[DEMI] Another question

[Tree N6TR]

Recently built the 432 pre-amp.  I broke off one tab of the ceramic 
trimmer cap (the one that goes on the input).  Seems like the SMT
version might be a better choice.

I was able to solder it down anyway - but was wondering if it was shorting
out.  When adjusting the cap, it seems to almost "pop" into the max gain -
almost like an oscillator turning on.  Is this normal?  If not, I probably
need a new cap.

Tree

PS: Would be great if DEMI has a line of beacon transmitter boards!  Put
one up for 432, but it could sound better.