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Post by rtg97229 on Dec 8, 2014 13:35:54 GMT -5
Yes and to add to that crazy low impedance load the speakers have such low distortion that you can potentially hear the distortion of the amplifier that is being run in a worst case condition that is almost defiantly outside the specs and testing conditions of the amp.
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Post by rtg97229 on Dec 8, 2014 23:09:05 GMT -5
Steve Jobs listening to his Acoustat Model 3s Notice that he is using Threshold STASIS-1 monoblocks.  |
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Post by leonski on May 3, 2016 13:12:37 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. VERY true. It is a stereo myth that refuses to die. 'Maggies are a tough load' is rubbish. They ARE low sensitivity, but ANY amp capable of providing the current will work well. In White Bear Lake, (home of Magnepan) the lobby stereo has some wacky low-powered tube setup. And it works. The ONLY amp I've tried that didn't work well was a Rotel RB-1070 which has NO factory 4-ohm rating. That should have been the big clue. I don't know of ANY amp manufacturer that provides other than Resitive Power for amps. Too bad NO speakers are just resistive. There ARE dummy speaker loads which are both capacitive and inductive, just like a REAL speaker, but I don't know any which are 'standards'. Here is a link to the Power Cube measurement system which will provide the data, if only amp manufacturers would USE it. And publish the data. new.audiograph.se/wp-content/uploads/2013/12/PowerCube_12p_brochure_complete.pdfGo down to about page 3 for the easy to understand graphic. |
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KeithL
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Post by KeithL on May 3, 2016 13:37:16 GMT -5
One of the biggest reasons for misunderstanding is right there in the title of this thread. Maggies are PLANAR MAGNETIC loudspeakers; they are NOT electrostatics. While they may look similar, and electrostatics are also usually planar, they are far different internally. ELECTROSTATIC SPEAKERS present an almost purely capacitive load, which is then driven through a step-up transformer - and electrostatics are often VERY difficult to drive. Maggies are simply a relatively low impedance but mostly resistive load.... and, as you say, their only "problem" is that they require lots of power if you want to play them somewhat loudly. Magnepans are actually a pretty easy load, mostly resistive, they just like plenty of power. VERY true. It is a stereo myth that refuses to die. 'Maggies are a tough load' is rubbish. They ARE low sensitivity, but ANY amp capable of providing the current will work well. In White Bear Lake, (home of Magnepan) the lobby stereo has some wacky low-powered tube setup. And it works. The ONLY amp I've tried that didn't work well was a Rotel RB-1070 which has NO factory 4-ohm rating. That should have been the big clue. I don't know of ANY amp manufacturer that provides other than Resitive Power for amps. Too bad NO speakers are just resistive. There ARE dummy speaker loads which are both capacitive and inductive, just like a REAL speaker, but I don't know any which are 'standards'. Here is a link to the Power Cube measurement system which will provide the data, if only amp manufacturers would USE it. And publish the data. new.audiograph.se/wp-content/uploads/2013/12/PowerCube_12p_brochure_complete.pdfGo down to about page 3 for the easy to understand graphic. |
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Post by leonski on May 3, 2016 14:31:16 GMT -5
One other point about 'stats. The few plots of impedance V reactance I see show them going to VERY LOW impedance at higher frequencies AND at the same time, phase angles (measure of reactance) going thru the roof. Sometimes over 60 degrees. The only good news in that measurment mess is that above maybe 10,000hz, you only need about 10% of the TOTAL consumed power. Chosen at random from Stereophile data. Scan down to impedance / phase graphic. www.stereophile.com/content/martinlogan-montis-loudspeaker-measurements#VtsdFI4bRBKQTkRE.97It should ALSO be noted to NOT mess with the internals of 'Stats. High Voltages are present (polarizing voltages) which will shock the sh** out of you. Somebody on another thread bought a cheap DVM to check fuses. He hadn't a CLUE as to what he was doing. I just hope he UNPLUGGED the amp prior to cracking the case and let it SIT for a couple hours while the PS Caps discharge. PS caps AND 'Stat power supplies can provide a NASTY SHOCK. |
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Post by AudioHTIT on May 3, 2016 19:02:32 GMT -5
One of the biggest reasons for misunderstanding is right there in the title of this thread. Maggies are PLANAR MAGNETIC loudspeakers; they are NOT electrostatics. While they may look similar, and electrostatics are also usually planar, they are far different internally. ELECTROSTATIC SPEAKERS present an almost purely capacitive load, which is then driven through a step-up transformer - and electrostatics are often VERY difficult to drive. Maggies are simply a relatively low impedance but mostly resistive load.... and, as you say, their only "problem" is that they require lots of power if you want to play them somewhat loudly. To be fair the OP did ask about electrostats, Magnepans came into the conversation a few posts down, but it doesn't hurt to say it again, many people do think Maggies are stats. |
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Post by tchaik on May 3, 2016 19:45:39 GMT -5
as for the acoustic 2+2s, i had a pair back in the 80's and i was driving them with a pair of hafler dh-200's. a nice amp for it's time but nowhere near as robust as the xpa and xpr series. don't think there should be a problem.
tchaik……..
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klinemj
Emo VIPs 
Honorary Emofest Scribe
Posts: 14,740
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Post by klinemj on May 3, 2016 20:21:59 GMT -5
Ah,the Hafler Amps...fond memories! A friend had the dh-200...nice old amp.
Mark
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Post by stlaudiofan1 on Jun 4, 2016 22:07:47 GMT -5
One of the biggest reasons for misunderstanding is right there in the title of this thread. Maggies are PLANAR MAGNETIC loudspeakers; they are NOT electrostatics. While they may look similar, and electrostatics are also usually planar, they are far different internally. ELECTROSTATIC SPEAKERS present an almost purely capacitive load, which is then driven through a step-up transformer - and electrostatics are often VERY difficult to drive. Maggies are simply a relatively low impedance but mostly resistive load.... and, as you say, their only "problem" is that they require lots of power if you want to play them somewhat loudly. VERY true. It is a stereo myth that refuses to die. 'Maggies are a tough load' is rubbish. They ARE low sensitivity, but ANY amp capable of providing the current will work well. In White Bear Lake, (home of Magnepan) the lobby stereo has some wacky low-powered tube setup. And it works. The ONLY amp I've tried that didn't work well was a Rotel RB-1070 which has NO factory 4-ohm rating. That should have been the big clue. I don't know of ANY amp manufacturer that provides other than Resitive Power for amps. Too bad NO speakers are just resistive. There ARE dummy speaker loads which are both capacitive and inductive, just like a REAL speaker, but I don't know any which are 'standards'. Here is a link to the Power Cube measurement system which will provide the data, if only amp manufacturers would USE it. And publish the data. new.audiograph.se/wp-content/uploads/2013/12/PowerCube_12p_brochure_complete.pdfGo down to about page 3 for the easy to understand graphic. I had 4 XP1Ls Biamping my Magnepan 1.6QRs. One of the amps developed a problem. When I sent the amp in for repairs, I was told by an Emotiva tech that the 1Ls were not an appropriate amplifier for the Maggies, that I needed one of the 2 channel amps like the XPA-2. I was a bit set back, because a prior conversation with a different tech prompted me buying the extra pair to biamp. What is the real story with this? I have since picked up a second pair of traditional cone speakers, as I don't want to damage the amps again....but still have the Maggies. Is it the low impedance that makes the the 1Ls inappropriate for the 1.6QRs, or was I given bad info? |
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Post by leonski on Jun 4, 2016 23:40:28 GMT -5
No Reason WHATSOEVER that a competent amp with decent 4ohm power shouldn't drive the 1.6 to distraction. I'm using a PAIR of Parasound A23 on the SAME speakers. So that's 200x2 per speaker.
With a PAIR of the 1L, per speaker, you've got about 3db more power than I.
Ever blow a fuse?
By 'developed a problem', what exactly does that mean?
If 4 of 'em can't drive a pair of 1.6s, they are really only suitable for landfill.
With the 3 PAIR of connectors, did you connect to the correct 2 pair AND remove the 'jumpers? That's the only mistake on YOUR part I can imagine.
I had briefly considered the SAME amps for my panels. The additional expense for another circuit was off-putting.
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Post by stlaudiofan1 on Jun 5, 2016 15:22:31 GMT -5
The "damage protection" circuit kept engaging on the one amp. The four 1Ls are the only items on a dedicated 20 amp circuit. They were wired correctly. I have had many different amps that never had an issue driving the 1.6QRs.
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Post by leonski on Jun 5, 2016 15:57:58 GMT -5
How depressing. I was REALLY tempted to go with the1L amps, too. I looked thru a BUNCH of other posts about the 1L and one person who was having problems UNSTACKED them and the problem went away. That's all I got left. If you were stacking them behind the panels, was it the TOP amp that failed? The upper amp will run warm AND pick up plenty of heat from the amp beneath.
Even when pressed, my Parasound amps don't get anything past 'warm'. And than not for long. With the 600hz crossover AND running a low cut filter to the panel, the 'strain' on each of 4 amp channels is about equal.
Did your amp malfunction when running on the HF or LF end? Either? Both?
And while it's too late, probably, for you, did you ever consider a line level crossover and wire amps directly to the drivers and DELETE the speaker crossover?
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Post by jeffrey40sw on Jun 19, 2016 20:57:37 GMT -5
I have a pair of 1.6QR's and an XPA 3 and it will drive the maggies to ear bleeding levels. I have tried also driving them with my 24 year old Adcom GFA 535II, and it had no issues either. However, my Onkyo 809 was pathetic trying to drive them.
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Post by leonski on Jun 20, 2016 12:53:40 GMT -5
I have a pair of 1.6QR's and an XPA 3 and it will drive the maggies to ear bleeding levels. I have tried also driving them with my 24 year old Adcom GFA 535II, and it had no issues either. However, my Onkyo 809 was pathetic trying to drive them. Maggies are NOT ELECTROSTATIC. Planar? YES. 'Stats? NO. Maggies are generally an EASY load for any competent partnering amp with sufficient 4ohm power. More modern amps than your old Adcom will do much better. Nelson Pass was the designer of the original Adcom 555. |
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Post by jeffrey40sw on Jun 21, 2016 8:48:11 GMT -5
I have a pair of 1.6QR's and an XPA 3 and it will drive the maggies to ear bleeding levels. I have tried also driving them with my 24 year old Adcom GFA 535II, and it had no issues either. However, my Onkyo 809 was pathetic trying to drive them. Maggies are NOT ELECTROSTATIC. Planar? YES. 'Stats? NO. Maggies are generally an EASY load for any competent partnering amp with sufficient 4ohm power. More modern amps than your old Adcom will do much better. Nelson Pass was the designer of the original Adcom 555. I found that out after owning them. For years I had believed the maggie myths even though I loved their sound. They play very loud, have plenty of bass in the right room, and are not hard to drive. |
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Post by pedrocols on Jun 21, 2016 9:00:44 GMT -5
I now use tube amps but I used to power a pair of MG12 with 2 UPA-1s without any problems.
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Post by creimes on Jun 21, 2016 9:07:40 GMT -5
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