What is the best premp for Atma-Sphere MA-1 3.3 amp?
I 've never heard the MA-1, but I have the the MP-3 and it sounds fantastic. I can't see going wrong with the MP-3. You can get the MP-3 with or without phono section and you are on the right side of "diminishing returns". The MP-3 is wonderful for tube rolling, you can really tailor the sound to anything you like (some may see that as a blessing or a curse). Send Ralph at Atma-Sphere a message. His username is atmasphere. |
Another vote for the MP-3. I own and have been using an MP-1 with M60s for almost 20 years now. A close friend/audio bud has been using an MP-3 with MA-1s for about 10 years now. We have swapped preamps several times and I'm here to tell you that IME, the MP-3 gives me, minimally, 90% of the performance I get with the MP-1. It's probably even closer than that. In all that time, neither of us has had a failure beyond the odd tube giving up, whether it be amp or preamp. And Ralph and his staff are always available to assist you over the phone and will spend all day with you if the situation demands it. Honestly, I don't know how they ever get any product out the door considering how generous they are with their time. Truly a no brainer...go for it. |
@OP, I PM'd you, but didn't indicate the build model. I own the 3.3 version MP-3. Also, when I called Atma to inquire about upgrading the MP-3, he said the 3.3 was an entirely different build from earlier models, and to upgrade an earlier model would cost a significant sum. You can see the prices on Atma-Sphere's website. BTW, one of the reasons you find so many satisfied Atma customers is that you are only a phone call away from help, should you encounter an issue. Most likely it will be Ralph answering the phone, and most likely it won't be the Atma causing the problem- believe me, I know. Bob |
20 X 16 feet. MA-1 has tremendous power to run the speakers. MP-1 version 3.2 see this review also: https://parttimeaudiophile.com/2013/02/03/las-vegas-2013-sound-lab/ |
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Just to quickly chime in and please note I am a dealer for A-S. Yes the MP-1 is clearly better than the MP-3 but it's also substantially more $$$ not that $$$ has anything to do with SQ but in this case it does. The 3.3 vs 3.1 or 3.2 is also better in the MP-3. Personally I did prefer the MP-1 3.2 line section vs the MP-1 3.3 line section but the phono section in the MP-1 3.3 is again clearly better/quieter. These are my own subjective views. I can also say I bought SL 545's and as much as I really wanted to like them (I LOVE their bigger speakers) I just could not get them to sing. Roger West did take them back after almost 4 months but still it was a $$$ learning experience. (Dealer disclaimer) |
Room size is approx 16' x 26' with 10' ceilings. M-60's with Zero Autoformers (not enough power) Bricasti amplifiers as well as Merrill Audio Veritas and even tried the new Merrill Element 118's. There were other amps as well and again just could not get the SL 545's to sing.@sksos M-60s with ZEROs simply won't have enough power to make the Sound Labs play. Just as a FWIW: amps that have an extremely low output impedance like the Element simply won't be able to play a speaker like the Sound Lab- there likely was nothing wrong with the speaker; it just wasn't being set up properly. In a room of that size you'll need some power! For more on how this works see:http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php Sound Labs (like all ESLs) are not Voltage Paradigm devices. So amps that can double power as the load impedance is cut in half aren't going to work very well on them. Sound Lab is by no means the only speaker that is a Power Paradigm device- lots of horn a full-range single driver (example of the latter: ZU loudspeakers) are as well. SETs fall into the category as well. |
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@chungjh to answer your question I don't think room size was a factor. As I mentioned I knew the A-S M60's did not have enough power but I tried many other amps as mentioned earlier as well as Gold Note 1175 and a customer even lugged over his Hegel H30 and still could not get 545's to sing. Again I've loved their bigger offerings which is why I custom ordered the 545's in a Birds Eye Maple frame, the speakers looked fantastic! Since I love electrostatic/panel speakers I then went to Sanders 10e speakers which worked GREAT in the same space. (Dealer disclaimer) |
@chungjh Yes I tried the Sanders Magtech amps then tried the Bricasti M25 amps. Bricasti brought out more 'soul" to the music so used 2 x M25's to drive the 10e speakers. (My opinion is using 2 of the same amps on the speakers is the smart thing to do....Roger Sanders may/will disagree). Yes the magtech has more power but the Bricasti never had a problem with my listening levels at 85-92 dB and peaks in the high 90's. (Dealer disclaimer) |
@OP I just did a quick google on the m545's ( I don't know which level you are using- Audiophile/Majestic/Ultimate, not that it seems to make a difference in power requirements). All seem to be 50-500 wpc. So, the MA-1 should have plenty of power- unless you want rock concert levels. The Sanders and Bricasti seem to be SS amps. Are you interested in SS? Bob |
I don't listen at rock concert levels. Some people have recommended Pass X350.5 for SL because of its "tubey" sound despite being SS. But as Ralph at A-S stated, at bass frequency, impedance is 30 ohms and X350.5 is only putting out about 90 W. SS is fine with me, but it seems to me MA-1 will give more even SQ across the frequency range. Of course, X350.5 is giving out 350W at 8 ohms in the frequency range where most music lives and is therefore much more powerful than MA-1. Then the question is whether I need 350W in the flat portion of the impedance/frequency curve if I don't listen at rock concert levels and my room is medium size 400 sq ft. What do you all think? |
@OP, In my limited understanding of such things, amplifier power ratings are for ballpark estimations of a speakers demands/capabilities. The real issue is how well an amp can handle transient power demands. Which is why I lean toward having an amp leaning toward the higher power ratings. Your speakers are rated for 50-500 wpc. Both the Pass and Atma amps fall nicely in the middle. And, given how Mr. Pass tends to underrate his amps, I bet they can put out a bit more power without issue of clipping or distortion. Now, the reality check: Unless you are really cranking up the volume, I doubt you will be using more than a few watts with normal listening. So, why get an amp with 140 or 350 wpc? Like I said, it is the ability to handle the transients within the music, and not taxing the amplifier to the point where it introduces distortion. Like I said, I am no expert, so there will probably be some disagreement. Perhaps Almarg can provide a better description. He knows and can write a very clear explanation, if anyone can. Bob |
thanks gdnrbob May be people with experiences in both tubes (especially Atma Sphere) and Pass Labs can chime in. In <40 HZ, A-S MA-1 is more powerful than Pass X350.5 (for Soundlab), but X350.5 is more powerful than MA-1 everywhere else. Did I get this calculation right? Obviously MA-2 would be a great solution (220W), but it is mucho $$$$ especially if I don't listen at rock concert levels. |
@gdnrbob, thank you kindly for the nice words. I of course agree that the major factor in determining how much power an amp needs to be able to supply is the ability of the amp/speaker combination to be able to cleanly handle the peaks of brief high volume transients in the music. With recordings having particularly wide dynamic range (dynamic range referring to the **difference** in volume between the loudest and the softest notes) being the most challenging in that respect. Many classical symphonic recordings, for example, being far more challenging in that respect than most pop and rock recordings. As I’m sure you know. In choosing between two amplifiers which differ greatly in terms of their maximum power capability, though, such as the MA-1 and the X350.5, what I would do initially is to determine if the lower powered amp is powerful enough to support the listener’s desired peak volume capability, that may occur on brief transients. And if that criterion is satisfied I would then look at other variables in choosing between them. And if one amp is a solid state model and the other is tube-based, given that the impedance of the speaker varies widely over the frequency range the other variable I would look at first is which amp would result in the best tonal balance, taking into account the interaction of the amp’s output impedance and the speaker’s variations of impedance as a function of frequency. In short, what Ralph has discussed in his “Paradigms” paper. I see that the Sound Lab 545 models have sensitivity specs of 86 db/2.83 volts/1 meter, with a specified nominal impedance of 8 ohms. Presumably the 8 ohm nominal impedance occurs somewhere in the mid-range, e.g., at or near 1 kHz. While the X350.5 is presumably capable of providing only 90 watts or thereabouts into the impedance of the 545 at low frequencies, let’s make an optimistic assumption in its favor that it can provide 350 watts into the speaker at all frequencies. (And in any event the difference in maximum volume capability between 90 watts and 350 watts is only about 6 db, for a given speaker). And given the OP’s indication that his listening room is 400 square feet let’s assume the listening distance is around 4 meters. Let’s then use the following calculator to determine the maximum SPL 350 watts can produce with 86 db/2.83 volts/1 meter/8 ohm speakers at a listening distance of 4 meters, noting that 2.83 volts into 8 ohms is 1 watt. But let’s use a listening distance of 2 meters in the calculator to reflect the fact that SPL falls off much less rapidly as a function of distance in the case of planar (or line source) speakers than in the case of point source and most dynamic speakers (which are what the calculator is based on). https://myhometheater.homestead.com/splcalculator.html Converting meters into feet and neglecting room reflections the result is a maximum volume capability of 108.4 db at the listening position. And if we make the less optimistic assumption that the X350.5 can only provide 90 watts at all frequencies the result would be 102.5 db. Those levels will be adequate for many and probably most listeners, but not for some. For example I know that Ralph sometimes listens at considerably higher peak volume levels than those, in part because his system can handle higher volume levels without significant distortion. And I listen to many classical symphonic recordings having very wide dynamic range (e.g., on labels such as Telarc, Sheffield, Reference Recordings, etc.), and for my purposes an amp/speaker combination that can’t comfortably reproduce 105 db peaks at my 12 foot listening distance, plus a little margin, is a non-starter. In any event, the specified power capability of the MA-1 is only about 2 db higher than 90 watts, and is only about 4 db less than the 350 watt specified capability of the X350.5. So given the OP’s indication that he doesn’t listen at rock concert levels let’s assume that a little more than 100 db at the listening position is adequate for his purposes. Which would be satisfied by both amps. So I would then focus on other variables, starting with the tonal consequences resulting from the interaction of amplifier output impedance and the speaker’s wide impedance variations over the frequency range. And that would clearly seem to favor the MA-1, given numerous anecdotal reports I have seen over the years here and elsewhere involving Sound Lab speakers, as well as what Ralph has explained in his “Paradigms” paper. Best regards, --Al
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Of course, X350.5 is giving out 350W at 8 ohms in the frequency range where most music lives and is therefore much more powerful than MA-1. Then the question is whether I need 350W in the flat portion of the impedance/frequency curve if I don't listen at rock concert levels and my room is medium size 400 sq ft. What do you all think?@chungjh You've put your finger on the issue. ESLs in general have their impedance curve deriving from a capacitance which is intimately involved in the electrostatic principle. As a result the impedance curve does not reflect on the efficiency of the speaker! In a normal box speaker, the impedance bump in the lower frequency is a common example of how the speaker has a higher efficiency at the resonance of the woofer in the box- and this is seen also as an impedance peak. The higher impedance of ESLs in the bass is not caused by resonance- and so for the speaker to do 86dB at one meter in the bass region takes the same watt of power to do so as it does at 1KHz or 10KHz. Yet the impedance of the ESL is quite different at these frequencies; in the bass the Sound Labs get to 30 ohms and are much less at 1KHz and even lower at 10KHz. If the amp can double power as the load impedance is halved this also means that the amp's power is cut in half as the load impedance is doubled. This is why the MA-1 makes more power than the Pass on the Sound Lab. Al has already gone over that bit; the one thing not mentioned was the issue of transients which gobble power mostly in the bass. This is why the MA-1 will seem across the board about the same power on the Sound Lab as a solid state amp that makes over 400 watts. One other thing to keep in mind- while the 86dB number makes most speakers impractical in many rooms, a line source such as the Sound Lab can be corrected by adding about 6dB once you are about 10 feet back. So 92 dB is then more practical. This is exactly the same phenomena where the volume does not appear to increase as you move closer to the speaker, unlike point source speakers. |
@atmasphere Thank you for the explanation. If I understand you correctly, you are saying that even though Pass has more power at 1 kHZ than MA-1, it is the power requirement at bass that is more rate limiting because transients at bass frequencies makes up much of the amplifier's power demand. Did I get your concept right? |
I’m running fully updated MA-1s and MP3 with my big Sound Labs and I couldn’t be happier. The new Atma-sphere amp and preamp replaced a set of Manley Neoclassic 250 monos and an ARC SP16. And at the suggestion of Ralph Karsten, I am now running affordable balanced interconnects which replace multi-thousand dollar MIT Oracle RCA interconnects. I feel like I’m finally hearing the music instead of being a neurotic audiophile. To say the least, I'm happy with the changes as well as the level of support I’ve received from Atma-sphere. I've been an audiophile for 30+yrs and I'm experiencing levels of transparency and low level resolution I never knew I was missing. |
