Electrons are yellow and more is better!
Join Date: Apr 2002
Location: Göteborg, Sweden
transducer's balanced phono amp
Originally posted by transducer
I'm not sure, I didn't own a scope at the time. What was happening was that only one channel would work. If I touched the ground of the input RCA jack, both channels worked. I had originally had the small caps in place and the unit worked fine. Upon removing them it started to cut out on me.
The design is a balanced input using a BB INA103 opamp, although I use RCA jacks for input, both the hot AND ground are isolated from the chassis. The circuit is basically stolen from the BB app notes, with a passive RIAA network from the Analog Devices applications guide, and then an OPA604 output (will soon replace with OPA627.
Thread from my 1% polyprop discussion.
Ron, have you thought about that the signal from your pickup is floating but if you want to use this "balanced" signal you must change cable, a shieled pair cable or two shielded cables per channel.
Check Klaus Böning and his balanced amp ”La Bohème”
Check especially his balanced inputs.
/Per-Anders (my first name) or P-A as my friends call me.