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!
@simao I have both a Freya S and a Saga +. Speakers are Magnepan .7 and various dynamic speakers. I'm pretty confident the Pass and Odyssey amps will both do the job well, I'm just torn between the two. I expect the Pass to be a bit more magical but the dual power supplies of Stratos monos are very tempting.
whatsmyname OP

You make what could be a good stereo amp into a mediocre mono amp by bridging the two stereo channels together to make a mono.
Yes you gain a lot more watts, but everything else that makes for a good amp takes a hit.

Current ability is less
Stability is less
Distortion is more
Damping factor is worse
The ability to drive low impedance’s is reduced by half.
I’m sure there are more.

Cheers George
In my 10+ years stricken with the audiophile illness, I have learned that you should always keep an eye out towards resale value. 

You may keep something for 5-10 years, or you may not.

I purchased many boutique products over the years that were supposed to be giant killers, and always took a bath when I went to sell them.  

With that in mind, the Pass is 100 percent the better option. I had Odyssey Monoblocks a long time ago. They were very good sounding amplifiers, but because of the variability of the product (different boards, cabling, caps, etc, etc) resale usually isn't the greatest. 

Pass, hands down.  The after-market support from that company is second to none.
I don't see where any of the above responses mention sound quality.  Resale value, after sale support and some theoretical technical issue are relevant, but they should only be considered after sound quality.  I have not tried either amp with you particular setup so I really don't have an opinion.  I just wouldn't be so quick to dismiss the Odyssey.
 I just wouldn't be so quick to dismiss the Odyssey.

I would not have dismissed so quickly, if it were just a stereo version and not bridged into mono, stereo amps.
But still would have given the Pass the nod.

Cheers George
Odyssey Kismet monos!

 Read reviews, Kismet monos!

 Standard a
Stratos, are great amps, but when you go to Kismet level, you will hear a huge difference.

pass amazing.... of course they are!

 Do read kismet reviews, and call and talk to Klaus!
he is honest, and will tell you truth.

no matter amp (s) you choose, you will be happy!
I actually owned a pair of Odyssey Audio Kahrtargo monoblocks and found they were horrible in my system. 
It could have had something to do with the output/ input impedance mismatch between my preamp and amps. Make sure ratio is at least 20 to 1 
I own Pass Labs now and will never look back 
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My buddy had the  Stratos amps for many years.  I brought over a Luxkit Class A amp that simply crushed it in very way.  He sold it the next day.  I'd would without any thought go with the Pass not even close.

Happy Listening.
I owned a stereo Odyssey amp and a pair of Odyssey mono blocks at the same time and I can confirm that the stereo amp sounded better than the monos. I have heard a lot of Pass amps and would agree that they are probably better to my ears. Odyssey makes a good product though.
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I recommend the Kismet amps, they are in another world!

 Check out
 The kismet amps are amazing, they as close as you can get to Symphonic Line amps.

 Bridged or not, they are amazing, gobs of current, and capacitors that are huge.

 Pass is amazing for sure!

 Don’t short change the Kismet monos!!

 The stratos both stock and extreme, are shadowed by the Odyssey Kismet Reference amps!

 As mentioned, either way your golden. 
 These Kismet reference amps are on another level 

 you won’t regret the purchase!

fanboy, NOPE, I just enjoy high quality stuff.  
I’m only one person, but the Kismets are way above the stratos!

give em a try, call and talk to Klaus.
Nod to Pass. Tubelike sound with excellent detail. Great resale because you’ll be selling eventually. It’s a sickness ( bad choice of words). 
The information on the Odyssey web site about the Kismet Reference amps is pretty sparse. Dimensions and 8 ohm power output is about it. Also, no price. Anyone know what these things cost?

The weird thing is that the Stratos line is well documented on the web site. This doesn't inspire confidence.
Stable to 2 ohm or less.
 Almost doubles from 8, 4 and 2 ohm.
   Read the reviews.

    Read lots of reviews!
real deal!
research em’
 enjoy the reading!
I actually owned a pair of Odyssey Audio Kahrtargo monoblocks and found they were horrible in my system.
It could have had something to do with the output/ input impedance mismatch between my preamp and amps.

It was because of this, your Revels looked like a 2ohm load to the bridged Kahrtargo monos and probably were going unstable.

Cheers George
The Kismets range in price from 5500 in the top tier cases.
to lower in different cases.
its not the cases, it’s the guts and top tier parts, capacitors etc!

 Don’t want the best cases, get the top amps in smaller cases.

 Call Klaus and chat and hear him!
he will put you in the correct direction.
Too much bias.

 Kismet monos are top tier.
pass labs are top tier.

 Read some of the kismet reviews.

 Read the Pass labs reviews.

 Make a choice. Enjoy.

  Or if you want something which will drive anything, and sound amazing,

 try the Sanders Magtech.

Pass allows a 2 week trial with a 5% restock fee and freight both ways.
Maybe out $600 if they are returned.
Do not know what Klaus offers.
My advise is to try the Odyssey first.
Thanks everybody. Please note that the Pass I reference is a dot FIVE not eight. I can’t afford an 8. The .5 can be bought used for roughly the same price as the Stratos Stereo Extreme or Stratos monos basic. I’m aware of the fact that Klaus does custom builds and there are multiple tiers/options. The Kismets are out of my price range so they are not a consideration.
Kismets can be put in the stratos cases for a great price reduction,
or even the  khartago cases to save even more.

 Same amazing,amps in smaller cases,
give Klaus a call, call between 9-11pm for best answer.
tell him I sent you, or that you are interested in. The Kismet amps in different cases,
you will be pleased. 
 Kismets in the top tier cases are about 5000k roughly,
Kismets in strato or khartago cases much less.
  Cake Klaus, see what he has to offer, tell him your speakers, tell him your considering the Pass amps, he will be honest with ou.

 Give him a shot.
He will be there now, ready for your call.

 Give Klaus a call, he’s amazing to talk to.
smart, honest, knowledgeable, 

 hit the website and call the 219 number.
he is always happy to chat with audio lovers.
Ask about the Kismets in khartago cases,
should be not too bad.

 Hope you find what your looking for.

 Either the Pass or Odysseys are great amps!

 Happy fun time!
the search/demo of new amps is always awesome!

let us know what you choose and how you like the amp...
I never look at equipment with resale value in mind. I just want to enjoy it and if I choose well it should stay with me ad infinitum.
give em a try, call and talk to Klaus.
Do read kismet reviews, and call and talk to Klaus!
give em a try, call and talk to Klaus.
Call Klaus and chat and hear him!
give Klaus a call, call between 9-11pm for best answer.
Cake Klaus, see what he has to offer

 Wow! now that’s freaky
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I can see this thread turning into a shitshow so I'll move on. Thanks for the comments and advice, enjoy the music!
Good idea, skip the ads

Cheers George 

nothing wrong with a bridged amplifier if done properly!
Really? then please show how to bridge this common simple Nelson Pass Threshold S300 amp "properly" so it’s just as good as the stereo version.
Um - let’s see. What should I choose a Lexus or a Kia. Sure Kia make some nice cars that people love and have great warranties and so on but so what. This is not a legit comparison by any stretch. 
I believe that the Odyssey Stratos monos are not bridged, and the use of the term "bridged" in their description (" RCA & XLR (bridged) inputs") is misleading.  There are several indications of that:

1) See the posts by me and Stereo5 dated 6-4-2018 in this thread.  Apparently the word "bridged" is confusingly used to refer to a direct connection between one of the two signal pins on the XLR connector and the signal pin on the RCA connector.

2) The specified power capability of the monos is only slightly higher than that of the stereo version (180 watts vs. 150 watts into 8 ohms).

3) The specified damping factor of the monos is higher than that of the stereo version (>800 vs. >500).

That said, and although I have no experience with Odyssey products, as a Pass owner (XA25) I would second the comment by @fsmithjack  above.  The two brands are not in the same league IMO. 

Good luck.  Regards,
-- Al

I believe that the Odyssey Stratos monos are not bridged

Al have a close look at my first post links to the "Stratos stereo" and then the "Stratos mono", and I’ll see if I can get some better shots if you still can’t see it.

This is better shot of the stereo
The Stereo
The Mono has a transformer case and some extra PS caps around it, but it’s a bridged stereo Stratos

Cheers George
I have been following this thread from the start.  As the OP stated, only two options were to be considered: Pass and Odyssey.  But there actually is a logical third option: Symphonic Line (SL).  Have a look at the link below and I will explain further.


Jonathan Valin states that the circuit in the Odyssey is the same as in the SL RG-11, the lowest model in the SL lineup.  Maybe so, but that is where the similarity stops.  I have an older rev 15-20 years old) of the RG-11.  I borrowed a stereo Stratos amp a couple years ago.  I believe the Stratos was higher power rated, but the comparison was no match.  The SL had so much more clarity and refinements throughout it was not even close!  I honestly don't know how JV went so crazy for the Odyssey amp, and referenced h super-fi amps in his coismparisons.  The Stratos simply sounded like a budget amp to me.  And here I had a very early version RG-11, and it walked all over the nearly new Stratos.

I have no idea what is going on with SL amps, but they are just incredibly stunning.  I got the RG-11 for $700 a few years ago and I am absolutely positive that nothing on the new or used market can touch it for anything even close.   JV did mention it was 5K at the time of his review, and I can clearly understand why!  I have gone through a ton of amps trying to make my speakers sing.  Even the coveted Nelson Pass SA1 mono amps of years ago, that were able to drive the woofers of the Sonus Faber Amati speakers in a most awesome fashion, were easily outclassed by the RG-11 in clarity, tonal coherency and mid and upper-octave refinements.

I had heard of SL a few times along the way, but this little RG-11 amp can do a darn good job driving the big Sound Lab A1 speakers and could even make the SF  speakers sing fairly well too at medium volume.  Inserting the Stratos to drive the SF's, and the result was severely dimensionally flat.  So Rolf Gemein, chief SL designer, just does something special here.

I have since purchased a new version of the SL RG1 amp.  This is the next up the SL line, and it has much more capability to drive my speakers to impressive levels.  And it brings on a much more refined portrayal of space.  A shoot out with the big BAT amps gives the pros and cons of refined detail and finesse of the SL vs. the big bold powerful BAT.  I can only dream to go up another level or two within SL.

So @whatsmyname, yes, I suggest that you do indeed call Klaus at Odyssey?  And why do I say this?  Because he is the SL distributor in the US.  There is a good chance he might have an SL amp for you to audition.  And the SL will give the Pass a serious run for the money, and likely take the checkered flag.
Hi George,

I think I see what you are referring to in the photos. In the mono version there is a sleeving containing a red wire and a yellow wire, which appear to connect the amp’s output connectors to the printed circuit board. With the red wire going to the part of the circuit board that is associated with one channel in the stereo version, and the yellow wire going to the part of the board that is associated with the other channel in the stereo version.

Which is suggestive of a bridged design. However I suspect that the two channels are paralleled, rather than bridged. With one wire, probably the yellow one, going to circuit ground, and with a connection between the outputs of the two channels being made somewhere where we can’t readily see it, perhaps underneath the board, and in turn connected to the red wire.

As you know, bridging can potentially increase power capability into 8 ohms by 4x (i.e. by 6 db), although most bridged designs fall somewhat short of a 4x increase due to current and/or thermal limitations. But in this case the increase in 8 ohm power capability of the mono version relative to the stereo version is almost negligible (less than 0.8 db). And as you indicated bridging reduces damping factor, while the damping factor of these monos is substantially higher than the damping factor of the stereo version.

Also as you know, paralleling can potentially increase power capability by 2x, while increasing damping factor rather than decreasing it. But IMO it doesn’t speak well of the robustness of the power supply and/or other aspects of this design that the mono version only 20% more powerful into 8 ohms than the stereo version.

In any event, it’s really a moot point as far as we are concerned, as you, I, and several other posters recommend going with the Pass amp whether the Odyssey monos are bridged or paralleled or something else.

Best regards,
-- Al

As you know, bridging can potentially increase power capability into 8 ohms by 4x
Just not to confuse others "power" is "wattage" only in this case, current is halved.
And yes Al I agree, Pass amp by a long way.

Cheers George
I'll go with the Pass as it's a respected, musical, quality amp. No offense to Odyssey - I was curious if it was close enough as it would allow me to get more power for the money. @jafox I'll check out the SL amps out of curiosity. Thanks.
Personally, I have owned 2 sets of Odyssey Monoblock Amplifiers. They were enjoyable, yet both sets were sold. No plans on buying more. I have never owned a Pass Labs amp. It sounds like they are the real deal. If the Pass Amps are anything like Balanced Audio Technology Amps, I can see the attraction.  
Nelson Pass' products are head and shoulders above anything Clause supplies. Not even in the same ballpark. My experience with Odyssey is, purchased a Candella/Kismet. Never had any trouble with noise from amps prior to this. This pair you could hear noise from the listening position. Clause send new power components including a  new transformer and had me change things out. No help. Returned it all to Clause who withheld shipping both ways and even credit card fees from my refund. Then told me all his amps make that much noise. Really? On top of that, I wasn't impressed with the sound over the noise either. I own Pass products too. Exemplary performance. If you can afford it, go with a Nelson Pass designed product. 
Last year I bought a pair of Kismet Monoblocks in stratos cases. Thery were used and I had them sent to Klaus for an inspection and upgrade.He installed the latest soda can sized output caps and an power supply upgrade. He said that the time that this is the same configuration that he has in his personal system. I have $5000 all in. I have heard Pass Labs amps and I they are better but that degree of better costs a lot more. If you go to any audio show where Klaus in showing his room is always among the best sounding rooms in the show.I would love to own a Pass amplifier but for the money Odyssey Kismets are hard to beat. I'll keep mine until I have the $20-30K to buy a Pass product.
I’ll keep mine until I have the $20-30K to buy a Pass product.

Don’t know where you buy used Pass X150.5 that we're talking about here, but they go for $1500 to $3000 all over the place.

Cheers George
I would disagree with you regarding my speakers/amp combo. Actually at the time my speakers were Dali Rubicon 6's that actually had a nominal impeadence of 4 ohms when I aquired the Kahrtargo monoblocks. The Kahrtargo monoblocks had a input impedance of 10k ohms 
My Dehavilland UV 3 had a output impeadence of 800 ohms so that was the deal breaker. At minimum my Dehavilland needs to "see" 18K ohms per Kara at Dehavilland.
Happy Listening