I was wondering at what point would you audibly notice the benefit of an amp? I own an Onkyo 805 and don't listen all that loudly. Can't really unless the kid, or soon to be kids, are not here. Anyway, is there an audible difference at any spl level, at some level, or only at high volume levels? I have always wanted to know this. I run my onkyo in 7.1 with axiom Epic 60 500 system. I am finding that I am becoming quite the movie soundtrack listener, such as Braveheart, The Patriot, Conan the Barbarian, BSG syfy channel, and other movie scores. I never thought I would enjoy this. I was strictly just a movie person until I got my speakers. Now I love to just hear MUSIC! Strange how that has changed. Anyway, I digress. Thanks for the input. Good Night All!

JH, higher maximum power capacity, regardless of whether the amplifier is in a receiver or is separate, becomes audibly significant only when the lower powered unit would audibly distort at the highest sound levels which the listener is using. Putting the amplifier in a separate box can in itself have no audible effect. So, in your case, unless you exceed the power capability of your 805(highly unlikely at safe listening levels)there would be no benefit to be noticed from a receiver amplifier or separate amplifier having a higher maximum power output rating.

JohnK believes all (well designed) solid state amps of equal output sound the same at any given sound level. There are many who disagree with this theory.

Neverthless, the Onkyo 807 has a very strong amplifier section, stable with 4 ohm rated speakers. That having been said, I'm watching a Cox Cable 5.1 broadcast of the "Event." I'm using a Sony TA E9000ES processor (pre-DTS), an Anthem PVA 5 (5 channel) amplifier, a pair of Michaura M665 front L/R speakers (like the Axiom M60s [2 x 6.5" and 1 x 6.25" Axiom drivers and a 0.75" titanium tweeter], a VP150 center channel, a pair of Mission 77DS surround speakers a Dahlquist PDQ1500 15" subwoofer.

The sound quality is stunningly excellent. My last integrated surround receiver was an Onkyo 797. There is no comparison in sound quality. Maybe it's the difference between processors. Maybe it's the amplifier section compared to the Anthem separate. I don't know.

Years ago, I had a Sony STRDB 1070 receiver. The Sony amp section was weak. I used it as a processor, a pair of Onkyo M282 2 channel amps and aKenwood KA9100 for front L/R. The Sony using outboard amps sounded better, even at relatively low volumes.

I've had a cheap Sony receiver rated at 100 wpc, then switched to a Pioneer Elite rated at 110 wpc. I don't give much credence to the wpc rating, but I do think that the power supply has just about everything to do with the sound. The sound difference was tremendously different. One unit was light and the other was heavy, hence the better power supply.

All of this is hearsay and most of it would fall flat if subjected to a double blind listening test.

That's my story and I'm stickin' to it.

I am, however, honestly happy that your chosen equipment brings you obvious sonic pleasure. That's really what matters in the end.

2x6spds, is that Onkyo M-282 ok with a 4ohm load(ie did you try it)?

I never tried the M282s with a 4ohm load. I don't think they were 4 ohm certified.

With my brief period running Axiom's A1400 with my M80's and using my Denon 3808 as a pre/pro I could hear a difference at all volume levels, albeit minor at low volume. The bass out of the M80s was more substantial at lower volume with the amp. That was pretty much the only significant difference there was at lower volumes, not really worth the price of an amp for low volume listening, IMO. At higher volumes the difference was across the board, better bass and the mids and highs were cleaner, more open and airy. The M80s even seemed to have wider soundstage.

On the other hand I listened to the A1400 amp at onn's and never really heard the same differences. Whether or not this difference was due to room configuration/layout I don't know so YMMV.

Jason, would you say that you had to crank things above your loudness comfort zone (beyond the loudest you typically listen) to really notice the differences?

I noticed an audible difference between my 3801/3808, and my Emotiva RPA-1 when running my Paradigm Monitor 9's or M80's. The RPA-1 just seems to bring the speakers to life; it's like a breath of fresh air as everything sounds cleaner at all levels.

Don't tell Pmbuko.

This would have been a good double blind test to do at the Axiom plant last month....an "off the shelf" 100 watt receiver vs an Uberexpensivestein Mach 2 amp running the same speakers.

+1 to what wheelz is saying.

When I had older Yamaha 5 chanell amp, adding an Emotiva UPA-2 amp made a startling difference with my then Energy Speakers.
Most multi channel amplifier measure WATT output power by the stereo.

Two Pioneer Elite AVR example specs.

VSX23THX
Front (stereo) 110 W + 110 W
Power output (1 kHz, 6 Ω, 0.05 %, 1 ch driven)
150 W per channel
Guaranteed speaker impedance 16 Ω to 8 Ω,
less than 8 Ω to 6 Ω (setting required)

SC-05
Multi channel simultaneous power output (1 kHz, 1 %, 8 Ω)
7ch total 700 W (SC-07)/630 W (SC-05)
Continuous Power Output (20 Hz to 20 kHz, 8 Ω, 0.09 %)
Front 140 W + 140 W
Center 140 W
Surround 140 W + 140 W
Surround back 140 W + 140 W
Continuous Power Output (1 kHz, 6 Ω, 1.0 %)
Front 180 W + 180 W
Center 180 W
Surround 180 W + 180 W
Surround back 180 W + 180 W
Total harmonic distortion 0.05 %
(20 Hz to 20 kHz, 130 W, 8 Ω)

SC-05 is continuous power. I love it, my M22, M2 and QS8 are unreal on the SC-05 (which I upgraded to from the VSX23THX).

Never heard of that guy .

No, as I said at low volumes the bass was what I could easily notice, but at normal levels there is a difference, the bass as mentioned but the vocals and instruments seemed to have better seperation, more detail and at high volume levels the music is just crystal clear, no distortion until I went well beyond anything anyone would try to listen to. I think I had the SPL meter at 105-110db and still pretty clean sounding.

It still comes down to diminishing returns, is the ~$4000 of the A1400-8 or ~$2500 of the A1400-2 worth the costs for this better sound. For some it is for others not so much. I still don't own one, maybe someday.

Thanks for the clarification. I read the subtle difference in bass at low volumes and the more dramatic difference at loud volumes but was curious about the "in between" or normal to moderately loud listening volumes. I definitely would like to own a separate amp someday but there are a lot of other things I need to put my money toward first.

External amplification can have benefits. It depends on a lot of factors the extent of its benefits, in some cases it could be none at all. Such factors as room size, listening distance, SPL levels, sensitivity, impedance curves most notably the dips all can play important roles if a more robust amplifier with more dynamic headroom is needed.

A great example of the need for external amplification is this thread right here.

http://www.axiomaudio.com/boards/ubbthreads.php?ubb=showflat&Number=326093&page=1


The OP noted "harshness" during loud/dynamic passages. In these instances those brief dynamic passages are creating audible distortion. In this case the receiver does not have enough headroom to reproduce those peaks without distortion. Moving up to a more robust external amp with more dynamic headroom and lower distortion will certainly have audible improvements in perceived sound quality.

Bill, you've in part misinterpreted the Pioneer specs and amplifier power ratings in general. All amplifiers sold in the U.S.(and effectively, Canada as well)have to comply with FTC(Federal Trade Commission)regulations in issuing a power rating for the units. In relevant part, it's required that FTC ratings be at the full rated power for at least five continuous minutes. Both of the Pioneer units that you mention are in compliance. They meet exactly the same continuous power standard, with the VSX23 being rated at 110 watts per channel and the SC-05 140 watts per channel. The difference between 110 watts and 140 watts is 1dB of maximum output. For example, a brief split second peak in very dynamic material could be played at 105dB using 110 watts and 106dB using 140 watts. That's all.

It can also be pointed out that this isn't, as an earlier reply characterized it, merely an individual who "believes" in a "theory". It's a very basic point of audio amplifier technology that power delivered with flat frequency response and inaudibly low noise and distortion(typical of even modest units these days)results in transparent amplification without any added audible coloration to differentiate the units. Enthusiastic and sincere contrary reports are available in abundance, but the only reliable way to determine such matters is by a controlled double blind test. Such tests have failed to show the differences reported in open hearing. When the name plates and price tags disappeared, so did the differences which were previously reported.

Yeah. I don't capitalize my screen name.

So in essence it basically like me trying to lift 200 pounds by myself, I may be able to do it, but not very well, I might jerk, slow down, or drop it, In other words causing distortion in the sound in the form of peaks or clipping. As opposed to 3 or 4 people picking up the same 200 pounds. It can be done simply, smoothly, and without much effort. Basically giving me clean, smooth distortionless sound. So I guess the question becomes at what weight limit can I easily handle without stress. How do you go about finding this limit? When does it become audible?

Static and crackling coming from the speaker are common stress signals which is noticeable to just about anyone. "Harshness" is another.

JH, analogies aren't really helpful, so don't be thinking about lifting weights. When the question is instead electronic amplification, the limits of the unit in question would depend on its rated power output capability and then whether the amount of power required by speakers of the given sensitivity for the maximum sound level used by the listener would exceed the output capability of that amplifier.

You know me well, buddy .

John,

If you look at my post again, you will see that the VSX23THX specs for watts are measured for two channels only (stereo). The SC-05 power measurements are across all channels.

Hooking up 7 speakers to the VSX23THX, will not get you 110W of power per channel. You will probably end up somewhere around 65-80W per channel. Adding an external 2 or 3 channel amp to the VSX23THX to drive your mains will garner you more total output per channel.

With a SC-05, you are in a different class of amplifier that CAN generate full power across multiple channels. The benefits of an external amp with an SC-05 would not be as noticable as with a VSX23THX.

This article measured the watts per channel output of an Onkyo TX-SR706B when driving 5 speakers. The published spec of 100WPC fell to 75WPC. I would imagine it would be much lower with 2 more channels added.

http://www.hometheaterhifi.com/power-amplifiers/824-emotiva-upa-5.html

That's a good thing to know. Right now I'm driving 4 M22's and a VP100 with the VSX23THX, using 2 channels. Whenever I have the money to do a second room with 3 M80's and 2 SQ8's then I need to get a bigger AVR for them. I'll probably go Denon though.

CatBrat - I like Denon alot. Almost went for the Denon 3310. When HDMI and audio soundtrack technology advance making my Sc-05 redundant, I will be ditching the AV receiver and going for a dedicated multi channel amp with a separate processor. A certain US company offers a 40% rebate for future purchases of their processors when specifications change. I would love to have the Axiom
A1400-8 fed from a dedicated processor.....

In my tyro, neophytic opinion, after asking the same question here and to other people, is that first and foremost it is getting enough power to drive your particular speakers, period. Depending on their sensistiviy, the desired SPL in your room size. Once that is achieved, its only a question of how clean the power is, Signal to noise ratio and THD, all of which most decenet amps/receivers have so low it is unoticable (am I somewhat correct?). I believe amps do not (or shouldn't anyways) color the sound in any way. They should be absolutely transparent, just the source material amplified and sent to the speakers. I always hear things like "Marantz has that nice warm, middy sound". I believe these to be generally fallacies. Let me reiterate again, I am an amateur in every sense!

DT, that sounds about right to me. I admit, I am still very curious/confused about reports like Jay's, but what you say logically makes sense to me.

Ken, I am not the only one that heard these differences in my room with the A1400, Mel also had a listen and heard that difference. My wife also heard the difference, she even said I could get an amp based on what she heard . I just have to pay cash for it after everything else is paid off, so basically it will never happen

I was very surprised to hear a noticeable difference. I even had my SPL meter in hand and adjusted levels to match from 3808 alone and with the A1400. Yet at Mel's place the differences were not noticed, I have no idea what made the difference other than the rooms themselves, my smaller area vs. Mel's larger room

I want to try a few other amps to see if I can get that same sound in my new house with a vary large open area to work with.

If you assume that solid state amps neither add nor detract from the signal, merely amplify the signal, then you may conclude that all solid state amps sound the same at the same output level so long as that output level does not provoke clipping or audible harmonic distortion.

In the real world, however ... that's a boat load of assumptions.

On the subject of boatloads ... I have some solid state amps - Anthem PVA 5, Kenwood KA9100, Harman Kardon PM665, Yamaha M80s (3), Integra M504. There are subtle differences. I don't know that any of these amps would differ in an A/B test (they might). I think you have to live with the amp for a while. You love some, you like others and some, well ...

Bill, that was the point; your post misinterprets the numbers in two respects: that only the SC-05 rating is "continuous"(the VSX23 and all other amplifiers have to use a continuous rating under the FTC regs)and that the basic FTC rating of the SC-05 is with all channels driven(both ratings, 110 and 140 watts, are at the minimum required two channels driven). A requirement to drive all channels simultaneously at the full rated power for at least five consecutive minutes is totally unrealistic in the real world of home listening. Such a condition essentially never occurs; the two-channel requirement is closer to reality, and most manufacturers, including Pioneer, use it. Audioholics, among others, has pointed this out in connection with their lab tests.

I too have an Onkyo 805 and was curious what adding a power amp would make. What I had on hand was an old Rotel RB-985MK2. The 805 seems to have more power, but I prefer the sound of the Rotel. So now it's the 805 pulling pre-pro and zone 2 duties while the Rotel pumps the juice for zone 1. A big bonus is that the 805 now runs a lot cooler than before while the Rotel only gets slightly warm to the touch despite relatively high volume movie marathons. IMHO YMMV yadda yadda yadda, hope this helps.

I think outboard "anything" but especially with amps will give one benefits already discussed in power output BUT, in my view,these benefits kick-in especially over the long haul. I went to outboard amps and later video processing along with an AVR used as a pre-pro back a couple of years ago and the benefits, to me, are just now forthcoming. With the mainstream companies bringing out new models at various price levels at a record pace every year, one can go a little crazy about this IF one wants to keep "up-to-date" with the current features.

Since the mainstream companies offer AVRs at different price levels, whether it is the mid/lower level or top line AVR, they generally share the same audio processing chips. The difference in price in the various models usually comes in amplifier power, more exotic video processing capabilities, some connectivity issues and miscellaneous items that often are superfluous to many buyers.

Having outboard amps(which never suffer from obsolescence)allows me to purchase the lower level AVR(as long as it has pre-outs)at usually considerable less money but still essentially getting similar results in audio quality.

It should be noted, I use my system almost exclusively for audio/video HT purposes so other forms of connectivity are of no value to me. Others may want the features only available in the higher end units and are willing to pay that considerable extra for them.