Tubes and less sensitive speakers

I thought I heard Atmasphere amps can work well with Maggies but could be wrong.  Worth checking or maybe @atmasphere can chime in. 

Convergent amps will drive anything, but tend to be pricey.  

I thought I heard Atmasphere amps can work well with Maggies but could be wrong.  Worth checking or maybe @atmasphere can chime in. 

@soix We have a number of customers using our OTLs with Maggies. The smaller amps like the M-60 tend to be used with the smaller Maggies in tandem with a set of ZEROs. The bigger Maggies like the 3.7 might have MA-1s. Willard Diller of Magnaplanar used to make a point of telling me the best he ever heard the MG20s was with a set of our MA-2s.

At any rate, if you want the best out of the tube amp, whatever it is, it makes quite a difference to keep the speaker cables as short as possible. To this end I've seen 8 inches of really heavy cable (8 gauge) make an enormous difference in how the amp made bass impact as opposed to 6 feet of a regular cable! But to do that you need monoblocks so you can put the amp right behind the speaker so its speaker terminals are as close to the speakers as possible.

Rogue Audio amps have prodigious bass and slam for tube amps, and are a great value per dollar. Especially as you step up to M180 monos or (even better) the discontinued Zeus and Apollos

I haven’t heard Maggies myself, but hear from others I trust this is a favorable pairing. I even know a dealer who prefers big Rogue amps on Maggies over (much more expensive) ARC amps (the ARC Reference preamps are much better than Rogue’s RP line, though - IMO and others too).

The downside to Rogue tube amps is they won’t have a "tubey" midrange like many other tube amps. They can sound sort of like a hybrid between tubes and SS, though they’re all tube. But the bass, dynamics and power - wow.

I'm very familiar with Maggie 3.6s. I would not recommend a tube amp for these. Although some of the bigger powerhouses sound good but with lots of heat and heft. Your Hegel is probably a decent amp.  I would add a tube pre-amp, a good one. 

If I was you I’d strongly consider Atmasphere’s GaN amp (no affiliation with the company BTW).  You’ll get a lot of the tube sound with solid state bass control and none of the tube hassle, heat, or expense.  I think you can even do a trial period with them, which would seem to be a no brainer to me.  Put a good tube pre in front of it and that could be a magical combo.  That’s what I’d do anyway FWIW.  Best of luck. 

@boxcarman - Magnepans are typically very inefficient and require high current amps to get the best out of them.  This is why most amp recommendations for Maggies are on the solid state side.  Not to say there aren’t tube amps out there that sound good with them (I will differ to @atmasphere as more of an expert on that subject). 

There are a lot of older threads on Audiogon that go into this in greater detail.  I’d search through them and spend some time reading.

@russ69 does have a good suggestion on using a tube preamp with a solid state amp or even a hybrid amp with a tube input section, to keep the tube sound in the mix.

... my 2 cents....

Magnepans are typically very inefficient and require high current amps to get the best out of them. 

@jeffbij Just so you know, this statement is false. 

To understand why the first thing you need to know is how current plays out in a speaker like this, which is a fairly resistive four Ohms without odd phase angles.

To make 200 Watts into that speaker you need an amp that can make just a tiny bit over 7 Amps. As you probably know, in the scheme of solid state amps that's not a lot of current.

A 'high current' amp is probably called that because it can double power into 4 Ohms from 8 and maybe again from 4 Ohms down to 2 Ohms. But the Maggies really don't require an amp that can drive 2 Ohms with double the power. They only require that the amp make power into 4 Ohms and can do it in such a way that very minor variations in impedance don't result in variations in output.

Many so-called 'high current' amps advertise a current rating that doesn't square with the power ratings they claim; IOW the 'current' stated is often far more than the amp could ever produce. That is because that rating is the amount of current that would flow for 10milliseconds if the power supply were shorted out. Its not anything to do with the power the amp can make.

Since the speakers don't have a box, they don't have the same sort of resonance that requires a low output impedance to control them, even in the bass. They just need the amp to be able to make the power.

It is true Maggies don't seem to be very efficient. But since they behave as a line source, you really have to add about 6dB to their measurement to understand what is going on. If you've been around a set of Maggies, you may have noticed that they sound just as loud ten feet away as they do when you are only a foot away. That is because at a distance, more of the output of the speaker is reaching your ears while when close up it does not. The same is true of a microphone placed 1 meter from them.

So this means the speaker really is more sensitive than the rating suggests. The model 2.7i for example is similar to an 8 Ohm box speaker of 89dB or a 4 Ohm speaker that is 92dB.

Crazy Suggestion since they are hard to find and long out of production but perhaps the 400 watt Melos monoblocks(triode output). They easily put out 400 watts(under rated, especially earlier versions) with a relatively high damping factor too(20 if I recall). The big problem is taking care of them and rare tubes(EL519).

@atmasphere  -  I stand corrected.  I've always based my efficieny for Maggies on their published specs, but the reasoning about the line source behavior makes sense.  I even took a moment to test the

...they sound just as loud ten feet away as they do when you are only a foot away.

and I agree.  In my ~20 years of Maggies in my secondary system, it was something that I never paid attention to.

Just goes to show, we can always learn something new every day.

One thing to consider is installing a high pass filter on the input jacks of the power amp (inside the amp)---or in a little box containing the filter plugged into the input jacks (as the video below will explain)---feeding the Maggies, to remove low bass frequencies from entering the amp and therefore the Maggies. The "corner" frequency of the filter is determined by the value of the capacitor used and the input impedance of the amp. There are formulas available on the internet for determining the cap value required for different amplifier input frequencies and the desired x/o frequency. Removing the low bass from the input signal to the amp will significantly decrease the power required to run the Maggies, and improve the sound of the amp and speakers as well (decreased power amp distortion produced, less excursion of the Maggie Mylar diaphragms). Removing the bottom octave (20-40 Hz) cuts the amplifier power required in half!

One amp to consider is the no-longer-in production Music Reference RM-200 MK.2 (review by Michael Fremer and John Atkinson available for reading on the Stereophile website), available used for around $2500 (one just sold at that price yesterday on USAM). The RM-200 was designed specifically to work well with low impedance loudspeakers, and puts out 125 watts into 4 and 8 ohm loads (the amp also includes 2 ohm and 1 ohm taps!). It uses only a single pair of KT88 (or 6550) tubes to produce those 125 watts, yet the tubes last around 10,000 hours.

Then add a pair of subwoofers to reproduce the low bass. Planar devotees have employed this tactic for decades, all the way back to the QUAD ESL of the 1950’s. I’ll post below a video Danny Richie of GR Research made on the subject of high pass filtering loudspeakers and adding subs:

https://youtu.be/65eFr2rKy3M?si=rftln4L2ryHM_yvf

Have you ever thought about getting a hybrid amplifier?  I’m currently using PS Audio BHk preamp and 300 mono blocks.  They have a tube input section and the amps have a Mosfet output section. Plenty of power and warmth.

The sanders magtec was developed for this type of speaker.they work well great synergy.the music room has one for sale around 4k.you can go to sanders sound website and read his white paper.enjoy the search

An inexpensive option would be a pair of PrimaLuna Evo 400 power amps in mono?  Each is capable of running with 8 KT150 tubes in Triode or Ultra Linear mode.  Just a thought.  Cheers.

The noble exchange between @jeffbij and atmashere is worth noting . Well done gentlemen .

I agree - nice job by both in providing clarity and reaching a unified view.

Regarding proper subwoofer integration, I would caution that while this is a valid approach, in my experience, it can also be quite challenging due to the true dipole dispersion of Maggies. A number of years ago I was running a set of Quad 2805 and Maggie 1.7i with Atma-Sphere amps and wanted to supplement with subwoofers. Unless the subs were truly fast enough to match the speed of the stats and planars and impeccably integrated, it tended to cause smearing through the frequency extreme because of interference between the subs and the speakers’ radically different rear dispersions. In my opinion it would be best to first address the amp / speaker matching to the best of your ability as this will deliver the optimal control and tone out of the speakers. Doing so will also make it easier to integrate subs if/when one is ready to do so.

In short, don't use subs as a band-aid solution, but only to improve upon performance that can already be gained elsewhere.

Also to answer the OP's original question, Audio Research and Magenpan have have had a nice love affair going on for some time now, so perhaps look into their amps.

I agree that with Ralph that if you're using the 3.7's and want to look at Atma-Sphere, look into the MA-1 and not any of the smaller models. I've been in the camp of trying to mate his smaller amps with autoformers on larger planars / stats and while it's pleasant, you won't get the best out of them. The MA-1 MK3.3 is highly recommended as long as you can handle the number and heat of the tubes.

Thanks for all the info and opinions.  I admit I have a case of upgradei itis and am approaching this with caution.  I am also considering Magnepan's new X models from which I have heard very good reports.

The Music Reference RM-200 MkII might make for a nice amplifier choice for Maggies as @bdp24 noted. One of the reasons is that it is one of the few if not only amplifiers with a tube output stage that outputs more power into lower impedance loads. As measured by Roger Modjeski on his bench the amp puts out 112 watts into 8 ohms, 145 watts into 4 ohms, and 125 watts into 2 ohms.

Regarding the poet by @blisshifi: Mating subs with Maggies (in fact any and all dipole loudspeakers) is indeed a challenge. The solution is a dipole subwoofer, which Magnepan has been working on a for a few years now.

There is already a real good one available, the Rythmik Audio/GR Research Open Baffle Servo-Feedback Subwoofer. It employs two or three (your choice) 12" servo-feedback-controlled 12" woofers in an open baffle frame, and works splendidly with dipole loudspeakers. Check the GR Research website for details.

I have no personal experience with the Sanders Magtech amps (other than reputation), but they are manufactured by CODA, and that is never a bad scenario

Many years ago when they were current products, William Z Johnson came to our local dealer to demo his new model Maggie Tympani.  He was using ARC tube electronics, including large amplifiers.  That system sounded absolutely wonderful and with a wide varied of music.  Of course there was a connection between Magnepan and Audio Research for many years.  But tube amplification can work well if of sufficient power.