Re: Leslie Speed Change Noise

[bpb@bpbsn.cca.rockwell.com (Brad Baker)]

>>>>> "Spence," == Spence, Colin <cspence@nelson.env.gov.bc.ca> writes:

    Spence,> My Leslie 145 sometimes produces a "pop" or "snap" in the
    Spence,> audio when changed to fast speed.  This is not someting
    Spence,> that you would ever notice in a live mix, but I find it
    Spence,> irritating at home.  The problem is variable and does not
    Spence,> occur in fast --> slow transitions.  I use this speaker
    Spence,> with an XB-2 and 1147 pre-amp, but also noted the problem
    Spence,> when I first heard the unit, when it was attached to an
    Spence,> older Hammond of some kind (one of the T series).  The
    Spence,> 125 I played as a kid had the same problem.  Does anyone
    Spence,> know a fix for this?

I believe this may be characteristic of the unbalanced series of
Leslies. The relay is switched with 115VAC. Depending on the line
phase at the switching point a big transient can be coupled in to the
unbalanced input signal. My 145 does it too. My 122-like model does
not (non-stock switching). A couple of fixes come to mind, though i
haven't settled on something i like yet. I want to fix this too but
i'm not to anxious to hack up my stock 145 amplifier yet.

Regards,

Bradley Baker
bpb@mlb.cca.rockwell.com