Start here:
https://www.audioholics.com/audio-amplifier/basic-amplifier-measurement-techniques
Lots more all over the Internet. Maybe you can synopsize your findings for the rest of us.

I have been thinking about that approach. Have not seen one for $200.00If it's for personal use, spend $200 on a plug in spectrum analyzer and call it good.


You can get good results economically by using a good quality USB-audio interface and inexpensive or free software. I've got an Alesis IO2 and using it with Visual Analyzer can get most of the measurements you wish to perform.I look forward to reading the link in depth.
I am aware of the Audio Precision units, if I win the Mega Millions Lottery I plan to purchase one!
Now for the reality World, any other ideas? Don't need 8 channels maybe only two.
Recently we've replaced the venerable SYS2722 with the AP APx585 HDMI Analyzer which tests up to 8 channels, and is much easier to use. Ever since using the APx585 we've been able to apply a consistent measurement test suite to each amp and receiver we've measured on it which is outlined below. The APx585 doesn't come cheap. In fact the version we have represents a $40k investment.
Has anyone been able to find an update on the QA403 availability?https://quantasylum.com/collections/frontpage/products/qa403-audio-analyzer
is a modern day economical audio test set
To bad the silicon shortage is causing long delays for mfgs using specialized parts.
Photo is a web capture with no additional photos or informationAny other front panel markings? What does the sticker on the back (or bottom) say?
Thank You very much, you are correct: Panasonic VP-7725 $2,995.00It’s a Panasonic VP series, I think. Quite good.