The Leslie 251 is a 2-channel Leslie that is the ideal fit for an A-100 series organ, since it has an additional channel to make use of the reverb amp that is found in the A-100.

How to hook up a 251 to a Hammond Model A-100 using Leslie-kit 8253

1. Attach the echo and tremolo controls to the wooden rail in front of the lower manual with the black oxide screws provided. Use two mounting screws in the rail. Make sure the organ is turned off for the following steps.

2. Remove the organ back and pass the control cables into the console by the following method:
Clip the red and green interceptor plugs and sockets off the echo control cable and strip the wires 3/8″. Push a small screwdriver over the felt dust seal between the lower manual and the knee panel. Push the cables through this opening into the console. From the back of the console, reach behind the tone generator and pull the cables through

3. Position the console connector near the power amplifier so that the power and control cables will reach. Install it with wood screws.

4. Cut the green lead which connects the amplifier output to the main speakers. Remove 3/8″ of the insulation from each of the cut ends. Connect the amplifier end of this lead to the red lead from the echo control with a wire nut. Connect the speaker end of the lead to the green lead from the echo control.

5. Disconnect the reverberation input lead (green) from the main speakers. Strip and connect it to the orange lead from the echo control with a wire nut.

6. Detach the “hot” lead (gray or blue) from the reverberation speaker terminal, strip it and connect it to the blue lead from the echo control with wire nut.

7. Solder the yellow echo control lead to the “hot” reverberation speaker terminal.

8. A100: Connect the plug from the console connector into the contact socket on the rear apron of the power amplifier chassis.
M100: Cut off the 5 -pin plug from the console connector and strip all three leads about 1/4″. Solder the brown cord to the outside AC-terminals under the metal cover on the left-hand side of the rear apron of the power amplifier. Fasten the red lead to any convenient ground point on the amplifier chassis.

9. Connect the brown lead from the echo control to the short, single, brown lead from the console connector, with wire nut.

10. Connect the black lead from the echo control to the black lead from the console connector, with wire nut.

11. Connect the brown double wire from the tremolo control to the short, double, brown wire from the console connector, with wire nuts.

12. Connect the speaker cable between the Leslie and the socket on the console connector.

13. Replace organ back

If the organ’s reverberation control does not work properly, reverse the gray and black leads (marked “Speaker”) on the reverberation amplifier terminals.

WARNING: the 251 connector uses the “6C” pin-out, which is distinct from either the 122-style or the 147-style single-channel pin-outs. Make sure you know how the connector is wired before you plug in that six-pin.