MOTM

--- In motm@egroups.com, "thomas white" <djthomaswhite@h...> wrote:
> Hey fellas,
> 
> I have noticed in my two VCO system that when I use the transpose 
switch on 
> my Roland M-181 keyboard or play higher up in scale thru my Kenton 
that the 
> VCO's do start to sound flat or slightly off key. Especially one 
compared to 
> the other. 

A little detective work is in order here before you blame your 300s. 

First, it's hard to please 2 masters, so to speak. Your Kenton and 
Roland may be calibrated slightly differently. If so, you will be 
able to calibrate your 300s to play in tune with one or the other, 
but not both.

Second, the Roland may track fairly accurately when you play the 
keyboard, only to introduce errors when you use the octave switches.

If the 2 vcos track differently than each other using the same 
source, you need to calibrate them as closely as possible.

If they stay in tune with each other in the low mid range, but get 
further out of tune in the higher range, you may have one that needs 
the high frequency tracking resistor change that Paul mentioned. The 
problem with only 2 vcos is that it may be hard to tell which one is 
tracking correctly, and which one is not linear.

My fave calibration technique is to beat a tracking vco against a 
nontracking drone vco. Hendry likes to feed the drone into the 120 to 
get exact suboctaves, so you can do close comparisons over many 
octaves.

Moe