Thoughts on hearing a Wilson XVX Chronosonic System at Evolution Hifi

[Lagonda]

Here’s what John Atkinson said about the XVX load. Personally I would not feel safe driving such a speaker with a tube amplifier. When impedances start falling below 1 ohm, bad things are likely to happen. It just begs the question of why a manufacturer would design such a loudspeaker.

The magnitude remains between 2 and 4 ohms for almost the entire audioband, with a minimum value of 1.5 ohms between 310Hz and 340Hz—roughly consistent with Wilson's specifications. Using an Excel spreadsheet to calculate the EPDR (footnote 1), the resistive load that gives rise to the same peak dissipation in an amplifier's output devices as the loud speaker, revealed that the XVX is a very demanding load, with EPDR less than 1.1 ohms between 52Hz and 66Hz and between 197Hz and 287Hz, with minimum values of 0.91 ohms at 450Hz and 0.94 ohms at 3250Hz. The Chronosonic XVX should be used with amplifiers like MF's darTZeel monoblocks that don't have problems driving loads of 2 ohms and lower.

You just need amps that can drive them, most people don't bother with tube amps anyway.

 

[Salectric]

Here’s what John Atkinson said about the XVX load. Personally I would not feel safe driving such a speaker with a tube amplifier. When impedances start falling below 1 ohm, bad things are likely to happen. It just begs the question of why a manufacturer would design such a loudspeaker.

The magnitude remains between 2 and 4 ohms for almost the entire audioband, with a minimum value of 1.5 ohms between 310Hz and 340Hz—roughly consistent with Wilson's specifications. Using an Excel spreadsheet to calculate the EPDR (footnote 1), the resistive load that gives rise to the same peak dissipation in an amplifier's output devices as the loud speaker, revealed that the XVX is a very demanding load, with EPDR less than 1.1 ohms between 52Hz and 66Hz and between 197Hz and 287Hz, with minimum values of 0.91 ohms at 450Hz and 0.94 ohms at 3250Hz. The Chronosonic XVX should be used with amplifiers like MF's darTZeel monoblocks that don't have problems driving loads of 2 ohms and lower.

That warning certainly doesn’t apply to all tube amplifiers. The one time I heard the XVX was using the new ARC Reference 330M and they didn’t have any trouble driving the Wilsons.

 

[godofwealth]

Stereophile has reviewed tens of thousands of multi-driver loudspeakers over the past decades, many of whose measurements are available online. I would seriously doubt you'd find many that have such a challenging load. On the other hand, looking at the measurements of other Wilson Audio speakers, like the Sasha, it seems their designers like to create such challenging loads. I have no clue why. It's not necessary, and it simply makes the choice of partnering amplifier that much more difficult. Most solid state amplifiers, even good ones, would go bonkers driving 1 ohm impedances. Like I said, it's the Apogee Scintilla reborn....

 

[Ron Resnick]

In my Masters & Makers interview with Daryl Wilson I asked him:

Over time your top loudspeakers have trended to slightly lower sensitivity and more difficult impedance loads. What design philosophy or sonic objective is driving this trend?

 

[sbo6]

I found a detailed set of measurements of the XVX on Stereophile.

https://www.stereophile.com/content/wilson-audio-specialties-chronosonic-xvx-loudspeaker-measurement

Boy, that’s one nasty impedance. I’m not surprised your Mac is having conniptions. It’s a 1.6 ohm load at frequencies that require plenty of current. Why would one design such an impedance curve?

Likely because Wilson assumed almost everyone at this level of $ would be using high quality SS amps.

 

[abeidrov]

Likely because Wilson assumed almost everyone at this level of $ would be using high quality SS amps.

This is not an advantage. There must be some design philosophy that led to this. Perhaps it’s easier to get lower base with this design? However, we have some examples like Sigma Acoustic Maat Vector with minimum impedance of 5.2 ohm at 300 hertz and sensitivity of 100 dB, that goes down to 20 hz. Go figure.

 

[Maril555]

In my Masters & Makers interview with Daryl Wilson I asked him:

Over time your top loudspeakers have trended to slightly lower sensitivity and more difficult impedance loads. What design philosophy or sonic objective is driving this trend?

Did you get an answer Ron?

 

[mtemur]

If the XVX is really a 2.5 ohm speaker, I’d recommend switching to solid state amplifiers. The best and heaviest one I owned was a Krell 700cx, which would comfortably output a few thousand watts at 2 ohms, assuming your power lines would support that current. It ran pretty warm as well. My current ARC 750SE will output perhaps a thousand watts into 4 ohms, but I would not use any tube amplifier into 2 ohm loads, no matter what the specs say. That could be why your McIntosh is blowing tubes. My general impression of Wilson’s is that they are quite efficient and friendly to tube amplifiers. ARC uses them to voice their products. Perhaps yours are different.

+1

There is a more important aspect like phase characteristics than impedance for speakers powered with tube amplifiers. In this case, the XVX changes phase on bass frequencies dramatically. Speaker becomes capacitive which tube amplifiers hate cause they’re not good current sources . Just like SS amps hate high impedance.

 

[abeidrov]

+1

There is a more important aspect like phase characteristics than impedance for speakers powered with tube amplifiers. In this case, the XVX changes phase on bass frequencies dramatically. Speaker becomes capacitive which tube amplifiers hate cause they’re not good current sources . Just like SS amps hate high impedance.

David Wilson had VTL amps in his main listening room to power his WAMM Master Chronosonic. Was he not aware of this issue or maybe Chronosonic is a different design compared to XVX?

 

[Ron Resnick]

Did you get an answer Ron?

Yes. See starting at 0:37:

And please subscribe to the channel!

 

[sbo6]

This is not an advantage. There must be some design philosophy that led to this. Perhaps it’s easier to get lower base with this design? However, we have some examples like Sigma Acoustic Maat Vector with minimum impedance of 5.2 ohm at 300 hertz and sensitivity of 100 dB, that goes down to 20 hz. Go figure.

But again, at this level price point, who cares. Surely anyone who can afford the speakers can afford amplification that provides adequate power.

 

[godofwealth]

That warning certainly doesn’t apply to all tube amplifiers. The one time I heard the XVX was using the new ARC Reference 330M and they didn’t have any trouble driving the Wilsons.

ARC have long used Wilson speakers to test their amplifiers, so I’m not surprised the 330M is up to the challenge. I don’t know what the output taps are on the 330M. My 750SE has 4,8, and 16, so I’d use 4 on mine. There will be some loss of power, but I don’t think it would be critical. ARC amplifiers at this level have healthy current outputs, and the Wilson’s have reasonably high sensitivity.

 

[godofwealth]

But again, at this level price point, who cares. Surely anyone who can afford the speakers can afford amplification that provides adequate power.

I’m guessing the large Accuphase class A monoblocks might make a good match. They are guaranteed to double their wattage from 8 to 4 to 2, and even the smaller 50 watters should produce 200 watts into 2 ohms, which should be enough except for very large rooms. I’d personally spring for the older Krell MCx series, one of the few that’s really stable into 1 ohm impedances.

 

[Lagonda]

I’m guessing the large Accuphase class A monoblocks might make a good match. They are guaranteed to double their wattage from 8 to 4 to 2, and even the smaller 50 watters should produce 200 watts into 2 ohms, which should be enough except for very large rooms. I’d personally spring for the older Krell MCx series, one of the few that’s really stable into 1 ohm impedances.

If you don't mind a slow amp with limited high-frequency, you could do that.

 

[Lee]

A couple of changes have brought new sound to this XVX setup:

1. Peter McGrath visited and changed out the resistor pack.
2. Scott added a Relentless preamp stack. Prior, he used the Vivaldi as the preamp.

The dynamics are improved, bass is just tremendous, and there is a new level of midrange clarity and resolution.

He is still refining the cable and line conditioner but this is truly world class sound.

 

[Audiohertz2]

If you don't mind a slow amp with limited high-frequency, you could do that.

Really , is that how modern Accuphase amplifiers sound, is this consistent from speakers to speakers and with different pre amps .. ?

 

[Lagonda]

Really , is that how modern Accuphase amplifiers sound, is this consistent from speakers to speakers and with different pre amps .. ?

I was referring to the old Krell amps, i owned them for 2 decades.

 

[Audiohertz2]

Ok , never heard a Krell described as sounding slow or lacking in top end thou .,

 

[godofwealth]

If you don't mind a slow amp with limited high-frequency, you could do that.

Subjectively of course you can say whatever you like. That’s the prerogative of being on WBF. Objectively speaking, you’re about as wrong as you could be. I owned the Krell 700cx for about 10 years. My subjective impressions aside, Martin Colloms reviewed this amp for Hi-Fi Critic and did a detailed set of measurements. The 700cx measures flat into the high hundreds of kilohertz. It will deliver almost a 1000 watts into 8 ohms and keep doubling that into 4 and 2 ohms, and if your power input can handle it, into 1 ohm. Dan D’Agostino is an engineer’s engineer. He would never produce an amplifier that didn’t measure perfectly. Massive power amplifiers can sometimes subjectively sound “slow” because they are not distorting like low powered amplifiers and running out of steam. I ran my 700cx into many speakers, from highly inefficient Magneplanars to far more efficient B&W 800 Diamonds. It simply controls a speaker better than anything else I’ve heard because of the massive power on tap. It weighed 200 pounds and did a good job of heating my Massachusetts listening room in the long winter months. Moving to the west coast 7 years back, I sold it back to my dealer. I miss that amp.

 

[Charles S]

Mike and everybody, I agree with all the above with some comments. Man! the 3500 just does a tremendous job on my XVX off the 2-ohm tap. I was listening to Mahler's 6th last night. It's my favorite symphony. Several times during it, especially the ending the needles pegged even with watt hold on to 350 watts plus. The bass and sound quality was amazing. The amp wasn't even warm. Then I listened to Abba. I'm a roller skater, maybe the best 75+ year old skater in America, and I like it loud. The 3500's were rocking along at 300 + watts with incredible slam, pace, bass, and beauty. At the end the amps weren't even warm. My audiophile buddy will be arriving any minute. He is anxious to hear my new system, so I got to go, but I am not exaggerating in the least. I've found audio nirvana with these amps. I worked hard to get them and have 15K of reserve EL509s in a closet, over 100 tubes. I'll send you a pic of the connection very soon. Then you can judge for yourself. Got to go. Big day, Halloween contest at the Brentwood TN rink tonight, dinner afterward, and high end all day with my buddy, with some skating in my private rink. Life is good. Girlfriend tomorrow. I'm going as Einstein, ha, ha! I will attach a pic or two tomorrow. She picked out my costume.