How Much Power is Enough?


I'm thinking of upgrading my YBA 2 Alpha HC amplifier (70 wpc). I'm currently using PMC OB1 speakers that are fairly inefficient at 87db. I really don't play my system at very loud volumes...and I don't think that I'm stressing my current amplifier...but I'm not sure. I'm looking for an amplifier that will bring about a wide soundstage, tighter bass, and exceptional smooth execution of mirco-detail. Would having more power make much of a difference? ...or should I be looking at a higher quality amplifier and stay with lower power like my current YBA? Some amps I've been considering on the USED market are: Pass XA60 monoblocks (lower power), Pass X150.5, SimAudio Moon W-5....
Would these amplifiers be a good match for my system? Would it be an upgrade from my YBA? Any advice or discussion would be appreciated.

calgarian
calgarian5355
I have in-efficient Aerials and recently upgraded from 125wpc Linn to 350wpc Levinson and the difference was staggering.

The extra power (and current capacity) tightened up the bass and improved everything else along with it. Micro-details, slam, punch, etc....

I truly think that you cannot have enough clean power.

I'd see if you could borrow a higher powered amp and see for yourself. I think you will be very pleased at what more power can give (the more current the better).
With 87dB with one watt at one meter sensitivity, you will need a little more than one watt if 87dB is the loudest sound you want, or a four watt amp for a maximum of 93dB, or a 16 watt amp for a maximum of 99dB, or a 64 watt amp for a maximum of 105dB, or a 256 watt amp for a maximum of 111dB. The formula for this is quadrupling the power will double the loudness (which is the same as adding 6dB). To be more precise, use a Radio Shack dB meter to measure the loudness of your speaker at three feet. Increase the volume until it is at a steady 80dB. Then step back to your listening distance and see how much it drops. You will have to compensate for that in your final calculation. The level probably won't drop too much.

Personally I have Klipschorn speakers with a sensitivity of 104dB/watt/meter. My 125 watt amp will produce about 125dB which is twice the threshold of pain. I have to attenuate the preamp 20dB so a quarter turn on the volume knob won't drive me out of the room.
The difference between 30 watts and 60 watts is only 3db. You need a 10db increase to get a noticable difference.
In my opinion, the pass XA60's will sound a lot more powerful than you think. They have much greater dynamic headroom than may amps 3 times their power. The Pass amp will recover faster from being driven hard and shouldn't distort on loud peaks due to massive power supplies and transformers. If the average listener uses only 3-5 watts, you will never notice the difference. If you play quite loudly, then you will.
Would having more power make much of a difference?

No. Not for what you describe.

I'm looking for an amplifier that will bring about a wide soundstage, tighter bass, and exceptional smooth execution of mirco-detail.

-have you considered room modal problems/acoustic reflectivity?

-perhaps the tube pre might be giving you a little too much bass punch
Your speaker are probably some of the best. From what I know, PMC's demand fairly high power to get the most of out them. I'd suggest you contact PMC, get the name of one of their reps and pose this question to them. Of course, your dealer may have the answer too, although they might be anxious to sell something they have. Your on the right track though. Seems like the only way to have speakers like those is to power them correctly.
OBWANKANOBEE
PMCs are known to be good matches with Bryston amps.

I have heard the smallest PMC driven with Bryston, Krells, Classe& Rowlands.

One thing for sure they really eat power for lunch. The 100watters can drive them but when you start pumping them up with 150watts >, wow, they really come alive and the bass starts to really boogie.

I think, the more "quality" watts you can afford, the better. Pass and the Sim you got listed are good choices but look into the Rowlands and Bryston.

good luck
I would also look at one of those modified mccormack dna 1 (170w) from SMC audio. Those would be awesome amps for the PMC and at the same time more affordable than Pass & Sim Audio
Elvick, you're a little mistaken with your calculations. you mean 3db not 10db. 10db= twice the loudness.
"When I pull this lever, the whole world dies"...Simon Bar Sinister.
Warrenh said "Elvick, you're a little mistaken with your calculations. you mean 3db not 10db. 10db= twice the loudness."

Warrenh, an increase in wattage by a multiple of four will double the loudness which is an increase of 6dB not 10dB. An increase of 3dB is a 50% increase in volume. Therefore, an increase from 30 watts to 60 watts will double the power, but only provide a 50% increase in volume. An increase from 30 watts to 120 watts will quadruple the power, but only double the volume by adding 6dB.

I bet this makes things as clear as mud.
Go with the old audiophile maxim, If some is good, more is better