Stellar M1200 Mono Beta Test

Thanks very much.

It Takes A Village✊🏻

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Sorry to be late to the party, but I had some storm damage to deal with and couldn’t play with my new toys until this past weekend. My man-cave is being upgraded with new gear and is still a work in progress.

  • Gem Dandy Polytable with Super 12 upgrade and Hana ML cartridge
  • PS Audio NuWave Phono Converter
  • PS Audio DirectStream DAC with Windom
  • PS Audio BHK PreAmp
  • PS Audio M1200s replacing M700s
  • Revel Performa F208 towers
  • Definitive Technology center & surround speakers
  • Oppo UDP-203
  • Anthem MRX1120 AVR for the home theater & playing 5.1 SACDs
  • JRiver Media Center 26 on an HP PC running Win10 feeding the DAC (for now, looking at Sonore or Octave or d.Bob for future use)
  • PS Audio P20 regenerator provides the juice for all the above

Interconnects are a combination of Kimber Hero & Audioquest King Cobra all XLR
except for the Oppo’s link to the BHK which is a Kimber Hero with WBT-0114.
Speaker cables are Kimber 8VS.
Niles Audio SPK-1 switch for sharing the Revels between the M1200s and the AVR

I had planned on doing some extensive A-B testing, but it quickly became painfully obvious even with only a couple of hours warm up that the M1200s are indeed in a different league and that what I was doing was wasting my time. The M700s (as good as they were and they sounded terrific) are now back in the box awaiting a trip to Boulder.

I listen to a lot of 70s prog rock (Moody Blues, Yes, Floyd, ELP, Genesis) with plenty of more mainstream classic rock (Zep, Beatles, Stones, CSNY, Doors, Hendrix, Springsteen, Allman Bros, Steely Dan, etc…) and go to Jeff Back for a change of pace into jazzier fare, then to Brubeck & Miles. For classical I have a bunch of SACDs that I’ve picked up over the years and I’m slowly working my way through the George Szell box set.

The M1200s just blow me away. I’m reminded of the time when I bought my B&K AVR 507 back in 2003. I auditioned top of the line AVRs from Pioneer, Denon, Onkyo, Yamaha and maybe Marantz and they all sounded great, but the B&K just blew them all out of the water and I had to have it. That’s the way I feel listening to the M1200s. More clarity in the mids, better sound stage, heftier bass. They are keepers. Kudos to Darren and the entire team.

Walt

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Your complete review was a very pleasant read. Thanks.
For me this point, details, low frequencies, soundstage, yet the feeling of dynamics at low volume are what distinguishes a very good sound system from the rest.

I love the PolyTable and really enjoy mine!

So I finally peeled myself away from listening 11 days later to share my 2nd round of observations. :slight_smile:

I am fortunate enough to have a dedicated room that serves as both my audio room and office and have had the opportunity to listen to my system for 8-10+ hours a day as I work and relax. It has been a immense pleasure to have the M1200s in my system. There have been many many times where I stop working and turn around and just listen because of how engaging these amps are. Several songs later I find myself reluctantly getting back to work.

My initial impressions that these amps are “effortless” and have “increased depth and separation” on my system still hold true and have only increased. I echo many of the observations of other testers. holographic :white_check_mark: smooth :white_check_mark: revealing :white_check_mark: punch and neutral tone :white_check_mark:

The M1200s have definitely have brought an increased appreciation for well recorded\mastered recordings. :wink: I found it sometimes frustrating to listen to less than optimal recordings since the bar has been raised by others and you know what they could sound like if only…

In my day to day meanderings I have listened to a wide range of music styles and they have brought new and interesting things to each listening session. I can’t help but feel I leveled up multiple times in one purchase. Keepers for sure!

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Nice speakers! Have an all Revel system myself.

I have the same equipment rack as yours but in grey. No clue who the manufacturer is. Would you know ? Nice setup BTW.

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Love the listener-centric speaker and listening positioning…

I’ll bet you are enjoying an immersive and detailed presentation, especially with exceptionally good recordings.

Regards.

If you use the Home Theater function of your BHK preamp you can eliminate the Niles speaker switch between the M1200s and your speakers.

My rack is the Lambda from Schroers & Schroers, purchased in 2003. I don’t think they make that one anymore. Their name is pretty boldly etched into the glass shelves.

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Thanks, I’m aware of the HT bypass, but chose not to use it.

You might want to give it a try. I use the HT by-pass function on my Stellar GCD for HT. That way when I’m watching a movie, the Marantz AVR controls the volume for all speakers without a separate switch. It works well. It would be a simple matter to try it both ways and see which one you like better.

I thought I had read an early post by someone who said they are currently using McIntosh equipment and would be comparing the sound of the 1200s to that. Now I don’t see it.

I currently own a McIntosh MA6500 integrated amp which I have loved for a good 15 years or more. But if there is a Beta tester who is comparing to McIntosh I’d very much like to know what they heard as the did their comparison.

Thanks.

Geoff,
I saw that same post and have been eagerly awaiting their post and McIntosh comparison.

Final Beta Review/Thoughts:

After approximately 200 hours of burn-in with the amps, and many additional listening sessions, the following represents what I will consider my final thoughts/last review on the M1200s.

At 100 hours of burn-in (review at 197), I had a criticism on the sonics of the amps that the highs could sometimes sound a touch bright. To address this, I changed tubes as mentioned in the manual which shipped with the M1200s: “changing to a different 12AU7 tube can result in a sound that is more to one’s preference and allows the opportunity to optimize the system’s synergy”

I ordered and rolled in a pair of matched and low microphonic/balanced triode Golden Lion (new stock) 12AU7s. This wasn’t without some sonic tradeoffs, but I preferred the Gold Lions and have kept them in.

Listening now at 200 hours, the issue I had with the occasional amp brightness is largely gone. The highs are clear and airy, the mid-range pleasant, and the bass excellent.

I will give a few other positive comments on it with song context, as I listened to different music for this final review (largely acoustic instruments and dominant vocals). Aaron Neville’s Rainy Night in Georgia was a lot of fun. I could hear the vocal cords work as he changed his range, he sounded in the room and lifelike. Neil Young’s Cowgirl in the Sand – Live – I forgot where I was for a moment and could clearly “see” him on stage. Eva Cassidy’s Fields of Gold , was emotional and rich, my speakers did a disappearing act a couple of times which I hadn’t experienced prior to these amps.

Lastly, the tube change itself. I thought this could use clarification. In review 202 I posted a criticism of tube changing, which I still stand by (albeit with some conditions due to recent PS Audio clarifications).

Judging by Jamesh’s last response (229), this is NOT designed to be a frequent tube rolling amplifier. However, even as a beta tester that messaging was a bit unclear at first. The question for me on that tube change process was one of product longevity. With that clarification, and the relative infrequency of needed tube changes, I don’t see a problem with the current design. However, if people tinker, it might be worth looking at a little bit. But that’s just me – the 200lb gorilla who changed the tubes.

For me, ultimately these amps are great performers.

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You’re right - it was post #84, 11 days ago, and immediately after in post #85 I said right away this would probably be the most interesting comparative data comparing m1200s to the Mac gear. I hope the beta reviewer of post 84 comes through with the review. If the 1200s can hang that would be impressive. If they can’t, will be interesting to hear why. If we never hear anything from that tester, dunno what to make of that… hopefully he/she safe and just taking time to post the results.

Ok, here’s my review of the Stellar M1200 monoblock amps.

Scott sent me an email in February inviting me to be part of the beta test team. I agreed because I’m retired so I have the time to do it and thought it would be interesting because I have never spent any time listening to class D amplification. I have been interested in high performance audio since the mid ‘90s and have always relied on class AB amplification to drive my relatively inefficient speakers (Thiels for many years and now Rockport Artias). Refer to post 74 for details of my current system.

As we rolled into March, all of our lives were changed by the pandemic. The beta test was scheduled for that month and I wondered how COVID-19 would affect PSA’s production schedule. I kept an eye on this thread and we got word from @jamesh that the beta amps would be shipping in early April. Serial numbers 053 and 064 arrived at my home on April 9th. After a 24-hour quarantine, they were placed into service. At the time of this posting, they have been playing music for 100 hours and on (tubes lit, no music playing) for 160 hours. They have been a standby mode (tubes off) for 55 hours. I think users will note a change in their sound during break in. I haven’t noticed any changes in their sound for the past few days so I think my current impressions represent a fully broken in product.

Before I address their sound, I have a few “operational” observations. First, the packaging is very good. They are shipped individually in double boxes with tight fitting foam inserts. The tube is factory installed. Not all manufacturers do that, but for a single tube unit this well packed, it should work fine. There’s a paper sticker covering the power connector warning the user to make sure the power switch is off before plugging in the cord. The paper sticker is probably fine for the “maiden voyage” but I suggest PSA add a permanent warning label as a reminder to the user later. I liked the speaker terminals. It was easy to clamp down on the spade terminations of my speaker cables using a finger tight twist. The case is functional, nothing fancy and I assume it is of similar construction as PSA’s other amps in the Stellar line. The metal used for the case isn’t perfectly smooth. It slightly dimpled. The tube (12AU7s) is accessed from the back panel via a removable panel held in place by two spring loaded screws. My amps were shipped with Psvane gold pin tubes. The amps come to life by first flipping the mains switch in the back then pressing a blue square button on the front panel. The button first flashes for about 20 seconds while the tube warms up then is solidly lit when ready to make music. Aesthetically, I would have preferred the button in the center of the front panel, as I think it looks more symmetrical with floor mounted amp stands (see my post 76) but YMMV. When fully on, there is an ever so slight buzzing sound coming from the amps (not the speakers) but per the manual, this is normal. I had to put my ear right up to the vents on the top panel to hear it. No way you’ll hear it once they start making music. Regardless of how long or how loud I played my music, the amps never got more than slightly warm.

At this point, some of you are probably thinking “OK boomer, tell me something I don’t know” so I’ll move on to my impressions of their sound. As stated in an earlier post, I have no aspirations of starting a second career as an audio reviewer. I made a commitment to young James to post a review of this product and I can assure you I’m neither a shrill nor a troll. Even while under a stay at home order, I got better things to do than take on either of those roles. During the review, I made no other changes to my system; same upstream and downstream components, cables (power, speaker and interconnects) and power conditioning. The last change I made to my system was over 6 months ago and I listen to it nearly every day so I think I know it well and can recognize any deltas caused by the M1200s.

First off, these are incredibly powerful amplifiers. I can’t imagine any speakers that these amps can’t properly drive without any hint of strain. I played the most dynamic music I have, and my Rockport Artias were always there to deliver the goods. Two examples of the amp’s dynamic power were Yes Fragile (the whole album!) via the Mobile Fidelity One Step 45 RPM LP and Freeway Jam from Lee Ritneour’s 6 String Theory CD. I really enjoy the One Step version of Fragile. Until this release I felt the recording was not as good as the material itself. MoFi has eliminated the gap with this release and the M1200s did an excellent job of handling the dynamic swings of this album.

It’s not all about power though. Assuming the speakers are positioned properly (yup, mine are), one should expect high quality amps to present a clear 3-dimensional soundstage. I used The Sidewinder on The GRP All Stars CD to evaluate soundstage. It took a while for the M1200’s to lock in the soundstage. The left to right soundstage was there from the start but it took about a week of break in for it to become 3-dimensional. It was good but not as good as I enjoy with my Levinson 536 amps. The soundstage did improve even more when I swapped the Psvanes for a NOS pair 1969 vintage GE 6189 tubes. These are a low noise variant of 12AU7s made for the military back in the day. They were tested and transconductance matched to within 2% triode to triode and tube to tube. I’m not wishing to fan the flames of controversy surrounding M1200 tube rolling. I did it before it became a hot topic on this thread and my version of the instruction manual seemed to encourage it:

Changing to a different 12AU7 tube can result in a sound that is more to one’s preference and allows the opportunity to optimize the system’s synergy.

Yes, I got a better optimization of my system’s synergy (more 3-dimensional soundstage) by swapping the Psvanes but YMMV. I predict a “M1200 tube rolling” thread with hundreds of replies once these amps are available to the public.

To my ears, the amps had great linearity across the the entire audio band. The bass wasn’t boomy, the mids were crystal clear and the highs were clean without being too soft or screechy. This frequency linearity was independent of power levels. It was especially impressive at lower levels. I think the M1200 were actually better at low power level linearity than my Levinsons. The 536’s need a little volume to really shine in this regard.

The last thing I noticed was how the amps performed during complex music music passages i.e. “Organizational Skills”. For example, when Spoon is layering all kinds of percussive instruments in You Got Yr. Cherry Bomb (Ga Ga Ga Ga studio version on Vinyl), can the amp allow the listener to hear all of what’s going on? In this particular example, the M1200s performed well but at times I felt I was missing some of the action. Not totally missing, or out of control, just not as well delineated my current amps which is a totally unfair comparison. I noticed this with the Psvane and GE tubes. Readers should not interpret this observation as a ‘dis on the M1200s. When I posted my system info to this thread, a member was anxious for a comparison of my current amps to the M1200s. It’s not reasonable to do a value judgement of the two devices because they are totally different technology and price classes.

At the conclusion of a component evaluation, I like to revisit the system using the previous component to confirm my observations. I reconnected the 526s and listened to the Spoon song again. Yes, things were a bit more delineated with the Levinsons. Then I put the Psvane tubes back in (I have long thin fingers so I’m not struggling with this task) and the next morning gave the The Sidewinder another listen with the M1200s. Not quite as full and 3-dimensional soundstage. Yup, I heard what I heard.

In summary, I think the Stellar M1200’s are excellent performers. They are extremely powerful and I think they can drive any speaker that is connected to them. There is a clean and linear sound across the entire audio band at all volume levels. Based on my experience, the M1200s are good candidates for tube rolling for those so inclined. I enjoyed having them in my system and am glad I waited until now to spend some quality time with a class D amp. If you are looking to spend this kind of coin, or perhaps as much as twice more, on your amp, give these an audition. What’s to lose with the PSA 30-day free in-home trial?

Lastly, I think Paul should give Darren a raise.

Stay healthy everyone.

Jeff C

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Nice review, thanks! Sounds like the m1200’s held up well for their cost. Appreciate the comparison to the Levinson’s. Sweet system, BTW! Stay healthy!

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I am guilty as charged!

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