Pass x250.8 vs Boulder 850 vs Spectral DMA250

The McIntosh preamp is a really weird match for any of the amps that you list. I wouldn't buy any one of them unless I could try it in the system first.

Thanks Zd452, yes of course I will try them on my system. Maybe I don't try Spectral due to it needs normally the preamp of the same brand.
I was in the path to buy a MC452 but... in the meantime... I connected a very simple class A amplifier (Audio Exklusiv P1, 35W) and I enjoy the kind of presentation. So my intention to investigate some solid state that can match my preamp.

I agree that the Spectral may not be the best match because of the Spectral preamp issue. I haven't heard a Boulder amp in years so I'm really not sure if that would work well. I will say that I think they were a little overpriced for what they give you. I don't know how different their newer models sound, though. And that leaves the Pass. Its a great amp, but if you look at how its designed, its very different compared to your Mac preamp. So much so, that I think the 2 pieces would be working against each other. For example, Mac believes in using a lot of neg feedback, where Pass doesn't use any. Pass believes in using a very simple design (very few components in the signal path). McIntosh is just the opposite. Looking at it that way, its easy to see potential conflicts. I'll use one of my systems for another example. The components are made up of several different brands: Ayre, Wadia, Aesthetix and Vandersteen. Even though I'm using 4 different brands, they work well together because they are designed by companies that think in a similar way. If I took your Mac preamp and put it in my system, it wouldn't allow the other components to sound they're best. If I took the Pass amp and put that in my system, it would be a much better match. It wouldn't take the fully balanced, 0 feedback, in phase signal coming from my Wadia and Aesthetic front end and turn it into something else. It would retain those properties as it continued to the speakers. The Mac preamp would introduce feedback to the signal. Feedback also alters phase. So just putting 1 odd component in a system can have a serious impact on SQ.

It depends on which kind of sound you prefer. They all 3 sound different. The Pass will be the most musical one in the mid freq.

You only know how it work out with your pre-amp when you connect it.

At the end it is a personal thing. It can be fun to compare, so enjoy it!!

I suspect the Boulder amp to be better sounding!, this is based on preference like anything else, The Boulder has very good Transparency!, A member named Melbguy1 can chime in on this subject, He knows alot more than I do about Boulder equipment.

What I said it is a personal thing. I heard many Boulder
amps in the last 7 years. There was not even one time that I
thought: this is great I want it. I would not even want it
for free in my room!!

It never gave me the emotion I want in music!!

"It never gave me the emotion I want in music!!"

I thought you want 3D? No more? Now you want emotion? You keep changing.

Hi Max65.

I would say the best amp of the three you mentioned for the Sonus Faber Elipsa Red is the Spectral DMA250 being BJT (bi-polar)output it can almost double it's wattage for each halving of load impedance all the way down to 2ohms, and that means it can do current better than the other two which are Mosfet and cannot do the doubling act like the Spectral can.

Your Sonus Faber Elipsa Red are magnificent speakers but are a pig of a load in the bass region and demand an amp that do current, even though they are 91db efficient.

Quote from Stereophile:
"Though this is slightly lower than the specified 91dB, the shortfall is not important. While it will therefore require less of a voltage swing to play loud, the speaker is still a demanding load for the partnering amplifier, with an impedance magnitude that drops to 2.5 ohms throughout the upper bass (fig.1). There is also a punishing combination of 4 ohms magnitude and –50 ° electrical phase angle at 70Hz that will suck gobs of current from the amplifier."

And that -50% phase angle could mean a load down to even 1ohm at 70hz.

Cheers George

Thanks for everyone contribution.
Just to be focused on my genres they are both 50% rock and jazz, not so much classical music.
Now I own a C2500 preamp because my intention was to go with a MC452 amp, and I can't exclude now the C2500 will be an intermediate solution.
@Zd542: I partially agree with you about the possible degrading of SQ using different solutions due to a couple of facts I experimented in these days: the C2500 sound quality is very high compared to some friend's SS preamps and it is (suprisingly for me) neutral, and I'm not a fan of Mc gear.
Second, a good match, in my experience, can be completely unexpected as this little class A ss amp that changed my vision, even with its limits, and convinced to me to try the solid state way without Mc output autoformers (slam, nuances, etc.)
I'm coming from a Vitus RI-100 it was a good integrated amp but not so fast and with a little roll-off on bass area.
@George, sure I will try the DMA 250 even if it not the bes coupling with a non-spectral preamp. Thanks fory your contribution about phase and angle.. yes the SF Elipsa Red needs a lot of (good) power.
@Audiolabyrinth,@Bo1972 I mentioned Boulder because in Italy the same Spectral dealer is also Boulder dealer, I know him very well so it is easier to ask him the equipment for home testing. My only concern about Pass is I don't want another Vitus, and as far as I remember they are very similar in sound presentation, but it is only memory, I need to listen them again ;-)

I will also try to listen some recent Krell stuff like the evo series, but the 402 evo is too big in depth for my shelf (take a look on my system pictures). So the 302 is the only ooption.

Any suggestion will be welcome. After my holidays I will do the auditions in my home, end of August or after September 10th. And of course I will tell you my preference best matching my actual system.

The thing is, when you audition a lot of stuff, you remember all the good things. As a perfectionist at the end you want it all.

All parts you judge an amp for, need to be exeptional. When you have done a lot of lestiening, you are able to listen to all different parts in a very short time. Most people who have this as a hobby, can often listen to a few of these parts at one time.

Beside this, audio always will be a personal matter.

Jump on Pass 250.8 ASAP!!!!

I loved my x250.5, but my xa60.8s were in another league.

Check out the pass xa.8s

@Bo1972, you hit the point, and I'm lucky: I will have enough time to test those amplifiers, not only a day, but sure I want to:
- get emotion, the only parameter I personally consider when all other parameters are substantially correct
- be absolutely calm ! :-) very high risk of compulsive buy!

Seriously, an hi-end journalist said that a correct equipment evaluation is made on the first 3 minutes and the next 3 months.
I was asking for suggestion because coupling tube preamp and solid state amp could be very critical but I feel to follow this way, because I hear the potential of this solution.

@Ebm, thanks, an audio reason to do so without any doubt.. will be welcome.. :-)

@Skootb if you take a look at my system pictures, there is no space to place on it two monos like the XA... I will double check again.

"@Zd542: I partially agree with you about the possible degrading of SQ using different solutions due to a couple of facts I experimented in these days: the C2500 sound quality is very high compared to some friend's SS preamps and it is (suprisingly for me) neutral, and I'm not a fan of Mc gear.
Second, a good match, in my experience, can be completely unexpected as this little class A ss amp that changed my vision, even with its limits, and convinced to me to try the solid state way without Mc output autoformers (slam, nuances, etc.)
I'm coming from a Vitus RI-100 it was a good integrated amp but not so fast and with a little roll-off on bass area."

I wasn't suggesting that you would have a bad match using your McIntosh preamp. I don't see your system sounding bad because of it. I think it may not be the best match to some of the amps you are looking at. Also, the preamp has a huge impact on the overall sound of the system. All the pieces in the system have to work together to get the best possible sound.

I would choose for Pass Labs directly. But...that information is just personal and totally not interesting for you.

Often you know what you prefer or like in a very short time. A good remark is a big smile on your face. :)

Before owning it, you need to enjoy the search for your ultimate amp.......have fun....Bobby

08-15-14: Maz65
@I was asking for suggestion because coupling tube preamp and solid state amp could be very critical but I feel to follow this way, because I hear the potential of this solution.
Maz65 (System | Threads | Answers | This Thread)

Yes Maz65 a tube pre to a solid state power amp/s needs to be thought about, as it's just like impedance matching a passive pre to a solid state

A tube pre's are generally much higher in output impedance than a solid state pre's, therefore they need amp/s that have higher input impedances, 47kohm or higher would be a good start, there is no problem with tube amps because they are usually 100kohm input.

But your Sonus Faber Elipsa Red to get the very best out of them demand an amp like I outlined above, one that gives current all the way down to 1ohm, and that means solid state BJT (bi-polar) output stage that can almost keep doubling it's wattage down to at least 2ohms if not 1ohm.

I can think of even better ones, but out of the three amps you gave us to recommend, only the Spectral has close to goods I've mentioned above.

And it is tube preamp and passive preamp friendly as it has 100kohm input impedance.

Cheers George

Thanks George, about input impedance I also see Pass x250.8 has input impedance 50k unbalanced and 100k balanced.
Bouder 850 have 50k balanced and 25k unbalanced, so it seems not working at its best with a tube preamp.
Very intresting.
Now I'm writing do McIntosh asking them the C2500 output impedance: I was not able to find this info elsewhere.

Maz65 look in your manual of the C-2500 under specs, it's 220ohm so no problem either.

As you still mention the Pass and the Boulder these are both Mosfet output amps, while they both are very good amps, for your speakers they are not going to drive them to their absolute potential. Because of the nasty phase/load they have in the bass, only a bi-ploar (BJT) output amp will do that.
And the only one that can that you mentioned is the Spectral.
But there are even better than this if you care to know, just say so and I'll do searching for you and post them up.

Cheers George

George, any contribution in that sense will be greatly appreciated by me. So please give your suggestions. I'm in the situation where I'm "free" to test almost everything.
Max

@George, yes the C2500 output impedance is 250 ohm (I just received the email from macintoshlabs).

I don't know the vintage of these and there are many many others to look at, so this is a bit of a guide only for you to do your own home work with.

Here are just some that look to have bi-polar output transistors as they seem to come close to doubling wattage for every halving of load impedance from 8ohm 4ohm 2ohm.
I dug these out of Stereophile's test results they seem to do the current needed for the heavy load in the bass your speakers have, but as for the sound it's up to you to decide

Parrasound JC1 monoblocks

Ayre MX-R monoblock

Simaudio Moon Evolution W-8

Mark Levinson No.431

Mark Levinson No.436 monoblock

Classé CAM 350 monoblock

Classé Omega power amplifier

Most of the older big Krells, the ones with masses of heatsink are bi-polar (BJT) So is Dan Agostino's new Momentum and others are out there.

With your speakers stay away from Mosfet output and look at bi-polar (BJT) if you want the very best out of an amp that can drive that nasty bass load your speakers have.

Cheers George

Thanks George, you gave me a lot of material to study for :-)
Max

"Here are just some that look to have bi-polar output transistors as they seem to come close to doubling wattage for every halving of load impedance from 8ohm 4ohm 2ohm.
I dug these out of Stereophile's test results they seem to do the current needed for the heavy load in the bass your speakers have, but as for the sound it's up to you to decide"

Bipolar transistors are not the only option. There's plenty of amps that don't use bipolars that will be able to drive the op's speakers. An amp is the sum of its parts put together by a designer that knows what they are doing. I don't know if you have ever heard any of the 3 amps the OP mentioned, but the Pass and Boulder will will drive the SF's just as well as the Spectral, if not better.

@Zd542 definitively yes. BJTs that George suggest are valid and with no doubt they potentially drive the SF at their best. But the sound pressure I can drive these speakers is for a normal listening room (50sqmt in this case) so the power request can be managed also by Bouldes or Pass.

If you know the SF Elipsa Red or Stradivari sound, they have a wonderful bass but it needs a lot of control.

First I was oriented to pure Class-A amplifiers but when I realized that most of them are monos -and I don't have space for two amps- I was looking elsewhere.
From the George list I guess the only amp I can ask for a test is the Ayre.

Sure I will test all initial three.

My dentist plays with the first generation Amati's. He uses Krell amps of about 7 years old. The sound is stunning. I heard these also with ML. It sounded dead, without emotion. Even depth was of a very low level. Yes SF needs power and speed, because SF does not use units with the best response. You need a lot of power and speed to solve this limitation. But....also you need emotion. It is easy to get a clinical sound out of a SF. I love classical music with SF. I think SF will be my new brand in speakers I will start to sell. I will use SF for it's design and for the options of more expensive speakers.

@Bo1972 It is not a mistery that Franco Serblin (r.i.p.) tested its own products, in the first instance, with Spectral, his personal setup, and (maybe not confirmed) Krell stuff.

In 16 years of time I heard many spectral demos. There was
not even one time that it gave me a smile on my face. What I
said earlier; in a few seconds I can hear to all different
parts which need to be there. There is a lot missing with
Spectral in my personal opinion. In a few demos I really
liked the speed and depth. But.....other things were still
missing. For me this is incomplete. I don't want it. I prefer
and even demand a small and realistic intimate sound. I never
heard any Spectral do this as I want it to be. I hate
classical music played by spectral. It irritated me a few
times. I asked the dealer;do you think a violin sounds like
this? I said: it sound like a clinical violin. That is not
how it sounds in real. This brand I also not even want for
free. Pass labs is superior in emotion compared to Spectral.

"08-19-14: Maz65
@Bo1972 It is not a mistery that Franco Serblin (r.i.p.) tested its own products, in the first instance, with Spectral, his personal setup, and (maybe not confirmed) Krell stuff."

Speaker manufacturers test their speakers with a lot of different amps. They have to make sure the speakers work with a large variety of products. Aside from Krell and Spectral, your speakers were probably tested with another 10-15 amps. At least.

Bo's right about the Spectral amps. They do have a unique sound. You may like it, but there's no way I would buy them without listening to them first. Also, with the Pass amp, you can't put it into the same class as other mosfet amps. Pass is the best guy there is with mosfets. He gets them sounding just as clean as most bipolars. Another amp you may want to look at is Ayre. They do use bipolars, but they don't sound like anything else. For solid state, Ayre is my favorite. But whatever you decide to do, you need to listen for yourself. Going by reviews and opinions is very risky.

I tested a few Ayre amps in the past. They do not have the
width and depth of Pass Labs. I know from email contact that
the new .8 series even have a wider and deeper stage. Only
class a will give you all the colours in the mid freq. you
want and need. Ayre is also in my personal opinion
incomplete. It does not have all the parts for what I call
Total Sound. Same thing; I don't even want them for free!!

@all I mentioned Spectral because the personal home Serblin setup was Spectral (and -not confirmed- Krell KSA also), of course the sepakers are tested on a wide range of amplifiers but sure in the first instance, for the old SF production, was Spectral.

Also for me Spectral is not my taste, even with non-classical music: recently I auditioned a Stradivari + DMA260 + 30SS2 with of course Oracle MIT cabling and the result was poor if you consider the expectations from the level of these electronics.
In other words: when I listen a system like this, I expect a jaw-drop :-)

But I want to give Spectral a chance in my personal setup becuase it is easy for me obtain a power amp from the distributor (who is the same in Italy as Boulder).

MIT with Spectral doesn't make any sence at all. You must be a F... mongol to make this combination. Why? Very simple you need to be aware of the properties Spectral owns. And the properties of MIT. They both give a deep and wide stage, but they lack to give an intimate and realistic proportion of instruments and voices.

In the last 2 years I have proven that MIT are poor cables. I did win all battles with Audioquest against MIT cables. How simple life can be.

All these people are now aware of what an intimate image means. They all use the same words; I enjoy my music a lot more.

Many people believe what people say in audio. Use your own ears. That is why the best sound always wins. With products with a higher endresult it is very easy for me to eliminate products like MIT.

@Bo1972: The only MIT I really appreciate are the digital ones (oh, but they don't have any filter !).
For the rest I agree with you, note that MIT and Spectral is often used in Italy because the dealer is the same ;-) But now we are OT...

The dealer is the same and that says all. In the past when I sold Avalon they said MIT is the best combination with Avalon. This was bassed on political grounds. This I really hate. I want to end this.

I have proven in the last years that Audioquest cables eliminates MIT with Avalon with ease. Just put the Audioquest against the MIT in a battle and you understand why it is inferior.

Many people in audio work with their own political agenda. This is not based on the best endresult possible for a client. These people I will eliminate out of the world of audio personal!

"For the rest I agree with you, note that MIT and Spectral is often used in Italy because the dealer is the same ;-) But now we are OT..."

It probably goes a step further. Spectral usually makes the dealer use MIT or they won't be allowed to sell their products. I think that's how they do it here in the US. Spectral forces the dealers to use MIT. A few years ago when I went to a dealer to demo Spectral, I brought some of my gear into the store to see how well it would match with what I already had. The dealer got mad at me. When he went away to help other customers, I hooked up some Tara and AQ speaker cables that I brought with me. They were both better than the MIT. lol. When the dealer saw my cables his face turned bright red. I don't know if he was mad because I changed the cables without asking or he was mad that they sound better than his MIT. He chased me out of the store. lol. This probably happens to Bo all the time.

My way of working is always creating a higher level in sound
than any competitor. When they come with MIT I always laugh.
Because I know the outcome. Only people with less knowledge
in music and sound would buy the MIT cables.

It is very easy for me to explain to people what the
differences are. This makes it very easy to understand what
the limitations are of the MIT cables. I could not sell MIT
to my clients. I would stop working in audio. I hate
inferior quality. For a perfectionist it always needs to be
the best. The rest I eliminate.

Hello,

I can not comment on the amps mentioned, but my Sonus faber Red Elipsa give excellent results with my Hegel H4SE amplifier.

Good luck.
Ari.

@Ari
you are right about Hegel: some weeks ago I considered the H30 because there was one available in a shop very close to my house, and no doubt it is a great amp with the Elipsas.
But... the aesthetics in my living room is not fundamental but important (see my system photos), and IMHO the H30 is impossible to exhibit open air, simply I don't like its design for the big dimensions.

Anyway, next Thursday Sept. 28th I will try the Spectral and the Boulders mono, and maybe something else. I will post an update about the test of these two amps.

Max.

Hi guys, a short follow-up.
In these days I compared two amps, in the same time, in my setup. Some friends helped me diring listening sessions.
- Boulder 850 monos
- the new Spectral DMA 200 s2

There is a clear winner, no competition: wow, the name is DMA 200 s2.

Let me some days in order to fix the initial feeling.. next week I will post my impressions. Thanks to everybody for suggesting me a way to the right direction, thanks George :-)

You welcome Maz, it's all about the current delivery (even at low volume level) with speakers like yours and many others that have nasty load areas.
(Good current delivery is Doubling watts or close to it.)
EG: 50w-8ohms 100w-4ohms, 200w-2ohms, 400w-1ohm.

This is why at normal listening levels the very old Mark Levinson ML2 monoblocks, even though they were only 25w into 8ohms (yes 25w!!), sounded more powerfull than 400w amps driving the same speakers that had hard loads, like yours and many other expensive ones that are around.

Cheers George

Hi Maz65,

I'm glad you've found your nirvana :-)
I agree with you about Hegel amps - they are big, but far from ugly, IMHO.

All the best and good listenings,
Ari.