Paul Stamler wrote:

David, it's not clear from your post -- were you using Otala's
sine/square test signal? Or were you doing a different sort of IM test?

I was trying to come as close as possible to Otala's DIM 30 sine/square
test signal. But I wasn't able to duplicate it with the equipment I
have available, and in fact don't know the actual maximum slew rate of
the test signal that I ended up with--surely less than intended, though.

That's why I'm offering no numbers, and why I suspect that the test could
have been made quite a bit more sensitive.

If you or anyone else here has suggestions for affordable ways to generate
a DIM 30 signal, I'd appreciate them greatly. (DIM 30 = 3.18 kHz square
wave + 15 kHz sine wave in a 4:1 ratio, low-pass filtered at 30 kHz --
see Leinonen, Otala and Curl 1976, "Method for Measuring Transient
Intermodulation Distortion," AES preprint #1185.)

--best regards