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Emotiva XPA-2 driving 2 Ohm load (Infinity RS-II)

Seppo

Seppo

Super Member
My vintage Infinity RS-IIs are a double whammy for weak amps, having low sensitivity, and very low impedance across a wide frequency range. The impedance in RS-II's drops down to 2 Ohm above 5 kHz and never looks back, and moreover hangs around 3 Ohm around 100-150 Hz (where there is a lot of action when the higher woofer and all three midranges cross-over), and then the sensitivity is lowly 85.6 db. For details, please see the lab test article in this thread:
http://www.audiokarma.org/forums/showthread.php?t=621716

Now, could Emotiva XPA-2 handle the RS-IIs? I do not need insane volume levels (as the listening room is mid-sized), but I want to have good headroom at quite high volume levels so that these fantastic speakers can deliver to their full potential.

People report good results using clean 200 wpc at 4 Ohm vintage solid state amplification, and excellent results using clean 400 wpc at 4 Ohm amps (ala Perreaux PMF2150B, or Krells, and Thresholds) driving these speakers. My current Onkyo A-9070 (clean 140 wpc at 4 Ohm) does a good job, but goes to protection at a bit louder volumes. I bet that even at lower volumes it is not able to feed all the current as needed.

Any thoughts / experiences with Emotiva XPA-2? It looks like a great deal...
http://emotiva.com/products/amplifiers/xpa-2
 
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For no other reason than I haven't changed out the present amplification in the audio cabinet, I currently power my RSIIs with a modest Yamaha A-1020 integrated(rated 125 per) and the synergy seems quite good.
 
Seppo said:
My vintage Infinity RS-IIs are a double whammy for weak amps, having low sensitivity, and very low impedance across a wide frequency range. The impedance in RS-II's drops down to 2 Ohm above 5 kHz and never looks back, and moreover hangs around 3 Ohm around 100-150 Hz (where there is a lot of action when the higher woofer and all three midranges cross-over), and then the sensitivity is lowly 85.6 db. For details, please see the lab test article in this thread:
http://www.audiokarma.org/forums/showthread.php?t=621716

Now, could Emotiva XPA-2 handle the RS-IIs? I do not need insane volume levels (as the listening room is mid-sized), but I want to have good headroom at quite high volume levels so that these fantastic speakers can deliver to their full potential.

People report good results using clean 200 wpc at 4 Ohm vintage solid state amplification, and excellent results using clean 400 wpc at 4 Ohm amps (ala Perreaux PMF2150B, or Krells, and Thresholds) driving these speakers. My current Onkyo A-9070 (clean 140 wpc at 4 Ohm) does a good job, but goes to protection at a bit louder volumes. I bet that even at lower volumes it is not able to feed all the current as needed.

Any thoughts / experiences with Emotiva XPA-2? It looks like a great deal...
http://emotiva.com/products/amplifiers/xpa-2
Click to expand...

There are some threads here on AK that states the Emotiva amp was put into protection mode driving some of the Larger Infinity speakers. I recall, a couple of years ago I went to the Emo forums and asked if the Emotiva XPA-2 was stable into a 2 ohm load, and moreover could it drive Kappa 9s. Nobody gave me an affirmative answer on that one. That said, you can buy the amp and try it out and if it doesn't perform as you would like, send it back. Emo supposedly has a good return policy.
 
Yeah, I remember reading about that, also some of the big Axiom speakers putting the XPA amp into protection.

I'm not sure about these days, maybe the 2nd generation amps have been tweaked some. But many manufacturers proudly state it when their amps are 2 ohm stable, it's kind of bragging rights. You've got very unique speakers, as you've found with the Onkyo amp.
 
for_p1 said:
Emotiva might be OK. But I would rather go with Krell, and probably Bryston.
Click to expand...

These would drive it for sure. Can probably throw Parasound into the mix too. I've always longed for the A21 Halo amp, or cheaper the 2200 0r 3500 amps. In fact, I sent an email off to Parasound inquiring on the A21 ability to drive a 2 0hm load. I was surprised when the owner of Parasound answered my email and stated the A21 can drive a 2 ohm load all day without breaking a sweat.
 
Thanks for all the suggestions. I am hoping to go on a budget, while also having all the protections of modern / new equipment. For example I am not comfortable with GFA-555's not having the speaker protection relays. I like and value my RS-IIs too much to jeopardize them in any way... :)

I have sent an email to Emotiva asking about 2 Ohm load and XPA-2, but they have not replied anything yet.
 
That's kind of telling. The Parasound email above got a response from the OWNER. No response at all from Emotiva.

You're in kind of a tough spot. Your Infinity speakers are a very difficult load, so you have to buy a better quality amp.
 
geode said:
There are some threads here on AK that states the Emotiva amp was put into protection mode driving some of the Larger Infinity speakers. I recall, a couple of years ago I went to the Emo forums and asked if the Emotiva XPA-2 was stable into a 2 ohm load, and moreover could it drive Kappa 9s. Nobody gave me an affirmative answer on that one. That said, you can buy the amp and try it out and if it doesn't perform as you would like, send it back. Emo supposedly has a good return policy.
Click to expand...

And I would be one of those. My QLS-1's put an XPA-2 into protect mode.

Twice.

I sold it immediately.

Soundcraftsmen MA5002, Threshold s/300 and Aragon 8008 powered the Quantums with zero problems. The Threshold, though having the lowest rated output of all three, sounds the best with them.
 
Just to confirm speaker and amp output quality doesn't rely on large scale wattage Good quality coils e.g. used in the drivers used in monitors seem to prove the best.
 
Most pro amps are up to the task and can be had at reasonable prices.

Here're a couple quotes from the late Brian Cheney (of VMPS) talking about using a pro amp (QSC PL236) for low end duty. Unbenounced to me, I actually purchased the very amp he had been using.

the amp provided detail, definition, extension and dynamic impact which put every other audiophile amp--Class A, AB, C, and D--I have ever tried to shame. Yes that includes big Krells and Levinsons, my Plinius 250/IV, the BBQ, and everything else. Everything else.
Click to expand...

I recently used the amp in our CES booth driving the bass column of big ribbon speakers up to 124Hz, and believe me, I could have had any amp I wanted for that application. This was my choice.
Click to expand...

Bear in mind the above reference "recently" is relative to January 2001.
 
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whoaru99 said:
Most pro amps are up to the task and can be had at reasonable prices.
Here're a couple quotes from the late Brian Cheney (of VMPS) talking about using a pro amp (QSC PL236) for low end duty. Unbenounced to me, I actually purchased the very amp he had been using.
Bear in mind the above reference "recently" is relative to January 2001.
Click to expand...

Another option for sure :yes:
 
Seppo said:
I have sent an email to Emotiva asking about 2 Ohm load and XPA-2, but they have not replied anything yet.
Click to expand...

If you get a reply please post it. Or if you don't hear a reply within a week please note that.

I was very very close to pulling the trigger on the XPA-2 to drive my Infinity Kappa 8's. I decided not to buy it because I could find no evidence it could drive a 2 Ohm load. If you read the specs on the XPA-2 carefully you won't see any mention of below 4 Ohm loads and when the amp is bridged to one channel the specs only say 1000W for 8 Ohms. No specs for anything lower.

Go post the question on the Emotiva board. You will hear crickets chirping.
 
Seppo said:
My vintage Infinity RS-IIs are a double whammy for weak amps, having low sensitivity, and very low impedance across a wide frequency range. The impedance in RS-II's drops down to 2 Ohm above 5 kHz and never looks back, and moreover hangs around 3 Ohm around 100-150 Hz (where there is a lot of action when the higher woofer and all three midranges cross-over), and then the sensitivity is lowly 85.6 db. For details, please see the lab test article in this thread:
http://www.audiokarma.org/forums/showthread.php?t=621716

Now, could Emotiva XPA-2 handle the RS-IIs? I do not need insane volume levels (as the listening room is mid-sized), but I want to have good headroom at quite high volume levels so that these fantastic speakers can deliver to their full potential.

People report good results using clean 200 wpc at 4 Ohm vintage solid state amplification, and excellent results using clean 400 wpc at 4 Ohm amps (ala Perreaux PMF2150B, or Krells, and Thresholds) driving these speakers. My current Onkyo A-9070 (clean 140 wpc at 4 Ohm) does a good job, but goes to protection at a bit louder volumes. I bet that even at lower volumes it is not able to feed all the current as needed.

Any thoughts / experiences with Emotiva XPA-2? It looks like a great deal...
http://emotiva.com/products/amplifiers/xpa-2
Click to expand...


If you need something for 2 ohm service, it wouldn't be wise considering something which doesn't even list a spec for it. Not implying the amp is bad, just not likely cut out for what you want.
 
And something else to note is that in the specs for their higher end amp the XPR-2 it specifically states that the "minimum recommended load impedance is 4 Ohms." So if their higher end reference amp that sells for twice as much as the XPA-2 can't handle it then what does that say about their "economy" model?
 
I got the following response today from Emotiva:

Hello Seppo,

Thank you for your interest in Emotiva. I apologize in the delay in response we have been playing a little catch up from the overwhelming number of emails we have received during the holiday week!

The XPA-2 would be very well suited for your speakers. We have thousands of customers who are using the XPA-2 with their electrostatic and planar style speakers, some of which drop to a minimum impedance of 0.8 ohms. The XPA-2 has a very robust power supply and is able to provide a very high current and voltage swing. I would also recommend looking at the SA-250 special edition amplifier (http://emotiva.com/products/amplifiers/sa-250). This is a limited release product and is by far one of the most impressive two channel amplifiers available. The noise of the SA-250 is half that of the XPA-2 and it will be well designed to support your speakers as well. You cannot go wrong with either choice. If you have any questions please let me know. We appreciate your support.

Best Regards,
Nick Kaumeyer
Department Head of Sales
Emotiva Audio Corporation

So...I got interested on the SA-250 limited edition special they have:
http://emotiva.com/products/amplifiers/sa-250

The description on the website is a bit confusing and the specs are not better than the cheaper XPA-2. SO what gives. I went to the Emotiva forums, and clearly people there were also confused, and not that excited. But they did mention this Emotiva podcast:
https://emotiva.com/sites/default/files/podcasts/112014/podcast.mp3

If you go to the 11:15 mark, they start talking about SA-250...basically this is their best sounding amp, better than anything in their line-up at the moment, very quiet, local studios were asking for an ever high-end amp than what they had before, so they "made a limited run for the fun of it"...

In short, I just took the leap and ordered one...I hope I do not turn out to be a sucker for marketing talk here, but they do have 30 day return policy if this is really bad or underpowered.

I will keep you posted.
 
So the XPA can run 2 ohm loads? Then why don't they simply list the feature on the XPA page? Not that hard to do and it's feature that would put them head and shoulders above other brands. And yet owners on this very thread found issues with low impedance speakers.

It just doesn't make sense. I asked this question of the XPR line(the newer flagship amp line) when it was being released. The owner himself joined the thread to say that indeed the XPR amps were 2 ohm stable, but they didn't want to advertise this lest customers abuse the amps. Say what?

If a company wants customers to think their amps are 2 ohm stable they should do more than release the info on internet back channels, it's another way they do business that I don't care for. Another is the rapid introduction then retiring of lines and models. The UPA line of amps has just been retired. They've introduced with much fanfare; speakers, subs, previous UPA amps, RPA amps and pre amps, receivers and cable line ups, all to be quietly retired. Never mind their take over of Sherbourn which they ran into the ground.

This new amp, they say it's bascially their "best sounding amp"? That's what they said about the XPA-2, the XPA-1L, the XPA-1 and the XPR-2. And NOBODY spends the hundreds of thousands it takes to engineer a new amp just for the fun of it, what a lame sales pitch. Probably they are trying to introduce a new amp with a different marketing technique. Limited run, eh? Local studios were begging for it, huh? Whatever.
 
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