[sdiy] Ratio switching!

[John Loffink]

If the trimpot is 1/10th the value of the total resistance string, then its
contribution to the overall stability is 10 ppm, not 100 ppm.

Does the rest of your CV structure and VCO frequency control have 5 ppm
accuracy?  I doubt it.

John Loffink
The Microtonal Synthesis Web Site
http://www.microtonal-synthesis.com
The Wavemakers Synthesizer Web Site
http://www.wavemakers-synth.com


> -----Original Message-----
> From: karl dalen [mailto:dalenkarl at yahoo.se]
> Sent: Friday, May 25, 2007 12:00 PM
> To: John Loffink; synth-diy at dropmix.xs4all.nl
> Subject: SV: RE: RE: [sdiy] Ratio switching!
> 
> You have to divide down the cermet multiturn to 5ppm
> if the resistor strings are made out of 5ppm resistors.
> it would be meaningless to have 5ppm resistors an 100ppm pot.
> 
> LT1013 i have a couple! :-)
> 
> But what value of the string would be best fitted?
> Some use 200k others Pro1 use 100k, Roland use 2k and 1k?
> 
> Reg
> KD
>