DIY Pre-Amplifiers

Building a Pedja Rogic Buffer

DSCN0670A while ago I embarked on a simple project to build a PCB version of Pedja Rogics 2SK170BL driven buffer. This buffer has a very good reputation within DIY circles due to its sound quality. For my project I wished to build as good a buffer as possible.

This article covers the populating of the PCB

Read more: Building a Pedja Rogic Buffer

The Son Of Zen (v6)

SoX Super-Symmetry

image The last in a series here from Brendon Lee.  This is his Version 6 of The Son of Zen amplifier.  The original design was published by Nelson Pass a prolific and much respected designer of Audio equipment.  Brendon suck to a similar design to his previous Zen builds.  He uses heavy duty heat-sinks to keep this  Class A design cool.

Thanks go to Brendon for his kind permission to re-publish this article to preserve it beyond the closure of his Geocities hosted web page.

Read more: The Son Of Zen (v6)

The Penultimate Zen (v4)

image Brendon clearly has had a long and persistent love affair with the Nelson Pass Zen Amplifiers.  This article describes the build of his Version 4 Zen amplifier.  The casework for this amplifier is hefty and by his own admission over engineered cooling wise.  I cant help be impressed though with the sheer size and finish that he has achieved on his mono block pair.

Nelson Pass’s Zen amplifiers are Class A devices which expend a lot of their power as heat.  Within the Hobby community they are renowned for their quality.

Thanks to Brendon for his kind permission to re-publish this article.  Originally hosted on his Geocities site, I am proud to preserve it beyond the closure of Geocities web hosting

Read more: The Penultimate Zen (v4)

Balance Zen Line Stage Pre-Amp



A pre-amplifier is used to control the volume and input selection to your power amplifiers, this can be something as simple as a switch and a stereo volume pot.  However there are advantages in using a powered pre-amp.

A line stage can be used to match impedances between a source and a power amplifier stage.

Brendon Lee opted for a design by Nelson Pass, a familiar name in the DIY audio community.  Nelson’s design is a flexible design that can be used to convert un-balanced signal lines to balanced.

This article has been re-published with kind permission of Brendon Lee, originally published on Brendon’s Geocities hosted site.  The article was republished to preserve it beyond the closure of Geocities

Read more: Balance Zen Line Stage Pre-Amp

Son of Zen

Front_Plate_LEDI am delighted to introduce this project from Brendon to the site.  Named the Son of Zen, this is a true Behemoth of an amplifier.  The original design is by Nelson Pass, a very well known figure in the DIY Audio Scene.  More details can be found at his website.  This amplifier design is a flexible hexfet based design that requires little adjustment and no capacitors in the input line.  Brendon kept it simple and true to Nelson’s original design.

This article was originally published on Brendon's Geocities website, it is with his kind permission that it is re-published here to preserve it beyond the closure of Geocities.

Read more: Son of Zen

R2R Buffered Pre-Amp.

clip_image004Adam Walker has produced an incredible looking pre-amplifier, In this article he talks though his build. Although casework was manufactured for him by a couple of companies the design work for the front panel is his own. This project really shows off the resources that are available to the hobby builder from specialist firms. Adams design I think really shows that home built equipment can rival and surpass many commercially available audiophile equipment. In Adams words…

Read more: R2R Buffered Pre-Amp.


complete_bufferThis is my version of the Pedja Rogic Buffer.  The Jfet buffer is a very popular project with "gaincloners"


It uses a 2SK170 jfet at the input.  this is cascoded with an IRF510 chip and current limited by a J310.


So far I am in the testing stage with the buffer, but all appears well.  The Oscilloscope shows a very nice sine wave,

Read more: Buffer