In Reply to: RE: Losses in Output Transformers posted by Tre' on September 15, 2021 at 17:03:40:
The EL34 amp made enough power to meet my requirements, so I didn't go to much trouble regarding troubleshooting. The output tubes were new EH.
The 6L6 amp is on the bench now. I brought it up with brand new 6P3S-Es in both channels, later subbed one channel with a NOS pair of Sylvania 5881. The 5881 performed slightly better, maybe squeaked out two more watts or so. Plate and screen voltages were measured at full output, just below clipping, and they're close to the chart. I also subbed screen voltage from 300V to 400V with a regulated bench supply. No improvement. I don't know the DCR of the anode windings, but the drop at idle isn't large, I think it was about 5 volts. And just to cover all the bases, the driver has much more gain and swing than is needed to drive the 6L6s to full output.
Again, I really think there's a significant loss in the OPTs, and I came to the same conclusion regarding the EL34 amp. Do either of you know how companies like RCA arrive at those output numbers? Did they actually build an amplifier with output transformers? Or did they load the plates in a different way and make voltage/current measurements?
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Follow Ups
- Tim and Tre - - Triode_Kingdom 09/15/2119:55:36 09/15/21 (1)
- RE: Tim and Tre - - kobasa@xs4all.nl 13:14:26 09/16/21 (0)