Quad VCA-Mixer THAT 218x based.
This is PCB for assembling hi-quality Quad VCA-Mixer. I used maybe best available VCA chips THAT2181 (or THAT2180) and OPA2604 at VCA out. Design based on THAT Corp. design notes is simply: just 4 identical VCAs and mixer to mix channels in pairs and all together with normal and inverted outs, each channel has separate out too.
VCAs have logarithmic responce and feed both AC and DC signals. Normalized to 5.5V and attenuated by LEVEL pots, CV INs control VCAs gain. VCA's have tempco CV inputs as suggested in THAT Corp. design notes for more accurate results.
15V and 12V versions can be made, board has EURO, MOTM and Dotcom power connectors.
MUFFWIGGLER forum thread http://www.muffwiggler.com/forum/viewtopic.php?t=48476
Boards have some SMD components already installed: 4 x BC847BS dual transistors, 4 x 2K TEMPCO resistors, 14 x 0,1 mkF decoupling caps.
SOLD OUT
PCB with SMD parts.
Devices analyzer shots. 500 Hz triangle modulated by 16 kHz triangle. 16 kHz triangle modulated by 400 Hz triangle.
Ready-made device.
Euro panel from clarke68@MUFF
Documents:
Partlist.
(c) 2012 L-1 Synhesizer. E-mail: info@greenexpo.by