When I travel with my Series 1, on my days off I use headphones for practicing in my hotel room. Ron W. said originally Alembic wired the jacks for stereo output, using high impedance headphones like the old Sennheiser open air type. I've been using Sony MDR-7506 phones which are 63 ohms. The old Alembic brochure that came with their basses recommended the Sennheiser HD 212 which online states 32-35 ohms. When I use the Sony cans I can't turn the bass' volumes up to max for each pickups as volume jumps quickly just before the max setting of each pot, and adjusting any higher near the end of pot rotation will distort. I can only get a decent sound if I back off each pickup volume to just below max rotation of each pot. This makes me have to max out the individual gain trims to max to get a good output from the phones. With this circuit it does not like it at all if maxing the volume pots when using low impedance headphones, no matter what the trim settings are. Maybe I should look at 300 or 600 headphones. Has anyone tried the Series 1 circuit with phones in the 300-600 ohm range?
