[FretfulDave]

In my job as a lead engineer, I say that no technical question is stupid or dumb. Ask away. Hope the same can be had here on this one.

OK, buffer. So what I understand after reading most of all the threads on this subject is that the buffer, such as Waldo's and similar, basically converts the output from the guitar pickups, which is a relatively high impedance signal, to a lower impedance and feeds that out with a current driver so as to not totally lose signal strength over long cable distances. In most cases, the signal runs through the effects boxes and goes back into the guitar, goes past the volume control and over to the amp. I expect that through all the pedals the impedance has not changed, so one has a low impedance signal still coming from the guitar, just current driven for power(?). I realize some buffers are unity gain and some are more than unity gain or even adjustable, but I don't think that plays into this queston.

The question: I understood that guitar amplifiers are designed for regular guitar input signals and that implies a high impedance signal pretty much directly from the guitar. So with the buffer, you are putting a low impedance signal into a high impedance input. Does this have any effect on the sound or tone, etc.? And I'm talking about how folks chase Jerry Garcia's tone all the time.

Seems like it is a mismatch to me. Or am I misunderstanding something in the electronics chain? I dropped out of EE after transistor theory, didn't do well in that but did do well in communications theory and I turned out to be a computer network guy .

Anyway, my basic query is buried somewhere in the ramble. Do the pedals change the impedance? Would just having the buffer into the amp w/o pedals create similar tone to Jerry's (presuming all the additional support components, i.e. pickups)? Seems like there should be something to the low impedance into a high impedance circuit deal.

Peace,

Dave

[SarnoMusicSolutions]

Great questions Dave.

The idea is partially about the lower impedance, and partially about buffering or "isolating" the pickup. Whatever happens after the buffer can not affect the pickup itself. Pickups are high-z devices and are highly inductive. This means they're very sensitive to cable capacitance, switch contacts, jack connections, etc. By buffering right near the pickup, you capture the purest, unadultered tone the pickup can make, and by then making the signal active and sending it on down the line with a low impedance, that captured sound remains very intact all the way thru the runs of cables and bypassed pedals. Once that signal hits an active effects pedal, then that pedal becomes the next line driver in the chain. But imagine that you have the 2-cord effects loop setup like Jerry. Also imagine that each pedal is bypassed. If you engage the loop, but nothing is on, then the signal goes all the way to the pedal setup or routing device with it's many switch contacts, all the way back to the guitar, and then on to the amp thru the final cable. You can get 40 to 60 feet of cable in that setup very quickly. Without a buffer, all that cumulative cable capacitance and jacks and switch contacts will most definitely load down the pickup and react in a way that will both darken the treble and also shift the pickup's resonant frequency downward. The buffer prevents this and when it's done properly, the tone you hear with the loop engaged or bypassed should be identical. Also, the lower impedance signal allows you to use a lower value volume pot, and this presents another bonus. With the low value pot, you can retain the clarity and presence at any volume. A high value pot may slightly attenuate the highs as you turn it down as the pot's resistance and the cable capacitance interact.

The amplifier doesn't care at all if you send it a low impedance signal. The reason amp impedances are so high (1 Meg typically) is because this prevents the amp from loading down the pickup and altering the treble response. A low-z source into high-z load is just fine. A high-z source into low-z load can present problems. It's actually a fairly complex interaction of inductance, capacitance, resistance, reactance, impedance, etc., and the buffer with both it's isolation function and it's low-z drive capability virtually eliminates the issues.

Brad

[FretfulDave]

Brad, thanks for the very, specific and detailed information. Makes sense and I thank you.

the way you guys come through is just unreal.

Best,

Fretful Dave

I see that my dyslexia has shown up in the topic header Tried to change the spelling but can't figure it. *Sigh*

[JonnyBoy]

This is a question that probably electrical engineers at MIT ask in grad school. That can't be a dumb question!
Like Brad said,the guitar Buffer DOES change the Tone significantly, and once you put a loop on your guitar, you will see how much if you have a Boss-like-buffered pedal in the chain and no buffer in the guitar. The other pedals do re buffer or go through the pedals buffer circuit. The buffer like Waldo's, if you have a buffered pedal in the chain, is primarily for the line before the pedals and the non looped signal especially. If you have an O.B.E.Loop and no buffer you will see the huge difference in tone between the effects line and the non effect line (or buffered line and non buffered). To have equal tone on both, you need the buffer in the guitar. If all of your effects are true bypass, you don't have much of a signal difference between the two lines, but you are still a step away from the higher articulate treble, or clear Jerry tone we seek. The Buffered signal gets you a step closer to the Jerry sound. Think of your cable, effects, plugs and connectors like one large resistor, the buffer almost eliminates its resistance helping preserve TONE. There are different buffers and slightly different tones resulting, and Waldo's seems to be the closest to what Jerry was using in his Tiger, if you listen to Vic and John's playing, its close. An example of what a buffer sounds like, turn your tone knob all the way down, that's non buffered. Turn it all the way up and that's buffered.

[strumminsix]

I see that my dyslexia has shown up in the topic header Tried to change the spelling but can't figure it. *Sigh*

I was only able to help with that the rest Brad did! HA!

[Tennessee Jedi]

Dave -
Figure this shit out so you can help me understand it !
When I get the FrankenWolf we will mess around with it.
Maybe with it in my hands I will grasp it better.