Marantz 2270 - Never meet your heroes?

[marcpitt]

Almost half way up on the attenuator with 96 spl speakers and it clips, you need bigger speakers. My 2225 has me turning it down with 90 spl speakers at that approx level. Bigger speakers or smaller room for 70wpc.

Thanks for your reply. Different/new speakers are next on the list. I actually talked to a store which will allow me to bring in the receiver to try different speakers. The room will of course be different but at least I can get a better real sense compared to them running super clean non vintage gear as a source.

 

[marcpitt]

IMO, you need to do a frequency response test to find out if the thing can make reasonable power from 20 Hz to 10 kHz or so. I don't like to take vintage stuff to full power at high frequencies. Look at the manual or service manual to find out what the unit should be capable of. A good 70 W/ch receiver should go satisfyingly loud in a medium sized room with reasonably efficient speakers. Even the onset of clipping shouldn't be terribly obvious. Usually the speakers complain first by bottoming out or burning up.

I think I have what I need to do this. Need to read up a bit more on the scope to see how I might hook it up to a computer to help me automate the sweep and the saving of the results. Sounds like an exciting Friday night plan.

 

[ConradH]

Being a dinosaur, I'd just hook up a sig gen and turn the knobs. You can also generate a sweep in Audacity (I think) and measure that, but if you're looking for maximum power (IOW, clipping) at various frequencies, just turning the sig gen knobs and reading the scope should be the easiest method. You don't need all the frequencies, maybe just 4 or 5 points between 20 and 20k. I use a sophisticated data collection method. It consists of a wooden tube containing a clay and carbon mixture. Cautioning again, if the unit isn't in tip top shape, with good thermal grease under the outputs, I wouldn't go too high in frequency or dwell at maximum power for very long. Or, if you like to live dangerously, you can use my motto, "It was built by the hand of man, so it can be fixed by the hand of man."