How well would some of the better receivers from the 1970s work as a front end to a power amplifier? I'm thinking of Yamaha, Marantz, Sansui or Kenwood receivers with the preamp out, main in jacks. The tuners in most of these receivers are very good, how about the rest of the preamp parts?
The tuner sections may be pretty decent, at least usable depending upon how much FM you listen to these days. I do not kid myself about my 70's Hafler gear I use to drive my computer music now. It is still nice sounding, but I would not consider it state of the Art in High end land. It does not mean it is not a good music maker, but it is much better than any table radio we know of. I still wish I had some of the old Marantz gyro-tuning receivers I have gone through way back. I thought they were great looking as well. Enjoy.
Depending on the kind of music you are going to listen to, they might perform extremely well, although most of them will require the loudness compensation to be listened to at low levels. I'd say I will prefer them to modern mid-fi receivers to listen to cd music.
DVDs are a different story.
I agree completely with Jim , when he says they will not give you the last bit of resolution, but depending on recording quality they might sound pretty good.
It would be good to know the rest of the system before making additional comments.
What would be an iteresting test for you is how some of the better FM stations in your market sound compared to XM or Sirius radio home units. Those who live in Chicago, NY, and Boston with excellent engineering at the local PBS FM stations know where I am going here. If you have Direct TV you now have XM to listen to. Those who own Magnum Dynalab tuners really get how good FM can be in those markets.
ps I just picked up an older Kenwood seperates tuner off of www.free cycle.org for free. I'll see if it is servicable and if so give it to an older couple in our church who might still listen to FM. You might sign up for yourself and you can select the local counties near where you live and people offer stuff for free if you just pick it up. You have to be careful and not pick up something that is really "dump bound", but... my wife found two automobiles that she gave to New Orleans hurricane victims who relocated to Atlanta. Your junk may be someone elses treasures.
The preamp is the most important link in a system as everything most go through it. It is also the most often overlooked or underappreciated. It is true that loudspeakers and source components are very important as they determine the ultimate clarity but the largest bottleneck is always the preamplifier where everything is routed through. It is also the first stage of gain which means that it has the job of amplifying the signal without adding noise. Any subsequent amplification such as through a power amplifier will not only amplify the signal but the signal plus noise introduced by the preamplifier itself.
Using a vintage piece has several problems. One is that parts quality was not as good simply from a technological point. So more noise is a given. Then secondly, age has to contribute to this as the circuit cannot hold its specs indefinately and after thirty years there may be more than a couple of things amiss. You could take advantage of a cheap tuner by connecting the tape outputs of an old receiver into a modern hi-fi preamp or integrated amplifier. That would allow you to use the tuner section and avoid listening to the noisey preamp section. Lastly, you really don't want to look at that old thing do you?!