I repeatedly get asked about the possibility to offer an integrated amplifier and also headphone amplifier based on the 300B and preferably in a single chassis.
So I decided do develop one and see if there really is demand. I mocked up a test circuit using a new Lundahl output transformer with a new high bandwidth winding technique and which has optimum values to be used with Elrog ER300B.
Above the bread boarded test circuit, one channel completed. To fit all into a single chassis no interstage transformer and no transformer volume control. Volume control is done via a DACT stepped resistive attenuator (not seen in the pic above yet)
I selected the 6DN7 as driver tube. The two systems offer the right amplification factors and plate resistances for this job.
Initial measurements and listening tests with a bunch of lab supplies gave very good results. So time to bread board a power supply as well.
Some older metal plates got recycled for the test. The result is very pleasing. A headphone version of this will be offered as well with selectable impedances for 32/150/600 Ohm. Now everything will be fitted into a single box and the metal plates for that have to be designed.
Drop me a mail if you are interested to become one of the first owners of a 300B integrated amplifier or headphone amplifier. Other tubes will also be possible.