[sdiy] Thomas Henry VCO-1

[Stewart Pye]

Hi,

I'm thinking about building a VCO similar to this and have a few questions.
http://mypeoplepc.com/members/scottnoanh/birthofasynth/id33.html

Would a schmitt trigger using the LM13700 (like the VCO in the LM13700 
datasheet) be as fast as the discreet one?

I'm thinking for stability it would be best to use a precision voltage 
reference for the schmitt trigger reference and the tuning pot 
reference. The LM4040C10ILPR 10 volt reference from Mouser seems to be 
good bang for the buck. Does this make sense or is it just overkill?

Also, I have 1k tempco resistors. Instead of having the 2k tempco in the 
feedback loop of the CV summing amp and having 100k input resistors, 
could I keep the 100k input resistors, have a 100k feedback resistor and 
have a 51k in series with trimmer into 1k tempco voltage divider 
arrangement.

I hope they don't seem like silly questions.

Ah, one more. For a VCO using the LM13700, does a triangle core 
inherently track more linearly because it doesn't have to reset the 
integrating capacitor quickly?

Regards,
Stewart.