The 89Y SE Amplifier – In Progress
My next project has been cut, painted, and mechanically assembled. This is going to be a small single-ended amplifier with speaker and headphone output similar to the 1626 “Darling” amplifier below. The 89Y output tube is a military grade “type 89 – triple-grid amplifier” with a micanol base and graphite coated glass. Type 89 is a precursor to Type 41, 6K6/G/GT, 7B5, and 6AR5. It has a cap for control-grid connection and separate screen-grid connection pin at the base. Here it will be connected as a triode and driven by the 6C8G. The 6C8G is a tube I haven’t used before which has good linear curves and looks good in the amplifier. It contains two triodes, one of which has a grid connection at the top cap. If both stages prove linear enough and the output impedance isn’t too high, no loop feedback is planned. The schematic I’ve worked up for it is still on paper and not installed underneath the chassis yet. The output transformers aren’t cheapies this time! These are Transcendar 8K:8Ω from Gerry at Transcendar Audio Transformers.
More to come!