That's interesting the points you raise #3 and #4 which my MX110 is exhibiting neither of those maladies. Volume control tracking in fact is excellent throughout the range as verified on the MPI 4, whereas on the MX113, tracking is only accurate in the 12:00 - 3:00 range. (Maybe I just got lucky - )
- I've never observed any noises associated with the illumination of MPX Stereo on my example either. In fact I've always found the MX110 relatively free of crosstalk issues and interference in general.
- I cannot comment on the flatness of the tone controls except to say 12:00 seems to work fine to my ears..
Otherwise, I have no major criticism of the MX110's overall performance but I will also add that MX110s that are still essentially original which only received bare minimum servicing to keep operational over the years - it's unlikely to be performing to spec and won't be long before a full fledged restoration will be needed. I still appreciate the MX110 for its classic beauty but much like a classic car, it definitely needs a fair amount of attention!
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All I can say is what I found on my 110. However....it’s entirely possible considering the complexity of these units, normal production variation and running production changes that unit to unit variation is greater than we’ve come to expect from today’s highly automated assy. So luck may indeed be a factor. And as the old proverb goes, “I’d rather be lucky than good any day”.
Regarding stereo light noise, I found it resulted from AC rectification noise generated in the light driver transistor. Fixed it using shielded wiring and basic reroute. This was annoying to me because I typically use high eff speakers with the 110 so faint noise is exaggerated. Ultimately I’d like to redo that entire circuit but not high on list of priorities.