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PS Audio Stellar M1200 Monoblock Amplifiers...

192.181.133.141
Posted on June 1, 2020 at 16:54:17
John Elison
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Posts: 23900
Location: Central Kentucky
Joined: December 20, 2000
Contributor
  Since: January 29, 2004
 Has anyone bought the new PS Audio Stellar M1200 Monoblock Amplifiers? I just bought a pair and I've been listening to them for about a week. They sound very good and I'm wondering whether anyone else has a pair? They come in silver and black; mine are black.


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M700s, posted on June 1, 2020 at 18:08:58
Mike K
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Posts: 13975
Location: 97701
Joined: September 23, 1999
 I have a pair of the M700s and I love 'em.

Lack of skill dictates economy of style. - Joey Ramone

 

The silver ones sound better. nt, posted on June 1, 2020 at 21:21:33
viridian
 Nt

 

How are they compared to your Parasound ? - nt, posted on June 2, 2020 at 05:49:56
AbeCollins
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Location: USA
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Contributor
  Since: February 2, 2002
 .

 

RE: PS Audio Stellar M1200 Monoblock Amplifiers..., posted on June 2, 2020 at 06:54:00
Tre'
Industry Professional

Posts: 17304
Location: So. Cal.
Joined: February 9, 2002
 I call BS.

"Rated at 600 Watts into 8Ω and a whopping 1200 Watts into 4Ω, the M1200 combines the best of two worlds: ultra-linear, high-current, ICE Edge Class D technology for the output stage; and a discrete, Class-A vacuum tube for the all-important input stage. The M1200's rich, warm, and beautifully nuanced reproduction of music comes first from the zero feedback, class A vacuum tube input stage. Here nothing is lost in its hand-selected 12AU7 vacuum tube, fed from its own analog power supply."

Without feedback the 12au7 is very non-linear (distorted). The 12au7 is fine for a cathode follow circuit, a circuit that relies on 100% feedback but as a zero feedback gain stage it sucks.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

Have you listened to them? , posted on June 2, 2020 at 07:13:11
Mike K
Audiophile

Posts: 13975
Location: 97701
Joined: September 23, 1999
 Maybe the designer knows something you do not. Or maybe the ad copy
writer was, er, misinformed.

Lack of skill dictates economy of style. - Joey Ramone

 

RE: Have you listened to them? , posted on June 2, 2020 at 07:32:21
Tre'
Industry Professional

Posts: 17304
Location: So. Cal.
Joined: February 9, 2002
 Listening is subjective. The statement I made is objective.

The designer can not magically change the fact that a 12au7 is a very non-linear tube. So, I don't know what he knows vs. what I know but either way it doesn't change the facts. I try to only deal with facts.

The 6cg7 is a 9 pin miniature 6sn7. The 6cg7/6sn7 is a very linear (very low distortion) tube. They could have used that. If they had, their ad copy would have been more believable.

Here another fact that needs to be factored in, some people like the sound of distortion.

"There's no accounting for taste"

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

The objective, posted on June 2, 2020 at 11:45:44
Story
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Location: NJ
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please explain how these curves for the tubes in question differ and under what conditions that make one low distortion and the other high....



 

That might be why I like mine so much., posted on June 2, 2020 at 11:48:40
jeffreybehr
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Posts: 5719
Location: Phoenix, Arizona
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Contributor
  Since: December 13, 2004
 Bought pairs of British Mullard and BRIMAR 'U7s from Brent Jesse.. Got a full week (c. 170 hours) on the first pair and 3-1/2 days on the 2nd pair; the movies I've watched sounded rather good. Really haven't listened critically yet.



This is part of my system-simplification project.
.

 

RE: The objective, posted on June 2, 2020 at 13:00:46
BenM
 The more linear tube (lower distortion) will have the curve lines straighter and equally spaced (parallel).

https://www.passdiy.com/project/articles/the-sweet-spot

https://jacmusic.com/techcorner/SBENCH-PAGES/sbench102/po-dis.html

https://www.youtube.com/watch?v=-c1DMM06Trs

 

RE: The objective, posted on June 2, 2020 at 13:55:21
Story
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Posts: 10457
Location: NJ
Joined: December 11, 2000
 what is it I am missing on these 2 tubes?

with a grid at 5v and the plate voltage swing of 150-250 the graphs show:

6cg7 - 4ma to 18ma

12au7- 6ma to 21ma

where is it that one is acceptable and the other is distorted? I realize that these graphs are not showing the grids at equal V, but they don't look that much different to account for gross differences



 

RE: The objective, posted on June 2, 2020 at 14:11:46
Tre'
Industry Professional

Posts: 17304
Location: So. Cal.
Joined: February 9, 2002
 Here is one example where the 6cg7 can be operated and it will behave in a linear way.

6cg7 operating point = Idle current 14ma., idle plate voltage 200vdc., CCS plate load giving a horizontal load line, Idle grid voltage -4 volts.

When the grid voltage moves to -2 volts because of the positive half of a 4 volt peak to peak sine wave input signal the plate voltage moves down, when the grid voltage moves to -6 volts because of the negative half a 4 volt peak to peak sine wave input signal the plate voltage moves up. The plate voltage change is symmetrical. That is, the plate voltage moves up the same amount as it moves down.

Show me one operating point for a 12au7 that you can say that about.

When the plate voltage movement is not symmetrical, harmonic distortion is the result.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: The objective, posted on June 2, 2020 at 14:17:30
Tre'
Industry Professional

Posts: 17304
Location: So. Cal.
Joined: February 9, 2002
 I want to understand what you are saying/seeing but I need more information.

What is the idle point? What is the idle plate voltage and idle current and load impedance for the examples you give?

You can just show us the plate curves with a load line added.


Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

Here's one, posted on June 2, 2020 at 15:40:45
Tre'
Industry Professional

Posts: 17304
Location: So. Cal.
Joined: February 9, 2002



6sn7 13ma. plate current, 200vdc plate, CCS load
8 volt peak to peak input.
Plate voltage up 82
Plate voltage down 83
That's pretty darn linear. That will produce very little distortion.

For a triode a horizontal load line will give the best linearity.

As the load line moves more diagonal the distortion goes up.

The 6sn7/6cg7 has very evenly spaced grid lines so when the load line moves towards the vertical the distortion stays pretty low.

Now that you made me check, a 12au7 is more linear than I thought when loaded with a horizontal load line but when the load line moves towards the vertical the distortion increases fast. This is because the grid lines on a 12au7 are not evenly spaced over an area of any real size as they are with the 6sn7/6cg7. If you look at the graph above you can see that there is a large area where the grids lines are almost dead nuts parallel.

Most triodes are not loaded with a horizontal load line. Maybe the 12au7 in the amplifier circuit in question is?

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: The objective, posted on June 2, 2020 at 15:44:02
Story
Audiophile

Posts: 10457
Location: NJ
Joined: December 11, 2000
 what from what I see - 6cg7 plate V will range from 160-240 from your example and 12au7 will range from 175-220 which is less of a range.

From this I interpret that the drive abilities of the 6cg7 are greater and therefore less distorted over a greater range?



 

RE: The objective, posted on June 2, 2020 at 17:29:14
Tre'
Industry Professional

Posts: 17304
Location: So. Cal.
Joined: February 9, 2002



It's not about the size of the range, it's whether or not the output wave form has the same shape as the input wave form.

If a tube causes one half of the wave form to be truncated then harmonic distortion results.

The grid lines, along the load line, need to be evenly spaced. If they are not, then the output wave form will not be symmetrical and that is how harmonic distortion is added to the signal.

I am not clear what you are looking at or how you are interpreting what you are looking at but search for triodes and load lines and distortion and you will find websites that explain all of this.

the crappy little graph above tells all if you know how to look at it. The input signal is the lower left, the middle shows what the wave form should look like and what it does look like (too big on the positive half and too small on the negative half. Edit to add, The little wave form in the middle of the middle is the harmonic distortion caused by the two halves of the wave form not being symmetrical.

The right side lower is the output wave shape. Too small on one side and too big on the other because the grid lines on the plate curves (top right) are not evenly spaced along the load line.

I should add that in this example if they would have run more idle current, with a higher load impedance (a load line that is more horizontal) there would be less distortion (the two halves of the output wave form would be more symmetrical) so this graph is a great example of how not to run a tube.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

Please re-read the above. It has been edited, nt, posted on June 2, 2020 at 17:51:37
Tre'
Industry Professional

Posts: 17304
Location: So. Cal.
Joined: February 9, 2002
 .
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: That might be why I like mine so much., posted on June 2, 2020 at 18:11:49
Tre'
Industry Professional

Posts: 17304
Location: So. Cal.
Joined: February 9, 2002
 How do you like the Folded Motion Tweeter(Heil ATM)in your center speaker?

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

ok, thanks /nt, posted on June 3, 2020 at 02:07:45
Story
Audiophile

Posts: 10457
Location: NJ
Joined: December 11, 2000



 

+1 on the M700's, posted on June 3, 2020 at 12:01:31
padreken
Audiophile

Posts: 8518
Location: San Diego
Joined: November 28, 2000
 I leave them on 24/7, always warmed up and ready to go. One of the most satisfying gear purchases I've made.




 

RE: How are they compared to your Parasound ?, posted on June 3, 2020 at 12:50:20
Rick58
Audiophile

Posts: 1118
Location: No. California
Joined: January 24, 2001
 I also want to know ... I hope they sound better! but also have been thinking about getting an A21 for many years ... interested in selling? :)

It should be well 'broken in' as the Thiels are <3 ohm loads!

 

RE: How are they compared to your Parasound ?, posted on June 3, 2020 at 14:51:07
John Elison
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Posts: 23900
Location: Central Kentucky
Joined: December 20, 2000
Contributor
  Since: January 29, 2004
 > Thiels are <3 ohm loads!

I've noticed that a lot of people are confused about the meaning of the two symbols "<" and ">". The way I remember is the pointed end of the symbol points to the smaller quantity. Therefore, your statement above means: "Thiels are less than 3-ohm loads!"

Actually, the Theil CS3.7 has a relatively flat impedance curve that centers around 3-ohms +/-0.5-ohms from 60-Hz to 23-kHz. Theil lists them as 4-ohm speakers but I call them 3-ohm speakers. However, their lowest value is just under 2.5-ohms at 125-Hz. Here's the impedance curve I measured for my Thiel CS3.7 speakers.


 

That's a good question...., posted on June 3, 2020 at 15:21:27
John Elison
Audiophile

Posts: 23900
Location: Central Kentucky
Joined: December 20, 2000
Contributor
  Since: January 29, 2004
 I've been listening to my new Stellar M1200's for about 8 or 9-days and they've improved during that time. I'm planning to reinstall my Parasound Halo A21 in a day or two, so I'll have a better handle on your question when I do. The M1200's sound different from the A21 and originally I felt the A21 sounded better when I first installed the M1200's. However, it took me a few days to integrate my Rythmik Servo Subs correctly and the M1200's improved during that time as well. Consequently, I'm now uncertain whether the Parasound actually sounds better or not. Presently, I'm really enjoying the M1200's. Therefore, let me get back to you on the comparison after I reinstall the A21.

I will say that the Parasound Halo A21 is no slouch. I bought mine brand new in 2012 and I think its list price was $2200 if I remember correctly. If my new M1200's are truly representative of a $6000 amplifier, I believe my original choice in buying the Parasound Halo A21 was definitely a good one.

Anyway, I plan to reinstall the A21 in a couple of days and then switch back to the M1200's after listening to the A21 for awhile. I should know for certain which I like better after that.

Best regards,
John Elison

PS. If you want to read what the Beta Testers have to say about the Stellar M1200 monoblocks, check out the link below:

 

RE: How are they compared to your Parasound ?, posted on June 3, 2020 at 17:29:38
Rick58
Audiophile

Posts: 1118
Location: No. California
Joined: January 24, 2001
 "Thiels are less than 3-ohm loads!" yep. Average = 3 ohms, basically.

I assume the A21 and new PS Audio amps have no issues with these ...

 

This is a great pic, posted on June 4, 2020 at 06:49:15
Barry
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Posts: 1003
Location: PA
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Contributor
  Since: January 18, 2009
 Thanks for posting it. I learned something and think a few others probably did too.

 

RE: This is a great pic, posted on June 4, 2020 at 20:09:14
Tre'
Industry Professional

Posts: 17304
Location: So. Cal.
Joined: February 9, 2002
 They say a picture is worth a thousand words.

That graph really does explain it much better than I can.

Thank you for your kind words.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: How are they compared to your Parasound ? - nt, posted on June 5, 2020 at 12:11:52
John Elison
Audiophile

Posts: 23900
Location: Central Kentucky
Joined: December 20, 2000
Contributor
  Since: January 29, 2004
 I reinstalled the Parasound Halo A21 and played it for a day. It wasn't necessary to play it any longer than that. The PS Audio M1200 monoblocks are noticeably better sounding than the Parasound. I guess they just needed to burn in for several days because they now sound noticeably more robust with a larger soundstage. They also sound smooth and musical in the highs when at first they were a little harsh or bright. The Parasound A21 is a very natural sounding amplifier but it sounds a little small and somewhat weak compared to the M1200's, which now present a very full-bodied soundstage.

Best regards,
John Elison

 

RE: M700s, posted on June 5, 2020 at 12:26:14
John Elison
Audiophile

Posts: 23900
Location: Central Kentucky
Joined: December 20, 2000
Contributor
  Since: January 29, 2004
 I was considering the M700's, but when I talked to Chris at PS Audio he suggested the M1200's for my particular speakers because of their low impedance. When I originally connected them I was a little disappointed, but they now sound very good after about 9-days of burn-in. They present a very full-bodied soundstage with excellent bass and midrange, and nice musical highs. I now believe they are well worth their price tag. I'm sure the M700's are also exceptional amplifiers for their price, too.

Best regards,
John Elison

 

RE: PS Audio Stellar M1200 Monoblock Amplifiers..., posted on June 12, 2020 at 07:36:02
HiOnFi
Audiophile

Posts: 1645
Location: Florida
Joined: January 11, 2004
 Please tell me you placed them on top of the subs for photo op only

My EVS 1200 has dual mono IcePower 1200AS modules in one chassis.

I had the M700s for a few months. Good though they were, the 1200AS modules are vastly superior, but $5999?

 

RE: PS Audio Stellar M1200 Monoblock Amplifiers..., posted on June 12, 2020 at 07:42:55
HiOnFi
Audiophile

Posts: 1645
Location: Florida
Joined: January 11, 2004
 Please tell me you placed them on top of the subs for photo op only

My EVS 1200 has dual mono IceEdge 1200AS modules in one chassis. No stinkin tube input stage needed here $2500. Alas, due to health issues he's not making any more

I had the M700s for a few months. Good though they were, the 1200AS modules are vastly superior, but $5999?

 

RE: PS Audio Stellar M1200 Monoblock Amplifiers..., posted on June 12, 2020 at 10:32:48
John Elison
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Posts: 23900
Location: Central Kentucky
Joined: December 20, 2000
Contributor
  Since: January 29, 2004
 The M1200's sound the same whether the subs are turned on or turned off. I used a one-inch thick piece of slate to isolate them from the subs. The slate sits on four rubber feet at its edges so it's not contacting the center of the sub enclosure where most of the vibration occurs.

Yeah, $5999 is pretty expensive, but just about all amplifiers are expensive these days. There aren't very many amplifiers around that can drive my 3-ohm Thiel speakers properly. These M1200's sound noticeably better than my Parasound Halo A21. The only other Parasound that might sound as good is the JC 5, which costs $5995. I'd love to own the JC 1+ monoblocks, but they now cost $17,000 a pair. Amplifiers are expensive these days. However, I pre-ordered my M1200's before they were available for sale and received a 20% discount, so I didn't pay the whole $5999.

Best regards,
John Elison

 

What about Benchmark?, posted on June 27, 2020 at 13:15:39
creativepart
Audiophile

Posts: 1898
Location: Spring Branch, Texas
Joined: March 1, 2004
 John, Did you consider the Benchmark AHB2 Power Amps? They are in the same price class and are reported to be very very good.

 

RE: What about Benchmark?, posted on June 27, 2020 at 14:12:59
John Elison
Audiophile

Posts: 23900
Location: Central Kentucky
Joined: December 20, 2000
Contributor
  Since: January 29, 2004
 My 3-ohm Thiel CS3.7 speakers require a bit more power than the Benchmark amplifiers are capable of. I selected the PS Audio M1200 monoblocks because they provided substantial power and I think that might be one reason they sound so good with my Thiel's. The M1200's have three-times the power of my Parasound A21 and it's noticeable. I can turn up the volume without experiencing the slightest hint of distortion in the music. It's really remarkable how awesome these Thiel's sound at high volume! When I originally heard them at the Thiel factory they were being driven by gigantic Krell monoblocks and now I have a pair of amplifiers with equivalent power.

Best regards,
John Elison

 

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