[sdiy] Oberheim Xpander VCF

[Antti Huovilainen]

On Fri, 16 Jan 2009, Adam Schabtach wrote:

> The schematic specifies 1% resistors. There are no trimmers. I had an
> Xpander and I'd bet a box of donuts that it didn't have a 40db
> voice-to-voice variation in the low side of the BPF response. One of its six
> voices was audibly different than the others, but it wasn't a 40dB
> difference and my memory is too vague to really say what the difference was.

It's not so much about how large the difference between ideal and actual 
response is, as it's about how much the actually heard difference is.
1% resistors should give roughly 40dB attenuation and that's likely below 
the masking caused by the passband harmonics (not to mention other 
instruments in the mix).

Antti

"No boom today. Boom tomorrow. There's always a boom tomorrow"
   -- Lt. Cmdr. Ivanova