MIG-LRS Tube Preamp Addendum
For Use With Electronic Leslie Simulators
By Carsten Meyer & Tonewheel Tubeworks, info@keyboardpartner.de The MIG-LRS Leslie Tube Overdrive works with a real miniature tube, designed for standalone use or to build into a Leslie Simulator. It even has a remote control input for switching between tube limiter and bypass mode.

Installation

Please read the MIG-L manual carefully, this is an addendum for the MIG-LRS only. Addendum covers installation in a Leslie simulator like the CLS-222 from Dynacord. Installation in other devices is similar. The MIG-LRS has to be inserted in the Leslies simulatorss signal path right behind the input gain pot. It has its own power supply wired fr 230V AC. Remove plugs from power supply. Remove top and bottom of your CLS-222. Affix MIGLRS board to the bottom as shown in next picture. 4 holes 3.5 mm have to be drilled. Use M3 screws and plastic spacers to hold the board in place. The board-to-bottom-clearance must be 5 mm or greater to ensure insulation of 230V mains voltage. Please refer to VDE regulations. Attach 230V wires to Power input pins, coming from CLS mains switch. Use heavy wires appropriate for main voltage. Locate capacitor C026 on the CLS main board, it's near the input gain pot Refer to picture next page. Remove C026 and solder two wires into the pin holes. The wire towards the CLS front routes to the MIG-LRS input (yellow in picture), the wire towards the IC I001 (violet) routes to the MIG-LRS Output. MIG-LRS ground has to be connected with the shield pin of the CLS input wire, coming from input jack

Adjustment

The MIG-LRS has an input sensivity of 100 mV RMS. Adjust MIG-LRS output level with trimpot that at full tube distortion the Peak LED on CLS-222 just lits up (50 mV output to CLS-222). When properly adjusted, distortion will occur only in the MIG-LRS, not in the CLS-222. The MIG-LRS will limit the level before transistor clipping occurs in the Leslie simulator. Bypass mode (effect off) can be activated by grounding Bypass Pin or by installing jumper PL6 (normally open). Additional information and this PDF can be found at http://www.keyboardpartner.de/hammond/lesliemods.htm

C14 470u 35V U4 7824

AC AC 3

PL7 230V

FSmA C12 10n C15 10n C13 10u 40V

PL8 230V GND

TR1 Trafo flach 4VA 2x12V 166mA

RB1 GL 1A rund MISC

PL1 +24V R16 10k R6 1k8 R5 680R 3W R8 470k R18 (3M3)

C1 100u 35V R4 27k

GND R19 150k

C4 47n R7 220k R10 10k

U2a R11 1M

VDD 2 Z VSS U3a

C3 47n

U1 1SH18b

R17 (3M3)

C8 470n

PL5 Output
R1 100k R3 6R8 D2 C5 100n C10 22u 10V C6 10n R12 120k C2 47u 6,3V

VDD 3 Z VSS U3b

PL2 Input

R13 150k

C9 22u 10V

ZD1 5.1V

PL3 Gnd GND R14 100k

PL9 Gnd

PL4 Bypass

R15 10k

VDD 9 Z VSS

U3c 4066

PL6 Jumper Bypass

VDD 10 Z VSS

U3d 4066