Can you ever have too much power?


Is there a limit beyond which power is counter productive? Or is it like cars, where there no reason to have a 454 hp Corvetee other than because you can afford too?
rogocop

Showing 3 responses by fatparrot

Nalu...great post, and thanks for the info about Plinius. I was unaware of the class A/B standby mode. Great idea...but are there any trade-off's (there usually are in audio). Things like more complicated circuit design, with a greater cost and pehaps more electrical devices (to fail), or a circuit that is not quite as stable. Again, I'm not saying any of these are true, I just don't know. But the following is truism of life, espescially in audio design, "T.A.N.S.T.A.A.F.L." or, "there aint no such thing as a free lunch!"
I used to go for MONDO power when running SS amps (class A/B). Now that I've switched to tubes, I like to use reasonable powered amps (say 50%-75% of rated speaker handling power). I'm using an Atma-sphere M-60 MkII.2 (60 watt mono's). Replacement power tubes 6AS7's are relatively cheap ($15-16 ea.) but even so, at this price, a set of 16 (8 per monoblock) will still cost $240-. At least Ralph doesn't run the tubes at maximum parameters, so a set should be good for 2-3 years. Other manufacturers run their circuits with the tubes maxed out (and some can be much more expensive than the 6AS7's) and are know for chewing up tubes (under a year). The MA-2 Mk. II.3 mono's at 220 watts requires a total of 40 tubes...you do the arithmatic! Not to mention the the way, WAY higher list price for an increase of slightly less than a 6 dB's of power gain over the M-60's! Why pay "mucho dinero" for something that you don't need (braggin' rights?) Especially since "tube watts" don't clip out like transistor watts will. Then there's the heat factor. Since I'm in an apartment, the air conditioning fan unit is in the hallway, and I must shut it off for any serious listening. Windows are closed (so as not to piss off the neighbors...and the management). This can be a challange on 110 degree day of an Arizona summer! At least I can keep the amp in standby (filaments on, plate voltage off) when not listening. It's a class "A" amps, so the filaments aren't the heat generators or power hogs). If you're running a class "A" transistor amp, you should leave it on all the time. Not only do they generate a ton of heat, but the idle current (power on, with no signal) can EASILY add $20 to $100 to your monthly power bill. But who ever said "braggin' rights" come cheaply!
Stne418, here you go!

Basically, it's a geometric progression. For POWER (watts) a 3dB increase requires a doubling of power, a 6 dB increase a quadrupling of power, a 9dB requires 8 times the power, 12 dB requires 16 times the power, etc. Voltage dB is the same doubling, except the measurements are expressed as 6 dB increases when voltage is doubled. Here are the formulae:

dBv (volts) = 20 x log E2/E1 (where E is voltage)

dBw (watts) = 30 x log P2/P1 (where P is watts)
by Fatparrot