Pass X150.5 or Odyssey Stratos monos?


After months of research and mental anguish ;) I've narrowed down my search for new amplification to the two in the title. There are obvious differences like the fact that one is a stereo amp while the other are monoblocks. Anyway, if you had to, which option would you go with and why? Thanks!
whatsmyname
The bridged ones, would have been crap also into your Revels as well for the reason outlined.
And as for pre to power impedance, I don’t see 800 ohms into 10000 ohms such a bad mismatch either.

Cheers George
I'd go with Pass. Pass amps are recognized by MAGNEPAN, as the "go to electronics, when it comes to driving "MAGGIES" . Superlative in every respect. You might also consider PASS monoblocks and pre-amp if your budget can stand it. I am confident you will thank yourself.
I have Odyssey Kismet Monos (In Kartango Cases) & they are fabulous.  Significantly cheaper than Pass & with somewhat better Specs in Damping Factor & Slew Rate, which are important in Bass & Slam.  I do use Sub Woofers, as I am somewhat of a Bass Freek.

Pass is a Class act, but Odyssey Monos will stand up to Pass, check out this review of Kismet Monos ~ https://6moons.com/audioreviews/odyssey2/1.html

Mine are driven by an Assemblage Pre-Amp; both Amps & Pre-amp were purchased used, @ significant savings.  Amp SN's are in the 52xx range & may even have better parts than those reviewed in the link above, as Klause of Odyssey is continually improving his products.

When I got the Odyssey Amps, I used my existing 8 Foot Twisted Silver Plated Copper Cables on my Anthonney Galllo 3.1's  Later, I replaced these with 3 Foot, 20 Gauge, 5 Strands ,Twisted Pure Silver Wire with Teflon shielding  (wound myself from wire of which I had bought some 30 Years ago).  WoW did the HIGH Frequency Response Jump out!

Yes, a big advantage of Mono's comes from using Much Shorter Speaker Wires!

Best of Sound as you continue your quest for Audio Perfection.






 

 
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+1 Klaus I have a pair of his Kismet References that he upgraded from Stratos and I couldn’t be happier. When you buy from Klaus or have them modified he does bias them to your electrical supply which is very important to getting them to sound right in your system. You get tremendous value for your dollar with Odyssey audio products. 
I owned Kismet extremes for 3 years. Never really enjoyed them that much. Very smooth sounding but when it came to musicality they never really cut the cake.
Besides they’re very quirky amps: Need to be biased to each speaker to sound their best, must be left on continuous, brake in period 3 months. More trouble than their worth. Also, as much as people have praised Krause, after sale support was average at best for myself.
I usually don't get too involved in discussions about my products,  just let it go.  Served me well over the past 32 years.  HOWEVER,  there are times when enough is enough,  especially since a casual reader really might be influenced by some posts,  which, without a doubt,  are key intentions for some.  So,  it's time now to set the record straight on some outrageous posts.

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First off,  to the original post....yes,  why not Pass if you don't want to go with Odyssey...Pass amps are good, and as long as you'll be happy,  more power to it.  Obviously many people seem to prefer Pass over Odyssey regardless if they ever had any direct comparison experiences,  and how can you not be swayed by that much opinion ????   and I'm sure that there are some honest posts in this regard as well......  As for direct comparisons,  and notwithstanding nilly-willy shadow posts,  I can also point to a more professional,  in-the-open and published comparisons:  https://parttimeaudiophile.com/2013/11/27/magnepan-and-tekton-meet-pass-labs-odyssey-job-merrill-red...
Keep in mind though that these were early Kismets and have since then improved massively. 

-----------------------
As far as I and Odyssey are concerned,  a little background here for the following points:  In the past 22 years we have over 6800 individual customers who by far mostly bought amplifiers from us.   In the past 4 years alone we have had over 400 of them who upgraded earlier models to Kismets...over 90 % of original owners still have their amps...just to show satisfaction levels of our customers.  And yes,  I have been nuts busy  all the time,  and at times simply can't find the time to address all of the issues a customer might have,  but I always find time on the phone when someone calls.

Now,  in the same time span there were a couple dozen deals that went sideways...some of them really, really bad,  and yup,  of course I screwed up several times myself and could have done much better,  yes.  However,  I'm also not in the habit of taking s...... and am able to shut down any cooperation if I feel it's warranted.
1.  Brings me to  Robert's ( Bullit 5094) post.   Let me just say without pulling email threads that it didn't really get down this way.  Let me just say that I'm quite sensitive to being taken advantage of.
2.  On a side note to Hifigeorge:
Man,  I have no idea,  but anything Odyssey that he ever mentioned is negative.  Has been brought to my attention a few times already.  As for our monos which he called crap,  let me just say this,  knowing all of the different models well,  of course:
The monos are vastly superior to their stereo counterpart...and yes,  while the wattage stays in the same neighborhood,  the more important current goes up big time,  however.  Either way,  specs aside,  in musical terms the monos are much faster,  detailed, fuller and richer with staging and pretty much everything in the micro- and macro area improved.   Don't have any idea as to what experience he might have with other stereo vs. mono amps,  but certainly not with ours.

3.  Hiendmmoe:   This is a legitimate former customer,  yes.  However:No,  you don't have to constantly re-bias the amps.   And the custom bias setting is not based as much on speakers,  but more on the actual voltage,  as the bias itself is directly dependent on it....voltage goes up,  so does the bias,  and vice versa if it goes down.  But then again,  some people just have a need to tweak and tweak and tweak,  and never seem to sit still....and yes, biasing any amp is one of these things.  Regardless, what peeves me off here is customer support being average at best ????
Excuse me ????  Just by pulling right now a quick search I came up already with 19  (nineteen)  separate email threads with mmoe.  In addition 21 (twentyone)  phone calls.  Hours and hours and hours of my time talking about the amps,  biasing help, synergy and set-up advice,  etc.   Yup,  just below average support after I already pocketed the thousand and thousands of $ in profits (not). 

----------------------------------------------
Again,  it is not the best policy for a manufacturer to get involved in online discussions about their products for obvious reasons. (and not the ones where some manufacturer or dealers go anonymously online to either hype their stuff or put down the competition,  which is rampant.) It also never looks good to appear too defensive,  especially since this might give more credence to the points that you address.   For direct discussions we have our own circle at Audiocircle,  where I also stay out of discussions  for the most part.  But there are moments where I have to speak up,  and this is one of them.
Stay safe,
Klaus

Hifigeorge: but anything Odyssey that he ever mentioned is negative.

This is incorrect, only the stereo’s that are made into monoblocks Klaus. The stereo’s amps I’ve said sound quite good if you search.

This was after my friend who was going to be your Au dealer saw had me check them out. After I pointed it out to him when he lifted the lid in the samples he got, the Monoblocks were just a pair of the stereo’s monoblock’ed, when he showed me the inside.

As for the stereo sample he got at the same time, I said to him it should sound better on the speakers we had, 89db-90db but a hard impedance load, and it did.
So Klaus I only put **** on the monoblock’ed stereo’s amps, not the stereo amp.

 George
Fair enough...and yes,  the monos are mono'd out stereo amps,  BUT. for one,  man oh man,  that's been a long time ago with AU...and secondly,  no matter what,  the monos are superior.......
the monos are superior.......
Only for wattage Klaus, only for wattage. All other parameters that make for a good amp take a hit, especially low impedance speaker drivability and stability.

George 
@georgehifi 

 why are you so negative against the Odyssey amplifiers?

 After 15-20 years, I just received my upgraded stratos to Kismet amps, and they are great!

just curious mate. 
I first heard of odyssey long time ago, and have been waiting for about 20 years, maybe a little less, 

 I have read EVERY available review and article on Odyssey kismet amps.  They are very good!

 Have you heard a pair of the newest carnation of the Odyssey kismet amps?  
Wow, are they fast, powerful, deep bass, amazing treble!

  I would put these kismet monos against many,amps Twice  their price!   
They drive my modified cerwin Vega D-9’s great, as I have gone through no,less than 5 amplifiers which all were drained and owned by the D-9 speakers.
anyway, I’m happy with them, and thousands of customers are happy w them.

 Owned great amps, and cruddy amps past 30 years, Kismets are nice tubey sounding,amps which have great control of my speakers.

 I’m sorry you don’t like them bro.
    Great weekend all!
why are you so negative against the Odyssey amplifiers?

You really need to read more sunshine/mate/bro.
I’m only anti the monoblocks that are just mono’ized stereo amps (not true mono amps at all). NEVER!!! have I said anything against the stereo amps.
The gullible here think the mono’ized stereo’s are better than the stereo amp.
Only in wattage being far higher are they better, no where else.
Sound quality into the same speaker that both have enough wattage for without strain, the stereo amp will, without a doubt sound better!

BTW: Cerwin Vega D9, 101db 8ohm load, 125db before they distort. Yep! your on the money🤦‍♂️
Nope, my d-9’s are modded, rebuilt crossovers, aircore, Teflon capacitors, all new drivers, wiring, etc.
they go about 3 ohm at lowest.

 Not any stock d-9’s
 they are great, so please don’t throw arrogance at me.
im not a mean person. And don’t deserve the belittling.

 The monos are nice amps.
your hatred is ignored.

great weekend dude.
cheers. 
 Monoblock owner can't take the truth, that the stereo is a better amp.
I own the latest version of the Kismet Stereo amp and all I can say from 'my personal' experience is that it is fabulous.  I have owned lots of of quality gear from quality manufactures over the years and my Kismet stereo amp is my favorite amplifier that I have had in my listening room. 

I have a friend who owns Pass Lab gear and it is great, love it.  It has some advantages such as astectics and resale.  I have not done a direct comparison in my listening room so I can't comment on which sounds best. I would suggest not to underestimate the Kismet. 

Just got a Pass Labs X-150.5 for under 2500 dollars.  I have Pass Labs X-250.5 driving Audio Physic Virgos.  The amp is fed by a heavily modded Air Tight Tube preamp fed by a Asi Teknology mid-level mod to a Cambridge 841 CD player.  The sound of this system is sublime - impactful, visceral, dimensional with a tremendous soundstage.  For my reference system I opted for the x-150.5 because 150 wpc should be more than enough for my Revel F208s and does not weigh 100 pounds like the x-250.5.  
@georgehifi @odysseyaudio 

I bought 2 Stereo Stratos used this year.  They sound really really good, and being an audio tech, I "mono' ized" the 2 Stereo amps nothing else modified, just converted to mono by Klaus instructions.  All i can say is that you (Georgehifi) are wrong about the monos being crap.  The sound from the monos is up to another level! The sound is richer (tube-like), the soundstage is really better too.  
And if that wasn't the case, I could re-convert them into stereos right? 
So, please @georgehifi stop BS about Odyssey if you even didn't listen or test those amps.

@odysseyaudio Thanks Klaus for all your implication in your products! They really give us the highest price/performance for our hard earned money!!

I presently own Lorelei, Tempest pre, Stratos monos.  Very happy!!😊👌
So, please @georgehifi stop BS about Odyssey if you even didn’t listen or test those amps.

Sorry but obvious, if you knew but don’t, what happens to all measurable parameters that make for good amps, they all go backwards when an amp is bridged (mono'd), only the wattage is higher, everything else takes a hit.
Cheers George
@georgehifi
Blah blah blah...you're always repeating the same thing...measurable parameters... but thats true if only it was true bridged amps, what they aren't.  And thats why the wattage is not doubled or tripled like true bridged amp do.  They're only 20watts more, but alot of increased current 45amp stereo vs 120amp mono.

So what you're arguing about is applicable for true mono amps only, not in this case, Odyssey stereo-to-mono amps.

You honestly have no idea what your on about, if it were just about wattage, just go get yourself one of these 4000w!!! for $450!!! and you’ll be happy.
https://www.amazon.com/Behringer-NX6000-Power-Amplifier/dp/B07JJKV6JH

So what you’re arguing about is applicable for true mono amps only, not in this case, Odyssey stereo-to-mono amps.
"True mono amps" don’t have a problem, only stereo amps that have been bridged to be monoblocks have worse specs.

As you can see this is a Stratos monoblock extreme "was clearly a stereo amp" that has been bridged to be mono, as I’ve shown with the two large left and right channel red circled, and the one set of input and speaker terminals omitted small red circle
https://ibb.co/kG04kTv

🤦‍♂️🤦‍♂️🤦‍♂️ Oh my.... You just didn't read what i said in my first post!! I KNOW that theses are stereo bridged version!!! I MADE the conversion MYSELF!!!!🤦‍♂️ 

Ok, that enough for me. I said what i have to say about it. And you dont have any other argument than " these are crap cause they're just a bridged stereo version".

I'm done with you...bye 
I’ve owned both Odyssey and Pass Labs.
3 wks ago, I purchased a Pass XP-22 and X250.8 with the hope of adding another system to another house, adding balanced connections, and perhaps bettering my Odyssey Tempest Extreme Preamp and Dual Mono Stratos circa 2006. Sonically, the Pass has more dynamics, punch, dimensionality, wider image, holographic, refinement, extended frequency, and bass. It’s also 3x the price.

PASS LABS:

However, the XP-22 hummed, and I could hear it from the speakers at 6ft. It defeated the purpose of having a separate chassis for the PS. The X250.8 had wobbly XLR connectors. The cables would also lock into the connectors. I used 8 pairs of speakers with known impedance curves, ranging 86 to 104 dB/W/m. I had to do exhaustive testing with the setup, and even lugged it to another house to rule out the electrical system. I ended up returning the Pass after 5 days for a substantial restocking fee, because dealer said that wobbly connectors are within the normal range for Pass. They’re designed to wobble to release stress in the cable - It didn’t inspire confidence. At 100 lbs., it sounded bogus! I didn’t want to be shuffling these amps anymore. Not after paying $14k! These were 2 month demos from the most reputable Pass dealer in the U.S. I wonder if demos are subject to QC. In this case, no, which resulted in the loss of a sale and new customer. Who knows if they’re recirculating the same equipment to an unsuspecting customers?

The X250.8 was stellar with my Don Sachs Model 2 tube preamp. The gain of the XP-22 is too low. On low-level recordings I had to turn the volume to 80/99 for engaged listening. The first 60-70 settings seem to low to be of any consequence.


ODYSSEY AUDIO:

Initially, I had problems with Odyssey too. The Tempest Preamp hummed very badly. I sent the Odyssey back, and Klaus upgraded the preamp to the Extreme with a Plitron transformer. That cost me $650 in 2006. It seems the Stratos Amps require biasing about every 10 years. I rebiased them 3 years ago after they started to get very hot to the touch, and sounded lean. I find they sound magical at 21mV - great balance of highs/bass. Since the Dual Monos, are stacked boards, it’s very difficult to get the voltmeter leads on the bottom channel. The Single Monos have much easier access points. Odyssey amps require biasing to your outlet voltage. However, I find them to be sensitive to IC too, which is good because you can voice them to your liking.

Klaus asks you to supply the voltage of your house when biasing the amps for custom build. He recommends you keep the system on 24/7. I don’t trust any equipment to be on continuously as it cuts into the lifespan, and risks damage during surges. I leave them on periodically, during anticipated listening time, and find that it takes a few hours to charge the capacitors - then they’ll sound ideal. This is true for many amps with large capacitance PS. The Odysseys sound great, but require experimentation to dial in the sound and voicing.

Please, don’t waste time telling me how impeccable Pass or any other company is to protect your own resale interests. I had such high hopes, and had no intention of returning the Pass since they sounded sonically amazing, sans the hum in the XP-22. There are quirks with products, some we can live with, some are unacceptable, some we don’t know about. Ignorance is bliss in audio, believe me! I’ve owned Odyssey and Pass, and had QC issues with both over the years. But, Pass was substantially more expensive, so I was unwilling to deal with questionable QC in 2021, especially at a much higher price point.

To each his own.I’m ecstatic with my odyssey monos’
and other equipment.
if George don’t like odyssey monos, and feels they are inferior and a poor amplifier, that’s ok.
I know the kismet monos I power my modified cerwin vega D-9’s with control, and make them sound amazing, even more so than the old Rotel rb1090 with much more power I had used for them.

   What’s nice w the odyssey, they are upgradable. 
Havvy Valentine’s Day y’all!

George don’t like odyssey monos, and feels they are inferior and a poor amplifier, that’s ok.
Not just me, but any audio tech will tell you, when you bridge a stereo amp into mono "everything takes a hit" except you get more watts.  
Not just me, but any audio tech will tell you, when you bridge a stereo amp into mono "everything takes a hit" except you get more watts.  
Again, and again and again....the same argument...🤦‍♂️🤦‍♂️🤦‍♂️
I would take Pass over Odyssey any day of the week. I won't go into the ugly details why.
@88man 
I examined a X250.8/XP22 combo at my dealer, no wobbly XLR connectors and a dead quiet XP22.
Again, and again and again....the same argument...🤦‍♂️🤦‍♂️🤦‍♂️

One day it'll sink in, that bridging a stereo amp is a big musical compromise just to get more watts, may as well say it's now a P.A. amp.
The McCormack dna-750s’ are overhyped junk then???

The dna 750s are basically bridged dna-500 amps.....?


Many of the high quality amps which are bridged, area just not good then. ??
My Odyssey amps are bridged, there are many different ways to get specs, power, s/n, etc .....it up to the designer, person who is doing the work.

I read an article week ago, or so, the McCormack dna-500 amp was bridged to become the dna -750 monos.....!???

Which means the dna -750 monos are poorly bridged, and the specs are subpar, and these amps will sound horrible?.
We have heard nothing but great things about the dna 500 - & dna-750 amps.
Many of the people who love these McCormack amps have been jipped by buying the mono version (dna-750) ??.?


Please explain why the dna -750 monos are subpar, because they are bridged versions ?.




We spoke with Mr. McCormack and Mr. Sanders. We heard such different explanations from these two distinguished men, than the conclusions You came up with.
I do NOT DOUBT your experience/knowledge.
Whatever 🤦‍♂️ get someone to show you on the test bench, where all decent amps are designed/measured and worked out.

It’s a very easy way for a manufacturer to have a much more "powerful mono pair model" without much re-designing and tooling put into doing it, like the original stereo one usually does
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call Steve McCormack , tell him  his dna-750’s are less of an amp because they are nothing more than bridged dna -500’s. That they lose sound and are inferior because their bridged. 

   Really,  call Steve, and let him explain it.

   Cheers George!



You need to educate more, https://ibb.co/x5CGWHQ

Better still find "just one amp designer" that doesn't bridge amplifiers to sell. To back bridging to have the same quality measured specs as the same amp non-bridged, into todays high end quite hard to drive speakers. 
Gotta wonder: how does the Odyssey Stratus Mono SOUND on a test bench?         It's been my experience: dummy load resistors have a very limited frequency response.      
Do you think that’s all it is, driving a dummy load resistor? you have a lot to learn.

And a non bridged amp will drive a 2-4ohm load better than the same amp bridged if you’d like to know.

Don’t you guys think a designer like Nelson Pass would have just bridged amps like his stereo X250 to make his mono X600????? or his XA30 stero to make his XA100 monos???
The kismet mono amps will drive 2 ohm speakers all day.....

same with the McCormack dna-750 amps.
they are no good, and their specs are tripe because they are bridged.

First ever I heard the McCormack dna750 amps called no good.
wow, maybe it’s you that needs to learn a bit.

call Steve McCormack, tell him the dna 750 amps which are bridged dna 500 amps are no good.
really, he loves to speak audio.

Or call roger sanders about his Magtech monos, which are bridged magtech stereo amps...

the Sanders amps are stable below 1 ohm, with the specs to back up!
   Old school maybe needs to go to school a wee bit to learn about modern electronics

"Do you think that’s all it is, driving a dummy load resistor? you have a lot to learn."         No, but I do believe how any particular amp SOUNDS, is vastly more important than how it measures.      But then, that's just my personal opinion.

Sorry but you two have much to learn.
You can’t fathom it for yourselves, you just mimic what your been told by who’s selling them to you.

That’s enough .
"Learn"?      About what ?       How to use one's ears?                                                                           What (and/or: how many) courses must one take, before you'd consider actually sitting down and listening to any particular amp, to see if one enjoys it's sound qualities (or not), "educated"?
I read on a forum that If Odyssey placed a giant colorful $5 VU meter on its amps, they could raise the price by a significant amount. When I shop for an amp again, Odyssey will be on my list. I've never heard anything but positive things about them. 
I love meters!!!  L. O. V. E.   M. E. T. E. R. S.  ,,!!

  LOVED MY  Old Onkyo m-504 amp, only 165w @8. But those cool green meters made it sound that much better “to me”.  
  Been on the lookout, and found some meters to plug in, but, it’s not the same. 
  Ordering the Avantone cla-200 Tuesday, if all goes well!

  The huge faceplates on the odyssey stratos, would look wicked with a vu  meter.  Or wouldn’t they,,,,,,,?
 That faceplate is anodized aluminum.     There’s room for a massive meter, if you can do without the logo and own a Dremel (or access to a Bridgeport).                                          Then too: LED meter kits are available, that offer other possibilities.                                Would be sexy, if you’re into meters!                                                                                       btw: If anyone got that kind of itch: I could do the milling job, for a pittance.

Anyone heard from Klaus?

 

tried sending him an email, maeler@daemon email returned it sent error, etc.

 

called phone, “auto voice, the number not set up.

Hope to hear from him,soon, as per the great LP preorder release

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