Thanks, Ghosthouse. Perhaps in addition to clarifying who OV is, Realdeal can provide a link to detailed information about that amplifier. I find it hard to imagine, to put it mildly, that a practical audio power amplifier using a single-ended 6A3 as its output tube could be implemented as an OTL (i.e., without an output transformer).
Charles, Rleff, Onhwy61, thanks also :-)
Best regards,
-- Al