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Amity Info

Posted by Lynn Olson (M) on January 5, 2006 at 01:45:55

In Reply to: Calling Lynn Olson: Question about Amity Amplifier posted by Tube747 on January 4, 2006 at 11:53:25:

The frequency response is mostly, as you might expect, a function of the output and interstage transformers. With all-Lundahl transformers, you can expect -1dB points around 10 Hz and 70 kHz.

Power output is about 16 to 20 watts, depending on how deep the amplifier goes into Class A2 - this is a function of available current in the driver, and its output impedance. This is just barely enough for a 91dB/metre speaker, but that depends on listening taste and how large your listening room is. The Amity, Aurora, and Karna are almost entirely insensitive to load impedance, though, so that's no issue.

Let's see, 12dB of gain is 4x voltage gain, so if the CD player puts out 2V rms at max output, 8V rms will appear at the input of the amplifier. There won't be much reserve, though, so quiet CD's may not be loud enough for you.

I should mention in passing I've had good luck with the bigger Sowter 9100 input transformer, and the 5687 and 7044 input tubes. The drawback of the little bitty input transformers is they can start to saturate at high input levels that also have strong bass below 30 Hz - this gives the illusion the amp is clipping in the bass when it's really the input transformer. Chunky input transformers seem to have the best performance overall - the ones the size of matchbook aren't as good, at least for input duties.

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