On Mon, 27 Jul 2015 12:50:31 +0000 (UTC), Cursitor Doom
wrote:

On Sun, 26 Jul 2015 20:18:28 -0700, Jeff Liebermann wrote:

The RH variety is inductive. For non-inductive, you want the NH series,
which Newark and Digikey do not seem to carry.

Is that inductiveness seriously likely to be a problem at audio
frequencies?

Disclaimer: I am not an audiophile or expert on audio equipment
beyond a few occasional repairs and some long past work at a recording
studio and several radio stations.

Well, that depends on what you're trying to accomplish with the dummy
load. If it's performance tests for a data sheet with calibrated
equipment, then yes, every divergence from exactly 8+j0 is important.
However, if you're using the load to simulate a real loudspeaker to
test for ringing, oscillations, crossover distortion, resonant peaks,
and such, then there's no way a purely resistive load is even close to
a real world loudspeaker impedance:
https://www.google.com/search?tbm=isch&q=loudspeaker+impedance

Let's do some measuring and math. Digging through my junk box, I find
a dummy load that I think was used to test power supplies:
http://www.11junk.com/jeffl/pics/drivel/slides/dummy-load-inductance.html
That's 2ea 2.5 ohm and 2ea 5.9 ohm inductive RH type resistors in
series for a total of 16.8 ohms. Measured inductance of 16 uHy at
1KHz yields:
Xl = 2*Pi*f*L = 2 * 3.14 * 1000 * 16*10^-6 = 0.1 ohms
So, this load looks like:
16.8+j0.1
Good enough.
However, if you were making measurements up to 100 KHz, where the load
would look like:
16.8+j10
methinks a non-resistive load might be useful.

Considering that your original question was about testing a used
amplifier to see "what it was capable of", y'er right. You can do
that nicely without using overpriced non-inductive terminators. When
you actually build your load, you might want to do the above
measurement and calculations.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558