Gary Schafer wrote:
>>
>> An 813 only has 125W dissipation, so by today's standards they are small
>> tubes. You'd need four to equal a single 3-500Z, which will glow just as
>> nicely.
>>
>> A pair would be struggling to reach even the "1kW input class", and the
>> clean linear output is unlikely to be more than 400W. Even if you have a
>> box full of 813s, is it worth the effort of building such a small amp?
>>
>>
>>
>> --
>> 73 from Ian GM3SEK
>
>A pair of 813's will easily produce 600 watts output and do it for years and
>years. They are very rugged tubes. I have an amp with a pair of them that I
>built in the mid 60's and it still has the same pair of tubes. At one time I
>ran them with over 3000 volts on the plates for several years with the
>plates regularly showing color and power out well above 600 watts.
>The same tubes now run at around 2500 volts and still put out 600 watts and
>no color.
>
>Not the best tube in the world but for the price and as rugged as they are
>they are hard to beat.
>They will perform well on a wide range of voltages too. 2000 to 3000 volts.
>
I don't dispute the raw output figures, or the ruggedness either; but
you didn't address my point about "clean, linear output". How do the IMD
levels at 600W output compare with a 3-500Z?
--
73 from Ian GM3SEK
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