Official Emotiva XPA-5 Owners Thread - Page 3

Sathron -- knowing you have a Denon AVR, was it worth the extra $$ for the XPA-5? What spkrs. are you running with it (F/L/C/SR/SL)?
Did you hear much difference before vs. after installing it? Did it make any difference with your subs?

Secret -- what is causing this Hiss in the XPA-5? Did you chat with Emotiva about it, and what did they say? Must be high freq. hiss thru the tweets -- is this noise? Have you put in a CD, and pause it, then crank up power a lot and is the hiss still there?

Household line 120V 15A can deliver max continuous power of (120x15)=1800 WATTS RMS

Typical Linear A/B Amplifier is between 40-50% efficient

Take the maximum 1800 watt power from wall outlet and multiply by amp efficient (let's say 45%)

1800x.45=810 the max power an a/b am can deliver on a continuous basis - assuming the amps power supply can consume the entire 1800 watts without causing the transformer to overheat or go into thermal meltdown

5 channels driven 810/5=162 watts per channel

(SINCE EMOTIVA IS GETTING MORE THAN 200 WATTS RMS PER CHANNEL -- THEIR A/B DESIGN MUST BE MORE EFFICIENT!!)

7 channels driven 810/7=116 watts per channel

Note:Rail switching amps (class G/H) can be 65% efficient and Class D switching amps can be 90% efficient assuming proper power supply Is used.

So 65% efficiency (class G/H)=1800x.65 = 1170 continuous watts from outlet

5 channels=1170/5=234

7 channels= 1170/7=167

90% efficient (Class D) = 1800/.90=1620 continuous watts

5 channels=1600/5=320

7 channels= 1600/7=228

This gives us an idea of some of the limiting factors that determines the maximum continuous wattage an amp can deliver to all channels (wall outlet, efficiency, number of channels driven)

To look at a real world exampleEmotivas Class H 7x200 watt channel amplifier (60%efficient) the MPS-2 ($1700) should then only be able to deliver 167 continuous watts per channel assuming the power supply is up to snuff. Keep in mind when you get into AVR's you need to take into account the wattage that is used up by the processing and video demands as well.

Now most of us would probably be looking at a UPA-7 which is a class A/B (45%) efficient. So you're looking to get 110 watts continous max out of each channel.

So my questions:

what is the benefit of going with a 200 Watt x 7 channel class H amplifier vs a 125 watt x 7 class B amplifier if your maximum continous wattage is limited by the power coming out of your wall outlet? My guess would be that you are only going to get 40-50 watts per channel more (continuos 7 channels drive) by going with the 200 wpc vs 125 wpc.

What would be the point of a 400 watt x 7 if there is no way in heck your amp can draw enough power from the outlet to support those numbers in the first place?

Should we then pay more attention to the efficiency ratings, THD, and power transformers of a piece of equipment vs the posted watts per channel to get an idea of what it is really capable of?

If you want your continuous 200 watts you better get class D. Anyone know how much those cost?

Edit...In any event a 200 watt seperate amp is going to hurt your ears. In the real world situations, an amp is never really called upon to delvier full continous power to all channels for prgramming content (music, DVD, etc..) The point is the manufacturer says 200 watt per channel X 7 which doesn't appear possible. They shouldn't be marketing with WPC numbers...They should be marketing with efficiency ratings, THD and power supply capabilities. After all, you can only get 1800 watts max continous from you wall (unless you change your circuit breaker) so it would make more sense to get the amp that is most efficient, meaning it can make the most out of those watts...So i would take a class H 100 watt amp over an Class A 125 w amp.

Such is the basis of the amp vs AVR argument. in most cases the Amp is going to be more efficient with those 1800 watts then the AVR becuase it has better transformers and less stuff to power on it..

Wow, I have the XPA-3 and never had all these issues with the manual I guess. I don't obsess over that level of detail

With reference to the above post on power talking about class AB efficiency...it's inaccurate to talk about really low efficiency when you are talking about max or near max power. As the amplified signal is getting close to the rail voltage, efficiency goes up.

I can do the math if you insist, but it's simple enough math...

Also, when you talk about max power, being produced the draw from the wall does not have to match that power, as the reservoir caps can help make up for deficiencies. And you can pull more than rated power from the wall for short periods of time (fuses don't blow right away - when the amp's caps are charging, it's probably pulling a lot of current for a short period of time, just like a light blulb would, before the heating of it's element starts increasing resistance.)

Also, the VA rating of transformers is their max safe rating for continuous operation far as I know. Which means they can pull more voltage from the wall than the VA rating would indicate perhaps. At some point, the wall voltage is probably the limiting factor IF the amps own limiter circuits are not engaging (which they probably are during a continuous sine wave test with all channels driven.)

In conclusion, I am pretty sure the XPA-5 will be louder than the UPA. But it may not be dramatic, because at best, with double the power, you get 3 dB more SPL per channel.

All electronic circuits have noise. It's physics at work. You can reduce, but not eliminate it.

By various accounts, the XPA series is not the quietest amp out there. Better than my Crown amp though. I can hear hiss from 18 to 12" from my Klipsch speakers with that thing connected.

MichaelJHuman -- before I planned on purchasing the XPA5, I wanted to compare the manual with their Emotiva web site, and thought all the data would be the same, of which it should be... Wow, it was like reading a manual for a Chevy, but was talking about a Ford within -- that was hard for me to believe with all the great write-ups on the forums, but that was the True Case. In fact, the User's Guide for the XPA-5 shows 250 Watts into 8 Ohms (0.04% THD), and the Web shows online 200 Watts into 8 Ohms (0.1% THD), and way to many other issues to mention here, so I was really confused -- All I knew was that it was not a Ford or Chevy (Laughs)... For your XPA-3 did it come with a "User's Guide" or what is the title of the Manual it came with? Maybe they have different manuals for the product, I don't know. Only have data off the web right now, since the XPA-5 is Backordered.

I think your best guide to the XPA series is the data they published from their audio analyzer (such as power and THD at various output levels.)

Assume they ran a sweep, not a 5 min continuous test though. In other words, it held the the power output you see, but not for minutes at a time.

Some would say that's not unreasonable. My only problem was that I thought that's what the FTC rule dictated (5 mins of continuous operation at rated power, with a preconditoning period.)

I am not sure they have come out and said 'yes we ran a 1 second sweep to get that data.' But evidence suggests that is indeed what they did.

It's a LOT of power, though, IMO. Based on what I know, I would say someone would have to have usual needs for the XPA to be lacking in their setup from a power perspective. Consider that it does not have to output 5 channels of identical sine waves in reality for one thing. So it may be able to do better than 200 watts dynamically.

All amplifiers have a noise floor. Dedicated amplifiers are usually slightly louder than the amplifiers inside of an AVR. Pro amps are often the noisiest. There are detailed things that cause noise floor hiss. I can't really name them all. The bottom line is that an amplifier is really a stupid device. It will amplify any sound that is present. Thats really its job. This includes noise from power supplies among other things. I believe the hiss you are hearing is normal and nothing to worry about. Unless you can hear it from across the room.

MichaelJHuman -- would you run an additional XPA-2 for Surround Backs, or just run those off the Denon, and let the XPA-5 run the F/L/C/SL/SR -- I really don't feel that spending the extra $ on the XPA-2 vs. letting my Denon run them is worth the extra money, but would only look nice in rack. Since I feel the Denon would run the Surround Backs easily once I get the load (5 speakers) off the Denon and over to the XPA-5. Anyone have comments on this post, please do reply. Thanks.

If you get an XPA-2 consider using it for your mains. Then use the XPA-5 for your center, surrounds, and rear surrounds. Im not sure what kind of mains you have. Thats what I would do. Im using a similar amp configuration except Im using a pair of XPA-1's for my mains and an XPA-5 for my center, surrounds and rear surrounds. It really sounds good.

Mcintosh LS360's
A foot away I can hear the hiss but never measured how far out yet.
Tweeter only hiss.

Emotiva recommends against leaving amplifier channels unused, because it would allow used channels to pull more power than is good for them when stressed. I surmise something similar would be true for under-used channels, too.

I use an XPA-5 for L/C/R/SR/SL and receiver amplification for surround back and DSX wides.

I would consider just using the Denon for the rear surround speakers. You are only asking it to amplify two channels. And it could be argued they are less critical than the other channels. Another option would be to use the Denon for the surround (not rear surround channels.) One reason to consider this is if your surround speakers are really close to your listening position, such that they need very little power.

I am powering my surrounds with my Yamaha Z7, my rear surrounds with my Crown. That leaves the XPA-5 for the front channels.

With the XPA-2 going out the door at $800, and with the Surround Backs alot closer to the listening position, am going to drive the SB's off the Denon and see where we are at, at that point in time. Then maybe next grab a couple speakers for Front Wides and drive them off the Denon also, as it seems to me most all like the Front Wides vs. the Front Heights. Then, if this is weak for SB's and Wides, will get another XPA (Of course, after the Uncle Pays Me!!) for the FL/FR (Klipsch RF-82II's) and drive all the rest off the XPA-5. One baby step at a time first here... Research, Spend, Hookup, Listen & Listen... then Spend again only as Required (Maybe in 1.5 yrs. the XMC-1) after all bugs are exterminated within it, and I am sure there will be more than one bug floating around within it, and after the Wifey gets new Shoes I'm told.

I love my 5. Now on to a couple of UPA-1's and a pair of Maggies

ReneV, thanks and that is exactly what I am going to hook up here, once XPA-5 arrives (back-ordered).

drewh01 -- why not just one XPA-2 instead?

I like the idea of a monoblock setup and the benefits that it provides.

I can hear tweeter hiss from all my theater seats with a 5.2 set up and 4ohm speakers.

Is this with all the XPA-5 amps?

Im considering in buying upa7 because is cheap now and i want to match it with one of this: a marantz sr5005 or onkyo708. I have not decided yet. I owned marantz and onkyo and i prefer marantz sq. Onkyo sounds bit harsh at hi vol; never happened on the marantz. Wondering if i get upa on an onkyo; does the harsh will get rid?

Another thing I dont understand is why this upa7 is so big and handle 125w per channel while the marantz 6005 or oknyo 707 can handle 110w per channel with same amount of 7 channels plus do processing and its smaller??????

The salesman's smile can be deceptive...

That Onkyo will only offer you the advertised 110w for a speck of time, with only two channels driven. Add seven channels, all driven and you would weep if you knew the actual power being sent to your speakers...

The above truth broke my heart years ago.

Ok; understood now why they are bigger. Thanks for that. And about matching UPA7; better with Onkyo 708 or Marantz 5005??????.... I dont like the tweeters too bright when playing at Onkyos AVRs. I love it how it sounds on Marantz; but same question; if I add UPA7 to Onkyo; does the "too bright" will be eliminated?

I am sorry, I just don't know for sure. I do not own a UPA 7, nor have I heard an amp'd Onkyo.

I do know that the further back, in the chain of gear, you can place the source, the warmer it gets. So to say, Disc player - Receiver - Amp - Speaker, will be warmer in theory than a chain without an Amp...and warmer still than set up that plays straight from disc. I don't know why, or how this happens though. Just my experience.

That said, I save a lot of my CD's to the hard drive of the PS3 and listen to long play lists; but I often find a much warmer sound from listening to my Disc Changer with it's analog connections (RCA unbalanced).

Odd theory, no offense. If that's true, and warmth is a good thing (whatever you mean by warmth,) we should all run our systems through numerous amps. Actually, with many types of music, some of the audio already traveled through many analog devices before the final bits get written.

Well...like I said I have no explanation

I just found it to be something I was noticing...then again, my teacher told me kissing girls would get them pregnant.

Any ideas why I might hear something like that? I would welcome (and likely learn) an opinion as experienced as yours?

I could best describe the warmth as "not being as crisp or cold" as digital can be...ahahaha I am social worker, so maybe I just hate computers and think they are life sucking digital silicon vs. older technology...ahahaha maybe I am outta my tree!

DPS, Yes I think it was worth it. The Denon (AVR 4810) does a great job by itself (especially calibrated with Audyssey and running DSX), but it sounds less strained and more detailed. Here are the speakers I'm running...
HSU ULS15 Sub, Polk RT55i Mains
Polk CS400i Center, Polk RTi6 Front Height Speakers
Polk LS f/x Surround speakers
Polk RT 15i Surround-back speaker

To answer the last question...yes and no. I did hear a difference after installing it..again, less strained and more detailed. I didn't notie a majore difference with my sub. I am running the Fronts, Surround(not rear surround) and Center with the XPA-5, the front heights and the rear surrounds are running off the Denon.

Thanks angelsfann...the picture may be a little misleading..there's about 2 1/2" above the amp...not as much as there should be, but it doesn't get that warm at all...it is open in the back as well.