PrimaLuna Dialogue Seven Tube Amp Review

[mhardy6647]

Price is for each so it will indeed set you back over 5000 for a pair.

Yowza!

 

[BostonJack]

Now, to the cost of purchase, add in the power consumption of this turd, even at idle…and perhaps the added burden to one’s ac system.

This thing is an assault on the environment and audio engineering.

Unless…you swap the stock tubes with $3500 cryogenically treated Russian made tubes from the first half of the Stalin regime…then not only will they solve the poor measurements, it will also use less power per watt than a class D. Enjoy it while it lasts cause those old tubes have an average lifespan of 8-20 hours.

This would be perfect for enjoying the 1/2 hour LP vinyl recording of applause after one of Stalin's speechs.
Cold war nostalgia.

 

[DanielT]

Art Dudley's was not the only one with a defect in his ears:
See a review of the Boyuurange Reisong A12 here
This one is very positive:

But if you look at the following video (especially the measurement at 14 minutes 15 seconds) you will think differently:

This is one big distortion machine....

I think that a tube amp design can at least be better than what Prima Luna gets out of it

Well, that's the way it is with these tube amp lovers, as shown in the first video from Thomas & Stereo in your post. The tube dude lover in that
Thomas & Stereo video think he hear some tube magic. Where is it one wonders when the Reisong A12 tube amp has 10% distortion at 2 watts and an abysmal FR.

BUT here's the thing, the X person or whatever it is called in this Skunkie Designs Electronics improved the Reisong A12. Still pretty lousy, but better. It shows my point as I said before. Tube amps are for electronics savvy to tinker with as a hobby.

 

[mmuetst]

Maybe we must have best from both world?

AGD THE AUDION MkIII Monoblock · AGD Productions

“The new AGD “THE AUDION” MkIII is one of the most Compact Amplifier Design in Hi-End Audio. “THE AUDION” Monoblock uses the unique GaNTube™ technology with

agdproduction.com

Class D in a tube looks Nice. The compacy even shows measuments

I think it would be nice to see it on @amirm's test bench

 

[Sal1950]

The DiaLogue Seven's measured performance in triode mode was notably worse than in ultralinear mode, yet Art Dudley ultimately preferred triode mode. A puzzle.—John Atkinson”

That's Dudley, if you've read his stuff for a while you learn the higher the distortion, the more he loves it.

Art Dudley, RIP, was a great writer and for all I know, a good person. There was, however, an inverse relationship between measurements and his recommendations. In most cases, the worse something measured the more Art liked it. (I used to subscribe to Stereophile.)

Yep, that's what I said.

Price is for each so it will indeed set you back over 5000 for a pair.

Ouch, add in $2,600 for the preamp and your pushing $8k before taxes. For a measly 2ch's distorted of audio?
What's the thought process over in the High End Subjectivist media world?
For SOTA music reproduction they recommend some of the worst possible gear you can find and then highly encourage spending tens of thousands of dollars on a vinyl front end that will forever be stuck at a 1960s level of transparency to the source tape/file.
What a damn shame.

 

[renaudrenaud]

There is still a question for me. @amirm compare this unit with his Topping LA90.

But I thought this Topping amp had a design error and all of them were broken after few weeks.

How the LA90 is able to play music after all this time (months or years) when the idea in the design is auto purify by fire ?

 

[milosz]

I have several tube amps and I like the ones I have. I use a Harman Kardon Citation II (with McShayne mods) to drive my Quad ESL-57's. I have a Heath AA-40 that I use with my Rogers LS 3/5a's. And I have an Audioromy M828A which uses a pair of 829 dual-tetrodes. which the sections of the tetrodes in push-pull.

I like these amps on certain speakers. The Ohm's-law interaction between the impedance of the speaker and the high-ish output source impedance of the amplifier results in a frequency response artifact that can be very pleasant. The Citation II uses nested feedback resulting in pretty low source impedance and quite linear operation- it sounds a lot like a solid state amp, really. But the ESL-57 has a wacky impedance curve and even with decently low source impedance, the upper highs are tamed a bit which sounds good in my room. The other speakers - 2 ways like the LS 3/5a and a pair of small boxes with 2-way SEAS Excel drivers- there is a certain frequency response that results which I like. Yes, I could use EQ but I'm and audiophile and we just DON'T use eq.... HAHAHA

The other thing I like about tube amps is they don't generate huge spiky square waves when you push their bass output a little past it's actual limit. I find I can get higher average levels without objectionable BLATTT using a tube amp.

I don't think there's much to this "additional low levels of even order harmonics" makes the sound "sweeter" - I think the "sweetness" comes from the impedance interaction.

For my most critical listening, I use very good solid state amps, of course. But tubes have a place for other kinds of listening.

 

[Alice of Old Vincennes]

Amazing that it can't get 100W out of four KT88s in UL. GEC's KT88 datasheet shows 100W per pair at 3% THD. Meanwhile, this isn't even hitting half that per tube!

My guess here is that there's very little if any global feedback (not that you can have a particularly large amount of it with tubes), and the AC heater supply (again) is the source of the high 60hz noise. You could probably, with very little work, improve this amp dramatically. Change which tap the feedback is sourced from (my guess is it's probably on the 8R tap if present, so going to the 16R tap) and reducing the feedback resistor values should help dramatically on the distortion front, then floating the heaters up about 60V should help.

Yea, I tried that on my AMC Gremlin in '72.

 

[Alice of Old Vincennes]

I have several tube amps and I like the ones I have. I use a Harman Kardon Citation II (with McShayne mods) to drive my Quad ESL-57's. I have a Heath AA-40 that I use with my Rogers LS 3/5a's. And I have an Audioromy M828A which uses a pair of 829 dual-tetrodes. which the sections of the tetrodes in push-pull.

I like these amps on certain speakers. The Ohm's-law interaction between the impedance of the speaker and the high-ish output source impedance of the amplifier results in a frequency response artifact that can be very pleasant. The Citation II uses nested feedback resulting in pretty low source impedance and quite linear operation- it sounds a lot like a solid state amp, really. But the ESL-57 has a wacky impedance curve and even with decently low source impedance, the upper highs are tamed a bit which sounds good in my room. The other speakers - 2 ways like the LS 3/5a and a pair of small boxes with 2-way SEAS Excel drivers- there is a certain frequency response that results which I like. Yes, I could use EQ but I'm and audiophile and we just DON'T use eq.... HAHAHA

The other thing I like about tube amps is they don't generate huge spiky square waves when you push their bass output a little past it's actual limit. I find I can get higher average levels without objectionable BLATTT using a tube amp.

I don't think there's much to this "additional low levels of even order harmonics" makes the sound "sweeter" - I think the "sweetness" comes from the impedance interaction.

For my most critical listening, I use very good solid state amps, of course. But tubes have a place for other kinds of listening.

Why?

 

[Alice of Old Vincennes]

20 years old tube amp still with the original power tubes? Then this is normal, those tubes are worn out and should have been replaced long time ago as they age the most. With tubes that are in good shape this amp is not that noisy in my experience. I got the stereo version (Prologue 4) and with worn out tubes it makes audible noise, that is true...

But it's a tube amp, it will never be low noise. But this measurment should be done with relative new tubes that are tested and confirmed in spec, not with 20 years old tubes. Then you got the real numbers.

Gee, if Amir had only known.

 

[Alice of Old Vincennes]

totally agree..unless this has a batch of fresh tubes... then its an invalid test.

Peter

Send on Musk's next rocket launch. Better measurements under zero gavity.

 

[Alice of Old Vincennes]

I'd say the same about any Class A/AB amp. We choose them because of non-technical reasons since, if engineered, the sonics will be the same as any other engineered amp.

Not sure what you mean. Benchmark coming out with tube amp?

 

[Alice of Old Vincennes]

This would be perfect for enjoying the 1/2 hour LP vinyl recording of applause after one of Stalin's speechs.
Cold war nostalgia.

Hate to see Stalin review.

 

[JSmith]

The company even shows measurements

Good to see... certainly not a cheap exercise either though at $7,850 to $8,600. Looks quite industrial.


JSmith

 

[milosz]

Why?

Because I like the sound.

 

[AndreaT]

The purpose of High Fidelity in sound reproduction is to achieve the best possible mimesis of the sound of human voice, musical instruments, and occasional nature, mechanical and electronic sources. One is free to get a kick by looking at a Monet painting or a Giacometti bronze with colored-lens glasses, or using a blue light to cast a new hue on his/her visual perception. The point is that IM and Harmonic Distortion, FR deviations from linearity (and colored glasses and lights) are additional “Maya’s veil” in relation to the experience of a live instrument, voice, orchestra or bird’s song, therefore changing in perceptible way our overall experience of the Musical Art Event. One could argue at length about thresholds for a distorted perception. However, it has been my experience to like more the Music when the electronics used in the reproduction chain have the best measured performance. On complex and fast-variable musical signals, the difference between impeccable performing electronics and speaker and flawed one is even more intensely evident.

 

[oscar_dziki]

I would love to see measurements of this amp in a chain with the preamp.

 

[AudioSceptic]

People did better than this in 1950...

Let that sink in

Yes, but they were trying to do that, for those who wanted the "closest approach to the original sound". Things like the PrimaLuna are not selling to that market.

 

[amirm]

I would love to see measurements of this amp in a chain with the preamp.

That would be pretty expensive because you would have to pay for my hernia operation. I just got done carrying the amp downstairs to put next to the pre-amp. No way are they walking their way back up to the lab!

Besides the amp was horrible as it was. The preamp would just make the situation worse.

 

[Ra1zel]

I would love to see measurements of this amp in a chain with the preamp

Pointless, knowing both results you can just calculate their combined thd, s/n etc.