Tube Amps, Best Connections, Ripping Music
How is it that tube amps only produce, say, 25 watts of power, and yet they provide enough output to drive speakers rated for hundreds of watts?
It all depends on the speaker's sensitivity, which defines the sound pressure level it can produce when fed an audio signal with 1 watt of power as measured on axis at a distance of 1 meter; it is specified as decibels per watt per meter (dB/W/m). Typical home speakers have a sensitivity somewhere between 80 and 90dB/W/m or so, whereas high-sensitivity speakers can reach 105dB/W/m or more. The higher the sensitivity, the louder the speaker can play with a given amount of power. Thus, tube amps, which typically generate relatively little power as you point out, are best suited for high-sensitivity speakers.
Interestingly, high-sensitivity speakers are often capable of accepting lots of power, which seems counterintuitive, but there it is. Also, most people don't realize that the vast majority of their listening is done with only a few watts of power from the amp.
The Impossible Dream
I recently purchased a Sony EX400 HDTV (four HDMI ins), Sony BDV-E570 Blu-ray home theater in a box (one HDMI out), and Optoma HD20 projector (two HDMI ins). I have a cable TV feed without a set-top box. I would like to be able to watch TV and Blu-ray on the TV and projector. Any suggestions on how to connect them? I'd prefer all HDMI if possible.
I see no way to do what you want with the equipment you have. The BDV-E570 has no HDMI inputsit's a closed system that outputs audio and video from Blu-ray, DVD, or CDso you can't use that as a switcher. The TV has no HDMI outputsin fact, it has no video outputs at allso you can't use that as a switcher. And without a cable set-top box (STB), you can't watch cable on the projector at all.
You could do what you want if you get a cable STB and a 2-in/2-out HDMI switcher. Plug the STB and BDV-E570 HDMI outputs into the switcher's HDMI inputs, then connect the switcher's HDMI outputs to the TV and projector. I recommend getting a switcher with more than two inputs so you can add source devices later.
Like Father, Like Son
I was raised on Magnepans by an audiophile father. Now I am a new father, and I look forward to raising my son on quality audio. I can't afford Magnepans this year, but I want to start compiling a music collection for my son now. In your opinion, should I rip music to high-bitrate MP3, Ogg, or AAC file format?
Congrats on new fatherhood! I'm touched that you want to raise your son on high-quality audio, in which case, I would rip music to uncompressed WAV files. Hard-disk space is very cheap these days, so that's not the issue it used to be. Once you have uncompressed files, you can then compress them in whatever format you need for any given device now and in the futurejust be sure to retain a copy of the original uncompressed files to use as masters. Who knows what devices your son will have at his disposal when he grows up? If you follow my advice, you and he will be ready for anything the future holds.
If you have a home-theater question, please send it to firstname.lastname@example.org.