Magnepan speakers use continuous power or dynamic?

 

Bronze Member
Username: Jackkessler

Post Number: 24
Registered: Jun-05
I bought a pair of Magnepan IIB speakers on Craigslist. They are en route to me (I hope). They have either 4 or 6 ohm impedance and require lots of power.

My question is: Must the power be continuous? Or is large amounts of dynamic power sufficient?
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 13875
Registered: May-04
.

Music is not continuous in nature so power need not be "continuous" RMS.

Music is "dynamic" in nature.

Are large amounts of "dynamic power" sufficient for the Magnepans?

Generally the answer would be, "No".



The magnetic planar speakers are a somewhat difficult load for many (most) direct coupled amplifiers in that the speaker systems (most often) possess a strong and rising inductive component in the high frequencies. Amplifiers which advertise "dynamic power" as their selling point are commonly relying on very short term bursts which can produce substantial voltage swings from the power supply. In the extreme cases of "dynamic power" marketing the amplifier is literally sucking juice from the wall outlet to fulfill the speakers' desire for M-O-R-E P-O-W-E-R!

As a rule reasonable amounts of current delivery and/or stability into low/high impedance reactive loads will be required for more difficult loads such as the Magnepans. Though of all the speakers that might be deemed "difficult" the Magnepans are by far one of the better choices as far as amplifiers are concerned. They tend to play well with others while remaining somewhat demanding of the amount of attention they alone receive.


It would be impossible to state with certainty that any amplifier touting "dynamic power" is not up to the task of driving the Magnepan load - there will certainly be music that comes from the combination - but in my experience this isn't the best solution for these speakers.

That is not to say the amplifier will not play along with the planars without major fuss and fluster but rather to suggest you might find better results with an amplifier of higher pedigree capable of long term "power" ('V' X 'A' = watts) delivery into more difficult loads rather than short term delivery into high SPL loads.

Since the problem areas of the Magnepans almost always exist in the high frequency regions where power requirements are minimal compared to the easier (but by no mean "easy") to drive mids and low frequencies of the planars the need for massive amounts of power will not be there and might even be counter-productive depending on your budget. A cheap 250 watt amplifier is still a cheap amplifier.

The need for an exceptionally stable amplifier is present and a modest amplifier designed for good performance into stressful, reactive (mostly inductive) loads is suggested. A transformer or autoformer coupled amplifier normally tolerates such loads.

A small amplifier with a very stiff power supply would be the first choice - "dynamic power" almost by its nature suggests a somewhat loosely regulated power supply that can swing voltage in the very short term - so you needn't spend big bucks to find the proper amplifier. OTOH, if you have the $$$, a large VTL or Audio Research would be quite the match.

Make certain the amplifier has a reasonably low output impedance (most direct coupled amplifiers do) to ensure the reactance between output and load doesn't drastically affect frequency response.



Finally, as a dipole type system the personality of the Magnepan should be taken into account. An amplifier that is too laid back in its presentation will tend to produce a soundstage and characterization that places performers well away from your listening position. That isn't necessarily bad depending on your concept of how you hear live music. A too "hard" or analytical personality in the electronics and source will produce sound that tends to obscure the music making abilities of the planars while producing short term thrills in detail retrieval. Ribbon tweeters are very particular about what amplifier they mate with and will quickly turn to bite the head off any offending suitor.


And, this being a public forum, you are free to ignore any advice you recieve here from the forum elders.




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Platinum Member
Username: Nuck

Post Number: 13284
Registered: Dec-04
No Sony receivers.
 

Silver Member
Username: Magfan

USA

Post Number: 492
Registered: Oct-07
Please check out the link provided:http://www.integracoustics.com/MUG/MUG/articles/speakers.html

This is a list of what appears to be Everything Magnepan ever made. The IIb models would appear to be the last of the 1st generation panels, based on frequency response. Later panels used thinner membranes and had wider limits.

Based on this chart, the speaker is 6ohms and
needs 60->80 watts/8ohm rating. For Magnepan more is usually better, if HI QUALITY watts.

Magnepan construction is sort of fragile, too. The adhesive used (3M 77) and an overcoat / sealant are said to be UV sensitive over long time periods. My original panels, some MG-1s were rebuilt at the factory many years ago. They are a great DIY speaker and many helps are available including rebuild kits from the factory in White Bear Lake Minnesota of all places. Please check out 'Magnepan Users Group' for more helps, pictures and WAY more information than you want to know!

Buying on Craigs list, unlistened, is sort of a gamble. It is possible, and some would say even likely, that the wiring has either begun to corrode or delaminate from the panel...which will produce either a buzz or rattle. This is fixable.

Please take the time for proper setup. Maggies are not for everyone and will require some adjustments on your or your spouses part.
Enjoy.
 

Gold Member
Username: Touche6784

USA

Post Number: 1353
Registered: Nov-04
I have maggies as well. To add to what leo has already said, also be wary of high humidity areas and locations near the ocean. I have read that the salty can cause the adhesive to fail. Many times adhesive failure cannot be detected with just listening unless it is very severe. Best way to check is to remove the socks and do a visual check. When I bought mine the previous owner had told be there was a failure that needed to be taken care of my Magnepan. I bought mine on Audiogon not knowing what I was getting and I have been quite pleasantly surprised.

About power. You don't necessarily need hundreds of watts for them to sound good. I have the MGIc speakers and used a 15 watt RMS tube amp to great satisfaction granted the room is small.
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