Strange Ruby behaviour I haven't found in the archives.

[sovtek50]

Built the Ruby, sounds great, but...
The sound shuts off at a certain position of the volume pot (turned up about a third), then comes in again when turned up higher. Has anyone of You Rubians ever had this? What could it be, a bad Jfet? I used a MPF 102…

[jimmy]

sounds to me like a dodgy pot. maybe the resistive material has worn off in that particular place, causing there to be no connection. i had this problem once on a distortion +, the volume pot was worn at the very end of its rotation, and it took me DAYS to work out everything was in fact wired properly!

change the pot and see if that helps.

cheers
Jim

[sovtek50]

I already tried a different pot, no change. I assume it has something  to do with the input buffer, but I'm not sure...

[sovtek50]

Aaaaaaargh!
Guess what, it WAS the pot. Actually, without knowing it, I had replaced an old broken pot with a brandnew one, which was crappy from the start.
When I rebuilt the unit, using Torchy's stripboard layout and another, third pot, it worked. Comparing the pots led to the above conclusion.
What do I learn this time? Never trust your pot.

[MartyMart]

Hmm, you really have to watch that "bad pot" buisness !!
I have changed the supplier, as I was getting 1 in 5 alpha pots NOT
working !!!   so I suspect that they were "pretend" alpha's and very cheap ....  :x
They had the same symptoms, "cutting out" and just failing very quickly

...... !!!!  GGrrrrrrr

Marty.