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Knurled hum adj pot for MC 30

C

cc43fan

I'll sleep when I'm dead
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The hum adj pot on my MC 30 has a "teflon" style shaft. I'd like to replace that with the knurled style that was on the amp.
I spoke to Andy at Audio Classics and the only one he has is the 500k (versus the 250k the schematic calls for) gain adjust. I believe I could put a resistor in parallel, but two things:
I'd really rather not "cob" this and I'm thinking the hum adj is linear taper while the gain is audio taper.

I'm hoping the veterans here will weigh in here with a solution or perhaps point me in the direction for finding the part I need. Maybe someone has used that 500K gain pot in the hum adj postion sucessfully?
 
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You can try here. You are looking for the linear taper, which is about 1/2 way down the page in the CTS section.

No affiliation, of course.....

Cheers,

David
 
Are you using the Macintosh C-4 or C-8 preamps that derive their power from the MC-30 thru an umbilical cord attachment?

As I understand it, that is the only time the hum pot has any influence on the sound. If you are using a separate preamp with its own power supply built-in, then you have no need for the pot adjustment.
 
Phototone said:
Are you using the Macintosh C-4 or C-8 preamps that derive their power from the MC-30 thru an umbilical cord attachment?

As I understand it, that is the only time the hum pot has any influence on the sound. If you are using a separate preamp with its own power supply built-in, then you have no need for the pot adjustment.
Click to expand...

No, I have no plans (at this point to use a C-4 or C-8), but I'd like the amp to have the "stock" look and I haven't found the nylon shafted pot in any pics I've seen. For $5. it's worth it.
 
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