A bit off topic, but, yeah...I don't like those clamp on tuners. I use one of these:

View attachment 323243

It's a bit bulky, but I have a tuner output on my bass head, so I just set on top, connect, tune and play.

Oh I see what happened I mixed this thread up with another thread that was mainly about guitar tuning and making a filter to filter the guitar output so that the string frequency could be measured. I would think a preamp would help there too though.

Long time ago I built a small preamp and installed it right into the solid body electric guitar body, in with the pickups and volume and tone controls. A 9v battery fit in there too, and a switch to switch it in or out (on or off).
I don't remember what circuit I used though but it was probably with an op amp also.

 

I find this thread to be interesting and confusing. I've been a tech for over half a century, and most guitar inputs I've seen are very similar, (if not identical), to the two main ones posted here. I've seen the 1M resistor before the two 68k's more often then the 1M after the two 47k's. But in all cases, almost every amp manufacturer, past and present, lists there input impedance as 1M.

I would think the designers and manufacturers would know their own equipment. Maybe???

 

Musical-Instrument manufacturers, et-al, tell You what they think You want to hear.
.
.
.

 

I find this thread to be interesting and confusing. I've been a tech for over half a century, and most guitar inputs I've seen are very similar, (if not identical), to the two main ones posted here. I've seen the 1M resistor before the two 68k's more often then the 1M after the two 47k's. But in all cases, almost every amp manufacturer, past and present, lists there input impedance as 1M.

I would think the designers and manufacturers would know their own equipment. Maybe???

You are correct for the high-gain input. It is 1M.
Because of the way the switched jacks are wired, the low-gain input has lower impedance..
It's 1M because it always has been, not because it works best!

 

It's also always been my understanding that the high, (aka "normal"), input is for passive pickups, while the low input is for active pickups. Not sure if that's guitar lore or technical.

 

It's also always been my understanding that the high, (aka "normal"), input is for passive pickups, while the low input is for active pickups. Not sure if that's guitar lore or technical.

It's true, but could just be a coincidence, because two-level inputs predate active pickups. I posted a link back in post #58 which gives a possible explanation.

 

Ah. Got it. Nice link.