Entwicklung Bau VCF

Taken a bit of a break from the Bergfotron VCO and whipped up a few boards last week. I know... what about the panels... This is quite an intersting VCF uses a different sort of OTA, the LT1228 from Linear Technology. It was designed by Stephan Winter for (I think) his final year project. The entire synthesizer is written up here. I was only really intersted in the VCF as it is quite different. The layout was quite pleasing as only one link! The tempco design is also quite intersting as it uses a realtively easy to get part and a couple of tricks to get it to 3300ppm/C. I don't usually bother with temperature compensating VCF's but I may try in this case just to so how well it works. The LT1228 seems to have really quite good specifications -- I did a bit of a comparison with the LM13700 today and I notice that quite a few parameters are missing from the LM13700 datasheet compared with the LT1228 which suggests that they probably aren't to special... The LT1228 is fairly expensive though... but not as much as a CA3280!