Matty,
I don't believe that the 21a is a hybrid, but a true tube pre with an emitter follower configuration. I had the pre at one time and remember it having 2 12Au7s and no FETs. The pre sounded great after replacing the coupling caps with equivalent Auricaps and rolling in Mullard CV4003s instead of stock tubes.
I don't believe that the 21a is a hybrid, but a true tube pre with an emitter follower configuration. I had the pre at one time and remember it having 2 12Au7s and no FETs. The pre sounded great after replacing the coupling caps with equivalent Auricaps and rolling in Mullard CV4003s instead of stock tubes.