# Would you forego mono-blocks for more power?



## TypeA (Aug 14, 2010)

In a dedicated two channel rig, speakers are rated at 200 watts into 8 ohms and are unlikely to be upgraded anytime soon. 

Both amp options being identical in price and either option has the exact same power modules, would you go:

A single 2 channel 300 watt per channel (1,200VA transformer) amp 

Or

A pair of mono-block 200 watt (300VA transformer) amps?


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## robbo266317 (Sep 22, 2008)

TypeA said:


> A single 2 channel 300 watt per channel (1,200VA transformer) amp
> Or
> A pair of mono-block 200 watt (300VA transformer) amps?


Why does the 2 channel amp have a 1200 W transformer? Is it rated to drive higher power into a lower impedance?
The monoblocks combined in your example are limited to 600 W total.

I think more information would be useful.

Keep us posted,
Cheers,
Bill.


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## Jungle Jack (Jul 28, 2009)

Hello,
The 2 Channel description seems to be exactly what the Emotiva XPA-2 offers in terms of Power Transformer size. If the Monoblocks really do have 300VA Transformers in each, there is no question that I would rather have the 2 Channel Amplifier.
Cheers,
JJ


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## TypeA (Aug 14, 2010)

Interesting inputs, thanks. As usual JJ, you show excellent expertise in audio. Yes the consideration is either a pair of upa1 mono-blocks or a single two channel xpa2. Put the question to a tech at emotiva, assuming both options are the same price, his opinion was to go mono-block. Something to the effect of superior secondary performance and dedicated power supplies still makes the mono-block solution the best pick, even over the venerable xpa2. onder:


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## Jungle Jack (Jul 28, 2009)

Hello,
After reading the Bench Tests of the Primus's, I would agree to disagree with the person you spoke to at Emotiva. I was quite honestly surprised that the Primus's really are not as easy to drive as I would have imagined and believe the much more powerful Power Supply will come in handy.
Cheers,
JJ


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## TypeA (Aug 14, 2010)

I greatly appreciate your opinion JJ, I assume you are referring to the 360 bench test done by stereophile wrote in 2005. This is the quote I thought most applicable, but then Im a rookie... 



> However, with an impedance magnitude that drops below 4 ohms in the lower midrange and high treble and an electrical phase angle that is extreme in the upper bass (fig.1), the speaker needs to be partnered with an amplifier or receiver that can drive low impedances with aplomb. (The combination of 5.2 ohms and –45º phase angle at 93Hz will tax amplifiers rated at 8 ohms.)


Plan on pulling the trigger very soon on my first ever amp but I do have time to drop them a line with a link to the graphs, see if they still disagree. Not saying either one of you is wrong.

http://www.stereophile.com/content/infinity-primus-360-loudspeaker-measurements


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## vann_d (Apr 7, 2009)

Hmm...

Which has the highest profit margin? I bet I can guess which one (or two) the manufacturer would recommend...


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## TypeA (Aug 14, 2010)

I suppose thats a possibility vann, but of course I hope not...


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## vann_d (Apr 7, 2009)

I'd like to think they'd give you a recommendation with your best interests in mind but, unfortunately, that is usually not the way the business world works.

The good thing is that you can post in this forum and get an unbiases opinion or two, which you have!

Either way you're gonna end up with some cool toys to play with.


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## Jungle Jack (Jul 28, 2009)

Hello,
While I am quite fond of Monoblocks, the UPA Series is Emo's current Entry Level while the XPA's are their Flagship Amplifiers. Add to that the XPA-2 uses the identical Toroidal Transformer as the 5 Channel XPA-5 and not a great deal less Filter Capacitance and it really makes it hard for me to advocate the UPA over the XPA-2 if strictly an either or proposition.

Emotiva is getting ready to change their Amplifier Lineup due to the acquisition of Sherbourn and the current Models will soon be gone. I am not sure if this is going to be a good or bad thing. What I can say is that the XPA-1 and XPA-2 are the 2 Emotiva Amplifiers that I am especially fond of.

I am quite partial to Amplifiers with large Transformers and high levels of Capacitance. Much of this is due to how much of a difference they make when driving Martin Logans and other difficult to drive Speakers.

What is nice about purchasing Amplifiers that are stable into low impedances and high output is that there is never a concern when shopping for Speakers. I have used the same Amplifiers for around a decade and have used Paradigms, Thiels, MartinLogans, Dynaudios, and many others during this time without ever having to be concerned about if I had enough power.
Cheers,
JJ


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## TypeA (Aug 14, 2010)

I must admit this is a dome scratcher, much pondering and flip-flopping has occurred over the last day or two (man I love this hobby). 

Frankly, I find the idea of a pair of mono-blocks driving my very first two channel rig as a very intoxicating proposition. On the other hand, Ive heard nothing but glowing reviews of the xpa as not only having greater dynamics and impact (obviously) vs the upa but in it also being a more _neutral_ amp, the upa being characterized as warm and more laid back by comparison. Since deciding on a budget and a maker (anything other than emo with a emo processor would actually bug me, OCD anyone?) I have been leaning towards my first mono-block almost exclusively. However, after reading most all the reviews and direct comparisons of the two amps in question, as well as considering input from JJ and emotiva, Im now officially leaning towards the xpa instead, go figure eh???


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## Jungle Jack (Jul 28, 2009)

Hello,
The XPA-2 does have a 2 times larger Power Supply per Channel and more Capacitance. I really think you will not regret the XPA-2. I wish the XPA-1 was less expensive, but it is still quite a good deal. However, you do have 30 Days to Audition it and worst case, you are only out for Shipping back.
Cheers,
JJ


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## GranteedEV (Aug 8, 2010)

The UPA-1 is essentially a monoblock version of an XPA-3 or XPA-5, with a slightly better power supply relative to the number of channels. It uses most of the same output stage circuitry, just a bit more current capability.
The XPA-2, is a step up in both output voltage and high current capability. 

FWIW I do not personally consider the primus' to be difficult loads for any amplifier besides entry level receivers. Even a mid level receiver around $900 should have little difficulty with it based on my experience. It doesn't seem to jive with the stereophile measurements but I think that goes to show you how somewhat overstated the "need" for separates amps really is.

Jungle Jack is right though - when you go the commercial hi fi passive loudspeakers route, you find eventually yourself running into speakers that satisfiy some of the following criteria:

Low impedance dips (IE 2 ohm) especially in the bass range (~100-300hz)
Difficult phase angles (this in particular taxes amplfiiers.. it can cause a some speakers to present really high current demands)
LOW sensitivity (IE 85db/2.83v/m)

often at the same time. Speakers like this can make amplifier differences apparent. If you want to future-proof yourself, then the XPA-2 is a superior choice.

Keep in mind that monoblocks, while fun, do not necessarily offer audibly superior performance. I don`t know why I prefer them - i think it`s totally not rational as any channel crosstalk advantages don`t take into account pre-amp crosstalk.

Personally I prefer active loudspeakers anyways :innocent:

My personal choice for an amp to drive difficult speakers would be the Hypex UCD700 modules. There are a few people who make them in completed form as well. The biggest thing with these is supreme efficiency (which is important with high current, higher voltage devices). Built accordingly, you can get these things stable with a 1 ohm load, and they won`t weigh as much as an anvil because you can skimp on heatsinking, relatively.


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## Theresa (Aug 23, 2010)

My L/Rs use the 4 ohm Revelator 7" drivers while my center uses the 8 ohm version. The Emotiva XPA-3 drives them with a UPA-5 driving the tweeters and surrounds. Never comes close to clipping. Some speakers, as mentioned above, are difficult to drive but I don't think these are even though some are 4 ohm.


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## Jungle Jack (Jul 28, 2009)

Hello,
I gave my answer strictly as which I would rather have as I reckon the OP started it as. I was surprised that the Primus's were a bit more difficult to drive than I would have expected Speakers that the vast majority of time would be powered by an AVR.

From the Stereophile Review: The Infinity Primus 360 was significantly more sensitive than average, at an estimated 91.5dB(B)/2.83V/m. Though this is slightly lower than the specified 93dB, the 360 will still play very loudly with only a few watts of input power. However, with an impedance magnitude that drops below 4 ohms in the lower midrange and high treble and an electrical phase angle that is extreme in the upper bass (fig.1), the speaker needs to be partnered with an amplifier or receiver that can drive low impedances with aplomb. (The combination of 5.2 ohms and –45º phase angle at 93Hz will tax amplifiers rated at 8 ohms.)"

Granted this was for the Floorstanding 360 and not the P162 which only presents a somewhat difficult load at the top of the Frequency Range. I am guessing with the newer xx2 Series, they made the Impedance Load more AVR friendly.

Moreover, another factor is the size of the Room, preferred Listening Volume, and where the Speakers are crossed over. Regardless, I just think it makes sense to have the most current reserves if the choices are close enough to where it is one or the other.
Cheers,
JJ


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## GranteedEV (Aug 8, 2010)

Jungle Jack said:


> Regardless, I just think it makes sense to have the most current reserves if the choices are close enough to where it is one or the other.


Do I agree with this on paper? ABsolutely. What I don't agree with, is ever spending more on amplification than on Speakers. And that's what would happen if you were driving a ~$300 pair of (otherwise nice) speakers with a ~$900 separates amp. Is that perhaps a knock on harman's design team? On paper maybe, but just not in my experience. I don't know if more recent versions of the primus (the current being the P363) have easier loads, but even a 5 ohm load with a 45 degree phase angle is not too crazy... a good mid-level receiver like a Marantz or Yamaha shouldn't have difficulty with the load - IMO.


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## TypeA (Aug 14, 2010)

Thanks for all the inputs. Setting aside the numbers, real-world direct comparisons are few and based only on user reviews.... 



> The UPA-1 sounds extremely clear, natural, and provides outstanding detail. I've listened to the XPA-2 many times and it is a very fine amp, but I think the UPA-1 just sounds better, it's a bit smoother, more natural and musical and with detail resolution 2nd to no other amp that I've ever heard.
> 
> The XPA-2 does come accross as being more powerful and dynamic while still being detailed and the UPA-1 is a little more "seductive"(dead quiet background, very detailed and natural sounding, yet still has great dynamics).


Another:



> ...the XPA-2 has noticeable more bass power. What I mean by this is that the bass is more noticeable in direct comparison to the UPA-1 and having more weight in the overall presentation. But this does not mean more control, as both have a very good control over the lower end. This is and stays the advantage of the XPA-2. So if you main obsession is bass, stop reading here, buy an XPA-2 and never look back.
> 
> The UPA-1 is a little audiophile dream. This is an amp for serious listening. The UPA-1 has the ability to reproduce music more defined and with a stunning transparency and resolution over the XPA-2. It adds a little depth and width to the stage and is dynamically incredible (I was most astonished by this). Music just flows and is charming. Speakers disappear better than with the XPA-2 and music just “is” in the room. This is a very musical amp.
> 
> Two sum it up, letting apart my binding issue, the UPA-1 is a fine mono amp and its concepts puts it ahead of the XPA-2. If best possible music reproduction is what you are looking for I strongly suggest you give the UPA-1 a try.


Performance seems to fall in line with specs, or what you would expect given the pedigree and design...

Page 1 and 4
http://emotivalounge.proboards.com/index.cgi?board=amps&action=display&thread=9714&page=4


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## Jungle Jack (Jul 28, 2009)

Hello,
I would not put a great deal of stock in a Forum that is Owned and Hosted by the Manufacturer. Way too much of a Conflict of Interest. Moreover, they delete even the slightest Post that does not glorify Emotiva. Granted, they have a legion of fans who often come off as somewhat cultish to me, but I suppose that is just an opinion.

What I do know is that it is hard for me to believe that an Amplifier with twice as large of a Power Transformer and more Filter Capacitance would not be superior. With a well Designed Stereo Amplifier, Crosstalk really should not be a real issue. While Dual Mono Construction is ideal, a Stereo Amp that is not can still be fantastic. To me, the best part about Monoblocks is the ability to use short Speaker Cable Runs more so than the complete absence of Crosstalk.

The Primus's are really special Speakers are preform far better than the vast majority of Speakers priced near them. While I completely agree that in theory more should be spent on Speakers than on Amplifiers, when you have Speakers you are pleased with, I do not see an issue with spending more on the Amplifier when it can last you for well over a Decade and give you a great deal of latitude of Speaker choices in the future.

Again, I am just sticking with the original Post. In which, the question is would you rather have a more powerful Stereo Amplifier or less powerful Monoblocks. In this case, I am not concerned with the Speakers used and am simply looking at the question itself.
JJ


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## GranteedEV (Aug 8, 2010)

Jungle Jack said:


> What I do know is that it is hard for me to believe that an Amplifier with twice as large of a Power Transformer and more Filter Capacitance would not be superior. With a well Designed Stereo Amplifier, Crosstalk really should not be a real issue. While Dual Mono Construction is ideal, a Stereo Amp that is not can still be fantastic. To me, the best part about Monoblocks is the ability to use short Speaker Cable Runs more so than the complete absence of Crosstalk.


In this case, the difference likely being described is either

-Less IMD or crossover distortion in the lower powered unit (hence a cleaner FFT spectrum especially in terms of 3rd and higher order harmonics) which means supposedly audible superiority at lower volumes, moreso the same sound at higher volumes.
-a big... imagination


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## TypeA (Aug 14, 2010)

Thanks to you both, this has been a highly informative and enlightening thread. Certainly agree to take the UPA-1 vs XPA-2 shoot-outs with a big grain of salt and consider the forum sponsor being emotiva...

That having been said, heres another very interesting match up just the same...



> With the UPA-1's backordered, I was slowed in my plan to compare them to the XPA-2....that is until my buddy scored a pair on Craigslist! Better still, he planned to "probably" give them to me after we checked them out. So here's my comparison, just hours after several hours of listening to both.
> 
> Previously we had compared the Rotel 1090, XPA 2 and 3 along with the Odyssey Stratos using a Denon Receiver as pre-pro and a very nice and sweet sounding Rogue Metis tube preamp. Also on hand...a brand new Manley Stingray II amp which is a benchmark for soundstaging.
> 
> ...


http://emotivalounge.proboards.com/index.cgi?action=display&board=amps&thread=11444&page=1


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## GranteedEV (Aug 8, 2010)

There is absolutely no scientific reason a lower powered amp should have more control at bass frequencies. Both are extremely LOW output impedance solid state amplifiers. 

These people just have too much imagination, and don't appear to apply any actual CONTROLS to their listening tests. 

Same with the absolutely dubious claims of "better imaging" and "better soundstage". Gene at Audioholics said this about the XPA-2:



Gene Dellasalla said:


> This is the best crosstalk measurement I’ve ever measured in an amplifier and despite the XPA-2 having a singular centralized power supply, the channel to channel isolation was on par with the best monoblock amplifiers I’ve ever seen!


Yet i'm expected to believe that the monoblocks just magically sound better?

:rolleyesno:

One thing about sighted listening tests of amplifiers - most of these people don't have much of any idea of what they think they're hearing or whether they're even hearing a difference. Most of their opinion is formed based on preconceived notions but totally disappears when you throw in controls like blind listening, level matching, etc.

Any time you hear any of the following words to describe solid state amps with flat frequency response and low output impedance:

"warmer"
"brighter"
"deeper"
"wider"
"more neutral"
"a unique sonic character
"darker"
"more air"
"more detailed"

just roll your eyes and turn around. Even if there's differnces between amps, they're audibly negligible and unreliable AT BEST.

the only actual ways to describe solid state amps:

"Capable of driving x loudspeaker load"
"Low IMD"
"Low crossover distortion"
"Low output impedance"
"Loses/Keeps composure at high volumes"


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## hgoed (Mar 22, 2010)

Why is it that I never see people posting measurements of the power they feel comfortable surrounded by? It's pretty easy and cheap to set your system to your favorite listening level, measure the dB output and calculate the power needed. Then you can look at the amplification needed to drive that power at distortion levels below your own sensitivity (people hear a lot less stuff than they lead themselves to believe--just look at repeatability in precise auditory tests). It's also pretty easy to use decimal points and lots of zeros to make one thing look better than another, but at least from my experience, that doesn't have any practical value.

To me, it's not how much money you're willing to spend, or who's marketing you'd like to buy into, it's how to best fit your needs with little excess. Spending more on an amp, for .001% benefit means you have that much less to spend on speakers, discs, or even better popcorn. What's the goal?


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## TypeA (Aug 14, 2010)

Very interesting. Bummer there are zero actual descriptions of the mono-block.


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## Jungle Jack (Jul 28, 2009)

Hello,
If that Post from the Lounge was Posted on certain Forums it would get ultra ugly. I am not a huge believer in Solid State Amplifiers sounding a great deal different from one another when Level Matched. There is even a 10,000 Dollar Prize for anyone who can hear the differences between 2 different SS Amps at the same levels that has yet to be claimed.

I do believe in Parts/Build Quality and Stability into low Impedances, but have owned many SS Amps over the years without ever noticing giant changes in "warmth, pace, rhythm, etc"

**I did not see the other Replies until after my Post, but completely agree with them**

Cheers,
JJ


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## TypeA (Aug 14, 2010)

Thats my bad for giving those user observations any weight at all. As mentioned theres a couple of xpa2 pro reviews but nary a single one on the upa1 (letalone a shoot-out), just claims from Lonnie on down that there is a perceived (and seemingly very consistent and noticeable) sound difference between the two. Ive thoroughly read of the $10k contest and most all pundits clearly state there is no difference between amps aside from what GranteedEV mentioned. Really glad I asked the question, this has been a great learning thread.


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## TypeA (Aug 14, 2010)

My final choice was based on a unforeseen price change and physical dimensions, I ordered a new pair of upa-1s. 

Buying used from audiogon seemed to be a wash in price, apparently gear a year or two old is worth almost as much as new (with often shipping and/or paypal fees increasing the selling price to almost new prices). Considering the manufacture had a sale this weekend on the upa1's (and as always free shipping) my total price was $628 shipped for the pair, verses $799 for the xpa2. I think, in the long run, the upa's will be easier to live with (1" shallower and 30 lbs times 2 verses a 80 lb gorilla) and I see the 200 wpc being sufficient for all but the most demanding speakers, especially at the moderate listening levels Im known to frequent. Thanks again for all the help and advice on this guys, it was greatly appreciated.


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## Jungle Jack (Jul 28, 2009)

Hello,
Tyler, congratulations and I hope that you enjoy them. Again, with Emotiva purchasing Sherbourn, Emotiva is about to revamp their entire Amplifier Lineup. A great thing about purchasing them from Emotiva is that you have a Return Window should you decide that you need or want the additional power of the XPA-1.

Another ancillary benefit of adding the UPA-1's is that you are also lessening the burden on your TX-NR3007 by having to drive two fewer Channels. There are many fans of the UPA-1 and I hope the proclamations are justified.
Cheers,
JJ
'


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## GranteedEV (Aug 8, 2010)

Jungle Jack said:


> Another ancillary benefit of adding the UPA-1's is that you are also lessening the burden on your TX-NR3007 by having to drive two fewer Channels. There are many fans of the UPA-1 and I hope the proclamations are justified.


I wish I could say that would be a benefit for myself :rolleyesno:

WIth dual 2kW pro amps running my subs, I'd first need to turn that 15A line into at least a 20A line before I can even thing about adding a good separates amp


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## Jungle Jack (Jul 28, 2009)

GranteedEV said:


> I wish I could say that would be a benefit for myself :rolleyesno:
> 
> WIth dual 2kW pro amps running my subs, I'd first need to turn that 15A line into at least a 20A line before I can even thing about adding a good separates amp


Hello,
I totally understand the feeling. I live on a Barrier Island just off Sarasota (Siesta Key) and am Renting currently so I cannot add 20A Circuits to get the best out my Amplifiers as well. The 8008bb is truly limited by the available power from the Outlet. As are my HCA-3500 and to a lesser extent my HCA-2205AT.

I would imagine the Bass in your HT is amazing. Using a ML Descent i and Depth in my HT has resulted in tight, quality Bass, but it does not have that infrasonic punch that the IB Setups with Amplifiers like yours.
Cheers,
JJ


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## TypeA (Aug 14, 2010)

Im not sure how demanding Ill be as Im pretty moderate with my volume but the umc1, twin upa1s and a blu ray player will be sharing a 40A circuit. Ill make sure and turn off the window ac unit on that circuit before any serious listening but I would imagine moderate levels will share the circuit fine. Like JJ im a renter and pretty limited in options...


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## Jungle Jack (Jul 28, 2009)

Hello,
To add insult to injury, the day I moved across the Intercoastal Waterway, State Farm dumped my Renters Insurance. I had previously lived on the Peninsula and even with 75,000 Dollars of Coverage, the Premiums were quite reasonable. After State Farm dumped me, I called several Independent Insurance Companies and the Premiums were around 10,000 Dollars a year. I have been looking for a Suburban or Excursion for use as an HT Hurricane Evacuation Vehicle and will probably buy one pretty soon.
Cheers,
JJ


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## Dwight Angus (Dec 17, 2007)

Jungle Jack said:


> Hello,
> While I am quite fond of Monoblocks, the UPA Series is Emo's current Entry Level while the XPA's are their Flagship Amplifiers. Add to that the XPA-2 uses the identical Toroidal Transformer as the 5 Channel XPA-5 and not a great deal less Filter Capacitance and it really makes it hard for me to advocate the UPA over the XPA-2 if strictly an either or proposition.
> 
> Emotiva is getting ready to change their Amplifier Lineup due to the acquisition of Sherbourn and the current Models will soon be gone. I am not sure if this is going to be a good or bad thing. What I can say is that the XPA-1 and XPA-2 are the 2 Emotiva Amplifiers that I am especially fond of.
> ...


Yeah I agree. I have been replacing or upgrading avr's every few years. Now that I have outboard amps I am good to go for many years to come and need not worry about speaker compatibility


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