First post here - always search these helpful forums when I need audio advice, but this time I'm looking for some very specific advice.
I was lucky enough to inherit an old Marantz 2270 receiver from my father, which I've been using as headphone amp for my Sennheiser HD595 (112 db SPL, 50 Ohms). I know these phones aren't exactly in desperate need of an amp, but I find it much improves the sound anyway, and I can't afford anything higher end at the moment.
My problem is that I don't completely trust this 40 year old device. It mostly performs flawlessly. Occassionally there is some hissing, but it goes away if you play around with the knobs a little. Once or twice over the last year, there has been a quite loud popping noise, but I'm not 100% sure it was caused by the receiver. The headphones are loud enough with the volume as low as 10% - I imagine it would be unbearable at 25%. After having accidently turned the sensitive volume knob up a little while readjusting my feet (clumsy, I know) a couple of times, I'm starting to feel like I'm playing with fire. If the volume increases linearly all the way to 100%, I fear it could have a devestating effect on my hearing - within seconds - if the amp somehow goes to max effect, and I'm wearing the phones. So my questions are:
How reliable are these old amps? Can they go out with a bang, literally? Or is the only real risk me manually (or pedally..) turning the volume way too high up?
Would modern amps or receivers be any safer if I were to replace it?
How much sound pressure can such a pair of headphones really produce with the aid of an amp? Is there a reasonable limit, or would 100% volume on the amp really make the phones 10x as loud as 10% volume?
I have friends and relatives with premature hearing loss and tinnitus, and I'm not willing to take any risks with my hearing. The receiver is one of my favourite possessions, but if there is any realistic scenario where only the few seconds it would take me to react could cause significant permanent hearing loss, I'm going to have to pack it up. Any advice is appreciated.
