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Tauno Voipio Tauno Voipio is offline
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Default Tube mono-block amp with SIX 6L6 outut tubes

On 1.1.19 06:39, Tim Williams wrote:
"Big Bad Bob" wrote in message
...
sounds like a gimmick.* Tube plate/cathode currents are just way too
small to properly drive a speaker without an impedence matching
transformer.


So what, nothing comes out?...

They were definitely below the maximum power point (at clipping), if
that's more accurately what you meant.

6AS7/6080, 6S33S and the other regulator tubes have peak cathode current
in the ballpark of an ampere, so a modest number of tubes offers a
modest power output, say 20 or 40W, preferably into a higher load like
16 ohms.* The efficiency is poor, with more heat dissipated in the
heaters alone, than delivered to the output.

If you put dozens in parallel, the efficiency keeps going up as you get
closer to matching, but now your whole system consumes multiple
kilowatts...

There was also the Philips "SEPP" with a pair of EL86? driving a
100s-ohms voice coil at good efficiency, but those speakers are so rare
that this is practically a unique case.

Tim


The final triodes (6080) are special high-current tubes. The amplifier
designer rated the thing at 25 W into a 16 ohm voice-coil speaker.

--

-TV