You really can't compare 70's Peavey stuff with anything made today. Even though this thread is old, the amount of old Peavey gear in the used market that still works is absolutely amazing. The problem is the new younger purchasers don't understand how any of it works, and are destroying it without remorse. I guess because they don't have much invested in it.
Back in the mid 70's we bought every piece of used Peavey gear we could find, simply because that was all we could get our hands on. It didn't sound good, none of it, but it was Loud AF. And we abused the Hell out of it. But in ways Peavey designed it to be abused. We didn't have crossovers, so the cabs matched the amps. We blew speakers left and right too. Eventually blew most of the amps. But a lot of that stuff still survived.
Today kids are being given, for free, 70's and 80's 15" and 18" bass cabinets, not subs, and are crossing them over at 30/40hz with 1500watt power amps, and wondering why everything is blowing up. So l don't think there is going to be much of the old Peavey stuff around in 10 more years.
If you had an old Peavey PA and made it sound great, it's because you really knew what you were doing. In 1987 I bought the EV 1502 speakers and matching 18" folded horn subs, and those sounded fantastic. But l didn't want everyone else sounding Fantastic thru my PA, as l had to rent it out to pay for it, so l bought a couple Peavey SP2 speakers and 118 SUB HC bass cabinets to rent out. And those were Solid and it was a great working system.
Today when l pull out that same Peavey PA people say it's the Best sounding PA they ever heard. And that's because that is what Rock and Roll used to sound like. It's a lost Art. The EV pa system l have sounds worlds better, because l used it so little, but the Peavey was my workhorse.
Today Peavey and Rock and Roll are both dead, so it doesn't matter what they do anymore.
