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100W, 200W, or 300W?

I'm pretty new to this and could use some help. Working down my list of upgrades: did speakers, room treatment on order... I think next up is to replace my amp.

I'm currently using a Harman Kardon PA2000 stereo amp that I had sitting in storage. 100 WPC @ 8 Ohm. It's "OK", but it probably the weak point in my system right now.

For speakers, I picked up B&W 805D3 tabletops with stands.

88 dbSPL sensitivity, 8 ohm. They recommend 50-120W @ Ohm for the amp power on their site.

I pulled up an amplifier calculator and plugged in some numbers:

88 sBSPL, 8 ft distance, 85 dB volume w 15 dB headroom and this came out to 3W RMS w 94W peak

I have my heart set on blue watt meters so I see the following options:

1) MA5300 @ 100 WPC, no autoformers, integrated
2) MA7200 @ 200 WPC, has autoformers, integrated
3) MC302 @ 300 WPC, has autorormers, seperates


For the MA5300, I'm concerned that there isn't enough headroom. If I even get close to the 94W peak, it means that I'm pushing the amp to the max, so I'd probably be operating in an area of reduced sonic performance since it's being stressed. Is this a correct assumption?

The MA7200 looks like it'll leave plenty of headroom and it also has (for better or worse) autoformers which seems to be what puts the "mac sound" in macs.

The MC302 is just sexy as heck... but is there any realistic gain with my current set up that I would get by buying one of these? Or is it so much overkill that I am just throwing money away at this point?
eisenb11
ebm
9,311 posts
 
Get PASS 350.8 for the BEST sound.
verdantaudio's avatar
verdantaudio
1,563 posts
 
So, this is a good calculator that is pretty intuitive

https://myhometheater.homestead.com/splcalculator.html

If you are sitting 8' from those speakers, with 100w and it is even vaguely close to a wall your peak output is 106.3 dB.  That hits THX standards for output.  You are fine with the 100w amp.  

Also, peak output is usually at the deepest frequency.  While those speakers have good bass response, they aren't going to 20hz.  You would be fine with 20 really good watts as that would give you ~14.3dB of headroom at 85dB (Peak 99.3).

People get too caught up in terms of huge power numbers IMO.  I run less efficient speakers with 45w and they sound extraordinary.  


mozartfan
2,143 posts
 
Never buy speakers less sensitive than 90dB. Anything less is the difference between being able to drive them well with any of scores of amps with as little as 50 wpc, and being stuck with speakers that force you to try and find a good sounding 200 wpc amp. Not a lot of those arou


Well it is true 90db should bea  ideal cutoff point, But not always. 
I had a  Jadis Orch Refer and quite comfortably pushed the Thors rated 87 db. 
Seas drivers at least the EXCEL line are low efficient but offer dynamics, fidelity,, Thing is you will need a  tube amp that boasts hefty trans and a  good transparent design. 
So yes, low db requires a  tube amp that has power = will cost ya a  bit more,,but doable on the used market. 
eisenb11 OP
33 posts
 
@verdantaudio Intersting! So it sounds like between those options that the MC302 would be way overkill and I should consider either the MA5300 or MA7200 with the deciding factor really being where I want to stand on the autoformer vs no autoformer debate?
stereo5's avatar
stereo5
6,717 posts
 
I have a Mac MA6600 integrated which has the transformers and 200wpc. The sound is quite effortless and has that great Mac sound. I would not trade it for anything. I also own the MC302 300wpc amp in another system. Since the MC302 is a power amp only, what will you use as a preamp? I haven’t heard your B&W speakers but usually, the more power, the better sound to really make them open up.
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