I have an Sumo Polaris III amp which my brother gave me that was having issues.
While the case and the board within say Sumo III the contents visually are unlike any of the Polaris 310 images I've seen posted in this forum. It seems like a later move (based on the IC dates 9640) to combine the two boards on in the 310 into a single board. There is no stenciling on the rear of the case. That along with the socketed 741s and some odd resister mod on 2 of the MOSFETS makes me wonder if this was a prototype or some early build of the rev.
After looking at the schematic for the 310 they appear to be a similar design based on 240/9240 MOSFETs with 741opamps providing a servo loop for DC offset.
Have you or anyone else with Sumo experience seen or worked on a this variant of the Sumo Polaris III? .
While the case and the board within say Sumo III the contents visually are unlike any of the Polaris 310 images I've seen posted in this forum. It seems like a later move (based on the IC dates 9640) to combine the two boards on in the 310 into a single board. There is no stenciling on the rear of the case. That along with the socketed 741s and some odd resister mod on 2 of the MOSFETS makes me wonder if this was a prototype or some early build of the rev.
After looking at the schematic for the 310 they appear to be a similar design based on 240/9240 MOSFETs with 741opamps providing a servo loop for DC offset.
Have you or anyone else with Sumo experience seen or worked on a this variant of the Sumo Polaris III? .
Why yes they are 🙂. They're shot. All the caps are going to be upgraded as well as the MOSFETs and protection diodes on the right channel.
Yeah they're on the list along with all the electrolytic caps, MOSFETs and protection diodes. What's odd is there should be 1 uH inductors in parallel with those 10 ohm resistors but for the life of me I don't see them.