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Post by bobzilla on Oct 28, 2013 14:10:05 GMT -5
I need to have some idea of how Emotiva amps deal with the difficult loads presented by electrostatic speakers. I know I'm not alone in this question. Full range 'stats such as Acoustats and Quads are seen by the amp as primarily a capacitance load and many solid state amplifiers overheat, go into severe oscillation, trip protective safe guards or a fatal combination of all three. Not good. Example: Acoustat 2+2s not only appear (to the amp) to be one big capacitor, but also demand quite a bit of wattage at four ohms and it's practically impossible to predict, with any accuracy, which amp might be compatible. I think if you could include some pertinent testing with true 'stats, you would expand your market. Oh, and not so incidentally, I REALLY like what your doing with the "switchable class A/AB circuitry". The XPA-1L may be superb for my 2+2's ... you just never know...
Thanks for your work and the realistic pricing!
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bootman
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Typing useless posts on internet forums....
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Post by bootman on Oct 28, 2013 14:21:45 GMT -5
Excellent question for Lonnie!
These speakers do separate the men from the boys when it comes down to amp differences.
Not so much with other types currently popular with the HT crowd which are much easier to drive.
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Post by africanus on Oct 28, 2013 14:52:47 GMT -5
I can't say anything about the theoretical aspects but I own a pair of Quad ESL2905 and both XPA-2 and UPA-500 drive them with authority. I have never gone even close to the 50% of power.
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Post by luvtubes on Oct 28, 2013 15:03:10 GMT -5
I have found tube power to perform best with 'stats and planar-magnetic. I hope to see Emo come to the table with tubes soon, but for now, I would think the reference line would produce the best results, or perhaps something from Rogue Audio. The M-150/180 comes to mind.
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Jack
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Post by Jack on Oct 28, 2013 15:26:39 GMT -5
I am driving a pair of Magnepan 3.7's with an XPA-2 and have played it very loud without redlining the amplifier. I'm really pleased with the combination of amplifier and receiver.
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Post by pedrocols on Oct 28, 2013 17:52:21 GMT -5
I have found tube power to perform best with 'stats and planar-magnetic. I hope to see Emo come to the table with tubes soon, but for now, I would think the reference line would produce the best results, or perhaps something from Rogue Audio. The M-150/180 comes to mind. They are nice but nothing I can really afford....  If I could I would not be a member on this forum...  ...So in a way I am happy they are expensive...  |
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Deleted
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Post by Deleted on Oct 28, 2013 18:03:23 GMT -5
Damn electrostatic load!
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Post by AudioHTIT on Oct 28, 2013 21:34:38 GMT -5
I am driving a pair of Magnepan 3.7's with an XPA-2 and have played it very loud without redlining the amplifier. I'm really pleased with the combination of amplifier and receiver. Magnepans are actually a pretty easy load, mostly resistive, they just like plenty of power. |
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bootman
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Post by bootman on Oct 28, 2013 22:20:36 GMT -5
I am driving a pair of Magnepan 3.7's with an XPA-2 and have played it very loud without redlining the amplifier. I'm really pleased with the combination of amplifier and receiver. Magnepans are actually a pretty easy load, mostly resistive, they just like plenty of power. Not for your your typical avr.  But I do know what you mean. They are not like appogees. |
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Post by AudioHTIT on Oct 28, 2013 23:30:02 GMT -5
Magnepans are actually a pretty easy load, mostly resistive, they just like plenty of power. Not for your your typical avr. But I do know what you mean. They are not like appogees. Yeah, not many AVRs would do them well. Just meant that not being electrostats they weren't the nasty load the OP described. |
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Post by PoloOle on Oct 29, 2013 0:44:46 GMT -5
I run my Martin Logan's with a pair of XPA-2. I have no problems with heat or lack of dynamic power.....
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Post by mpower on Oct 29, 2013 15:17:40 GMT -5
I have had problems running my carver AL-III+. There's a 10 inch downfiring woofer that runs up to 150 hz and the 48" long ribbon takes over from there, specified as 4 ohm load. I can consistently trip the protection features of emo amps. I've tried one XPA-2 in stereo, two xpa-2s biamping vertically where each amp was dedicated to each speaker. Now I have 2 XPA-1s. The amps never overheat or sound bad, they just trip some part of the protection scheme and shut down with the flashing red lights.
The two XPA-2's handled the situation better than a single one, and the XPA-1's seems to be able to play at an even louder volume prior to shutting down. At this point - the XPA-1s trip if I play it significantly louder than reference (110 db) and a little more than 1/2 the blue lights are lit. Beyond that - the protection circuit steps in.
Sensitivity is 86db, 4ohm nominal but dipping down to 3ohm at 200-250 hz and 3 ohm at 10k hz. Supposedly has a pretty complex x-over to deal with notch filtering.
I am not sure- specifically, which of these demanding factors is causing the amps to trip. There is at least one other poster on this site that experienced the same issue with XPA-2 and this specific speaker. Despite all of this - the combination sounds fantastic. My latest change has been to power my two subs (not class D amps) on a separate circuit from the main amps. I have not yet played at a high enough volume to see if it still trips.
At some point - I'll probably pull the Carver's out of my HT and set them up for 2 channel where relative and dynamic volume levels aren't so demanding. I just haven't been "wow'ed" by other speakers that I have heard in person yet. Love the sound of ribbons.
Anechoic Frequency Response: 34 Hz to 20 kHz +- 3dB
Impedance Nominal 4 ohms
Sensitivity 86 dB ref. to 1 watt at 1 meter
Crossover 150 Hz
Ribbon Driver 48-inch dipole ribbon
Woofer 10-inch Quasi-butterworth 3rd order aligned downward firing woofer system
Recommended Power Up to 600 watts per channel - 65 watts minimum
Net Weight 80 lbs. each
Dimensions 14.5Wx16.5Dx72.5H
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Post by luvtubes on Oct 29, 2013 17:16:50 GMT -5
I have had problems running my carver AL-III+. There's a 10 inch downfiring woofer that runs up to 150 hz and the 48" long ribbon takes over from there, specified as 4 ohm load. I can consistently trip the protection features of emo amps. I've tried one XPA-2 in stereo, two xpa-2s biamping vertically where each amp was dedicated to each speaker. Now I have 2 XPA-1s. The amps never overheat or sound bad, they just trip some part of the protection scheme and shut down with the flashing red lights. The two XPA-2's handled the situation better than a single one, and the XPA-1's seems to be able to play at an even louder volume prior to shutting down. At this point - the XPA-1s trip if I play it significantly louder than reference (110 db) and a little more than 1/2 the blue lights are lit. Beyond that - the protection circuit steps in. Sensitivity is 86db, 4ohm nominal but dipping down to 3ohm at 200-250 hz and 3 ohm at 10k hz. Supposedly has a pretty complex x-over to deal with notch filtering. I am not sure- specifically, which of these demanding factors is causing the amps to trip. There is at least one other poster on this site that experienced the same issue with XPA-2 and this specific speaker. Despite all of this - the combination sounds fantastic. My latest change has been to power my two subs (not class D amps) on a separate circuit from the main amps. I have not yet played at a high enough volume to see if it still trips. At some point - I'll probably pull the Carver's out of my HT and set them up for 2 channel where relative and dynamic volume levels aren't so demanding. I just haven't been "wow'ed" by other speakers that I have heard in person yet. Love the sound of ribbons. Anechoic Frequency Response: 34 Hz to 20 kHz +- 3dB Impedance Nominal 4 ohms Sensitivity 86 dB ref. to 1 watt at 1 meter Crossover 150 Hz Ribbon Driver 48-inch dipole ribbon Woofer 10-inch Quasi-butterworth 3rd order aligned downward firing woofer system Recommended Power Up to 600 watts per channel - 65 watts minimum Net Weight 80 lbs. each Dimensions 14.5Wx16.5Dx72.5H Bob's speakers (all series of ALS) are what pushed him back to the vacuum tube. His speakers take an extraordinary amount of current to drive them properly, and at the time, the high-powered Silver Seven Vacuum Tube Amplifier was the answer. Your amps are being tapped out by the demands of the speaker, and rather than send a distorted "clipped" signal, the amps instead are shutting down. I would suggest getting an XPR2 or the monoblocks in the mix, or something of equivalent capabilities, such as the Black Beauties. |
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Post by basquiat on Nov 28, 2014 11:35:00 GMT -5
I have a pair of acoustat, model 4 electrostatic speakers. I run a pair of xpr1 monoblock amps, fully balanced, and they sound amazingly beautiful. Had these for a year and never a problem. The music is amazing
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Post by pedrocols on Nov 28, 2014 14:13:54 GMT -5
I hope you realized the original post is over a year old and that the person asking the question has abandoned this thread....just saying. Nevertheless, thank you for your input.
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Post by pedrocols on Nov 28, 2014 14:14:45 GMT -5
I have a pair of acoustat, model 4 electrostatic speakers. I run a pair of xpr1 monoblock amps, fully balanced, and they sound amazingly beautiful. Had these for a year and never a problem. The music is amazing I hope you realized the original post is over a year old and that the person asking the question has abandoned this thread....just saying. Nevertheless, thank you for your input. |
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Post by rtg97229 on Dec 8, 2014 2:09:12 GMT -5
I think people often get confused when someone brings up Acoustat speaks and says they are a difficult load for many amplifiers. I have measured acoustat speakers dipping down to under half and Ohm. Even the support guy at Emotiva started talking about "the XPA-2 is great even for Maggies" when I brought up that I have Acoustat speakers. He didn't seem to know that I already have an XPA-2. This is a strange case anyway seeing as how even a cheap HT receiver can run Maggies to some extent. Try running Acoustat speakers with an HT receiver and you better hope it has a good protection circuit. As far as Emotiva amplifiers running Acoustats goes the old class H amps noticeably handle the task better than my XPA-2 G2 but the XPA-2 is still better than most amplifiers I have tried. I have Spectra 11, Spectra 1100, and Spectra 2200 speakers from Acoustat and have had Model 2 and 1+1 speakers in the past. My next project is to build some Spectra 33s out of the 2200's and the panels out of my 11's.
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Post by vcautokid on Dec 8, 2014 6:57:20 GMT -5
The Emotiva XPA 2 I had ran my Maggie's great never once complaining about the load. No worries on Eletrostatics either as especially with the X series amps, power to spare.
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Post by rtg97229 on Dec 8, 2014 11:18:26 GMT -5
The Emotiva XPA 2 I had ran my Maggie's great never once complaining about the load. No worries on Eletrostatics either as especially with the X series amps, power to spare. Thats the thing, when if comes to Acoustat speakers bringing up that an amp can run Maggies adds nothing to the conversation. Even many Martin Logan speaks are a harder load for an amp than Maggies. When someone talks about Quad they are on the right track but remember that Acoustats are a hard load because of impedance but also need and can take as much or more power than Maggies along with that low impedance high capacitance load. Another thing is that just because and XPA does not fault does not mean that it sounds great into a 2 to 0.4 Ohm load while pulling over 200 W. |
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Post by vcautokid on Dec 8, 2014 13:07:47 GMT -5
The big Martin Logan's drop down to a ,75 ohm load too. Crazy huh?
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If I could I would not be a member on this forum... 
...So in a way I am happy they are expensive... 
