[alan.cassidy]

I'm sure this has been gone over many times but what the L I'll dive in again.

   I am getting a Lightspeed Attenuator and at some point I would like to use it with modified Mc Cormack DNA 0.5 monoblocks which have Lundahl transformers giving them an input impedanc e of 10K ohms. This means I will need a buffer and most of the cicuits I have seen seem to have a pot in them.

My question is, what is the purpose of the pot if the Lightspeed controls the volume and the buffer is to match impedances.

  I can solder and I recognize electronic symbols, when I have my book open to the right page, but I would not say that I can understand what values I should have through out a circuit and how it functions.

   Ideally I would like to build a straight through buffer with 2 in 1 out and a toggle switch to change between the 2 and if it needs a power supply an on off control.

   Simple is better, any ideas?

  Thanks Alan.

[alan.cassidy]

I found the B1 buffer thread so I'll look for my answers there but that doesn't stop you from posting replies here.
  Looks like a months worth of bedtime reading.

[richidoo]

You can eliminate the volume pot from the B1 circuit. Just jumper across the volume pot's in>out pads on the PCB.

From my own experience with the B1, I know that the low distortion Kuartlotron buffer would be a better choice to follow the ultra low distortion Lightspeed Attenuator. Opamps like LME49710 (requires 10dB gain to sound good) or MC33078 (great in unity gain) also great buffers worthy of Lightspeed.

EDIT: Another DIY option if you haven't already built the Lightspeed is to use autoformer volume control like Intact Audio. This sounds as good as LDR imo (slightly wetter from magnetics,) but does not require current buffer.

[Folsom]

Kuartlotron for sure. It takes a modicum of attention and outside your normal boundary just to properly set the DC offset. Overall pretty easy, new version has voltage regulator on it so it's pretty easy-peasy.

The DCB1 is nice, but it cost a small fortune by comparison.