My question is on my 100h.  When I use the od American  preamp the bass control does not work rite.

Seems that from 0 to 5 on the bass pot there is little or no response but when I go from 5 to 10 the amp gets very thin and  sounds like the mids are cut  vol seems to drop a bit too.

Only seems to happen on the od American preamp.   On The cr American preamp  the bass pot acts normal.

Anywhere would be great