James Custom Amplifiers

“The LoWatt”

By Bryan James

And

Rebel420 of Drifter Amps

Last updated 10/11/00

WARNING! - Please Read this Information Carefully:

The projects described in these pages utilize POTENTIALLY FATAL HIGH VOLTAGES. If you are in any way unfamiliar with high voltage circuits or are uncomfortable working around high voltages, PLEASE DO NOT RISK YOUR LIFE BY BUILDING THEM. Seek help from a competent technician before building any unfamiliar electronics circuit. While efforts are made to ensure accuracy of these circuits, no guarantee is provided, of any kind!

The Concept:

To build an 18 to 20 Watt amp based off of the DR504 HiWatt Amp.

The design:

A two channel preamp
Pre-amp and PI section based on the DR504 HiWatt
AB1 Push-pull fixed bias, using 2 El84’s
Solid State Rectifier with a B+ 360-385 volts
Easy laid out Turret board.

Status:

Proposed schematic is finished and posted on Ax84 and here.

Turret board has been made from the current layout (subject to change upon testing)

Chassis marked and prep for drilling.

11/04/00 add server changes to the schematic this is in the bias section and power filter section added a choke too

Amp is up and running sound clips and up dated schematic this week end.

11/06/00 added one audio file more to come

11/11/00 ver 2.0 of both the schematic and turret layout are finished. Record some mp3 should have them up by tomorrow

11/20/00 ver 2.1 of the turret layout. Fixed error in the PI section. Well try to post mp3 tonight.

Schematic:

The schematic can be found at http://home.james-gang.org/jca/lowatt/lowatt2.jpg this schematic is currently laid out on 17”x11” it well be reduced as development precedes. Please note there are changes to the working prototype that aren’t list yet. Please be patiant

Here is the current turret board Layout this board is laid out on legal size paper. The turret board is 13”x3 1/8”

Warning: This is a Beta Layout and though it has been tested, and does work. I’m still working on making it better.

Audio Clips:

I got 1 audio clip so far. It’s about 4mins long just goofing off with the amp sorry about the size 3.28MB Saturday I’ll Saturday I’ll be making smaller clips and better one’s this is so you can here what it sounds like. effects used Boss SD-1 and Cry-baby (sorry I didn’t check the battery before recording and it’s about have dead you’ll here what I mean when I engage it and it’s at half volume. The SD-1 is set level 12o’clock tone about 10:30 and overdrive is at 1 o’clock as for the amp it starts at all controls at the 12 O’clock position. At about the 3min I Dime the MV and shortly there after I dime the volume to the normal channel. All recording done at this point to the normal channel. Guitar used is, Ibanez super 70 series double neck (6-12) all controls are dimed, both necks are on both pickup selector is in the middle position. You will here the 12-string in there for a short while.lowatt1.mp3

Pics:

Any question, comments or suggestions please email me at mailto:bjames@james-gang.org or post to the current discussions at http://www.ax84.com