Finally!
Well, maybe. I've been working on this for years. Here is the Schematic that I reversed from an NE80100.
Here is what we need to do. If any of this looks funky please let me know and I will take a look and see if there is any errors... I will be double checking this over the next few days as well...
I can't really find any of these transistors in existence any more. Maybe we can get recommended replacements? Also, I can pull and test any diodes or try to identify them if somebody thinks any particular ones are/should be special.
**backstory**
Years ago I ordered a replacement NE-80100 from Yamaha. They guy was excited that I was still wanting to get the old Pm-700 going. He helped me diagnose the problem and sent me the DOA.
At the time I didn't think much of it, but it wasn't "potted" in the same way as all the rest. Instead of the Hard, Black, impossible to get off resin, it was potted with clear, regular silicone. Fast forward to now. I love the way these OpAmps sound and want to DIY them... I was obviously able to remove the Silicone and take a look at the parts.
This NEW one the guy from Yamaha sent me is NOT like the originals that were in the PM-700. I smashed one of them apart and can at least see that there are differences, must not able in the large transistor pair, marked as Q5 and Q8 on my schematic.
I hope we can make this Happen!
Well, maybe. I've been working on this for years. Here is the Schematic that I reversed from an NE80100.
Here is what we need to do. If any of this looks funky please let me know and I will take a look and see if there is any errors... I will be double checking this over the next few days as well...
I can't really find any of these transistors in existence any more. Maybe we can get recommended replacements? Also, I can pull and test any diodes or try to identify them if somebody thinks any particular ones are/should be special.
**backstory**
Years ago I ordered a replacement NE-80100 from Yamaha. They guy was excited that I was still wanting to get the old Pm-700 going. He helped me diagnose the problem and sent me the DOA.
At the time I didn't think much of it, but it wasn't "potted" in the same way as all the rest. Instead of the Hard, Black, impossible to get off resin, it was potted with clear, regular silicone. Fast forward to now. I love the way these OpAmps sound and want to DIY them... I was obviously able to remove the Silicone and take a look at the parts.
This NEW one the guy from Yamaha sent me is NOT like the originals that were in the PM-700. I smashed one of them apart and can at least see that there are differences, must not able in the large transistor pair, marked as Q5 and Q8 on my schematic.
I hope we can make this Happen!