Has anyone tried the SED 6as7? How does it compare to Ralph's Chinees tubes? Anyone try 6080s? I'm using GE 6080s and it sounds wonderful, but want an extra set of 6as7s for backup.
Atma-Sphere MA-1 amps
How good are these amps? I have 200w Class A mono blocks and have been eyeing these for sometime. What are your thought on them and hwo do they sound?
TIA
TIA
81 responses Add your response
Honest1, all I can say at the moment, that both amps are true to the music. Speaking of the Atmas, the amps give you a sort of middle of the hall placement with most classical recordings and a midrange which is impeccable, adding nothing, taking nothing away. However, if things get really loud, they do clip on the Sound Labs. The VTL's with their 600 pentode watts don't, they move you closer to the stage, are more powerful in the lower bass regions, something you don't miss though with the Atmas, because their blend between mid , highs and lows is almost perfect. Listening to the VTLs is like changing your seat more to the front, closer to the music, which is represented most realistically. I still have to find something to fault them. But getting that close, also in a real concert can have its drawbacks, you tend to concentrate on details, instead of taking in the entire "gestalt" of the music, which the Atmas achieve beautifully. In listening to jazz-combos, the VTL throws the happening right into your room, with absolutely uncanny realism and rocks teady players in excellent three dimenionality. The Atmas are a tad more polite, also again here a little more laid back, but in their way just as musically convincing. Both amps are excellent achievements I would say, at least to my ears. |
Detlof, That would be a very interesting comparison, but I would urge you to hear the Atma's at their best. If you haven't already I would replace the filament fuse with a premium fuse. Such a nice improvement for around $75 total for the two fuses. Not sure if the VTL's are in need of premium fuses - but it might be worth asking. |
Hi Honest1, Too early to say, I'm afraid. Thanks to their huge power reserves they wouldn't clip where the Atmas did, also it seemed to me, that on the piano LP I listend to, they rendered the decay of notes better than the Atmas, but I'm not sure at all. I was so taken in by the music, that I did not want to do direct comparisons. I'll do that later and keep you posted by mail. Cheers, |
My favourite combination in the MP3 (2 12au7, 2 6sn7s, and a 12at7 not in audio circuit)is the 1940/50s RCA 12au7 Blackgate combined with the Sylvania 6sn7GTA (not sure GTB would make any difference). I tried the RCA Cleartop and Siemens 5814 which seem some what similar to me, compared to the Blackgate 12au7. I use the pre with the M60 amps and I think the 12au7 lends a touch of warmth which is a nice touch with the neutrality and transparency of the amps and my Merlins. The RCA 5814 seems very similar to the Blackgates. My combination definitely performs very well for my music and ears, but I don't doubt there may be even better combinations out there, but I'll stick with this for a while. P.S. I use RCA combined with Sylvania GTBs in the amp - 2 RCA in front 2 Sylv. in rear slots; I prefered this to all Sylvania. This being said, the Atma-spheres sounded great with any of this combinations, it is just a bit of spicing to a basic recipe. |
Just a comment on NOS tubes. I have been rolling a few and I jst want let it be known that all tubes I have received from Andy Bowman at Vintage Tube Services are clearly matched and quiet, very quiet. With other sources I have not been so lucky. I'm sure you can get well matched from other sources, but Andy has never failed me. |
For some reason, the MP-3 doesn't seem to get the respect of the M60s, and I wonder if this is due to the phono stage. As a line stage it seems to let the M60s do the transparency, microdynamic detail, incredible timbral accuracy and expansive soundstaging thing that the amps are capable of. I've tried a Joule LA150MKII and Dodd Battery pre with the M60s and they sound quite different (and more similar to each other) than the MP-3 with the M60s (both warmer and plumper in comparison). To my ears, the Atma-spere pre is an important part of getting the Atma-sphere "sound" - for better or worse; I like what the whole package can do, and to my ears there is no better amp that I've heard with my Merlins than the Atma-spheres; that first amp after many tries, where I found an amp that let me sell my CAT JL2 with no regrets - at all; I prefer the Atmas with the Merlins - though I suspect the CAT can do its "thing" with a very wide array of speakers. |
Has anyone seen the new review of M-60 and MP3 in Absolute Sound? I am still waiting for my issue to come in the mail. BTW I use PS Audio Duet on my MA-1's. My MP-1 is plugged into Poew Plant Premier. I have always used the Duet on the MA-1's. I used to have much older MA-1's, and when I first got the Duet and plugged the amps in I though they were cleaner. I really should try taking the Duet out and see what the latest amps sound like right in the wall. I have also never tried the MP-1 direct to the wall. I guess I just have to much faith in PS audio power gear. |
Power conditioning: dedicated 20 amp circuits for each amp, plus an APC PMP2X whole house surge protector panel mounted at the breaker box. Otherwise, no power conditioning. Frankly folks, the MA-1 and MA-2 can draw so much power that the idea of putting anything in between them and a direct connection to the power company is hard to consider. |
I use a whole house surge protector/line conditioner made by Environmental Potentials. It installs at the service panel, and it costs $650. EPS's primary customers are industries that need clean power to ensure their machinery runs efficiently and at at lower cost. EP has a line of power products aimed at the residential/home audio/audiophile user. No BS. No audiophile mark-up. |
Hi Pubul57 My MP-1 Mk. III developed a problem due to shipping, which absolutely without Ralph's fault is not yet resolved. I had occasion to borrow a WAVAC which to my ears mated perfectly with my MA-2 Mk. IIIs driving my U-1PX Sound Labs. I was so enthralled with this combination that I later bought one used here on Audiogon, tube rolled the Ruskies for Mullards and am happy. Once my problem with the MP-1 is solved, I'll compare and sell one of the two preamps. Hi Tom, I've followed your advice digging out all sorts of jazzy software I could find on CD, LP and Steve Nugent's "SPOILER", a wonderful USB-DAC by the way, clobbers Zanden and the dcs-stack, and could -perhaps would(: not - hear what you did. As I noted above, at first I thought I had it pinpointed, but then it turned out it was an IC, starting to break in causing that anorexia in sound, which thanks to the Audio gods soon gained sufficient weight again to be out of danger... |
Hello Lewm, Thanks for the research and posting a response. I'm sorry if you got the impression from this thread that I own the Atma's. To be clear, I do not. I came awfully close though! However, I was fortunate enough to have spent time hearing the MA-2 with the speakers I own and speakers I previous owned in three different systems for a total of 5 lengthy listening sessions. Thankfully I was able to get over the things I thought they did so well and hear IMO what did not jive to my ears. When I talked on the phone with Ralph he mentioned to me that there were many Eidolon-Eidolon Diamond/MA-2 users in the field. I don't know for certain, but I didn't get the impression from talking with him that any of them were using the Zeros. If this helps, the MA-2's amps were able to drive the Eidolon Diamond to extreme volume levels without signs that the amps were running out of gas. Also, it might be of help to know I heard the IMHO texture thinness and treble abbreviations at low or loud volumes. But from the little technical knowledge I have of OTL's, tonal abbreviation is independent of volume. In other words, if the speaker in question is not a good match for an OTL, tonal coloration will be apparent at all volume levels. Is this correct? I would like to point out once again I think the Atma's are in certain ways .... "extraordinary" .... exceeding the competition. I also encourage others to audition them to hear the certain areas of cutting edge performance I feel Ralph has achieved with his design. Having lived and learned over the years from owning five different sets of electrostatics from Acoustat, Quad, and Martin-Logan, these also in certain ways were ....extraordinary.... and in my view, above, exceeding that of the competition. But they also lacked in certain ways, and for me in the long run their faults took away the enjoyment, that magic, the escape, the thrill of being fooled if only for a second that this could be real. Through my experience and from the mistakes I felt I've made, I have learned a balanced approach of choosing all components is what has endured for me. Best to all, Tom |
Good question about the Atma preamps. I know my MP-1 with M-60 combo was dead quiet. Ultimately though, since my gear is installed in a Salamander Synergy cabinet, tube troubleshooting and rolling with the MP-1 was a real hassle. Had the preamp been installed on top of an open rack, there would not have been a big issue with tubes. Also, in my system, the MP-1 had a bit of upper midrange "shout" with both the M-60 and Pass Labs XA-60.5 amps. I replaced the MP-1 with a Lamm L2 Reference, which has better tonal balance, better bass control, and is much easier to maintain. IMO. However, the L2 does not have the massive image size of the MP-1, nor the slightly warm tonality of the MP-1 (which I was frankly unaware of until I purchased the Lamm L2 and compared the two). There's always a trade-off. I'd be curious to hear the Lamm L2 Reference with Atma-Sphere amps. On paper, the impedance match looks good. |
Since we are on the topic, sort of, what are your preamps of choice with the Atma amps. I assume the Atma pre would be a natural pairing. Was that best for you? Have you preferred something else? Why? Or tried others and decided the Atma pre was best for mathcing with their amps? Why? Your thoughts? |
Lewm, Thank you! That is very interesting. In fact I wanted to research the same, but then was too busy to do so. By the way, it was the cable breaking in not the Atmas after all, when I began to seem to hear the same "thinness" through the Sound Labs, which Trcnetmscom had described hearing through the Avalons with them. Wanted to report that anyway. Cheers, |
This is a very interesting thread. Trcnetmsncom, I looked up the impedance curve of the Avalon Eidelon. It's below 5 ohms (closer most of the time to 3 ohms) between 50Hz and 20kHz, except for a narrow "peak" in the midrange, where it gets up to 7 ohms. This is not an optimal match for any OTL (like the Atma MA2) that does not use negative feedback to achieve a low output impedance. However, the MA2 has such huge power capability that you are able to overcome the impedance matching problem to a large degree. Nevertheless, I wager that if you were to interpose a pair of Paul Speltz's Zero autoformers between the amp and the speakers, the perceived unpleasant treble distortions would disappear. Given the large investment that you have already made in the amps and speakers, the Zeros amount to a trivial additional expense. I don't think one can ever talk about how an amp "sounds" without considering the speaker load. |
I agree with Pubul57. I used GTAs and was very pleased. When I looked to get more, Andy Bouwman at Vintage Tube Services told me there was very little difference in the sound of the GTBs up through the early '70s manufacture. That's what I'm using now in my MA-2s, and I don't notice a difference. From what I hear in the amps, I wouldn't pay a premium for GTAs over early manufacture GTBs (up to early '70s). The GTs have a bit of special, but as Pubul57 notes, you can only use them where the high plate voltage capacity of the As and Bs is not required. I need to get a quad to try once again. . |
I think the GTAs and GTBs are essentially the same sonically. The older GTs are preferred by many, but can't be used in all the Atma-amp tube positions becuase the can't handle as much current as the GTA/Bs - they seem to be fine in the preamps. I think you hear more about the Bs because thet are more readily avaiable. |
The American 6AS7G and it variants can be problematic due to early arc-over failure. We have had some reports that the tubes hold up better in the MkIIIs and in fact what little testing we have done seems to confirm that. If American tubes are tried in the amp though, it must be regarded as experimental. One recommendation I can make is that the tubes, if NOS, should be preconditioned (tubes placed in amp and run in Standby only) for 72 hours before being used. That seems to reduce arc-over failure with them. |
Please let's not forget that the Chinese-manufactured 6SN7s are actually very nice tubes. I've paid a bit of a premium for Sophia tester "A matched" metal base military pieces from DIY HiFi Supply, but still only $18 apiece. Matched pairs of Baldwin labeled 1965 vintage Raytheon GTB are being sold by Brent Jessee, a reliable vendor, for $45/pair. I just took a gamble on four supposedly "matched" quads of Baldwin labeled Sylvanias of late 50s/early 60s vintage with the BIG chrome domes from Ebay at under $15/tube. The photos are quite sharp and show very clean tubes with spotless pins. We'll see how they test on my B&K Model 700... One needn't pay upwards of $100/pair or even much, much more for quality 6SN7s. Just doesn't make sense. |
I swap tubes around every few months - there are many great combinations. NOS tend to last much longer than contemporary brands - or so everyone says - I haven't had a 6SN7 go south on me yet, so no direct experience. MA-1 Mk.III --- Driver: Sylvania GTA or RCA GTB Tubes 2&3: VT-231 Ken-Rads (these positions have biggest influence on sonics, imo), RCA Grey Glass Tubes 1&4: VT-231 Sylvania, RCA Grey Glass, or VT-231 Raytheon I really like the VT231 Ken-Rads in the the amps. They're still out there but getting a bit (more) pricey. Couple notes: i) My Mark IIIs are in the traditional narrow chassis, so position may be different w/ the newer style. Driver is understood as position #5 at the edge of the chassis facing the output tubes. ii) For NOS, the driver position requires a GTA or GTB - something that supports a higher 450VDC plate voltage; the other positions do just fine with other NOS (eg. GT or VT231). The preamp is both challenging and fun because of the phono section, where it is harder to get good *quiet* tubes - but its definitely doable. MP-1 --- forwardmost 6SN7: VT-231 Ken-Rad other 6SN7: Electro-Harmonix or stock Chinese phono (12AT7s): CV4024 Mullards, '60's Siemens 12AT7s, 6201 Sylvania Gold Brand I put Herbies Tube Dampers on 3 of the 5 6SN7 per channel and 3 of 4 12AT7s per channel. The dampers work well. check this out: The Reference 6SN7 Thread The gear is incredibly revealing of tube changes (for that matter any change) and tube rolling becomes lotsa fun. Good section matching w/in a tube is v. important. Tim |
In the preamp I use matched RCA GTs which are a bit more romantic than the Sylvanias. The GTs are generally not used in the amplifier because they can't handle as much voltage as the later GTA/Bs. RCA or Sylvanias are proably the most used NOS tubes by Atma-sphere owners as they are relatively available, affordable, and sound good. |
I use Sylvania GTBs with matched pairs in the two postions A-S recommend matching. The straight Sylvania lineup is a good match to my Aesthetix preamp. With a different preamp, some other mix might be better. The Sylvanias were a nice improvement in resolution, openness and timbre to the JAN Philips that I had once upon a time. Life expectancy on these is in multiple years of heavy service. . |
Hello Tom, HH sure does. I am glad you agree. Thank you for your additional information. I'll go an researching. I suspect, my Wavac phono pre kindly glosses over the shortcomings you mentioned, without being euphonic though, as was the case with the old Jadis gear I once owned, because today I had the occasion to try out a Boulder 2008 phono pre amp and heard exactly what you did, fiddling wildly with the VTA of my cart with no avail. But then it may be the cable between cart and Boulder not yet broken in. We'll see, but you may very well have a point, because the Sound Labs should be no less revealing than the Avalons from what I have heard. We'll see, respective hear, after all this is a work in progress. Cheers, Detlof |
Hello Detlof, Thanks for the kind and respectful response. It's nice to be able to discuss the audible differences we discern in components, agree or disagree, still have fun and learn from each others experience. BTW ... Hilary Hahn smokes!!! I haven't heard it myself yet, but from what I know the Sound Lab/Atma-Sphere combo is becoming classic. I'm sure your system must sound fantastic. Detlof, a live recording of a piano with a close up perspective may give you the best chance of experiencing what I heard. Something like a small jazz ensemble, recorded in a intimate night club played back at a "live" playback level. In particular, listen to the attack of piano notes about 2 and a half octaves above middle C and up. What I heard (at least) was a unnatural sharpness, glare, zippity-zing if you will on the attack of those notes. The sustained note also sounded too thin and glassy to me. I started to hear this treble abbreviation on a variety of instruments and recordings I'm familiar with. Another thing I try to listen for is the density of timbre/texture as a sustained note gets louder. Take for instance, a tenor sax player who plays one sustained note, he starts the note out at a medium volume and increases it to a loud volume. The note doesn't just get louder, the density of the texture also becomes more vibrant and more harmonically complex, it fills with ebullient energy. To me, some other amps convey this sensation with more conviction. Tim, I want to thank you also for sharing your experience. Who knows? Maybe it was still a break-in issue with the V-cap after all. Much of what you described about the V-cap break-in mirrors my experience. I think too many variables are at play here to know for certain. Enjoy, Tom |
Is it possible for you to characterise your experience with the Atma amps before, during (break-in) and after when the sound finally settled? Thank you Tom. I found the amps and preamp more similar than different across break-in. Out of the box there was plenty of resolution, but the sound was a little tight and closed-in. Relatively speaking, tonality had a wee bit of a greyish cast. During break-in, which I counted roughly at 120 hrs for the preamp, and a little more for the MA-1s, music gradually became relaxed and seemed to flow with a more natural pace. Tonal colors made something of a transformation towards the end of the break-in period - they really blossomed - all of which was rather startling. That final leap came over a few days for the preamp, and, say, over a weeks time for the MA-1. The subsequent addition of the V-Caps to the MP-1 took things back a step before going forward two. Highs and the mid-bass got a tad edgy and a touch of the greyish tonality returned. Over roughly 6 weeks, things smoothed out and the tonal colors deepened. Sonic memory is difficult, but I'm confident that tonality eventually improved beyond where things had got to prior to the V-Cap upgrade. Fwiw, I find both amps and preamp sound their best after being on for 1-2 hours - the hotter their tubes the better. Tim |
Amp-loudspeaker matching is no less important with Atma amps as with any other amps. I tried to make M-60s work with Talon Firebird Diamonds even using autoformers, but ultimately determined the match unsatisfactory to my ears. My present line arrays are a match made in heaven for the MA-1s. "Horses for courses" is no less true at the track, as any fan of the great John Henry can attest. |
Pubul57, my listening to both the MP-1 and the MP-3 have been as full function preamps playing LPs. You may have it right that my differing reactions come from differences in the respective phono stages, but I suspect that's not all that's going on. I will say that the MP-1 was a vastly more satisfying listening experience for me, getting in the ballpark of what I expect as the result living with the Aesthetix Io Signature with dual power supplies and volume controls. The MP-1 sounds like a great preamp. . |
I was quite fascinated with what Trcnetmsncom had to say about his perception of a high end flaw in the MA-2s. Tom's likening this flaw to the high end rendering of the Martin Logan CLS 2Z made clear to me what he meant, because I auditioned those speakers a long time ago and I disliked them right from the beginning just because of that. I have the latest version of the Ma-2s, haven't rolled the 6SN7s so far and I just don't hear what Tom hears on my particular speakers, the big Sound Labs. Not that I doubt the sophistication of his hearing, nor his experience with live music. I share that with him, being a regular concert goer and intimately familiar with the sound of both violin and piano and just cannot find the flaw he mentions in my particular setup, which he obviously heard on several occasions on different rigs. This may well be a hearing impairment on my part, because I am advanced in age, however my wife, who plays the violin also cannot find anything wrong with the Sound Lab's/ MA-2 rendering of her instrument. We listened again extensively to Hilary Hahn's exceptional rendering of Bach's Sonatas and Partitas and could not find this particular shortcoming. We then tried piano on LP: Martha Argerich's rendering of Liszt's b-minor sonata, an early DG 2530193, again the highs were clear, crisp, without a trace of harshness or brightness. So this is puzzling. The big Sound Labs are not an easy load, but obviously pair very well with Ralph's bigger amps. Possibly we have just struck it lucky with this combination and would have been equally unhappy, trying the MA-2s with the Avalons. No lack of "denseness" either, with our stators to our taste and ears. Thank you Tom. I found your contributions both important and thought as well as "hear" provoking. Obviously we strive for the same thing, the best balance of all "sonic virtues" as you put it so well, with "no area severely lacking". Obviously your benchmark is your experience of the live event as it is mine. We may have different tastes and rigs, but it feels good not be alone in this. |
Rushton, are your feelings about the MP3 based on the phonostage and the linestage? I'm using the MP3 with the VCAP and Powersupply upgrade and it sounds very good to me. I've heard more universal praise for the MP1, but I'm wondering if that is based on phono performance. If the MP1 is that much better as a line stage I would consider it. |
Pubul57, I've had the great pleasure recently to spend some time listening to an MP-1 in a friend's system. I'm impressed: very neutral, very resolving and transparent, very quick and detailed. The virtues of the A-S amps in a preamp. I've not been as similarly impressed with the MP-3 (heard elsewhere), but the MP-1 is a stellar unit that would fall among my top candidates if I were making a change. . |