looks like it had them at some point.
Body neck dates hail from the same time period.





Hope this helps Jos.

Cheers,
KF

[GGJaguar]

I'm pretty sure the change was made in October 1990.

GG

[yowhatsshakin]

I'm pretty sure the change was made in October 1990.

GG

Greg,

That would be my guess too. George's decked out Classic was assembled around that time and it does not have the resistor. So If we make the assumption that wire harnesses were identical between ASAT and ASAT Classic, that would be a a good guesstimate.

KF,

Thanks for your input. And "Char" remains to be an iconic guitar!

- Jos

[Katefan]

Chur!

You're welcome - true dat

Cheers,
KF

[yowhatsshakin]

I'm pretty sure the change was made in October 1990.

GG

Hi folks,

Received a new data point today. Trevor Midgley, better known under the artist name Beau and also previous owner of Lacewood #5, has a gorgeous ASAT Signature with S/N G026690 for sale on the British eBay site (http://www.ebay.com/itm/252403230550). What caught my eye was the original hang tag shown in one of the images with the date "4-10-1990". I contacted him and asked him to look under the hood. The body date is SEP 25 1989 and neck date FEB 26 1990, all jibing with the tag date. Trevor sent me this picture showing the wiring does not have the 6.8kΩ resistor even at the end of March 1990.


- Jos

[suave eddie]

All the technical stuff means nothing to me unfortunately.

How do these changes translate sonically?

[FZTNT]

All the technical stuff means nothing to me unfortunately.

How do these changes translate sonically?

I agree, What is the sonic gain or loss by not having the resistor?

And KF, your "prototype" has neither the resistor nor the caps. How does that change the sound?

Thanks,

Tom

[NickHorne]

KF's does have a tone cap; the brown ceramic between the ground-end of the volume pot and the wiper of the tone pot.
Unusually, the tone pot is just wired as a resistor between the hot signal from the volume pot, and the cap to ground; the actual tone pot track doesn't go to ground. This is more Fender / Gibson wiring than G&L, who usually use the extra 250k load of the tone-pot track itself to tune the pickup response. So I imagine KF's is bright! If that's the circuit of the Bluesboy in the next pic, it'd suit the Seth nicely, but with a Bakersfield-stingy back pup.
The effect of the 6K8 is simply to give the effect of the tone pot never quite going to zero; you don't get the really-muffled zero-position tone, but just a nice topless one.

[yowhatsshakin]

[quote="NickHorne"The effect of the 6K8 is simply to give the effect of the tone pot never quite going to zero; you don't get the really-muffled zero-position tone, but just a nice topless one. [/quote]
+1

There is a nice blog post I found that pretty lucidly (at least to me) explains the in/outs of guitar wiring.
If you look to the Tone Circuit diagram in that blog, that 6.8kΩ would sit between R tone and C tone.

A couple of other things: Usually the value for the volume pot has a much bigger effect , a 1MΩ pot makes the guitar much brighter compared to a 250kΩ value. This explains the prevalent values used on bucker Gibsons (higher values) vs. single-coil Fenders (lower values). For the tone circuit, the value for the capacitor has the most effect.

But all elements play together: coil DC-impedance and inductance, potentiometers, bleeding caps, tone caps. Leo was definitely a fan of bright but he also tried to use components that would create a "musical" frequency response for the MFDs, or in other words how bright your pup sounds and how broad the range of frequencies one hears. And it that game, different values for resistance and capacitance can be used since the physics dictates the (inverse of) the product of both appears in the formulae for the so-called cut-off frequency.

- Jos

[FZTNT]

KF's does have a tone cap; the brown ceramic between the ground-end of the volume pot and the wiper of the tone pot.
Unusually, the tone pot is just wired as a resistor between the hot signal from the volume pot, and the cap to ground; the actual tone pot track doesn't go to ground. This is more Fender / Gibson wiring than G&L, who usually use the extra 250k load of the tone-pot track itself to tune the pickup response. So I imagine KF's is bright! If that's the circuit of the Bluesboy in the next pic, it'd suit the Seth nicely, but with a Bakersfield-stingy back pup.
The effect of the 6K8 is simply to give the effect of the tone pot never quite going to zero; you don't get the really-muffled zero-position tone, but just a nice topless one.

Nick, yes, I see that now, Duh on my part. It just was not where I am used to seeing it which is on the volume pot, right. Never seen it wired from Vol to Tone pots. Even being an audio engineer by formal training and education I am supposed to know all the values and such of resistors and capacitors and what they due and so-forth, my practical experience and advice to anyone who asks is "turn the knobs till it sounds good."

It's just interesting to see the different ways people mess with the sound electronically.

Tom

[Katefan]

Hi Tom,

My Proto sounds pretty dang cool IMO… bright and spanky.

Have a listen...



(recorded straight into my loop pedal)

Cheers,
KF