I found the 3562A operating manual (03562-90001) quite well written and easy to follow. You may want to get a paper copy that's easier to navigate.
The unit takes some practice to get used to. Depending on what kind of amplifiers you work with, the 3562A may not have the dynamic range you need. However, it has many features that a typical audio analyzer does not have, and would be more useful in an R&D environment than in a production line verifying whether an amplifier is up to its spec.
I agree on the manual, it is well written and has good general operating principles. It just kind of lacks the "how-to" section for someone not at all versed in this type of equipment. At a cost of $20,000+ when new, I guess they would assume you more or less know what you are doing when you buy one of these. Nothing in the manual seems to direct anything towards "audio" testing either. Some of what I end up doing does involve some R&D on these repairs. I mostly work on semi-vintage solid state equipment, 70's, 80's, 90's. NAD, Parasound, Carver, Mcintosh Etc. You can't always find direct part replacements, sometimes you need to experiment with a modern version of similar components. For instance, below is the factory spec's for one of the amps I have a Parasound HCA-1500a. I would lkiek to think most/all of these specs should be measurable. Obviously output before clipping can be done with a scope fairly easily, THD I have figured out, but frequency response from 5Hz to 100Khz, headroom, SNR ratio .. those I do not know how to test.
SPECIFICATIONS
Continuous Power Output - Stereo:
205 Watts RMS x 2, 20 Hz-20 kHz, 8 ?, both channels driven
315 watts RMS x 2, 20 Hz - 20 kHz, 4 ?, both channels driven
Continuous Power Output - Mono:
630 watts RMS, 20 Hz - 20 kHz, 8 ?
Current Capacity:
60 amperes peak per channel
Slew Rate:
> 130 V/µsecond
Frequency Response:
5 Hz - 100 kHz, +0/-3 dB at 1 watt
Total Harmonic Distortion:
< 0.03% at full power; < 0.01 % typical levels
IM Distortion:
< 0.03 %
TIM:
unmeasurable
Dynamic Headroom:
> 1.5 dB
Interchannel Crosstalk:
> 80 dB at 1 kHz; > 60 dB at 20 kHz
Input Impedance:
33 k ?
Input Sensitivity:
1 V for 28.28 V, THX Reference Level; 1.2 V for full output
S/N Ratio:
> 110 dB, input shorted, IHF A-weighted
Damping Factor:
> 800 at 20 Hz
Power Consumption:
500 watts
Dimensions:
w 19" x h 5 1/4" x d 16", h 5 7/8" with feet
Net Weight:
40 lb