Tube Amps, Magnapans and Impedance

That might be true but Magnepan will not share much information so many have found the answers on their own.

I guess that explains why there is SO much nonsense online about them.

When I was amp shopping for my 3.7i I was considering McIntosh with autoformers but was told by the manufacturer themself that autoformers did not work well with Maggie's. As long as your amp puts out high amperage you will be fine, it matters more than watts.

I ended up going with a Pass 250.8 which really makes Maggie's sing.

If you enjoy your sound stay with it and enjoy the music 🎶.

My monoblocks are 80 watts. They do have Peter Dahl transformers which make a huge difference. They deliver the goods and the Maggies seem to like them as far as I can tell. One thing of note is I tend not to listen at super high levels. They are so articulate, musical and transparent, I don’t find the need for high power to get into the essence of the music. That, in fact, was their allure when I first heard them way back when.

Frogman knows of what he speaks. The Maggie's need for ridiculous power is a way overblown item that keeps being repeated. The high end dealer here demos 3.7s with a Rogue Cronus Magnum. I run 1.6s with the same amp. Even after having used an amp that pumps over 300 watts, there is nothing missing with the "low" powered amp.

 

PS...looks like the "not a robot" deal just got even more annoying.

For those who like the Maggie/tube amp combination but can’t or don’t want to spring for a high-powered amp, there is an alternative. Is everyone aware of the fact that Maggies are not the only planar-magnetic loudspeakers on the market?

Bruce Thigpen of Eminent Technology---already well-known for his linear-tracking air-bearing tonearm---found much to like in the Magnepan design, but saw a way to improve upon it: create a p-m driver that operated in push-pull fashion. All the early Magneplanar drivers were single-ended---magnets on only one side of the mylar diaphragm (if you don’t understand why that is a design flaw and weakness, a little research will reward you with the answer). Thigpen created a push-pull m-p driver over forty years ago, patented it, and uses it today unchanged in his LFT-8b loudspeaker. While he was at it, he made the driver an 11 ohm load, much more appropriate for tube amps than are the 4 ohm (and down) Maggies.

Used with a single stereo power amp, the LFT-8b’s p-m midrange driver and ribbon tweeter are combined with the 8" sealed-enclosure dynamic woofer (for 180Hz down), resulting in an 8 ohm load. But the LFT-8b is fitted with two sets of binding posts: one for the woofer, one for the planar panels, so bi-amping the LFT-8b is a breeze and allows one to use a ss amp on the woofer, a tube on the panels.

Magnepan eventually moved to push-pull operation in some of the drivers in their higher-priced models, but retained the 4 ohm impedance. There are some LFT-8b owners who bought them as replacements for their MG3.7’s, overall preferring the ET. $2499/pr shipped or from an ET dealer.

I myself am a long-time Maggie lover, having bought my first pair---the Tympani T-I---in 1972, and am a current owner of a pair of Tympani T-IVa, the ultimate realization of the 3-panel Tympani design (assuming you ignore the MG30 ;-). I very much like the ET LFT-8b, and find it to work quite well with a modestly-powered (100w/ch)---though unusually-well designed and built---tube amp in a moderately-sized room (14.25' x 22')

@gdnrbob

Many thanks.  I'll ping him.  I have no experience with them but they are intriguing.

@richopp525

For acoustic music, Maggies are incredible.  I always tell the story of how I went to a high-end shop in Palo Alto, CA., with a colleague.  This was 1978 and I was a school teacher.  I heard a sax playing in the back of the store and wandered back for a listen.  I saw instruments hanging on the wall but no sax player.  Turned out it was Magnaplanars powered by Audio Research (with solid silver cabling) from a vinyl recording of Sonny Rollins.  I was completely stunned. I stood there and the owner came in and explained the full set up.  He was gracious enough to play serveral jazz cuts and I was in nirvana.   In no way could I even afford the cartridge!

I made it my mission to own a pair.  I finally did so in 1996 or thereabouts.  I couldn't swing the Audio Research but the custom built Cary pre and amps have served them well over the years. Peter Dahl transformers and Class A all day long.  :-)  Oh, and they will boogie too!  Granted, there is nothing like a cone for moving air for rock and roll and all the derivatives, but they can hold their own.  I am more into timbre, tone and that enveloping natural sound they provide.  Sublime...  They are not for everyone though for sure.

 

 

@OP  Nice to read your reaction to Maggies.  I have been posting for years, based on my shop-owning experiences, that they were the ones to buy if accuracy of reproduction was the goal.

No, not every room will work with them, and you do need some quality hardware--I always recommend Audio Research--but whatever sounds best to you in YOUR ROOM is fine.

Happy listening!

@OP, 
Too bad you didn't post a few months ago. I recently sold a pair of Speltz  autoformers. 
There is another Audiogon member you should PM- Atmasphere.
He is well acquainted with autoformers an should be able to give you some relevant advice, as he designs tube amps/preamps.
B

Retreived my archived file and refreshed my memory on the criteria I used to build the system. It appears my recollection was consistent with the exception of the conversation with Magnapan. They did say it would not be a problem if I wasn’t trying to fill a large room with high volumne but they did not provide the impedance curve I cited.

My notes also reminded me I consulted several knowledgeable people, including Dennis, who further went on to say it was recommended to run the Magnapans on 8 ohm output transformers as the measurements were better, less distortion and more pleasant to the ear. This is consistent with you fellas with Magnapans and 8 ohm output transformers who said the same thing. This was the determining factor in not sending the blocks back for 4 ohm transformers.

Phew! Glad that is settled in my head. My ears always said, "I told you so!" I was dreading admitting my friend’s friend was right. Ugh! (But I would have begrudgingly).

Zero Autoformers are out. Now, back to my study for some jazz. Thanks again for the great repartee! Reminds me of days when, with only one snarky comment in the entire thread! An Audiogon record!

Best to all...

P.S.:  If I do get my hands on a pair of autoformers I can audition and return, I might experiment.  That's the Audiophile in me and all of us here on Audiogon, eh?  HA!

Roger Sanders makes two versions of his power amp, one for ESL's the other for magnetic-planars such as Maggies. It is very well regarded in the Magnepan community. Check the Planar Speaker Asylum for reviews.

Correction: Meant to say step up the speaker impedance to 8 ohms.

I just may have a set of Autoformers coming to passively step the impedance down to 4 ohms.  I'll give them a listen.  Could very well marry 'good practice' with 'good listening'!  👍

I'll post my findings to close this out and return back to anonymity.

Excellent, thank you very much!  I'll do so indeed. 

I was considering, at one point, Autoformers, to adjust the output impedance down to 4 ohms.  Apparently, they really help with Magnapans and are a good way to match amp to speaker load. I'll run that by your contact.  If anyone has any experience with them, I'd welcome the input.

Now, I'm off on a toot to get Walsh Ohms for my home office.  I heard a pair once and the way they hung an image in the middle of the room was breathtaking.  I'm not moving the Magnapans out of my study.  That's where they live.  I'm too spoiled by the intimacy of sitting in front of them in the sweet spot and getting lost in the music..

Lastly, I wanted to share another tid-bit.  I received some solid silver interconnects from a fledgling company as part of a transaction - source to pre and pre to amp(s).  I was told they would be good with tubes with their reputation for being detailed.  Well, I lived with them for many months and I did enjoy them.  After a while, I started thinking they were a bit too strident.  I replaced them with my original interconnects, Mogami studio wire, and voila!  

Damned if this isn't a OCD hobby!  

@OP,

Doubt was sown

Considering that you enjoy your system as it is, I would discount any  inference to the contrary.
But.
we are all subject to the opinions of others.
That being said(written), I would contact Magnepan directly with your concerns.
Another good person to contact is John Rutan (Audioconnection). He sells Maggies and knows just about every company out there. He can give you free, unbiased information that will help guide you.
bob 

@frogman 

Thanks for that 8 ohm comment! 

My memory of what I heard from Magnapan may be faulty.  It was in 1992-ish if I recall correctly. I got the tubes and speakers within months of each other. The file with my notes is long archived.  I just have the manuals on file but Dennis modified everything so it may have been he who said it wouldn't be a problem. At any rate, they sure sound good.  Thanks again!  

Contention, as the OP in that thread postulated, is counter-argument with little value except to personalize and incite discord.  This is counter productive and what has chased so many away.  Just look at the demographics of the forum and the sparsity of new posters. I've been around here and watched the decline.  No new blood, so-to-speak.

In the headphone forum, Head-Fi, Jude set up a separate place for objectivists to share their views, and several other forums followed.  The arguments were ruining the enjoyment with dogma and the overwhelming messianic compulsion to demean another's experience.  What one person hears isn't necessarily what another hears and no amount of recitation of theory will ever change that.  It is the passion of the hobby.

I am all about measurements, hence my stipulation.  My post was genuine.  I wanted to get my fellow audiophiles' experiences with tubes and Magnapans.  Doubt was sown and I needed a lifeline!  Frogman to the rescue!

As I compose listening to an acoustic jazz track, that double bass player owns that fret.  The drummer owns the high hat and cymbals and the piano has that wooden quality that one would hear sitting down front listening.  It was that which drew me to Magnapans.  

Best to all!

Keesue, my brother ran his 3.6s with a pair of Parasound JC1s in class A mode. It was a very nice pairing. 

"...Gotta love a forum where someone knows more than the people who build Maggies. oops..is that contentious?..."

That might be true but Magnepan will not share much information so many have found the answers on their own.

Gotta love a forum where someone knows more than the people who build Maggies. oops..is that contentious?

Of course, my experience only:

There is something very right about Maggies and a good tube amp(s). Much is always made about Maggies liking a lot of power. There is some truth to that; however, “liking” is not the same as needing; and “needing” is in good part determined by one’s sound priorities and listening habits. What I mean is, the sound that “3” series Maggies and a good tube amp in the 100 W range produce will be, for me, usually superior to what I have heard from most mega watt SS amps.

To my ears, Maggies’ inherent sound benefits tremendously from the plush dimensionally of a good tube amp that will also impart a bit of juiciness to the timbre of instruments. With SS amps the sound tends to be too timbraly dry, in my experience. I’m not talking about departure from what many consider “accuracy”, but actually bringing the sound closer to the sound of real. I know there will be disagreement about this point, but that is my experience having lived with MG3A’s for many years. My point with all of the above is that if you don’t need extremely loud (subjective) sound levels, be careful about switching to a SS “higher powered amp”; if that is your plan. You wrote:

**** I stipulated that it is good electrical practice to match the load to the amp ****

This comment goes to all the above and to the importance of, when all is said and done, basing your decision on LISTENING.

One of the amps that I drove my MG3A’s with before settling on a pair of Manley 100/200 tube mono blocs (which I still use) was the tubed Berning 2100. A fine amp that had a choice of transformer impedance taps. In spite of the theoretical electrical “advantage” of using the 4 Ohm or 6 Ohm taps, the Maggies sounded much better on its 8 Ohm taps. Yes, on the 4 Ohm taps there was a VERY SUBTLE sense of SLIGHTLY more powerful and better controlled bass, but the overall sound was cloudy and with less dimensionality than on the 8 Ohm taps. A clear (😉) choice for me. Btw, my Manley’s are switchable between 100W in “triode” and 200W in “ultra linear” modes. On the Maggies, with the exception of somewhat more powerful bass, with half the “power” the sound in triode mode was infinitely better.

Good luck and don’t be too swayed by theory, but by what your ears tell you.

buy a new or used beast you can return, hear, keep or return.

I think there are a lot of things besides amp/impedance matching that goes into our enjoyment, or lack of, a combination. The closest I could find were these measurements from Stereophile:

https://www.stereophile.com/content/magnepan-magneplanar-mg36r-loudspeaker-measurements

Speaking only about impedance matching, a speaker like this may have a slightly depressed mid-treble with a high output impedance amplifier. Is that bad? Well, depends on your room a great deal. You might have already tuned the room to compensate by making it less absorptive than you would have otherwise. Another thing to keep in mind is the amplifier’s output impedance. It may very well be complementary to the speaker’s and cancel out, or be a lot less reactive than you think.

With an ESL however, with an impedance curve that goes straight down, a solid state amp can really ensure you aren’t completely missing out on the treble.  My point here is that Maggies and ESLs are different beast and if you are happy don't let impedance curves make you unhappy alone.  ESL's however tend to be really good candidates for SS amps, but yes, there are exceptions.

So, no, changing is not a must. It will probably give you a different presentation and your judgement will tell better than armchair guessing based on the impedance curve of the speaker alone.

Points well taken, thank you. Guess its time for a higher powered amp!

I don't know whom at Magnepan you talked to, but the 3.7 "6-8 ohms throughout the audible range"? Nope, it is 4 ohms over most that range, dropping to 3 ohms at some frequencies.

The original version of the Tympani T-I (which I owned in the 70's) was a nominal 8 ohm load, but Magnepan re-engineered later Tympanis to 4 ohms (my Tympani T-IVa are), and all subsequent Maggies have been as well.

Fortunately the load is---unlike ESL's---almost purely resistive. It's not a difficult load, but Maggie lack of sensitivity coupled with it's modulus of impedance (the fancy term ;-) makes it a power sponge. While tube amps do work with Maggies, high-power tube amps are costly to buy and own. Low sensitivity/impedance loudspeakers eat power tubes for breakfast, lunch, and dinner. Lovers of Maggies and tube amps solved that dilemma in .6 and earlier models (which have parallel cross-overs) by bi-amping---using a high power amp on the bass driver, a medium on the midrange drivers and tweeters. In the .7 models Magnepan switched to series cross-overs, which cannot be bi-amped without surgery on the speaker.

Oh, they are Cary Audio SLA70s in monoblock configuration, which Dennis Had custom built for me just after he opened his company in Cary, NC. I was one of his first customers. He is a fellow Ham and I bought the amps and a SLP-70 which he heavily modified also with his RPC circuit, right down to the Peter Dahl. Spooky transparency. I was running the amps with 8 ohm Celestions before I bought the Magnapans. If Magnapan said I needed to alter them, I would have sent them back to Dennis. He wasn’t a fan of planars but respected my passion for them. Good guy, that Dennis.

Thanks, guys.  I don't listen at super loud levels and don't expect thundering bass. (I did have a sub, but it died, and frankly I don't miss it).  The Maggies sing with music on their own.  Double bass sounds like double bass, brass cymbals sound like brass cymbals and instruments and voices have timbre for days.  That is Magnapan's calling card and precisely why I bought them.  They are in a small office/study and the acoustics preclude me from blasting (although I have on occasion).  It is like listening in an intimate night club right in front of the musicians.  Magical, especially when I invoke the SS-X for live recordings which I acquired for just that purpose.  That thing is incredible.  I wrote about it which was the only other post I think I ever started in all these years.

I just thought you'd get a kick out of this.  There is an ongoing thread posing the question 'why topics get contentious' when this is just a hobby for fellow audiophiles wishing to share.  For everyman's passion, there is always a cold wet blanket in the wings.  I refer to it as 'the messianic compulsion'.  "Corvette parked next to a Ferrari".  HA!  Well put, indeed!  My friend did call me later to apologize, noting I never expressed interest in what his friend had for comparison.  I cared less.  

I will concede a high current amp with stable power into 2 ohms would drive the Maggies into nirvana.  Maybe I'll break down one day and score if I move my system into a larger room.  I have a friend who has a Krell driving Martin Logans which would be ideal. He has a large room and he can turn up the heat!  He also heard my system at full tilt and gave it the thumbs up. He is an audio technician and it was gratifying to get his approval.  

I am actually considering some speakers I could drive with a SS amp for full-tilt boogying where timbre is not the first priority. Perhaps some Klipsch Horns would do the trick, eh?  :-).  Actually, I rekindled my rememberance of some Walsh Ohms that knocked my socks off.  Hmmmm...

Good fun sharing this hobby.  I've learned over the years to tune the nay-sayin' know-it-alls out. When good suggestions are put forward for consideration, it is an entirely different matter.  Knowing the difference saves one's sanity in this passionate hobby.

Thank you for the positive responses and indulging me.  I have been on Audiogon for a bit and have always enjoyed seeing the sharing and camaraderie.  My hope is new comers to our community on Audiogon get a chance to read this for its true intent. Our younger brethren don't care to participate due to the contentious berating and that is a tragic shame.  

Best to all...

you let him park inside ?
just kidding
iF it sounds great move on, don’t worry be happy..

IF you have doubts borrow a high current amp, or tubes w more taps. My Music Reference has 2 ohm taps.

Lets look at this a minute. A class A tube amp running at 8 ohms. Not enough details for me but my guess, and I have a lot of experience with 3.6s running a class A amp, is that you are leaving a lot on the table. If you listen at low levels maybe...just maybe but I'll need to know more. What amp? 

I think the key question to answer is do you enjoy the music through your system.  Many respectable amp manufacturers only provide one hook for monoblocks or one per channel for stereo amps.

Maggies have some characteristics and one of them is not the ability to move air and create room shaking bass.  If that's your goal you'll likely not achieve it.  

The big thing is, does it sound good?  Everything else is as you said, a case of "wish I had a system like this blues".  I had some Maggie 3.5's and loved them.  I will have to say that they do love current.  I would tell people that they are slightly more sensitive than running power into a couple of rocks.  When the power hits though, HELLO DARLING, you sweet beautiful speakers.  We did try the Maggies with a Audio Research tube amp, that was in the 80 watt range and they just didn't wake up like they did with the solid state in the 300 watt range.  Sounds to me like you have a great match up based on the way they sing.  I have never worried about what other people think of my system.  The only thing I listen to about my system is my ears.  Had a old college acquaintance come over one day and listen and he did similarly and began to tear things apart and what wasn't correct.  This from a guy that played infinity speakers with a carver amplifier.  It quickly became apparent that he knew his Corvette was parked next to a Ferrari and it really pissed him off.  Enjoy what you have and don't worry about others.  

I run a Rogue integrated with 1.6s with no issues. I think they are on the 8 ohm tap. I never even bothered checking because it sounds great.