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Question about amplification for new Magnepan LRS speakers

Blake Klondike

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I hope it isn't a breach of etiquette to post several questions about the system I am trying to set up! I appreciate everyone's help! Thought this might be of general interest, as well. From Magnepan website:

The LRS (Little Ribbon Speaker) is a full-range quasi-ribbon speaker that was designed from the ground up to give you a pretty good idea what to expect from the 20.7 or 30.7. The LRS was designed using high-end electronics and mono blocks. The LRS will perform nicely with a receiver, but it was intentionally designed to extract the most from high-end amplifiers and electronics. The LRS expects more from a properly designed high-current amplifier. That is a radical departure from most entry-level loudspeakers. If you put your expensive high-end amplifier on the LRS, you will hear the difference.


So far, these speakers, playing Amazon Music streaming --> Oppo HA-2 DAC--> Cambridge Audio AM-10 Topaz Integrated, sound good but fairly anemic. Does anyone have any idea what "high-end amplifiers and electronics" actually means? In a world where $250,000 amplifiers and $75,000 CD players exist, it is hard to figure what price they consider "high-end". Thanks again!

By the way, I am a guitar teacher, so if there are any questions I can answer about the one thing I do know about, just ask! :)
 

SIY

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Pretty much what they said- current and power delivery, at least 100 watts and more can't hurt. Cost is irrelevant. Something like Hypex-based amps should work well, or if you're adventurous and cheap, find an old Adcom GFA-555 and have the power supply caps replaced if needed. At higher cost, but still not nuts, look at a Bryston.

And I could always use some lessons.:D
 

Bald1

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There have been some recent threads on the MMG and 1.7 where amplification was discussed. High current delivery makes a big difference with Magnepan bipolar planar speakers, opening them up to their unrestrained potential.

I noted that I had progressed with current delivery to my modified MGIIIa's I've had for the past 19 years ending up with Odyssey Stratos Monoblocks which provide over 120 amps current delivery. Huge improvement and significant increase in peak current delivery over a vintage Dynaco ST410 and Parasound HCA-1200 that I'd previously used.
 

RayDunzl

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Looking...

https://www.magnepan.com/model_LRS

https://www.magnepan.com/faq#questions

---

So far, these speakers, playing Amazon Music streaming --> Oppo HA-2 DAC--> Cambridge Audio AM-10 Topaz Integrated, sound good but fairly anemic.

Your Cambridge AudiAM-10 Topaz:
  • 35 watts x 2 channels into 8 ohms (20-20,000 Hz)
That calculates to 16.73V signal maximum signal

Oh wait, there's more:
  • 35 watts x 2 channels into 8 ohms (20-20,000 Hz), 0.15% THD at 80% of rated power
Not sure what "80% of rated power" means. Maybe 80% of 35W so 28W before it starts getting fuzzy above 15V.

Ok, that's rather "anemic".

---

More power won't hurt.

I run electrostats, with a 15x48 inch panel. Different technology, but similar, in that a large area is being driven.

Old amp was a simple Class A/B with 250/350W at 8 and 4 ohms, newer (still old now) rated 350/700/1400W into 8/4/2 ohms.

Both sound fine as loud as you dare at home. No anemia.

The newer old amp can swing over 50V across the speaker leads.

The speakers are 21 years old now, and speak very well.

---

New amps?

What to get?

I have no experience with any.

By the way, I am a guitar teacher, so if there are any questions I can answer about the one thing I do know about, just ask!

Yeah! How can I make my fingers move to the right place at the right time!

Hmm...

Maybe a small Crown... Low investment, much more powerful than what you have.

Most have volume knobs, so you could use the Cambridge as a switch (REC OUT) to feed it.

Musicians use them all over the world.

https://www.sweetwater.com/c455--Crown--Power_Amplifiers?mrkgcl=28&mrkgadid=3296446957&rkg_id=0&campaigntype=paidsearch&campaign=aaText - Live Sound & Lighting - Power Amplifiers - &adgroup=Power Amplifiers - Crown&keyword=crown amplifiers&placement=google&adpos=1t2&creative=341750902026&device=c&matchtype=e&network=g&gclid=CjwKCAjw2cTmBRAVEiwA8YMgzR1T7b6wST-2EIWcXGjFk_Adp5V67y3tkfKtxItz7YiMC4tM_C5sfxoCIsUQAvD_BwE

---

At this point I defer to any Magnepan owners for further advice.
 
Last edited:

Blumlein 88

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I'd second the suggestion to use a Hypex based amp. Plenty of power and good sound.
 

LTig

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I hope it isn't a breach of etiquette to post several questions about the system I am trying to set up! I appreciate everyone's help! Thought this might be of general interest, as well. From Magnepan website:

The LRS (Little Ribbon Speaker) is a full-range quasi-ribbon speaker that was designed from the ground up to give you a pretty good idea what to expect from the 20.7 or 30.7. The LRS was designed using high-end electronics and mono blocks. The LRS will perform nicely with a receiver, but it was intentionally designed to extract the most from high-end amplifiers and electronics. The LRS expects more from a properly designed high-current amplifier. That is a radical departure from most entry-level loudspeakers. If you put your expensive high-end amplifier on the LRS, you will hear the difference.

So far, these speakers, playing Amazon Music streaming --> Oppo HA-2 DAC--> Cambridge Audio AM-10 Topaz Integrated, sound good but fairly anemic. Does anyone have any idea what "high-end amplifiers and electronics" actually means? In a world where $250,000 amplifiers and $75,000 CD players exist, it is hard to figure what price they consider "high-end". Thanks again!
You need an amplifier which is happy driving 4 Ohm loads - meaning lots of current.

However, when you say the LRS sounds good but anemic I'm not so sure that the culprit is the amp. I have owned MG-1.6 for 12 years and with an insufficient amp (Kenwood KA80, rated 50W @ 8 Ohm) mine did not sound anemic but grainy and kind of distorted. Switching to a better power amp (Amber S70, rated 70W @ 8 Ohm) made the MGs sound much cleaner. Yes, there was also a bit more bass but not much if I remember correctly.

What I think may be the culprit is that the LSR is even smaller than the (old) MG-1.6 and you are just missing bass. With a small panel it's difficult to get deep bass at all and you should try to find a better positioning (both speakers and listening place). At my place moving the chair I sat on closer to the back wall increased the amount of bass (but not its quality). The distance of speaker to front wall also had a big effect.
 

BigJim

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I auditioned the LRS and they had it hooked up to the smaller Rega integrated amp and Rega CD player with good quality cables. Not sure it was the newest model since the Rega website did not have the same one listed. I found the LRS with this set up to have great clarity and imaging, but the midrange soundstage appeared to be way forward of the rest of the music. Not sure how to fix or adjust for that. I would have liked to try more amps to see if the sound changed but did not have the time. I want a pair but I heard there is a serious backlog on the speakers.

Decent bass but if you are going for the rumble, you will need a sub.
 

ronsbass

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I hope it isn't a breach of etiquette to post several questions about the system I am trying to set up! I appreciate everyone's help! Thought this might be of general interest, as well. From Magnepan website:

The LRS (Little Ribbon Speaker) is a full-range quasi-ribbon speaker that was designed from the ground up to give you a pretty good idea what to expect from the 20.7 or 30.7. The LRS was designed using high-end electronics and mono blocks. The LRS will perform nicely with a receiver, but it was intentionally designed to extract the most from high-end amplifiers and electronics. The LRS expects more from a properly designed high-current amplifier. That is a radical departure from most entry-level loudspeakers. If you put your expensive high-end amplifier on the LRS, you will hear the difference.

So far, these speakers, playing Amazon Music streaming --> Oppo HA-2 DAC--> Cambridge Audio AM-10 Topaz Integrated, sound good but fairly anemic. Does anyone have any idea what "high-end amplifiers and electronics" actually means? In a world where $250,000 amplifiers and $75,000 CD players exist, it is hard to figure what price they consider "high-end". Thanks again!

By the way, I am a guitar teacher, so if there are any questions I can answer about the one thing I do know about, just ask! :)
I don't think power is as important as current. I have Maggie QR10s. they have been used with a number of amps, BRB Systems 120 W/Ch.,Krell KAV 500 500 W/ch. the amp that sounds best is a ML2 clone from Breeze Audio (China) 35 Class A watts $500 delivered.
 

MickeyBoy

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I hope it isn't a breach of etiquette to post several questions about the system I am trying to set up! I appreciate everyone's help! Thought this might be of general interest, as well. From Magnepan website:

The LRS (Little Ribbon Speaker) is a full-range quasi-ribbon speaker that was designed from the ground up to give you a pretty good idea what to expect from the 20.7 or 30.7. The LRS was designed using high-end electronics and mono blocks. The LRS will perform nicely with a receiver, but it was intentionally designed to extract the most from high-end amplifiers and electronics. The LRS expects more from a properly designed high-current amplifier. That is a radical departure from most entry-level loudspeakers. If you put your expensive high-end amplifier on the LRS, you will hear the difference.

So far, these speakers, playing Amazon Music streaming --> Oppo HA-2 DAC--> Cambridge Audio AM-10 Topaz Integrated, sound good but fairly anemic. Does anyone have any idea what "high-end amplifiers and electronics" actually means? In a world where $250,000 amplifiers and $75,000 CD players exist, it is hard to figure what price they consider "high-end". Thanks again!

By the way, I am a guitar teacher, so if there are any questions I can answer about the one thing I do know about, just ask! :)

I used to own Maggie MG-IIIas and loved them. Big Maggies (5-6' tall) always were reputed to demand lots of power, which I believe is basically true. However, today we have technology not available in 1990 when i bought mine. Powered woofers and room correction software can make bass response deep and even, while giving the listener control over amplitude and phase relationships unavailable previously.

So the real questions are:

One: why not use the LRS like a mini monitor, say 80-100 Hz and up? This would reduce the power requirement considerably and perhaps give better midrange and treble response.

Two: what is new and different about the LRS? The .7 series of "quasi-ribbons" goes back to 2010. Is there any technical improvement? The .7 series is described by the manufacturer as "quasi ribbon" only, the LRS as "quasi-ribbon planar magnetic." Does this terminology conceal an engineering difference? It is not at all clear to me what designed for high power could possibly mean. Better dynamic range? (a frequent criticism of Magneplanars) Ability to play ear-splittingly loud? (doubtful for Maggie customers) ???
 

DonH56

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I do not know what the LRS panels look like.

In general, Magnepan has used "planar magnetic" to describe their older panels that used wires bonded on mylar (or whatever plastic sheet material they use) and "quasi-ribbon" to describe their new patterned traces on plastic approach (which to me is still conventional planar dynamic and not really a ribbon structure).
 

MickeyBoy

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Looking...

https://www.magnepan.com/model_LRS

https://www.magnepan.com/faq#questions

---



Your Cambridge AudiAM-10 Topaz:
  • 35 watts x 2 channels into 8 ohms (20-20,000 Hz)
That calculates to 16.73V signal maximum signal

Oh wait, there's more:
  • 35 watts x 2 channels into 8 ohms (20-20,000 Hz), 0.15% THD at 80% of rated power
Not sure what "80% of rated power" means. Maybe 80% of 35W so 28W before it starts getting fuzzy above 15V.

Ok, that's rather "anemic".

---

More power won't hurt.

I run electrostats, with a 15x48 inch panel. Different technology, but similar, in that a large area is being driven.

Old amp was a simple Class A/B with 250/350W at 8 and 4 ohms, newer (still old now) rated 350/700/1400W into 8/4/2 ohms.

Both sound fine as loud as you dare at home. No anemia.

The newer old amp can swing over 50V across the speaker leads.

The speakers are 21 years old now, and speak very well.

---

New amps?

What to get?

I have no experience with any.



Yeah! How can I make my fingers move to the right place at the right time!

Hmm...

Maybe a small Crown... Low investment, much more powerful than what you have.

Most have volume knobs, so you could use the Cambridge as a switch (REC OUT) to feed it.

Musicians use them all over the world.

https://www.sweetwater.com/c455--Crown--Power_Amplifiers?mrkgcl=28&mrkgadid=3296446957&rkg_id=0&campaigntype=paidsearch&campaign=aaText - Live Sound & Lighting - Power Amplifiers - &adgroup=Power Amplifiers - Crown&keyword=crown amplifiers&placement=google&adpos=1t2&creative=341750902026&device=c&matchtype=e&network=g&gclid=CjwKCAjw2cTmBRAVEiwA8YMgzR1T7b6wST-2EIWcXGjFk_Adp5V67y3tkfKtxItz7YiMC4tM_C5sfxoCIsUQAvD_BwE

---

At this point I defer to any Magnepan owners for further advice.
Hi Ray,

I seem to remember you have a room as small as my 15 X 17 X 82/3. Your stats are the same size as the LRS and put out some decibels. What room correction software do you use?
 

RayDunzl

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What room correction software do you use?

AcourateDRC, which is specifically for use with a miniDSP OpenDRC-DI (or others if there are any left in the OpenDRC series).

It comes from the Acourate (AudioVero) folks, but is a lightweight version.

I chose not to use the PC for correction, because I don't listen to or through it, so I have the miniDSP hardware in-line (digital in-out) for my various sources.

I'l rate it as giving a "good enough" improvement... both visually, and audibly, for the five minutes it takes to perform a measurement and correction.

Left and right before/after ERB smoothing, flat being the selected goal at the time:

1561244003536.png
 
Last edited:

VMAT4

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Maybe a pair of these mono block amps would do the trick. Outlaw Audio will put them on sale before the holidays.
 

VMAT4

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restorer-john

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Cost is irrelevant. Something like Hypex-based amps should work well, or if you're adventurous and cheap, find an old Adcom GFA-555 and have the power supply caps replaced if needed. At higher cost, but still not nuts, look at a Bryston.

Or a brand new Adcom GFA-555se...

https://www.adcom.com/product_gfa555se.php

1561446264740.png
 

SIY

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I think I paid $500 for mine in 1985, so that's pretty reasonable. And of course, the point remains that even 35 years ago, the problem of power amplification had long been solved.

I'm going to see if I can get one loaned to me for comparison to the original.
 

MickeyBoy

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I used to own Maggie MG-IIIas and loved them. Big Maggies (5-6' tall) always were reputed to demand lots of power, which I believe is basically true. However, today we have technology not available in 1990 when i bought mine. Powered woofers and room correction software can make bass response deep and even, while giving the listener control over amplitude and phase relationships unavailable previously.

So the real questions are:

One: why not use the LRS like a mini monitor, say 80-100 Hz and up? This would reduce the power requirement considerably and perhaps give better midrange and treble response.

Two: what is new and different about the LRS? The .7 series of "quasi-ribbons" goes back to 2010. Is there any technical improvement? The .7 series is described by the manufacturer as "quasi ribbon" only, the LRS as "quasi-ribbon planar magnetic." Does this terminology conceal an engineering difference? It is not at all clear to me what designed for high power could possibly mean. Better dynamic range? (a frequent criticism of Magneplanars) Ability to play ear-splittingly loud? (doubtful for Maggie customers) ???

The Magnepan instruction manual (https://www.magnepan.com/manual/LRS )gives a hint as to what might be different:

"The LRS uses a unique high-current connector (See Figure 1). Strip approximately 1/4-inch of insulation from the speaker cable end and insert it into the connector and tighten the set screw with the Allen wrench provided. Special spade lug adapters are available from Magnepan...call to order.
Magnepan encourages the use of large gauge speaker wire (preferably 16 gauge or larger). "

The illustration suggests that the connectors are the same as those for the MGIIIa and are set up for thick cables with tinned ends.
 

MickeyBoy

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The Magnepan instruction manual (https://www.magnepan.com/manual/LRS )gives a hint as to what might be different:

"The LRS uses a unique high-current connector (See Figure 1). Strip approximately 1/4-inch of insulation from the speaker cable end and insert it into the connector and tighten the set screw with the Allen wrench provided. Special spade lug adapters are available from Magnepan...call to order.
Magnepan encourages the use of large gauge speaker wire (preferably 16 gauge or larger). "

The illustration suggests that the connectors are the same as those for the MGIIIa and are set up for thick cables with tinned ends.

Taking another peek at the manual, I notice that the fuses are 4A. Perhaps suggesting that the LRS can take a lot of power without self-destructing or distorting.
 
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