I have what I think is a Knight KA-55 "40 Watt" amp using PP 6973 tubes. I am thinking of building a PP el84 amp and want to know what the impedance of the OPT are. Can I use them with el84 tubes?
Thanks
howard
Thanks
howard
A PP pair of 6973s will give you 20 watts with fixed bias. 24 watts if you push them with 400 volts. Not 40, unless you're talking about a stereo amp both channels. Yes you can EL84s in place of them as the recommended plate to plate impedance is 8K ohms for both. Caution, pin out is different. However, the EL84's will provide less power because their plate voltage rating is lower. (per the RCA tube manual) Of course you could push them at the expense of tube life.
Edit: Filament current is also higher.
Edit: Filament current is also higher.
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