PEC and Alps can fit, but it takes some modification to accommodate the larger size. The easiest way is to punch or drill a hole in the front of the chassis as is done with the new SE84C+.

The cathode resistance selector switch as well as the cathode resistors themselves may cause clearance issues.

If you have reluctance to change the factory layout, then the only way is to modify the speaker output posts as shown.



After cutting the grey washer in half, I used loctite to secure the top nut to the thead of the post. I then ground the post and nut down to make room for the barrel of the pot. There's a notch to allow for soldering the lead wire from the tranny's secondary flush with the nut. Cover with a bit of electrical tape before installing the pot.

I went with the PEC and enjoy it, but has such good internal contacts it is too stiff to turn without a knob. I found one with only a 13mm diameter which works nicely. Has a great feel and sounds better.

-Brett

For a direct replacement, I'd use the same pot that the Steve uses.

http://www.radioshack.com/product/index.jsp?productId=2062359

Probley isn't a better sounding mini pot.

-Brett

Received the pot and installed it in last night. Out  of the box, it sounds very good. A huge difference over the stock pot!!

shreekant