<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><BR><DIV><DIV>On Mar 29, 2006, at 12:15 PM, anthony wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">I have a couple of these uPC1406's that I scavanged from some digital cable receivers. Basically it's a double log-response voltage controlled attenuator. The log-response sounds interesting although I have read that a linear VCA and a log envelope sounds better, I know I have some uses for log VCA's in a very small package.</FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Helvetica; min-height: 14.0px"><BR></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">I guess it wouldn't take much effort to try one out on a breadboard, but I was wondering what anyone's first thoughts might be. My guess is that there will be a lot of control voltage bleedthrough and it will be mostly useless. Still having 4 log VCA's in two 9-pin SIL's...</FONT></P> </BLOCKQUOTE></DIV><BR><DIV>There seem to be a lot of similar voltage controlled attenuator IC's out there, in various package types. All appear to be designed for use in video subsystems or broadcast recievers, probably for some sort of amplitude modulation stuff. A common characteristic of these parts seems to be a fairly limited range of attenuation -- typically around 20 to 40 dB max, at least according to spec sheets. This may prove not very effective for synth use, where we need more like 80 dB range.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Please do let us know if you manage to get it working, and what the result is like.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV></BODY></HTML>