Comments on: Leaky AC128 Buffer Redux

By: Anton

Anton — Mon, 23 Jan 2012 05:37:44 +0000

You must have something wired wrong ‘vass’. I’ve built this and is wired into my Crybaby and it works fine. I should actually say that the wah sounds better with it. I love it. Thanks again, Jack!

By: vass

vass — Thu, 15 Dec 2011 19:38:17 +0000

Hei,
Tnx for this post and work.

I built this bufer. Why this bufer turn sound down 15% then pickup sound in original.

By: admin

admin — Sun, 02 Jan 2011 08:13:00 +0000

R5 is the output pulldown resistor and is only really needed if you use a footswitch with the circuit to toggle it on/off, and is included to prevent popping when the switch is stomped.

By: yot

yot — Wed, 29 Dec 2010 13:46:07 +0000

Hello
I’m curious about R5, why it’s 1M, What is the output impedance of this buffer?

By: AndrewCE

AndrewCE — Thu, 09 Jul 2009 19:46:39 +0000

Will this only work with leaky germaniums? cause I prototyped this with 2N3906′s, and i get no sound. Interestingly, though, the amp does respond to me touching the strings and bridge in the usual way. (humming when i’m not touching them, stopping when i do).

Also, i used 10uF polarized caps.
Are “leaky germaniums” necessary or what?

By: admin

admin — Thu, 16 Apr 2009 11:35:14 +0000

You can make the circuit go closer to unity by selecting a high HFE transistor, but it will never get to gain = 1, nor will any simple transistor buffer whether silicon or germanium.

By: Ian C.

Ian C. — Sat, 11 Apr 2009 17:24:21 +0000

Jack, can the gain on this buffer be pushed up to unity? Does it start to clip? I’m liking the way it preserves all the content in my guitar signal, but would prefer it without the attenuation.

I should have built it with a variable in R4 to play with the gain…

If you’re interested here is the buffer off/buffer on comparison: http://dl.getdropbox.com/u/870088/sounds/name-that-effect.mp3

That’s over a long cable run (~45′) with the buffer sitting mid-way.