[mlundy57]

I was able to get into the PS Audio Beta test for their new Stellar M-1200 power amps. These are a hybrid design with a tube input stage and a MOSFET output stage. Here is a link to their webpage for these monoblocks.  https://www.psaudio.com/products/stellar-m1200-power-amplifier/       While it looks from this web page like they are currently for sale, they are not. PS Audio is hoping to be able to go live sometime in May.





While they may not be all that impressive to look at, as the old saying really goes, The proof of the pudding is in the eating, or in this case, the proof of the design is in the listening.

Since I am currently running PS Audio's M-700 monoblocks which have a class D output stage and a class A analog cell it's going to be interesting to see how the M-1200s compare to both the M-700s and to my PrimaLuna Propldue 4 tube stereo power amp. Especially since I have a full complement of Telefunkin, Cifte, and Svetlana Winged C NOS tubes in the Prologue 4.

When the lockdown ends, Norman and another local HiFi buddy are going to get in on the comparison action.

[Sonicjoy]

Nice! I have been waiting to hear some feedback on these. I got the email for beta testing from PS audio and thought about trying them but my speakers have a 97 db sensitivity rating and 1kw per channel seemed a bit over the top. Heck my current class d mono blocks are  275 wpc and they are way over kill! Just effortless power.

Glad you got to try them and look forward to your review Mike. Have fun!

[mlundy57]

Nice! I have been waiting to hear some feedback on these. I got the email for beta testing from PS audio and thought about trying them but my speakers have a 97 db sensitivity rating and 1kw per channel seemed a bit over the top. Heck my current class d mono blocks are  275 wpc and they are way over kill! Just effortless power.

Glad you got to try them and look forward to your review Mike. Have fun!

They are 1,200 watts into 4ohms, 600 into 8ohms, and are 2ohm stable. That said, in my system they are going to be driving the 95dB efficient NX-Otica MTM monitors with a filter between the pre and power amps rolling off the bottom two octaves. So no real demand on the power amps. You would think that my PS Audio Stellar S-300 stereo power amp would have been more than sufficient for these speakers so there should not have been any improvement by going to the M-700 monoblocks but there was a big difference in sound quality in almost every descriptive category I can think of. There are more differences between the S-300, M-700, and M-1200 amps than just power.

I'm thinking the tube input/MOSFET output stages of the M-1200s are going to have a bigger effect on the sound than the power increase. Mahler will let us know if that's the case. 

Listening to them in the others' systems will be enlightening also. One system is a traditional stand mounted monitor/separate sub system and the other has a big pair of Maggies. So one system has high efficiency easy to drive speakers, one has moderate efficiency relatively easy load speakers, and one has notoriously power hungry speakers. This will provide a well rounded assessment of the M-1200s.

They are building the units this week and hope to get them to us next week.

[mkrawcz]

I got a pair of PS Audio BHK 300 monos a couple months ago and they are by far the best sounding amplifiers I have ever heard. They are currently powering a pair of the NX-Studios and it is epic! I am in the process of building a pair of NX-Oticas that they will soon power.

[mlundy57]

I got a pair of PS Audio BHK 300 monos a couple months ago and they are by far the best sounding amplifiers I have ever heard. They are currently powering a pair of the NX-Studios and it is epic! I am in the process of building a pair of NX-Oticas that they will soon power.

I lust after the BHKs but will never be able to afford them. The M1200s are half the price. Even though I can't really afford that right now, I couldn't pass up the chance to hear them. Both the M1200s and the BHKs have the tube/MOSFET hybrid design so the M1200s are probably as close as I'll get to the BHKs.

I'd also like a Direct Stream DAC and BHK pre. Heck, as long as I'm dreaming, why not go whole hog and wish for the complete electronic setup PS Audio has on the IRS Vs....

[Hobbsmeerkat]

Reading about the description you gave, I was wondering why its calledStellar not BHK, esp considering the hybrid tube/mosfet design, but i also haven't really dug into PSAs current developments aside from what they've talked about with the AN-3s & their Stellar integrated amp which is supposedly also coming soon.
But I'm glad to hear these new power amps are likely going to be worth the wait!

But I would love to hear the BHKs hooked up to Danny's Otticas, NX-tremes & Line Force. (Not that i wouldn't also kill to listen to the classic IRS-Vs... esp since they've upgraded the woofer towers.)

I wish I had the cash for a full PS-Audio stack... however, I've got a Sprout 100 coming, and hopefully by Summer, ill be building my NX-Studios, but that'll be good enough pair for me, until I'm in a position to build a set of Oticas & OB subs.

[Sonicjoy]

Mkrawcz

I got a pair of PS Audio BHK 300 monos a couple months ago and they are by far the best sounding amplifiers I have ever heard. They are currently powering a pair of the NX-Studios and it is epic! I am in the process of building a pair of NX-Oticas that they will soon power.

Would love to see a photo or two of your Studios! And to hear your thoughts on them. Feel free to add that to my NX-Studio build thread : https://www.audiocircle.com/index.php?topic=168181.0 or even better start your own thread. We need more feed back on these here.

I bet they sound awesome with the PS Audio gear.

[Sonicjoy]

You would think that my PS Audio Stellar S-300 stereo power amp would have been more than sufficient for these speakers so there should not have been any improvement by going to the M-700 monoblocks but there was a big difference in sound quality in almost every descriptive category I can think of. There are more differences between the S-300, M-700, and M-1200 amps than just power.

True. I'm not surprised at the improvement. You almost always get better performance going to mono blocks over a stereo amp. Even from the same product line.

I'm glad to see PS Audio expanding their product line and giving us more options and price points.

[mkrawcz]

Sonicjoy,

I will post some pics and my thoughts on the Studios over in your thread once I actually finish the cabinets. I am running them as bare MDF right now until the upstate NY weather warms up enough for me to paint outside.

mlundy57,

I think with the tube input stage, the M1200 will be in another league than the m700s. The tube input stage is simply not going to degrade the signal like a fet input stage does. I have not listened to any of the Stellar amps, but I have a DIY amp I built with ICEpower modules. I think the tube input stage is just what they need to open them up. The ICEpower amps have really good clarity and detail but there is always something not right about them when by themselves. There is a harshness to them. At the same time, I believe that putting anything else between them and the preamp is going to reduce clarity. So I think that the tube input stage will take away the harshness and minimize the signal loss. Like Bascom H King said, "There is nothing more pure than electrons moving through a vacuum".

[Captainhemo]

. Like Bascom H King said, "There is nothing more pure than electrons moving through a vacuum".

if this were  in fact  true,  would all tubes not "sound" the same ?

Don't get me wrong,  I'm not a  tube hater , in fact,  I'm  running  a pair of  6N30P-DR's in a highly modified  K&K Audio RakDac  in front of an IP AS 1200 which drives  a pair of  Super 7's.

Withboth the NX - Otica's and NX-pTremes,  the  IP AS1200  direct  from  DAC (no-pre) was a  fantastic combo.

jay

[genjamon]

I don't know where you guys are getting the mosfet output stage info.  Their product page says they're just using the latest Icepower class D tech for output stage: https://www.psaudio.com/stellar-m1200-mono-amplifier/

This makes sense, since the IceEdge 1200AS2 modules with the same exact output power specs have been out for a couple years now.  Many amp companies have put together relatively inexpensive amps based on sticking these modules in a box.  Looks like PS Audio is finally updating their Class D lineup to include this newest module/tech, but with a tube amp input stage, which is different than the others that are already available from the likes of Nord, Apollon, etc. 

This also explains why it's in their Stellar line (which is PS Audio's class d lineup) rather in the BHK line.

Still a pretty pricey markeup at $6k for a pair, if you ask me.  You can get monoblocks with the same tech without the tube input stage for around $2K from other companies.

[mlundy57]

I don't know where you guys are getting the mosfet output stage info.  Their product page says they're just using the latest Icepower class D tech for output stage: https://www.psaudio.com/stellar-m1200-mono-amplifier/

This makes sense, since the IceEdge 1200AS2 modules with the same exact output power specs have been out for a couple years now.  Many amp companies have put together relatively inexpensive amps based on sticking these modules in a box.  Looks like PS Audio is finally updating their Class D lineup to include this newest module/tech, but with a tube amp input stage, which is different than the others that are already available from the likes of Nord, Apollon, etc. 

This also explains why it's in their Stellar line (which is PS Audio's class d lineup) rather in the BHK line.

Still a pretty pricey markeup at $6k for a pair, if you ask me.  You can get monoblocks with the same tech without the tube input stage for around $2K from other companies.

Here: https://www.psaudio.com/products/stellar-m1200-power-amplifier/     second paragraph under "Product". There are multiple pages on the website for each product.

[gab]

Looks like nothing more than a tube buffer front end feeding an Icepower 1200AS2 module. These amps were available (without the tube front end) from former AC vendor Mivera Audio a few years back. I believe Danny has heard some version of these 1200AS2 amps but I don't recall what his perception of them was (not too impressed I think but I might be wrong - maybe he'll weigh in). Seems kinda pricey to me but what do I know.

Here is one for sale with pics of the inside : https://www.audiocircle.com/index.php?topic=168563.msg1791548;topicseen#new

[Captainhemo]

IIRC  from talking to Danny,   he  did not have enough gain in the system to drive the IP AS1200 to ful power,  it needs  around  6V, I think he was running out of volume  early. I  can tell you from first hand experience, these  due benefit from   decent quality connectors ,  input/ output wiring and even wire routing.

Ran  one for a while with my variable gain Dodd in front of it  with really good results  so hopefully  the PSA   unit will be good.

jay

[mkrawcz]

if this were  in fact  true,  would all tubes not "sound" the same ?

Don't get me wrong,  I'm not a  tube hater , in fact,  I'm  running  a pair of  6N30P-DR's in a highly modified  K&K Audio RakDac  in front of an IP AS 1200 which drives  a pair of  Super 7's.

Withboth the NX - Otica's and NX-pTremes,  the  IP AS1200  direct  from  DAC (no-pre) was a  fantastic combo.

jay

Good point on the tube sound. That was simply what he said when comparing to solid state in terms of transparency. He designed my amps and I can only really compare my BHK 300s which are hybrid tube input, class a/b mosfet output 80lb monsters with my ICE asc200/ac200 amps. On the NX-Studios straight from a Cambridge Audio Azure 851n dac, the ICE amps are not even on the same planet as the BHKs in transparency and detail. The BHKs also don't sound anything like a tube amp. I have not heard the as1200s so I don't know what the sound qualities of those are compared to my ASC200s. I had a pair of Parasound Halo JC1 monos before my BHKs and the ICEpower amps beat the JC1s in detail by a lot so ICE power amps are really good. I am really interested to see what mlundy57 thinks of the m1200 compared to his m700s since the only difference I see other than power seems to be a tube input stage vs a solid state input stage. I think PS Audio would be crazy selling the new amps at twice the price as the m700s if the tubes didn't make a significant improvement somehow.

[Captainhemo]

I can tell you,  the  IP AS1200's are  a signifigant  improvement over  any previous IP class-d amps  .
I too am  looking  forward to   hear  what  Mike has to say with regards to it  combined with the tube input  stage,  will be interesting

jay

[Norman Tracy]

IIRC  from talking to Danny,   he  did not have enough gain in the system to drive the IP AS1200 to ful power,  it needs  around  6V, I think he was running out of volume  early. I  can tell you from first hand experience, these  due benefit from   decent quality connectors ,  input/ output wiring and even wire routing.

Needing 6V to get an ICEpower module to max output indicates the implementation is minimal. ICEPower designs the modules to be driven from a balanced source at pro-audio levels. The quick-n-dirty way to use with single ended consumer level sources is ground the unused negative balanced leg and hookup the RCA jack to the positive input. More engineered implementations (as one expects PS Audio provides) add a buffer stage or transformer to convert single ended to balanced format and adjust gain accordingly.

[mlundy57]

The M-1200s have 30.5dB of gain and an input sensitivity of 2.08V for rated output power.

[poseidonsvoice]

The M-1200s have 30.5dB of gain and an input sensitivity of 2.08V for rated output power.

A standard ICEDGE 1200AS is 25.5 dB overall gain.

ICEDGE input sensitivity is roughly 6V peak to hit 1200w/4 ohms.

The 2.08V sensitivity of the M-1200’s is likely an RMS rating and that is the typical way of listing the input sensitivity. The equivalent for standard issue ICEDGE 1200AS is then 4.24V RMS, which makes sense.

So really the differences are:

25.5dB overall gain with 4.24V RMS input sensitivity
30.5dB overall gain and 2.08V RMS input sensitivity

Which means the 12AU7 tube gain stage in the M-1200 has a gain of ~ 5dB.

Whether the insertion of the 12AU7 gain stage is worth $6K price is up to the end user.

I do have a standard issue ICEDGE 1200AS if Mike wants to borrow it for comparisons. In any case, with the speakers Mike has, he doesn’t need a preamp at all. Ideally, a dac with a variable volume control or excellent sounding passive would be best and preserve the signal to noise ratio of the overall system.

Best,
Anand.

[Ric Schultz]

The IceEdge modules do not NEED an extra input stage.  This is added to give "tube" sound.  What is needed is modding the module....which is what I did on my no longer available IceEdge amps I sold last year.  I did 14 mods to the mono modules including a custom input circuit.  Again, these are no longer for sale....so this is not an ad.  Just telling you what is possible.  A stock mono module with a tube input stage will sound good......but not as good as what can be done if you just use the module and mod the hell out of it and implement it with audiophile tweakiness....like binding post bypass system....handmade input wire, super jacks, damped chassis, multi layer copper and aluminium plates underneath, etc. etc.

Within a month or so there will be two amps released using GaN fets on the output....everything being equal (which it rarely is)....GaNs should make a class D amp sound and measure better.  We shall see/hear soon if this is true.  These amps are the Voyager from LSA (Underwood hifi owned company) and the Premium-Audio amp (basically higher end version of Class D Audio).  Neither of these amps are super tweak (especially the Class D audio one)...so may need some tweaking to make them sing.  But, of course, I think everything needs tweaking.......here are links to these (hopefully) soon to be released amps.

 https://www.premium-audio.com/

https://www.underwoodhifi.com/products/lsa-electronics

Here is another great sounding amp that uses the Hypex NC 1200 modules with discrete input circuit....WBT jacks, etc....that would problably be better than the new PS Audio.....and available for $5K delivered (2 mono amps).

https://www.nordacoustics.co.uk/product-page/one-se-nc1200mb-mono-block-single

Lots of cool stuff out now and lots of cool stuff coming.  I personally really am looking forward to the $2500 LSA amp with the GaNs....could be real nice.