Anybody have a schematic the JG Tiger Unity Gain Buffer

[bdhact1]

The combination of components in the schematic produced the desired sound I was looking for. Some of it may not make sense; But all I had to go by was a picture. I have no way of gauging the accuracy of the circuit except for my own ears. I have attached the picture I used as a reference.
I definitely love tigers sound.

BTW, There is no on\off switch so popping isn't a problem. It is always on when the cable is plugged in.

[52 Bill]

I'm with Mark here, the circuit that you have created may sound right but it really doesn't follow any normal design practices.

...R1 should be connected to the non-inverting input in the manner shown. If it were to go anywhere, it would either be:

a) going between the input and ground, to avoid popping if the buffer is intended to be switched in/out while plugged in.

b) tied between the non-inverting input (pin 3) and the junction of R2/R3, as shown here: http://zohars.homelinux.org/tamarchi...es/mxrdist.gif

Or R1 and C2 could be going to ground from the inverting input.

Also the green metal film resistor in the original circuit appears to be marked 1000 (either 100 ohms or 1K?) which I think would be the correct value for R5 and not 100K.

[bdhact1]

I'm with Mark here, the circuit that you have created may sound right but it really doesn't follow any normal design practices.

Or R1 and C2 could be going to ground from the inverting input.

Also the green metal film resistor in the original circuit appears to be marked 1000 (either 100 ohms or 1K?) which I think would be the correct value for R5 and not 100K.

I think I tried R1 and C2 to ground and didn't get the right sound. I can't remember. It was a few months ago. I think I tried several layouts of the componants. The schematic I made has worked and sounded the best so far.

R5, (identical to R4 as far a i can tell) Marked 1000F on a manufacturer data sheet referenced to 100k .

If anyone wants have a crack at deciphering the the circuit from the picture, I'd love to try other interpretations.

[Mark Hammer]

If the unit is hardwired to be on all the time (which I assume means once you plug a guitar cable in to turn on the battery), then a terminating resistor on the input, from cap to ground, is not required. So, the likely arrangement then, is that the 3 1M resistors are used in the same fashion as on the Distortion+ to provide a reference/bias voltage from a single-ended 9V power supply.

Normally, if it was a noninverting unity gain buffer, there would be no feedback resistor, just a wire link between input and inverting pin (6 and 2 on a TL071). I was surprised to learn, however, that BiFet op-amps can actually behave better in some circumstances if a resistance is inserted there. A couple years ago, a fellow in Germany contacted me abuot adapting something I had designed and posted, for use with a 9v, rather than bipolar +/-9v supply. He also added an input buffer stage, using one section of a TL074, and stuck a 510k resistor in the feedback loop, with no additional resistor from the inverting pin to ground. I was baffled at first, but he explained that it resulted in better noise performance. So perhaps that is what the Tiger maker did too.

[hoonhout33]

Hmmmm

I'd really like to wrap my head around this and maybe I'm asking to much or not paying attention enough but I'd really like to build this thing and I'm retarded compared to what you guys know. My 1967 Les Paul Deluxe loses alot of body between output to my amp. I have some materials to build it but just need a simple schematic with the values. I don't want to sound like Jerry I just want to preserve my tone through all my pedals simply and efficiently. infinite input impeadance - zero output impeadance.....nothing else.
Can you help me?

Hoony

[bdhact1]

If the unit is hardwired to be on all the time (which I assume means once you plug a guitar cable in to turn on the battery), then a terminating resistor on the input, from cap to ground, is not required. So, the likely arrangement then, is that the 3 1M resistors are used in the same fashion as on the Distortion+ to provide a reference/bias voltage from a single-ended 9V power supply.

Normally, if it was a noninverting unity gain buffer, there would be no feedback resistor, just a wire link between input and inverting pin (6 and 2 on a TL071). I was surprised to learn, however, that BiFet op-amps can actually behave better in some circumstances if a resistance is inserted there. A couple years ago, a fellow in Germany contacted me abuot adapting something I had designed and posted, for use with a 9v, rather than bipolar +/-9v supply. He also added an input buffer stage, using one section of a TL074, and stuck a 510k resistor in the feedback loop, with no additional resistor from the inverting pin to ground. I was baffled at first, but he explained that it resulted in better noise performance. So perhaps that is what the Tiger maker did too.

I did try the distortion + setup and it was a little too bright sounding. I also tried using a straight link between 2 and 6 but there was a huge volume drop. The 1M going to pin3 in combination with the 100k between 2 and 6 makes it just slightly below unity with just a hint of dirt; And is a great line driver.

[bdhact1]

I'd really like to wrap my head around this and maybe I'm asking to much or not paying attention enough but I'd really like to build this thing and I'm retarded compared to what you guys know. My 1967 Les Paul Deluxe loses alot of body between output to my amp. I have some materials to build it but just need a simple schematic with the values. I don't want to sound like Jerry I just want to preserve my tone through all my pedals simply and efficiently. infinite input impeadance - zero output impeadance.....nothing else.
Can you help me?

Hoony

You can try the schematic I attached. It is a good non boost line driver. There are also a few other schematics that were posted here. General Guitar Gadgets
web site also has some buffer schematics.

[Mark Hammer]

I'd really like to wrap my head around this and maybe I'm asking to much or not paying attention enough but I'd really like to build this thing and I'm retarded compared to what you guys know. My 1967 Les Paul Deluxe loses alot of body between output to my amp. I have some materials to build it but just need a simple schematic with the values. I don't want to sound like Jerry I just want to preserve my tone through all my pedals simply and efficiently. infinite input impeadance - zero output impeadance.....nothing else.
Can you help me?

Hoony

I would suggest that, if this is not your usual past-time, that you seriously consider NOT building it into the guitar, but rather simply build something like this into a floor box. Unless you know what you are doing, with respect to risk management aspects of wiring and installation, there is just too much to bugger up on a nice axe like that.

A simple clean boost pedal, like this one - AMZ Mosfet Booster Guitar Effect - will give you all the buffering you could want, plus the option of some extra gain if you ever find the need to push other pedals, or your amp, a little harder.

The advantage of floorbox over built-in versions is that:

a) you can disable them with your feet instead of your hands (need those for playing!)

b) there is no risk to the finish of the guitar itself

c) space constraints do not oblige you to make any sacrfices with respect to design or features/options

d) you have a wider choice of powering options, including use of a wallwart or other regulated supply

e) if you screw it up, you can toss the pedal; hard to do with a guitar

There is also another approach: not the guitar OR a floorbox. http://www.till.com/articles/PreampCable/

[R.G.]

Here are some other circuits which are tested and quite good. I especially like the FET preamp. In all cases there will be little effect on the tone except the input impedance presented to the pickups (which you could model at the input with a resistor and a capacitor if you happen to like some loading).

Wow. Nothing ever dies on the internet. Those are my drawings from the mid 90s that went into the first schematics repository on the net - Leper's Schematic Archive. Pat Montagar seems to have his own private schematics wayback machine.

[bdhact1]

Update: Please disregard the schematic that I posted earlier.

After restudying the Tiger buffer photo I realized that I have 2 incorrect resistors. Both 100k resistors actually appear to be 1 100 ohm and 1 10k resistor. After switching them out I am getting a whole different sound from the buffer. The 10k seems to be the pulldown resistor after the 2.2 capacitor; The problem is I'm still not sure if the 100 ohm resistor is part of the feedback loop or is comming off the loop and adding resistance before entering the 2.2 capacitor. Further testing is needed.

[J M Fahey]

A 100 ohm resistor between an op amp output and a long cable capacitance is an old recommended stability add on.

[bdhact1]

So should the 100 ohm resistor should go into the feedback loop ?

[J M Fahey]

No. You build your regular preamp and put those 100 ohms in series with the hot pin of the output jack.

[bdhact1]

Thanks JM! I'm gonna try that on the breadboard tonight.

[bdhact1]

After testing and listening to the results, Here is the next revision. This revised buffer is so close to "The sound". I think I may have a final product.