Small Stone repair question - rate knob replacement log or liner + post size?

Started by big bustle, January 31, 2007, 01:45:47 PM

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big bustle

so...

a co-worker brought in a his small stone reissue. the russian made one in a big green metal box. it needs a new input jack and a new rate pot.

i want to make sure i'll be purchasing the right part. here's the confusing info i've found so far.

the pot it currently has is marked in russian. the stem has also popped out of it. it currently measures at 800k with my DMM.

i checked them schematic on tone pad to see what they said. it looks like a completely different circuit. this box has 5 ca3094e chips in it.

the schematic linked from GGG mentioned using ca3094 chips as replacements and has a 1m pot.

smallbear has a specific pot for small clones/stones.

this pot is labled:

Pot, Alpha, 1 Meg "C" - USA Small Stone/Clone
24mm PC-mount

what does pc-mount mean?
Alpha - brand
24mm - is that the body size?
"C" - c means it's nieth log nor liner but something else right? A = log B =linear correct?

regarding shaft size. i found that the original knob wont fit on a 1/4" pot i got from small bear. i wonder if this one will.






rockgardenlove

"C" indicates reverse audio taper I'm pretty sure.  Might want to wait for verification.
PC mount means it mounts straight to the circuit board.



stankyfish

Quote from: fucdemas on January 31, 2007, 01:45:47 PM
so...

a co-worker brought in a his small stone reissue. the russian made one in a big green metal box. it needs a new input jack and a new rate pot.

i want to make sure i'll be purchasing the right part. here's the confusing info i've found so far.

the pot it currently has is marked in russian. the stem has also popped out of it. it currently measures at 800k with my DMM.

i checked them schematic on tone pad to see what they said. it looks like a completely different circuit. this box has 5 ca3094e chips in it.

the schematic linked from GGG mentioned using ca3094 chips as replacements and has a 1m pot.

smallbear has a specific pot for small clones/stones.

this pot is labled:

Pot, Alpha, 1 Meg "C" - USA Small Stone/Clone
24mm PC-mount

what does pc-mount mean?
Alpha - brand
24mm - is that the body size?
"C" - c means it's nieth log nor liner but something else right? A = log B =linear correct?

regarding shaft size. i found that the original knob wont fit on a 1/4" pot i got from small bear. i wonder if this one will.


I'm pretty sure the Russian and American Small Stones do NOT use the same pot.  Steve also has (or at least had) the Russian OEM pots for sale -- I know because I bought mine from him -- and I bought the wrong one.  I need the one you've listed.

The Russian pot I have is not a PC mount pot -- it has regular solder lugs.  The original pot that I pulled out and stupidly lost was a PC mount pot with a larger diameter shaft (and body) than the Russian pot I ended up getting, so the original knob doesn't work on it.  It was mounted in the metal casing of the pedal and the long PC tabs were soldered into the PCB and the solder joints for the pot supported the board which sort of floated inside the case.  I've been meaning to pick up the pot you mentioned and fixing mine.

Does the original pot you have the long PC tabs?  Is the shaft plastic or metal?

I could probably take a picture of the pot I have if you're interested in seeing it.

big bustle

here are pictures of the original unit

notice the small size of the shaft. the 100k pot is there just for size comparison







stankyfish

I think I may have the pot you need (and consequently, the one I don't need).  I will double check when I get home, but if I do have the right pot for you, it's all yours.  Gives me an excuse to put together another Small Bear order...   :icon_wink:

big bustle


p1_ind

Smallbear sells an exact replacemet for the pot you have.

http://www.smallbearelec.com/Detail.bok?no=158

BUT...
if I were you I would order this pot (select the 1Meg)

http://www.smallbearelec.com/Detail.bok?no=116

because the pot in the Russian reissue Small Stone pedals are very prone to failure.  The stems come out easily or the rotation goes past the stops.  The Alpha 16MM 1Meg reverse audio taper pot is a much more reliable pot.  To use it you will have to drill a slightly larger whole in the case and use a different knob or do a little drilling on the knob but it will be worth the effort and the Alpha pot is cheaper.

Adam

big bustle


stankyfish