Greg, if your going to WOPL your amps then you really don't need a distortion analyzer as Joe has this all figured out.
If you want one because you want to learn more, then there are many options. Everything from older Hewlett Packard units that probably need repair and calibration, to Audio Precision units. PC based solutions from companies like QuantAsylum are becoming more common.
What other test equipment do you have? I'm slowly getting more test equipment as I learn more and gain experience, but as yet have no real need for a distortion analyzer due to my hobbyist status and lack of knowledge.
$250 won't buy anything worth a squirt and just having an analyzer won't help you much if you have no experience with any tester. What would you do IF you found distortion?
Yes My purpose is to understand the principle of audio signal distortion so I may apply that principle to other amps I have to validate they are within Spec rather than assume all is good. I already have a signal Generator.
I have a scope and several Meters that I use at work as an industrial electrician, but I am still on a learning curve regarding Audio equipment electronics.
Yeah, an industrial electrician is a far cry from what we do. As Lee mentioned, an AP ATS1 is your best bet. You eliminate a bunch of test equipment by it's use BUT,,,,,,, If you don't have a clue, you'll be treading water till you drown. Many that show up here think they can just jump in with no experience. Well, there is a reason some of us went to school for YEARS.
The ATS1 has more to it than just the Distortion. That meter is just scratching the surface but hey, have fun. All we can do is lead you to water.......
The AP units are very capable of running many tests without the need for any external programming, they have automated them internal to the unit. They are more expensive as a result.
To do the equivalent parameter sweep on the HP units, generally speaking, requires you to know how to program the units via HPIB programming. Not all that easy and the documentation supporting that is quite poor.
AP basically gives you the easy button, not easy on the HP units.
Both are good machines and can do impressive testing, depends largely on your capability and how much you want to spend. The QuantAsylum boxes are quite good but are nearly unobtainium due to production shortages at this time. I will own one of them once they clear their production problems in addition to the HP I currently have.
Sorry Greg, don't mean to rain on your parade but we see this weekly. Don't scrimp on the test equipment, it comes back to bite you. Also, many of us here went to school for years and some things you just can't pick up in a month of reading. Can you get by without a Distortion Analyzer??? Yep, many do. Do you plan on building many of these amps? If yes, you still don't need one.
Oh it’s fine it’s why I ask I have to decide if I want to NOT know what I’m doing with a $150 dollar unit or not know what I’m doing with a $2500.00 unit lol . If I get the cheaper one validated and am able to work with it I may become smarter for it . And still keep it all wife freindly .