2. home-theater
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Do I need to amplify all of my channels?

Gurus:

I have recently moved to a new house that has a media room, into which I am trying to harmonize my current equipment. My existing setup consists of a McIntosh MHT-100r, a pair of Bowers and Wilkins 803s, and a Bowers and Wilkins HTM2 center channel (wall mounted and left in the old house were the surrounds - decent klipsch).

My new media room includes high end front in-wall speakers (not audiophile but top of the consumer range that I may move to sides or rear), above average consumer in-wall sides and rear speakers, and a decent wall mount Sonance center channel that I will sell. There is also a solid Velodyne sub that I intend to use (I am writing from an American Airlines inflight wifi connection and cannot remember the model).

I have long believed that my MHT-100 (80w at 8ohms) is underpowered for my B&Ws. My desire is to add an amplifier to my system, but I don't know how many channels I really need. The MHT-100 has 5.1 incorporated amplified channels, but can pass 7.1 (for which my media room is wired) to an amplifier. The MHT does not have balanced outputs.

My primary goal for this room is media, though it is the best equipment in my house - so i will listen to Andreas Vollenweider Caverna Magica on this system.

So the questions are: do I just need 3 channels of amplification for my B&Ws or do I need 7; if I use an amplifier for just three channels, how does the system work (ie volume control) and how do I hook it up; if I use a 7 channel amplifier, will I overdrive my sides and rears (they are rated at 100w, I think); and any other questions I haven't considered.

I'd also appreciate any options that amyone would like to suggest, such as "get the Outlaw 7 channel 200w" or "McIntosh MC-x is the only way to go with the equipment you have." I am trying to do this on a smart budget, as media room furniture is also needed and money isn't endless. However, I want the right equipment so I don't have to buy it twice.

I appreciate any feedback/suggestions/advice/criticisms.

Thanks in advance,
Mark
msetexas
blindjim
3,092 posts
 

msetexas
>

IMO & IME... power amps which have great power supplies with an abundance of power storage capacity, are as good or better than those which double down their power with regard to impedance drops.

For ex. Krell vs. BAT amps.... Krell doubles output with a halved impedance load.. My KAV250 went to 500wpc at 4 ohms.

My previous BAT VK500 W/BAT pack opt.... put out the initial 250 as the Krell, but at 4 ohms less than 500wpc.

Theoretically you possibly could drain or use the total 500 or 440 wpc from each amp... but logically, with 89-90Db speakers like BW 803s, continuous power outputs of those levels simply won't occur with logical use.

Even some incidental peaks of high freq under sane listening conditions should fall short of the top rated output of either amp.

So there's that... simple doubling of power output is not indicative of any amp being considered either good or bad. Theres more to it. I sold off my 9NT + kav 250 due to it's sonic signature. Not due to power issues.

The BAT vk500 sounded worlds apart better.... and should have perhaps if $$$ means anything. The Krell then was about $3K new. The BAT was about $5.9 new.

Other than sound, I feel it was the power supply and design topology of the BAT which made that diff for me. KAV 250 = 45lbs.... BAT vk 500 = 105lbs. Where's the beef? it's in the power supplies or isn't. digital amps aside.

If you like Marantz' sound maybe you should look into McIntosh, odyssey, Butler, or ATI. Of those only ATI doubles down power with halved imp, though. All however sound very good.
srwooten's avatar
srwooten
694 posts
 
Blindjim-
I was stating that an amp that doubles its power with a 4 ohm load is a simple way to know if the amp has good reserves. Is this not correct?
I was not using this to state whether the amp sounds good or not.
blindjim
3,092 posts
 

Srwooten
it's as good as any I suppose. Not too many makers publish their power reserve capacities thoroughly IMO.

I sought merely to broaden the viewpoint by injecting some other facts. interjecting there are more criteria to this than noting if amps double up their outputs if speaker imp halves.

As fair a rule as is that, I've found with conventional transformer coupled output amps, I look at the over all weight... now. it indicates to me a general rule of thumb that serves me pretty good, as it speaks about the build of the amps power supplies most often. great amps have great power supplies more often than not.

Also the weight of an amp is not a physical worry for me, usually. It is for some I'm sure.

Voice, input impedance, topology, power reserves, negative feedback or no, are important things I look at when deciding on amplification. To buy an amp however it may not meet my expectations in those regards.

My latest amp acquisition for ex, meets but a few of my short list desires for what an amp needs. it's not heavy, doesn't have enormous power resivoirs and isn't my typical choice of transformer coupled output. In fact it is dainty IMO by my usual amp standards, but the sound and performance exceeded my expectations. A lot. it's price exceeded my predetermined budget too! IMO that's usually what happens to me though.

it's not eye candy either until energized and the lights are off. otherwise it's pretty plain and sort of dull looking as amps go. It's my first 'hybrid' amp too.

I was avidly seeking out an ATI amp for the last few months and a couple others. I almost pulled the trigger twice but both deals weren't quite to my own personal needs. Or this new TDB 5150 wouldn't have gotten here at all.

Hope that helps clear things up.
srwooten's avatar
srwooten
694 posts
 
Thanks BJ-I hope you like your TDB, it looked great online. Please update your page and let us know.
Steve
blindjim
3,092 posts
 

Thanks much.

update?

I jotted down some initial items and posted it yesterday... then saw this and responded. Once I get a bit of time on it in various ways I'll publish more, but it does sound really good.
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