[sdiy] Moog ladder theory questions

[Dave Manley]

cheater cheater wrote:
> Guys!
> this has completely derailed :)
> I just want to know what transistors you use in your circuit boards,
> and what beta they have.
> :)
> 

Hi,

If you google around and find the schematics for various moog products 
you'll find that even moog had a different implementation of the ladder 
filter in many of their products (often the differences are in the 
output diff amp - i think every Moog product uses a different diff amp 
structure!).  You can then look at various Moog clones and compare.  For 
example:

On YuSynth we find BC547C with CA3046:

http://yusynth.net/Modular/Commun/MOOGVCF/Moogfilter-sch.jpg

If you look at the ARP filter it used 2N5249 and 2N5367, which
people sub 2n3904 and 2n3906.

HTH,
Dave