2181 That VCA Question

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

jwhmca

Well-known member
Joined
Jan 28, 2009
Messages
931
Location
USA
Just a quick question on the operation of the "That" VCA...

I have noticed that if you adjust the trim pots the voltage stays constant going into pin 4. I looked at the internal schematic on "That's" web site and see a 25 ohm resistor to Ec+, which is at ground in this design.

My questions is... Are the VCA's using current to adjust the THD or is there an error somewhere in my thinking or the design itself?

Could some one please measure the VDC on Pin 4 when they trim the VCA and see what is changes to/from...?

Thank you!
 
The actual change is maybe 1 milliVolt internally, so you may not see any measurable change of voltage.
 
Back
Top