which is better

hexumjunkie

Channel Power Rating: 7 Channel Power Rating: 100 Watts Per Channel x7 (8ohms 1 kHz, THD 0.7%)


75 Watts per channel @ <0.07% THD, 20Hz – 20kHz into 8 ohms

jdhdiggs

If this is for a reciever, all the ratings are essentially worthless until you get into the NAD/Sunfire/HK arena since the rules for receiver amplification are so lax that the manufacturer can essentially claim anything. If those recievers are below $400 or so in price, I doubt they really push even 30W.

Look for an "All channels driven" rating and that will give you a more accurate portrayal of the actual power.

As for which is better in your case, I'd guess the lower THD which, to me, shows that the amp is not working as hard as the other to produce that power.

hexumjunkie

one is a cheap amp and the other is a better expensive amp in th 1200 dollar range

jdhdiggs

Ah, a different ballgame. Honestly, as long as you have decently efficient speakers, either will have more than enough power. Remember that the difference between 75W and 100W is just a little over 1dB in volume so no real difference there.

My guess is that the second amp has more than enough reserve to handle major peaks at earbleeding levels.

That being said however, only you can tell if it is worth the difference in $$$ by listening to it.

hexumjunkie

but the one at 100 watts isnt true continous power is it?

jdhdiggs

If it is an amp, it must be.

by law, if you advertise a power rating on an amp, it must be able to sustain that power, all channels driven. That being said, higher end amps seem to "underrate" their power. What I mean by this is that if you look at the transformer and caps, a 75W amp might really be more equivelent to a 130-150W of a lesser brand. The de-rate the amp to keep the great THD numbers to show how the amp performs in its best range. RuSsMaNs amp that he just sold in the flea market is a good example of an amp that is substantially stronger than what is published in the brouchure.

hexumjunkie

well this weekend is it im gonna either keep my sony or go get that harmon kardon the first ratings are from my sony and the second are from the h/k bad thing is i want to run a multizone from a bchannell and h/k doesnt have that

jdhdiggs

The HK you posted about is a reciever, not an amp so I'm assuming that the Sony is also a reciever. In this case, the HK specs mean something, the Sony's really don't. The HK ought to be about double the power in real watts

unc2701

Ok, wattage specs are tricky. The 75 watt one you could keep on cranking up until it hit 100 watts - the louder you put it the more the THD would go up.

But to help you compare, the 75 watt one quotes <0.07% for the full spectrum- meaning that it's at 0.07% at 20khz and more like 0.02% at 1khz. The 100 watt one is at .7% at 1khz... In the 20khz range the .7% is going to have THD >2%, which is going to run the risk of hurting your speakers.

So you have:
&nbsp &nbsp &nbsp &nbsp 75 watt amp 100watt amp
1khz &nbsp 0.02%? &nbsp &nbsp &nbsp 0.7%
20khz 0.07% &nbsp &nbsp &nbsp >2%?


THIS IS WHY YOU SHOULD HATE SONY: Basically Sony advertises their wattage based on where you will start damaging your speakers, everyone else advertises where you really start to see the THD begin to kick (it'll usually stay fairly flat for the first 90% of the watts, then jump). Sony even advertises like this for their top of the line ES products- and that's just not right. So to answer your question, without seeing the THD curves and marking off where the 75 watt one hits .7 in the 1khz range, you have to guess. My guess is that you could probably get more, cleaner volume out of the 75 watt one.