The Perfect Treble Boost - Help me build it!

[perfboarder]

I don't see it on the Rullywow site. Could you point me to it?

Dont know the latest version.

 

[mdc]

Just curious how hard it would be to change the SPDT switch to a 3-position so that you could bypass the buffer and AMZ stage? It might be useful to be able to take advantage of the low-z input in the absence of buffers upstream and wire it off/"single"/"hb."

I'm also really curious how well that AMZ circuit works compared to either a passive trim pot (like the catalinbread katzenkonig) or a series resistor (a common fuzz face/wah mod, I think?) or even a fixed, passive bandpass filter on the input. I remember reading a bunch of anecdotal info about the pickup simulator and opinions were definitely mixed. I think a few folks said they got equivalent results by simply wiring whatever single coil pickup they had laying around in a parts box into an enclosure with a couple of jacks attached.

I love tone benders but also the boss LS-2 for switching so I'm always interested in reports from the frontline of the low-z vs buffer war.

 

[mdc]

And of course kudos on working out the circuit and sharing it!

 

[daeg]

Just curious how hard it would be to change the SPDT switch to a 3-position so that you could bypass the buffer and AMZ stage? It might be useful to be able to take advantage of the low-z input in the absence of buffers upstream and wire it off/"single"/"hb."

Funny you should ask...

The center-tap position on the transformer wasn't doing anything noticeable, so I repurposed the switch for buffered / unbuffered. Bypassing something completely takes 2 poles, so no DPDT On/On/On magic is possible.

This is what I have on breadboard right now.

I'm using a new schematic software (LibrePCB) and don't have the suggested libraries imported, so the symbols are a little off, but it's all there. The pots labeled VR are intended to be external while the pots labeled R will be trimmers. The buffer is fully bypassable, the single Ge diode clipper works great, noise is low-ish, gain is medium and overall I'm very happy with it.

 

[daeg]

I'm also really curious how well that AMZ circuit works compared to either a passive trim pot (like the catalinbread katzenkonig) or a series resistor (a common fuzz face/wah mod, I think?) or even a fixed, passive bandpass filter on the input. I remember reading a bunch of anecdotal info about the pickup simulator and opinions were definitely mixed. I think a few folks said they got equivalent results by simply wiring whatever single coil pickup they had laying around in a parts box into an enclosure with a couple of jacks attached.

We're thinking alike. What you wrote above is exactly what I've been contemplating this past week.

While the circuit is coming along nicely, I need to tackle these 2 issues to tackle before calling this done.

1.) When unbuffered, C4 will load pickups and shift the resonant peak...
2.) The LPF formed by VR2 and C4 seems to make the inductor obsolete. You get icepicky highs at full CW and a dark grunty sound when fully CCW. I'm leaning towards omitting T1.