Jerry Garcia's Guitar Active Electronics Schematic

[vanessa]

I saw a schematic floating around for his unity gain buffer preamp a while back, does anyone have a copy?

[setboy]

is this what you are looking for?


http://dozin.com/jers/guitars/tiger/schematic.html

if not, check out the these yahoo Groups

http://launch.groups.yahoo.com/group/GearHeads/

http://launch.groups.yahoo.com/group/gratefuljams/?yguid=150284946

or maybe dozin.com has it some where

Raphael

[Stompin Tom]

So, I like the idea of switching pups with a footswitch... I assume that's what that diagram is showing (the first link above)... but I can't really make sense of what's going on there. What's that thing between the pups and the tone controls (where the red wires from the pups go)? Does that mean the neck pup is always on and he could turn the mid and bridge on and off by grouding them? Oh, my simple mind is failing me...

[vanessa]

I've seen the wiring for his tiger guitar before. Wherever I did also had the schematic for his unity gain buffer preamp.

[toneman]

article mentions a "stratoblaster".
another mentions "no gain" preamp.
the TI INA217 would make a killer/low noise/$5 preamp.
In fact, google for INA217 and find the "shootout" test results with a $1500 preamp.
afn
T

[waldo041]

So, I like the idea of switching pups with a footswitch... I assume that's what that diagram is showing (the first link above)... but I can't really make sense of what's going on there. What's that thing between the pups and the tone controls (where the red wires from the pups go)? Does that mean the neck pup is always on and he could turn the mid and bridge on and off by grouding them? Oh, my simple mind is failing me...

no, that schematic has both bridge and middle pickups coil tapped. and the third switch is the effects loop. the preamp was placed onboard before the volume knob.  so when the effects switch is OFF it runs the unity gain buffer thru the volume to the amp, and when the effects are on it runs a unity gained buffered signal straight from the pickups out to the effects, then back into the guitar and then back out the volume to the amp. he could run long cables with no signal loss and could better control the effects as they get a nice clean full signal. almost like having all the effects in his guitar. i imagine running 2 jacks and more cable's is a reason why more guitarist don't use this type of setup, but i have it in my guitar and i will never go back.

peace,
waldo

[cd]

I've seen the wiring for his tiger guitar before. Wherever I did also had the schematic for his unity gain buffer preamp.

You know, you gotta consider the time frame for this creation - the '70s.  I'd bet my left one it's just an opamp based, non-inverting unity gain buffer.  Probably built around a TL071 or some other "great for the time" opamp.  Doesn't need to be any more complicated than that.

[Peter Snowberg]

You know, you gotta consider the time frame for this creation - the '70s.  I'd bet my left one it's just an opamp based, non-inverting unity gain buffer.  Probably built around a TL071 or some other "great for the time" opamp.  Doesn't need to be any more complicated than that.

I was thinking the same thing, except the Dead always has serious technical hot-shots around so I would guess a slightly more exotic opamp, probably in a gold mil-spec package. I would also be surprised if it weren't a basic unity-gain buffer with some caps and a bias supply.

The guy who came up with the board was from San Mateo, California and was offering them for sale a few years ago, I don't know if you can still get them today.