Hi All
Long shot but worth a try.......
I've been fixing up a battered 8000A for a mate. Looks as though the thing was dropped at some point in the past as the volume pot shaft was sheared and the balance pot was missing altogether. I found a good 100K dual MN taper alternative balance pot that fit perfectly and stripped / refurbished the volume pot, re-pinned the shaft (fiddly job) and re-mounted - works great. Only thing is the flat lock nut is missing. I've gone through every spare pot in my stash and none of them fit. Does anyone happen to know what size/thread it is before I go buying replacements? I could be that the threads are goosed and nothing will go on. Other than that, after 2 power transistors, 2 drivers, 1 x DC servo IC, and a heap of caps and resistors, she's up and running and sounding a million bucks.
Long shot but worth a try.......
I've been fixing up a battered 8000A for a mate. Looks as though the thing was dropped at some point in the past as the volume pot shaft was sheared and the balance pot was missing altogether. I found a good 100K dual MN taper alternative balance pot that fit perfectly and stripped / refurbished the volume pot, re-pinned the shaft (fiddly job) and re-mounted - works great. Only thing is the flat lock nut is missing. I've gone through every spare pot in my stash and none of them fit. Does anyone happen to know what size/thread it is before I go buying replacements? I could be that the threads are goosed and nothing will go on. Other than that, after 2 power transistors, 2 drivers, 1 x DC servo IC, and a heap of caps and resistors, she's up and running and sounding a million bucks.
Yeah, closer inspection the threads are chewed...see photo. Maybe try a thin file or something and try to re-dress the thread. Don't know what size die to use so reluctant to go that route.
That's a damn fine idea. Thank you sir! Why didn't I think of that :-(
I've been doing some stress testing and have noticed the driver heatsinks are getting mad hot on all 4. Is this normal for these amps?, I mean you can barely touch them. I've wound back the bias too. The power transistors are fine.
Thanks - mines a later revision amp with the preset adjustments for the bias. Same 22mA though I believe. Just can’t decide if there is a fundamental issue I haven’t spotted or that’s just the way these things operate. Sounds great though 👍