Exactly what are you smokin'? These arguments ended in 1979.
As an engineering tech, and playtime amp repair/mod DIY'er, I've had my nose in more than a few amps, and there is little wrong with any of the vintage designs. If you want me to say that...Marantz, for instance, built a better amp because their 80WPC design used 12,000uf caps instead of, say, Sherwood, who might have used 8,000uf caps, i'ts not gonna happen. All the major players built amazingly similar designs that sound amazingly similar under average listening conditions. The differences (and they are not earthshaking) happen at the extremes of power output (few listen there for extended periods) and extremes of frequency response (not an issue unless one of your inputs is connected to a sine-wave generator-rather boring to listen to, BTW).
And as far as your comment about Kenwood (which shows you basically are clueless, deaf, or both), I happen to collect them for: (Listed in order of importance)
1. The sound. Even the lowly KA-3500 sounds as good as (and to my own ears, a little better) than the Marantz 1060 (eBay seems to be fueled my buying-and-selling beat up and abused 1060's). Yes, this is my opinion. Deal.
2. Design. Kenwood rarely incorporated any novel design techniques in their amp building, but rather used tried-and-true circuits which have proven themselves by offering excellent sound and reliable function. You won't find an amp with 63V rails and 63V caps (Marantz and Adcom), and you won't find the larger amps injecting hummmmmmm into the phono section (Pioneer). From time to time Kenwood introduced a few items designed to push the edge, such as the Supreme Series (Model 500 and 600 integrateds and the 700M, one of which is on eBay right now), and occasionally tried something technically bizzare, like the discrete op-amp that drives the output of the KA-9100, designed as such to achieve exemplary thermal coupling to the massive aluminum heatsink. But these are the exceptions, not the rule.
3. Price. The fact that you and others seem to believe that the old Kenwoods are means that I can pick up a kick-ass amplifier that I never could afford back in the day. I do not want to dissuade you of this belief.
4. Ease of service. The vast majority of the Kenwood gear is amazingly easy to work on (notable exception: the KA-9100, my favorite amp, is a SOB to deal with if it needs work...thankfully it is a rare occasion). Even then, the common stuff such as switch cleaning, is made simple by the open design of the components used. No sealed switches that are nigh-on-impossible to clean once noisy (several of your 'pet' manufacturers use these type of components). Lastly, the 'tried-and-true' design philosophy mentioned in point #1 means that, if you get stupid and blow something up, it is a simple matter to track down the problem.
Don't read me wrong. The only manufacturer of 70's gear that I am not impressed with is Sony, but even they made some good stuff if you travel up the line far enough.
Lastly, I have a little 60WPC 'Kenny' here that will stand up to pretty much anything you care to audition it with. Admittedly, it is somewhat modified, but essentially it is still a Kenwood design.
And as far as your JBL's, I too liked them at one time. Then my acne went away, I got a little older, and discovered Hi-Fi. :butt1: