living sounds
Well-known member
Attached is the channel output section of my console. Everything is handled by IC5, a TL071 originally. I've replaced this with a NE5534, with added compensation cap and a 75 ohm series resistor after the op amp for stability. Works fine.
I've got lot's of those nice 2520 DIY op amps with DIP8 connectors from our group member Abe (acsound) and I've tried one of them in there. It seems to work more or less fine, though there is a 1.7 db drop in output amplitude and increased low frequency distortion. I've dropped R46 to several lower values which increased the gain (as it should), but didn't otherwise change anything. It seems to be stable, and offsets are within the confines of the datasheet, I matched the op amps input transistor pair closely.
Sonically there is a little more low end with the 2520 (measureably), and the typical dynamic distortion happens. It sounds pretty good, a little smoother on top and punchier in the midrange than the 5534.
So, is this all, or does the circuit require adjusting for the op amp to work correctly? Thanks!
I've got lot's of those nice 2520 DIY op amps with DIP8 connectors from our group member Abe (acsound) and I've tried one of them in there. It seems to work more or less fine, though there is a 1.7 db drop in output amplitude and increased low frequency distortion. I've dropped R46 to several lower values which increased the gain (as it should), but didn't otherwise change anything. It seems to be stable, and offsets are within the confines of the datasheet, I matched the op amps input transistor pair closely.
Sonically there is a little more low end with the 2520 (measureably), and the typical dynamic distortion happens. It sounds pretty good, a little smoother on top and punchier in the midrange than the 5534.
So, is this all, or does the circuit require adjusting for the op amp to work correctly? Thanks!