What to drive new Magnepan 3.7i's

While I understand that the 48V power supply will give some increased overhead in power output, I’ve just not seen the need. Quite literally, with the 32V power supply the A07 can get 90dB average at my listening position without breaking a sweat. That’s way too loud for comfortable listening to me.

My only caveat is that I am also using a MiniDSP for PEQ functions. It can’t fix a bad amp in any way. The A07 is still an uber-capable little amp, easily capable of driving Maggie’s. I use it to help weak the output to suite my listening preferences.

If you have even the slightest doubt go ahead and order one. If it’s not working for you return it.
 
Stephen300 said:
In my experience Maggies benefit the most from amps that can double their 8Ω output power into 4Ω.
Click to expand...

That's another way of saying that the amp's output impedance is at least 4 Ohms.

If the output power didn't double when switching from an 8 Ohm load to 4 Ohm load, then that "lost power" manifests itself as all sorts of unfriendly things like heat, clipping, distortion, etc.

The ideal amplifier (and I mean ideal in an electrical engineering sense) is one that has zero output impedance, infinite gain, and infinite frequency response. No such amplifier exists. So find one that meets all the requirements that you currently (hah, current) have.

In the case of Magepans that would be an amplifier capable of driving 4 Ohm loads, with sufficient power to make your ears happy with the maximum sound output level, having linearity across the entire audio frequency spectrum, and no added noise or distortion.
 
Ordin Aryguy said:
That's another way of saying that the amp's output impedance is at least 4 Ohms.
Click to expand...

This is incorrect in so many ways I don't know where to begin. At minimum it demonstrates a complete lack of knowledge about how an amplifier works.

I believe you have confused an amplifier's ability to drive 4 Ohm or lower loads with the amplimers actual output impedance.

From Wikipedia: My bold underline and increased font size.

Source_and_load_circuit_Z.png

The real output impedance (ZS) of a power amplifier is usually less than 0.1 Ω, but this is rarely specified. Instead it is "hidden" within the damping factor parameter, which is:

{\displaystyle DF={\frac {Z_{\mathrm {L} }}{Z_{\mathrm {S} }}}}
dfbc65bdf9f6c63135de25418f77b54112b757e9

Solving for ZS,

{\displaystyle Z_{\mathrm {S} }={\frac {Z_{\mathrm {L} }}{DF}}}
d5bb5c30aeba089dd11813dbc1d5b83d070dd5a9

gives the small source impedance (output impedance) of the power amplifier. This can be calculated from the ZL of the loudspeaker (typically 2, 4, or 8 ohms) and the given value of the damping factor.

Generally in audio and hifi, the input impedance of components is several times (technically, more than 10) the output impedance of the device connected to them. This is called impedance bridging or voltage bridging.

In this case, ZL>> ZS, (in practice:) DF > 10

In video, RF, and other systems, impedances of inputs and outputs are the same. This is called impedance matching or a matched connection.

In this case, ZS = ZL, DF = 1/1 = 1 .

The actual output impedance for most devices is not the same as the rated output impedance. A power amplifier may have a rated impedance of 8 ohms, but the actual output impedance will vary depending on circuit conditions. The rated output impedance is the impedance into which the amplifier can deliver its maximum amount of power without failing.

FWIW: I've been using Magnepans or various ESL's exclusively since 1976.

Here's a link to the page in Wikipedia.
Output impedance - Wikipedia

The last sentence in the Wiki article is incorrect. However, the circuit diagram and equations are correct. The ability to drive various loads does not mean an amplifier is 2, 4, 8, 16 Ohm rated. It means the amplifier is rated to drive the specified load with no difficulty.
 
Last edited:
I just noticed that JoeESP9 is driving the Maggies with Dynaco MKIII. If memory serves those are 60W amps. Are you driving the 1.7's full range with sub augmentation or are you crossing them over at some point to the subs? Thanks
 
I've been offloading the bass from my previous ESL's and current Maggies via an electronic crossover set at ~65Hz for 20+ years.
 
JoeESP9 said:
This is incorrect in so many ways I don't know where to begin. At minimum it demonstrates a complete lack of knowledge about how an amplifier works.

I believe you have confused an amplifier's ability to drive 4 Ohm or lower loads with the amplimers actual output impedance.
Click to expand...

I stand corrected. In my haste I didn't proofread what I had written in that sentence.

What I should have written is "That's another way of saying that the amp's output impedance is sufficiently low to be able to drive at least 4 Ohms."

I still do stand by my assertions about ideal amplifiers. Infinite gain, zero output impedance, linear from 0 Hz to infinite. Those only exist on paper.
 
I hope this works and that it comes across in a simple to understand manner. I've attached a quicky schematic and a table of a couple values.

The simple schematic shows an ideal amplifier, with output impedance, connected to a 4 Ohm speaker. Since we're talking Magnepans, I used 4 Ohms as a speaker impedance.

The chart shows what happens as the output impedance increases from zero Ohms (an impossibility) to 1 Ohm. Note what happens to the actual voltage at the speaker versus what is expected at the speaker if there were no output impedance.

When an amplifier doesn't double it's delivered power when switching from an 8 Ohm load (speaker) to a 4 Ohm load, it's because it's output impedance is sufficiently high that there is significant voltage loss in the output stage itself. Loss of voltage at the speaker mathematically correlates to loss of power at the speaker.

If using 8 Ohm speakers, all of the losses would be reduced by one half. But we don't, because we like Maggies!
 

Attachments

techguy0192 said:
Most importantly may be the fact that Magnepan routinely uses Bryston amps at shows to demo their speakers
Click to expand...
During the forty plus stop 30.7 tour, Wendell brought only the speakers and relied upon the local dealer for the rest of the system. Naturally, your photo was shot at a dealer in Vancouver.

In this case, the dealer chose McIntosh and Nordost Odin cabling:


In this case, they used Ypsilon Hyperion amplification:

https://www.theabsolutesound.com/articles/magnepan-307-loudspeaker-part-one

Here, Ayre VX-5/20s were used.

https://www.audionirvana.org/forum/...rs/95901-magnepan-30-7s-visit-jacksonville-fl

Here, it appears to be Mark Levinson amplification. And there's a pic of the speakers in his van:

https://www.facebook.com/ShelleysStereo/posts/878249225693856

The best I've heard both 20.1s and 3.7s was with tube amplification at Sea Cliff. Using Joule Electra Right of Passage and McIntosh 2301s, respectively.

20.1.jpg


3.7-2301.jpg
 
E-Stat said:
During the forty plus stop 30.7 tour, Wendell brought only the speakers and relied upon the local dealer for the rest of the system. Naturally, your photo was shot at a dealer in Vancouver.

In this case, the dealer chose McIntosh and Nordost Odin cabling:


In this case, they used Ypsilon Hyperion amplification:

https://www.theabsolutesound.com/articles/magnepan-307-loudspeaker-part-one

Here, Ayre VX-5/20s were used.

https://www.audionirvana.org/forum/...rs/95901-magnepan-30-7s-visit-jacksonville-fl

Here, it appears to be Mark Levinson amplification. And there's a pic of the speakers in his van:

https://www.facebook.com/ShelleysStereo/posts/878249225693856

The best I've heard both 20.1s and 3.7s was with tube amplification at Sea Cliff. Using Joule Electra Right of Passage and McIntosh 2301s, respectively.

20.1.jpg


3.7-2301.jpg
Click to expand...

Yes, I was aware that was from the 30.7 tour. Here's what they had in their room at AXPONA 2022. A prototpye Magnepan amp was also there; however, I haven't seen any updates on if it will come to market or not. Very common to see Magnepan and their dealers demo with Bryston. Obviously, there are other brands that also do a good job of powering them.

MagenepanAXPONA_2022.png
 
techguy0192 said:
Tell it again.
Click to expand...
What I find most interesting in Darko’s report is the ongoing showing - if not product announcement - of their dipole subs. They have been developing them literally for years. Given they have a huge manufacturing backlog, I get why they are prioritizing resources on that challenge.

https://positive-feedback.com/audio-discourse/magnepan-focus-group-event/

I use a pair of conventional powered subs to augment Acoustat 1+1s in the HT, but would likely find dipolar versions better matched. I am spoiled by not really needing subs upstairs with the U790s.
 
MarmotDavid said:
I've got a new pair of Magnepan 3.7i's. Currently I'm using my older, unrestored Counterpoint SA-1000 tube/hybrid preamp and and old solid-state Conrad Johnson Sonograph SA-250 power amp. The setup sounds pretty good but I'm sure it could be improved with some newer preamp and power amp, so I'm looking to upgrade these aging electronics. I don't feel I'm getting the best out of these great speakers with this level of preamp and power amp

I'm willing to spend up to about $6000 on a new combination of a preamp and power amp. I have a medium sized listening room and I generally don't listen at really loud levels, so I'm not interested in really beastlike power amps or mono blocks. I like a detailed, warmer sound with good soundstage and very present vocals at moderate levels, if that helps. I need a MM phono stage, Maybe some combination of tube and solid state? I might even consider a big integrated if I knew it worked well with the Maggies. Also, I would definitely buy used if necessary but would probably avoid anything unrestored if it is over, say, 15 years old.

Please let me know all your ideas and comments. All will be appreciated. Thank you.
Click to expand...

What you've got is pretty good. Although Maggies work great with a lot of power, it's not entirely necessary. Be careful with the urge to upgrade. Figure out what you are looking for, what needs improvement. With any dipole speakers, position is everything. Before spending a dime, invest some time.
Get them optimally positioned. If you can't then all the money you spend is lost seeking a goal that technically can't happen.

Audio is both a blessing and a curse
 
ehoove said:
From my experience - ARC LS16MkII or better preamp and Aragon 8008B or Palladium mono block power amps will be fabulous with Maggies. Bought used will be well under your budget.
Regards,
Jim
Click to expand...
If I am looking for a preamp with a phono stage, which of the ARC preamps under about $3k used would you recommend?
 
Old Guy8 said:
I have 1.7i driven by Rogue Cronus Magnum tube integrated V1. KT120 power tubes and 100 wpc. BTW, KT120 tubes are "ONLY made in Russia." So there is that negative. And KT120 difficult to find and very expensive now. Mine was special ordered without phono preamp. It has a little warmth to it. Lovely adding a touch of warmth, with 1.7i.

I also have used a Bryston BP20 preamp and 3B NRB power amp from '94. 125 wpc @ 8 ohms. 200 wpc @ 4 ohms.. Of course, it's brighter than the Rogue. It had a 20 year warranty. It only gets warm driving Maggie. Never hot. Bryston offers component and cosmetic refurbishing services with 3 yr. warranty for thier older amps.

I listen to mostly jazz in a 400sf+ X 7 ft height room. 75db spl average volume or less, at 10 feet away. I can't speak to question, if higher power amps sound better than these. Not tried larger amps.

Cronus Magnum makes Maggies sound lovely with a little warmth. Little more midrange focus. Vocals are great. The Bryston gives more bass punch and more high end sparkle. My hearing has a little tinnitus that can mask high frequencies.

Edit: I use this SPL meter. Bought on ebay for about $16, while back. I tried phone SPL apps first. I found same app on different phones, gave reading variation. But, apps are cheaper.
View attachment 2629036
Click to expand...
I took your advice and tested my listening level with a meter. In my 450ish sq. ft room, ceilings about 7 1/2 feet high, listening at about 10 feet away from the Maggie 3.7i's, I like listening at about 60 dB average, peaks about 72dB. That seems a lot lower than others are listening. To me, this level seems like correct sound level for a live performance, with normal active listening, not background listening. Any louder for me is uncomfortable. This is why I am trying to avoid overspending on massive power amps. I would rather but something with superb quality and tone at these moderate listening levels.
 
About 17 years ago at a meeting of the Minneapolis Audio Society, I heard a set of 3.7s, usually driven by an Audio Research amp & preamp, but on this occasion driven by a very high-end integrated amp designed by Thorsten Loesch, fed by a CD player from the same designer, and connected with some very costly cables that looked like they had testicles (Hey, I didn’t design them). Those 3.7s produced some of the most lifelike sound I’d ever heard up to that point, far surpassing what was usually produced by that system. I remember some old curmudgeon growling, “Show off!!” at the conclusion of a CD played by the distributor that brought the equipment, but the old guy did nothing more than voice the general consensus. The whole group was blown away, and some of those guys were a pretty tough sell.

My point is that those speakers are capable of some pretty amazing reproduction given the right ancillary equipment. I’ve never heard a Pass amp, but I’ve owned a couple of Thresholds and was very happy with them, so I think a used Pass X-250 might be worth looking at. I have a lot of respect for Nelson, and those speakers deserve the best you can afford to drive them with. Just my $0.02. That and a couple of bucks will get you a cup of coffee, as the saying goes.
 
You must log in or register to reply here.
Back
Top Bottom