magtech amps?

[skypickle]

Has anyone used/heard/measured sanderssounds magtech amps? On paper they look awesomely powerful, 2000 watts into 4 ohms, linear power supply, 32 db gain
http://sanderssoundsystems.com/products/amplifiers/magtech-monoblock-amp

I am using a cinepro amp to drive 2 Revel ultima salon2 speakers but was interested in something 'better'. I looked into the purify thread, that class D amp has been used for salon2s. Some people suggested a benchmark ahb2 but the salon2s get down to 3 ohms in the 90hz region - they are hungry beasts- and bridged the benchmark is not recommended for low ohm loads. I don't really know what the sonic differences of class A, class AB or class D are. I do know that my sonos box really can't drive the salons well - the music literally sounds like it's stuck in a box. The cinepro is 3kilowatts and has plenty of oomph but I can hear a slight hiss out of the beryllium tweeters when nothing is playing. Music chain is pc → singer su-1 → Holodac → schist freya + preamp → amp

 

[CDMC]

If the music sounds like it is stuck in a box, then something is either wrong with your setup or broken. I had a first generation Freya that I purchased and it was definitely defective, it sounded extremely veiled and I returned it. I subsequently purchased a Freya S which worked perfectly. If it were me, I would proceed as follows:

1) Confirm all your equipment is working properly. The Cenepro amps, while not audio jewelry, were well designed and should have plenty of power and sound good with your speaker.
2) Take a look at your room setup. Is your room heavily dampened. Do you have the speakers positioned well (have you tried moving them around?)?
3) Get a Umik and REW (less than $100) and measure your setup. That will tell if there is anything really wrong with your equipment and help identify potential room issues.
4) As far as the hiss, how loud? Is it only when you are up against the speakers with the volume turned up? Is it there when the preamp is unplugged from the amp? Louder or quieter when you disconnect the preamp?

Going back to your original question, there are no actual third party measurements I have ever seen of the Magtech amp. What I can tell you is that Roger Sanders claims that you need different types of amps for electrostatic and planar speakers and dynamic speakers have no basis in fact, as are his different $600 speaker cables. An amplifier puts out a set voltage in response to an input signal up to its maximum rated output. The amount of current the amplifier supplies to a speaker is the amount needed to maintain the voltage into the specific impedance plus any phase angle. If there isn't enough current, voltage will sag. That is Ohm's law, no ifs, ands or buts.

I would not suggest you spend $11,000 on a pair of Magetechs or even $5,500 on a stereo model. If you want to spend a lot on amps, buy the Benchmarks and run them mono. They will drive your Revels, another member here has a pair and spoke to Benchmark and they said they will comfortably drive them in mono. Alternatively, do what the other member here ended up doing, buy a pair of March Audio P701 amps (Hypex NC1200) for $2,700, 400 watt into 8 ohms, 700 into 4 and 1200 into 2 ohms. March Audio will also sell you cables, but his are about $125 a pair and don't come with $500 of bullc*ap claims.

 

[Sir Sanders Zingmore]

I own a magtech.
I have a few reasons for this:
- I agree with Roger Sanders’ view that most amps are not powerful enough for most ‘normal’ speakers.
- I like his design philosophy. He designs his products by measurement only. No listening to “voice” his amps.
- he offers a free in-home trial of all his products (speakers included) anywhere in the world. Actually just thinking about this, perhaps Amir could ask him to send an amp to be measured

 

[Wes]

$4,500 - under what types of speakers, room size would one buy it over a Benchmark?

 

[DonH56]

I think Roger's Magtech would work just great, but so would Benchmark. There are a number of Salon2 owners powering their Salon2's with Benchmark AHB2's, bridged and not.

 

[CDMC]

I am going to modify what I said up above a little after reading through Magtech's information. I still disagree with his assertion that ESLs need a different amp than other speakers, but his amps appear to be well designed (look like a variation of a Class G), and appear to be backed up with good specs. He is also pretty clear that interconnects all the sound the same while speaker cables can change the sound slightly depending on the manipulation and interaction of the LCR with different speakers. I don't know why he charges $600 for a pair of his cables (which look like Belden), except thatin the market he is selling to, people find that a reasonable price and he makes a good profit on them.

 

[Sir Sanders Zingmore]

designed (look like a variation of a Class G),

I don’t know enough about amp design to say for sure but I *think* you are getting his voltage regulator confused with a class G amp.
I’m pretty sure his amps are A/B

 

[March Audio]

I am going to modify what I said up above a little after reading through Magtech's information. I still disagree with his assertion that ESLs need a different amp than other speakers, but his amps appear to be well designed (look like a variation of a Class G), and appear to be backed up with good measurements. He is also pretty clear that interconnects all the sound the same while speaker cables can change the sound slightly depending on the manipulation and interaction of the LCR with different speakers. I don't know why he charges $600 for a pair of his cables (which look like Belden), except thatin the market he is selling to, people find that a reasonable price and he makes a good profit on them.

Well this assertion of his isn't correct

A magnetic speaker presents a mostly resistive load to an amplifier, while an ESL appears mostly as a capacitor.

Since when have normal speakers been mostly resistive? Equally not all esl are just capacitors. Large phase angles can cause problems for amps wether the speaker is an esl or normal magnetic.

Im certainly not criticising the amps BTW, it's a good trait to be able to cope with reactive loads and have loads of current and power available. Important for normal and esl speakers. However I think some of the commentary just plays into the mythology that surrounds esl speakers and what is required to drive them.

 

[March Audio]

I don’t know enough about amp design to say for sure but I *think* you are getting his voltage regulator confused with a class G amp.
I’m pretty sure his amps are A/B

Class g means that the power supply rails switch level, it reduces wasted power. The amp itself is still class AB

 

[AudioJester]

Can someone point me to measurements of this amp?

 

[anmpr1]

Going back to your original question, there are no actual third party measurements I have ever seen of the Magtech amp. What I can tell you is that Roger Sanders claims that you need different types of amps for electrostatic and planar speakers and dynamic speakers have no basis in fact, as are his different $600 speaker cables.

On his site and to his credit he claims no special 'magic' for his cables.

By comparison he sells a 20' pair of balanced interconnects for $150.00. Benchmark sells a 25' pair of balanced interconnects for $130.00. So he is comparable in the interconnect department.

His speaker cables are $600.00 for 20'. Benchmark sells 25' of SpeakON terminated (pair) cables for $160.00. So there's a big difference by comparison.

As far as the need for a 'special' amp? He claims that his loudspeaker is rated at 94dB sensitivity (watt/meter?--not specified) which is not a particularly low sensitivity. At one point he indicates a 100 watt/ch amp is possible, but then states that 1000 watts/ch is preferable. I'm not sure what to make of that. I mean, a thousand watts is not unheard of. For short term peaks a thousand watts is a lot different than a thousand watts just to get the loudspeaker going.

If I read correctly, he wants customers to buy four channels of amplification for his loudspeakers--2 channels for the woofers and two for the panels. So he's asking for two thousand watts total (1000 for each speaker side). His speaker 'comes' with one amp, so you'd need to buy another 500 watt per channel amp, or two bridged AHB2 to get that much power.

Not an inexpensive proposition, however from the fit 'n finish of his wares (looking just at pictures) and his likely small sales, prices don't seem out of line for a boutique product. I'm not saying it is good value, I'm just saying-- in context. I'm not familiar with the brand; apparently he had something to do with the Martin Logan curved panel design. If you like the pluses (and minuses) of ESL, I'm sure his loudspeakers are fine examples of the genre.

 

[Sir Sanders Zingmore]

If I read correctly, he wants customers to buy four channels of amplification for his loudspeakers--2 channels for the woofers and two for the panels. So he's asking for two thousand watts total (1000 for each speaker side). His speaker 'comes' with one amp, so you'd need to buy another 500 watt per channel amp, or two bridged AHB2 to get that much power.

His speakers have fully active crossovers so yes, they require four channels of amplification.
He includes two channels of amplification in the price, so yes they come with an amp (not sure why the inverted commas?).
This means as a customer you only need to by the same amount of amplification as you would with conventional passive-crossover speakers.

At one point he indicates a 100 watt/ch amp is possible,

Interesting, I’ve not seen him say this. Is it in his website (quite possible I’ve missed it)

 

[pjug]

Here is their white paper on the power supply. It does just sound like Class G rail switching. Regulated?
http://sanderssoundsystems.com/technical-white-papers/161-the-magtech-regulated-power-supply-wp

Edit: read it more carefully and it seems the idea is more like a swtiching regulator, not Class G. Or an unusual switching regulator and also Class G. I hope someone else can offer more insight.

I would think running a switching regulator at low frequency would cause more problems than it solves, compared to SMPS or unregulated..

 

[anmpr1]

At one point he indicates a 100 watt/ch amp is possible,

Interesting, I’ve not seen him say this. Is it in his website (quite possible I’ve missed it)

From the FAQ:

Q. How many watts are required to energize an electrostatic speaker?

Sanders Sound Systems ESLs are far more efficient than any other ESL, and more efficient than most magnetic speakers. A biamplified 10A has a sensitivity of about 94dB, and can be driven with low-power amplifiers.

Please keep in mind that no matter how good an amplifier is, if it is clipping, it will not sound clear and effortless. There is no substitute for lots of dynamic headroom. So, we recommend powerful amplifiers (at least 100 watts per channel).

At his price range, I'm certain that most folks would be using something beefier than a 100 watt/ch amp. Of course, his loudspeaker 'comes' with a 500 watt amp for the woofers, so at the minimum you'd still have a 600 watt per side spread.

I see that Ed is somewhere in Colorado, so keeping it local, on the 'low end' you could have your PS BHK amp, and if you didn't want to slum it too much you could go with a Boulder (from Louisville, CO).

 

[echopraxia]

Has anyone used/heard/measured sanderssounds magtech amps? On paper they look awesomely powerful, 2000 watts into 4 ohms, linear power supply, 32 db gain
http://sanderssoundsystems.com/products/amplifiers/magtech-monoblock-amp

I am using a cinepro amp to drive 2 Revel ultima salon2 speakers but was interested in something 'better'. I looked into the purify thread, that class D amp has been used for salon2s. Some people suggested a benchmark ahb2 but the salon2s get down to 3 ohms in the 90hz region - they are hungry beasts- and bridged the benchmark is not recommended for low ohm loads. I don't really know what the sonic differences of class A, class AB or class D are. I do know that my sonos box really can't drive the salons well - the music literally sounds like it's stuck in a box. The cinepro is 3kilowatts and has plenty of oomph but I can hear a slight hiss out of the beryllium tweeters when nothing is playing. Music chain is pc → singer su-1 → Holodac → schist freya + preamp → amp

You certainly won’t hear any hiss out of any Hypex or Purifi or Benchmark amp. Right now with March Audio’s Purfi amps powering my Salon2’s, you can put your ear right up to the tweeter (with no content playing of course) and it’s dead silent.

In terms of sound quality: I plan to experiment by blind testing Purifi vs Hypex amps. Part of the reason I bought both amps is because I’m really curious what a blind test will show here. I honestly do not believe there will be an audible difference (as long as neither amp is clipping), but am open-minded to the possibility, because Bruno Putzeys (the designer/engineer) said during an interview that he hears more of a sound quality improvement than he expected from his Purifi amp designs vs his older Hypex amp designs.

In terms of power: Even with the Purifi 1ET400A (227 / 425 / 450 watts into 8 / 4 / 2 ohms), I can push them very loud. I have not yet had any issue with harshness (that would indicate clipping) even when playing extremely loud subjectively. Granted, I am combining my Salon2’s with subs most of the time.

Without subs, yeah you’ll want a lot of power, but I don’t think its a very good idea to choose that route vs investing the money in subs instead. Example:

Option A: You buy a pair of NC1200 monoblocks from a quality builder (e.g. March Audio P701) for $2700. You also buy a pair of e.g. Rythmik FV15HP for $2700. Total cost $5400.

Option B: You buy some even more exotic ultra high power amplification for $6k-$10k (or way more if you want to get really crazy). But no subwoofers now, since that budget is gone.

I claim that Option A doesn’t just cost less — it will sound WAY better. As amazing as the Salon2’s woofers are, I don’t think I’d want to push them to be flat down to 10hz at high SPL. With subwoofers, my setup is almost ruler flat (except with a gently declining slope) from 10hz - 20khz. It sounds absolutely amazing, and is capable of more than enough SPL for me. Without subwoofers, the Salon2’s impressively reach down to 10hz at -10db in my room (due to room gain), but with subs (where now 10hz is +5db in alignment with the declining overall slope), the difference is absolutely audible (and feel-able), and not in a subtle way.

Of course the ideal setup would be limitless power into the speakers AND subwoofers However, I don’t think the Hypex NC1200 would be particularly lacking with or without subwoofers for Salon2’s.

 

[echopraxia]

With that said, if @March Audio or others ever produced some Hypex NC2K amp products, I’m quite certain they’d have customers like us (with our power hungry endgame speakers) lining up immediately to buy them — because with speakers like these, who doesn’t want a little bit of overkill? [1]

I haven’t looked into the NC2K data sheet too closely, but the distortion still seems exceptionally low. Even if not on par with the other lower powered options from Hypex, I would not be surprised if it is still vastly better than the other 2KW amps on the market.

However, when I eventually blind test the Hypex vs Purifi sound quality, if it turns out there is a real audible difference, that would change everything. I’m just skeptical, given how extremely good the THD, IMD, SINAD, etc. is for all these amps.

[1] It actually is quite nice to be capable of much more SPL than you need — for example, if you have guests over who like it REALLY loud. For me, the desire for excess power isn’t so much a desire to be capable of going loud period, but capable of doing so without worrying too much that the amp will start clipping excessively and blow out a (very expensive) tweeter.

 

[skypickle]

Thank you all for your thoughtful input. @ CDMC I tried just for kicks to drive the salons with a Sonos amp - that’s when the music sounded ‘trapped’. The cinepro had plenty of dimension - but it is not dead quiet. It is getting old and I wonder if a capacitor is getting ready to expire Or if there is some other component that is giving the salon2s a reason for a quiet hiss out of its tweeter when no music is playing. Please also point me to the thread that talks about the Frey’s+ failing.

 

[CDMC]

Thank you all for your thoughtful input. @ CDMC I tried just for kicks to drive the salons with a Sonos amp - that’s when the music sounded ‘trapped’. The cinepro had plenty of dimension - but it is not dead quiet. It is getting old and I wonder if a capacitor is getting ready to expire Or if there is some other component that is giving the salon2s a reason for a quiet hiss out of its tweeter when no music is playing. Please also point me to the thread that talks about the Frey’s+ failing.

There is no thread on the issue I had with the Freya I purchased. There was something wrong with it, I returned it, Schiit refunded my money. A year later I purchased a Freya S when it came out, and it worked well.

it sounds like what you are saying is your setup sounds fine, except for the hiss. Did you disconnect the leads to the amp to see it if stays? That will tell you if it is the amp of upstream.

I suggest you consider echopraxia’s suggestion. A pair of subs will smooth out the room modes which results in tighter sounding bass. You can see I run a similar setup, but a not as high end. If want to really go crazy take the money saved with the hypex amps, get the subs and Mini DSP SHD or Anthem STR Pre, both of which offer room correction and crossover between the mains and subs in the digital domain. I avoided DSP for years, worried it would ruin the sound. Done properly, it makes amazing improvements.

 

[echopraxia]

If want to really go crazy take the money saved with the hypex amps, get the subs and Mini DSP SHD or Anthem STR Pre, both of which offer room correction and crossover between the mains and subs in the digital domain. I avoided DSP for years, worried it would ruin the sound. Done properly, it makes amazing improvements.

Yeah, this is so true that it’s worth reiterating: The impact of DSP on bass is HUGE. You can have the most expensive high end speakers and/or subs in the world, with the most powerful amplifiers money can buy, but if you don’t use DSP to achieve flat bass response, you are seriously missing out: you will almost certainly be experiencing huge nulls and spikes throughout your bass due to room effects (causing both thin bass sound on some tones, and boomy for others).

I was lazy about DSP for quite a while, partly also because some implementations do ruin your sound by EQ’ing high frequencies (you usually only want to fix the low frequencies below your room’s “Schroeder frequency”). But once you spend a little time doing it right, it’s well worth it (especially with a sub) — far more than improvements you’ll get from just about anything else.

Sorry if a bit off topic though, but it really is such an important thing.

 

[skypickle]

Yes I’d like to integrate the rythmik F12G subs. I measured my room without the subs here:

https://sound.stackexchange.com/que...-two-sources-as-a-function-of-dis/48677#48677


You can see from my naive question there that I didnt even know I was detecting comb filtering. I also did some waterfall plots that highlight the need for bass traps in the corners, Frequencies below 50hz seem to last significantly longer than all others. However, the Freya. + preamp does not have a dedicated pair of sub outputs. Although that doesn’t really matter from the subs point of view (it has a built in crossover to exclude frequencies above 120 hz) Rather, I would like to spare having to drive the salon2s at the low frequencies.