So with HDMI 2.0 and 4K2K around the corner... Amp question

[styrbjorn]

Bsed on the excellent info in this forum it appears I need to sit tight on my receiver, transport (sorry Oppo) and receiver until the new 4K2K/HDMI 2.0 formats become ubiquitous (i.e. cheap).

In the meantime, though, it seems like all of the above makes an eventual move toward separates (starting with the immediate addition of a dedicated amp) seem pretty sensible...

I'm running a Pio Elite VSX21-TXH (has 7.1 audio pre-out according to the spec) into a 3.1 system with B&W 804S fronts (bi-wired), B&W HTM61 center and an eD a5-350 sub.

I'm wondering if adding a good amp would improve my SQ. Also wondering if I'd want a 5-channel amp to bi-wire the fronts, and whether that would preclude later adding surrounds. Also want to make sure I won't blow out my speakers with whatever amp I get. Thinking Emo XPA-5/XPR-5, Marantz MM7055 or Outlaw 7500 might be early front-runners.

I'd then eventually look to upgrade to a 4K-capable preamp/processor and TV when those become affordable - I'm assuming my speakers/amp would still be viable partners for the new tech.

Would love to hear folks' thoughts.

 

[j_garcia]

You are correct an amp and speakers would be unaffected by technology changes. As long as they work and sound the way you like, they tend to be the sort of things you keep

 

[Steve81]

I'm wondering if adding a good amp would improve my SQ.

A good high powered amplifier will give you more output capability, but I wouldn't expect a massive improvement in sound quality; your Pioneer receiver isn't a weakling, and from what I can tell, your B&W speakers aren't especially difficult to drive.

Also wondering if I'd want a 5-channel amp to bi-wire the fronts

No special need.

Also want to make sure I won't blow out my speakers with whatever amp I get.

If you hear distortion or strain, turn it down.

Thinking Emo XPA-5/XPR-5, Marantz MM7055 or Outlaw 7500 might be early front-runners.

I'd ditch the Marantz in that lineup.

 

[j_garcia]

A good high powered amplifier will give you more output capability, but I wouldn't expect a massive improvement in sound quality; your Pioneer receiver isn't a weakling, and from what I can tell, your B&W speakers aren't especially difficult to drive.

IMO, the B&Ws would like an amp, but as mentioned here, unless you have issues with distortion now it won't be an improvement in SQ.

I'd ditch the Marantz in that lineup.

Was going to say the same. While it is a good amp, it isn't in the same category as the others.

 

[Pyrrho]

There are basically two sensible reasons to get a power amp when one already has a receiver:

1. One has difficult to drive speakers for which the current receiver is not suitable (e.g., low impedance).
2. One wants to be able to play the music louder than it can currently play undistorted.

And even in the second case, it could be that one's speakers cannot handle more power and are the source of the distortion, and so it might not help; it will only help if the amplifier is the limiting factor, and not if the speakers are the limiting factor.

For most people, buying separate amplifiers is equivalent to flushing their money down a toilet.


Regarding blowing one's speakers, as Steve81 states above, if you hear distortion, turn down the volume. You can safely run an amplifier capable of putting out more power than the speakers can take if you use good sense. But, having more power than the speakers can handle does not do you any good; it just means that the limiting factor in how loud your system can play is the speakers and not the amplifier.


As for adding a subwoofer, if you like the one you have, adding a second one like it can give you increased bass capability as well as likely improving the smoothness of the bass response (if sensibly placed in your room). You could also ditch your current subwoofer and upgrade to something better. Either would likely make a real audible difference in your sound that, depending on how much better bass would matter to you, could be valuable to you. On the other hand, if you are satisfied with the quality and quantity of your bass, then this would not be a good place to put your money.

As for going to separates, very likely, in the future, a receiver with the processing needs that you will want will cost about the same as (or possibly less than) a preamp that has comparable processing, so I really don't think that new formats are a cause to go to separates. For why you might want to go with separates, see the list above. If nothing on the list applies to you, save your money. And even if something in the list does apply, good receivers have preamp outputs to be able to be used with separate power amps, and so it often is just as well to buy a receiver even if one never uses the built-in amplifiers, because, due to the effects of manufacturing in quantity, it is often just as cheap or cheaper to buy a receiver than a separate preamp that is approximately equivalent. Besides, often one can use some of the channels of amplification for some of the speakers, like the surrounds, and so one can avoid spending the money to buy separate power amps for all channels.


If you must upgrade, the first place to look is virtually always the speakers. They determine how your system sounds more than anything else. Then consider room acoustics, which can make a significant difference as well.

 

[styrbjorn]

Thank guys - great info, and much appreciated. I'm kind of a research junkie and having the experts on this forum is a great way to get past the industry propaganda...

j_garcia and Steve81 - thanks for the input! FWIW I was only looking at the Marantz to have a non-ID option, but it did seem like less bang for the buck. The Outlaw and Emo offerings seem to be pretty great value points.

Pyrrho - sounds like I may just need to stand pat. I love my B&W's, was mainly concerned that I wasn't driving them with enough since they really haven't seemed to break a sweat with anything I've played on them. Thought they were pretty high-end when I got them but it does seem there's a whole wide world of speaker goodness to be explored.

Might have to start another thread for this but now I'm wondeing what a logical upgrade path for the speakers would be...

 

[Pyrrho]

Thank guys - great info, and much appreciated. I'm kind of a research junkie and having the experts on this forum is a great way to get past the industry propaganda...

j_garcia and Steve81 - thanks for the input! FWIW I was only looking at the Marantz to have a non-ID option, but it did seem like less bang for the buck. The Outlaw and Emo offerings seem to be pretty great value points.

Pyrrho - sounds like I may just need to stand pat. I love my B&W's, was mainly concerned that I wasn't driving them with enough since they really haven't seemed to break a sweat with anything I've played on them. Thought they were pretty high-end when I got them but it does seem there's a whole wide world of speaker goodness to be explored.

Might have to start another thread for this but now I'm wondeing what a logical upgrade path for the speakers would be...

If you are happy with the way things sound, then you don't need to upgrade. If there is something that you don't like about the sound, then it is a good idea to listen to a wide variety of different brands of speakers, and different types of speakers (e.g., ribbons, horns, etc.), to get some idea of what your options are. Usually, to upgrade, you need to spend more money than what you paid for the speakers you already have, though not if you overpaid for what you have.

What you already have ought to sound pretty good, so you will likely have to spend a lot of money to get something significantly better.

Of course, since you are just using your system for 3.1 channels, you could always "upgrade" by adding surround speakers.

 

[styrbjorn]

Thanks again Pyrrho - you're right in that my system sounds pretty amazing to me, but then again it's the first decent system I've owned and the upgrade over everything else I'd ever heard is just incredible. So now I find myself wondering if there's more out there... I can't help myself.

 

[Pyrrho]

Thanks again Pyrrho - you're right in that my system sounds pretty amazing to me, but then again it's the first decent system I've owned and the upgrade over everything else I'd ever heard is just incredible. So now I find myself wondering if there's more out there... I can't help myself.

There is always something else that will be better in some way or other. With speakers, they have different virtues and vices, so it is a question of which vices one can live with. I personally am a big fan of ribbon speakers; here is what I use in my living room system:

Stage

Although I like them very much, and they are, in my opinion, the best speakers I have ever owned, they are not perfect and someone else might prefer some other qualities instead. Since the old Apogee is out of business, if I were looking for new speakers, I would be looking at some Magnepan speakers. As things are, I am happy with what I have, and do not actively seek new speakers to make me wish I had many thousands of dollars more to spend on audio equipment.

 

[styrbjorn]

Interesting... also makes me wonder about the new Salk Songtowers with the ribbon tweeters. Will have to look into Magnepans this week and ribbon tweeters in general. Thanks yet again!

 

[fmw]

The only reason for you to buy a new amp is that you want one. It won't have any effect on the sound of your system unless you drive your system into distortion (not likely.) Bi wiring is silly and not worth the cost of cable. What is important in the audio side of the system is the speakers and you have some good ones. Should sound excellent.

 

[canelli]

The graphs I found showed the B&W 804s speakers dip to 4ohms and possibly a little lower into the high 3ohm territory with up to a 60 degree phase shift. Not being an expert, I would consider these fairly difficult speakers to drive even though they have a sensitivity listed at 90.

I looked up the operating instructions for the Pioneer Elite VSX-21TXH. There is a setting when the speaker is less than 8ohm but greater than 6ohm. I would do some more searching to see how that model handles 4 ohm loads. (it’s late and I didn’t spend much time looking into this.)

From personal experience with my Pioneer Elite SC-05 at louder volumes with B&W speakers, the amplifier would go into high distortion that was audible. I got a Halo amplifier and used the Pioneer as Pre-amp. The B&W are in a room with only 2 walls and open to the rest of the house. Plus, I like to listen to movies above reference. All these things added up to more than what the SC-05 could handle. Good luck!

 

[fmw]

Not necessarily hard to drive. B&W aren't considered extreme loads. All speakers have variances in impedance along the frequency spectrum. We normally use what is called nominal impedance to match power sources to speakers. The B&W have a nominal impedance of 8 ohms so that's the number you use. An AVR will have no trouble at all with them in a normal environment. I used to have a pair of B&W 802 that I drove with a 50 watt per channel stereo amp. I never used more than about 10 watts peak for the loudest passages at my normal listening levels. I wouldn't worry about it.

 

[Steve81]

I would do some more searching to see how that model handles 4 ohm loads. (it’s late and I didn’t spend much time looking into this.)

As a THX Select 2 receiver, it's certified to be stable down to 4 ohms on the front channels and capable of delivering a 12.5 ampere peak on each of those channels (625W into 4 ohms).

 

[Steve81]

We normally use what is called nominal impedance to match power sources to speakers.

Unfortunately, nominal impedance is also regularly abused. By the IEC method, an 8 ohm nominal speaker isn't supposed to dip below 6.4 ohms, although quite a few speakers nominally rated 8 ohms by manufacturers dip to 4 ohms and below.

 

[canelli]

As a THX Select 2 receiver, it's certified to be stable down to 4 ohms on the front channels and capable of delivering a 12.5 ampere peak on each of those channels (625W into 4 ohms).

The Pioneer SC-07 received the THX-Ultra badge, but still showed distress and shut down while driving a 4ohm load at 150 watts. (The THX Select 2 is designed for 2,000cu ft.? and the Ultra is for 3,000cu ft.?) Also, Pioneer and THX had to work out some details and “arrangements” to get the THX certification. These issues were document here and in my living room. I have come not to trust certifications and dealer specifications the hard way. Hopefully/Luckily this is past history since Pioneer dropped the ICE amplifier section.

An AVR will have no trouble at all with them in a normal environment. I used to have a pair of B&W 802 that I drove with a 50 watt per channel stereo amp. I never used more than about 10 watts peak for the loudest passages at my normal listening levels. I wouldn't worry about it.

At 3 meters, 85dbSPL, 90w/m speaker, and 20db head room (THX spec) the power requirement is 285watts (8 ohms). Based on simple calculations, if I had your 50 watts driving my speakers in my den I would have had less than 6db of head room at 8ohms. Did I miss calculate something?

 

[Steve81]

The Pioneer SC-07 received the THX-Ultra badge, but still showed distress and shut down while driving a 4ohm load at 150 watts.

Under what conditions? This bench test shows into 2ch driven @ 1kHz, the SC-07 can deliver 236.4W into a 4 ohm load with 0.1% THD. Of course, if you tried to do that all channels driven, I'd expect very few receivers would do better.

(The THX Select 2 is designed for 2,000cu ft.? and the Ultra is for 3,000cu ft.?)

Indeed. If you're interested, here's everything you'll ever want to know about THX:
Feature Article

Also, Pioneer and THX had to work out some details and “arrangements” to get the THX certification.

Haven't heard about that, but if true, that's rather bad...

 

[canelli]

Under what conditions? This bench test shows into 2ch driven @ 1kHz, the SC-07 can deliver 236.4W into a 4 ohm load with 0.1% THD. Of course, if you tried to do that all channels driven, I'd expect very few receivers would do bett

This describes the issue I had.

Driving 4-ohm loads was an entirely different story. The SC-07 simply fell apart when running full bandwidth (20Hz to 20kHz) continuous power measurements. As I tested at frequencies above 5kHz with only 1 channel driven, the internal cooling fan would instantly come on right before the receiver would go into gross distortion and shut down at levels above 100 watts. With two-channels driven, I was able to squeeze out a clean 150wpc at less than 0.5% THD. Anything higher would again run the amps into gross distortion and shut off the receiver. I was a bit perplexed in how the receiver managed to better cope with 2 channels driven over 1 and could only surmise that it had something to do with symmetrical load balancing on the power supply. How this receiver was awarded the THX Ultra2 rating was a bit perplexing to me.
Pioneer SC-07 Measurements and Analysis

 

[Steve81]

Very interesting indeed. The only real comment/explanation I can think of is that THX may not be testing amplifiers at full power on the top end since it doesn't really represent real world material. Of course, much of their certification process is opaque for obvious reasons, so I can't say with any real authority what happened there.