In article , Iain M Churches
wrote:

"Stewart Pinkerton" wrote in message
...
Okeley Dokeley. Quote me one valve amplifier from any manufacturer,
which is specified at 15 Hz to 50kHz, even to 1dB *at full power*. Not
a problem for any decent SS amp, but unheard of with valves.

I can't do that. But what I can do is to mention the C30/50 50W
amplifier which I have in my own music room. This was a shared project
between myself and a design engineer at Sverige Radio, and has the
following spec.

FR (+/- 1dB at 1W) 10Hz to 80kHz Power Bandwidth (+/- 3dB with 0.1%
THD) 15Hz to 70kHz

This amp has a formal test certificate, and six of them have been built
in the past three years or so.

I assume the above is with a resistive load of appropriate value.

I'd be interested to know the output impedance across the same bandwidths.
Also what maximum current the amp will deliver at various frequencies, and
how the THD varies into various difficult loads.

The problem is that - valve or SS - it is much easier to build an amp that
works nicely into 8 Ohm loads with sinewaves than it is to ensure the same
sort of perfomance into 'difficult' speakers with real music.

Slainte,

Jim

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