Leslie Remote Switch

[smilan]

I have a Leslie 10 LX unit.
I've built this remote control unit using a 5 DCV voltage to control the two relays (HFD2/005-M-L2).
One relay is an on / off  switch for the 120 ACV and the second relay switching the 120 ACV between the two motors.
Everything works but the only problem is that sometimes when I'm switching between the two speeds / turn the On / Off switch to position 'Off" while the bigger motors is running there's a strong 'pop' noise that passing thru other audio devices that connecting to the mains (mixer / monitors etc.)
How can I avoid those 'pop' sounds while switching between the two speeds?
This is the schematic of my remote control:

 

[pucho812]

I recently fixed a Leslie 122 with Loud pops, it had a bad cap.

 

[smilan]

I recently fixed a Leslie 122 with Loud pops, it had a bad cap.

I don't have a leslie amp, I have only the speaker and the rotary element with tow motors.
Do you think adding a cap can eliminate the switching 'pop'?

 

[smilan]

I added a .1/400V cap across the AC outlets to the motors and now it's dead quiet

 

[pucho812]

I added a .1/400V cap across the AC outlets to the motors and now it's dead quiet

the cap is on the Leslie's amps so it does quiet them. . I had one that was leaking causing the pop to be audible. it no longer happens after I replaced the cap.