PrimaLuna Dialogue Seven Tube Amp Review

[AudioSceptic]

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

Is there a simple way of adding measurements to get an estimate of the combined result? I suspect the experts here will know, or am I being too simplistic?

 

[milosz]

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.

This assumes that the recordings themselves are faithful to the original sound. Not a good assumption.

 

[oscar_dziki]

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

That's the point. We all love watching car crashes. But we care for your health much more.

 

[DSJR]

I will have you all know that in the newest Stereophile (October 23), one review and one article pointedly take shots at those who "prioritize measurements over 'subjective' listening" (in the case of Manley Mahi tube amps review) and with a bit of a high brow insult (quoting Krishnamurti where, in fact, the meaning of the quote might not apply...see following), and then again asserts that all audio reproduction technology has "a flavor" even after suggesting there might be a goal of "neutrality, transparency, and vanishingly low distortion" because, you know, it might be desirable to not color the original recording and engineered intent of the artist. The other article bemoans that "objectivists" never invite the author to listen to cool systems...

In any case, there seems to be some recent sensitivity in the audiophile community to increased interest in measurements. Boo hoo.

I take it the writer(s) in Stereophile haven't had their hearing tested lately, let alone suffered the final life-changing insult of borderline severe hearing loss in my sixties as I now have after years of trusting my ears to tell me the sonic truth on gear. All that's flown out of the window now and it's bloomin' depressing (I'm being polite)!

 

[fpitas]

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

Well, class D with GaN FETs:

The Gallium Nitride power MOSFETs used in the GaNTubeKT88MkIII power stage

Now, I realize I'm not the target audience. But the phrase, "Beaten with the ugly stick" comes to mind.

 

[milosz]

These Prima Luna pieces are just BAD. I'm not sure I could actually hear their defects, but I wouldn't want to spend money on a product that worked like these do.

There are good tube amps, good tube preamps. These are NOT good, and they are not bargain priced either.

Seems if you want tube gear for some reason you'd be better off getting well-designed examples rather than these.

 

[fpitas]

Seems if you want tube gear for some reason you'd be better off getting well-designed examples rather than these.

That's the trick, isn't it?

 

[Mart68]

These Prima Luna pieces are just BAD. I'm not sure I could actually hear their defects, but I wouldn't want to spend money on a product that worked like these do.

There are good tube amps, good tube preamps. These are NOT good, and they are not bargain priced either.

Seems if you want tube gear for some reason you'd be better off getting well-designed examples rather than these.

Radford make proper valve amps and their prices are similar to those of these units.

personally I still don't see the point but if you were to put a pistol to my head and say 'Buy a tube amp' then it would be a Radford no question.

 

[Purité Audio]

I can see the appeal if you are running a vintage system,

STA15/25 Reissue – Radford Revival

www.radfordrevival.co.uk

It would be a nice curiosity to see in somebody else’s system.
Keith

 

[rdenney]

Radford make proper valve amps and their prices are similar to those of these units.

personally I still don't see the point but if you were to put a pistol to my head and say 'Buy a tube amp' then it would be a Radford no question.

Even those are 3000 British pounds, which comes to $12.95 (I think I did that calculation wrong).

I put these in the Rest-O-Mod category, like late-60's and early 70's muscle cars refitted with proper disk brakes, wheels for which (radial) tires are actually available, fuel injection, a decent sound system, and proper seat belts. The intention is to get the look of a vintage car without actually having to drive one in its original form.

(Stupid sidebar: My hobby vehicle is a 1973 GMC Motor Home--aka the EM50 Urban Assault Vehicle in Stripes--which is the 70's muscle-car of RV's. Oldsmobile drivetrain with big-block 7.5-liter engine. I've rest-o-modded it: front suspension, hubs and brakes adapted from a mid-90's one-ton Chevy truck, which increases the size of the brakes by 20%, provides front bearings and CV joints that are relatively easy to replace, and beefs up (in particular) the lower ball joint and (especially) the lower control arm. I've replaced the fixed-rotation rear drum brakes with floating rear disks that provide four-wheel disk brakes on the rear tandem wheels. The mechanical fuel pump is gone, replaced by an electric back by the tanks to minimize the problem of vapor lock using modern oxygenated fuels. It still has the original four-barrel carburetor but that is in the queue for upgrade to fuel injection. The brass radiator is now aluminum and about 20% more efficient in addition to be much more durable. The original 16.5" bias-ply-tire-only steel wheels have been replaced by 16" aluminum wheels onto which generally available radial tires can be mounted. The sound system is now a touch screen that provides Apple CarPlay for music, phone integration, and satnav, with a modern Class D amp feeding vintage Dahlquist speakers. Point being: Most of the driving and use systems are updated to modern technology, but it's still a 50-year-old vehicle, and those upgrades don't change that. They just make it easier to live with.)

Rick "no modern engine sounds like that header-equipped big-block V8" Denney

 

[Elephen]

I’m not an engineer, and I’ve never owned a tube anything. However, I have to wonder whether reviewing a 15-year-old piece of equipment really tells us much about the quality of the product when new or the quality of newer products by the same manufacturer. In other words, did the owner give Amir the complete history of this unit? Perhaps the owner’s dog relieved himself on the unit while it was powering loudspeakers.

 

[SIY]

I’m not an engineer, and I’ve never owned a tube anything. However, I have to wonder whether reviewing a 15-year-old piece of equipment really tells us much about the quality of the product when new or the quality of newer products by the same manufacturer. In other words, did the owner give Amir the complete history of this unit? Perhaps the owner’s dog relieved himself on the unit while it was powering loudspeakers.

And did it in such a way that both channels were affected in exactly the same manner. Clever pup!

 

[fpitas]

I have to wonder whether reviewing a 15-year-old piece of equipment really tells us much about the quality of the product when new or the quality of newer products by the same manufacturer

They are free to communicate with Amir. That has happened before, and he made suitable notes and edits to his review.

 

[Mart68]

Even those are 3000 British pounds, which comes to $12.95 (I think I did that calculation wrong).

I put these in the Rest-O-Mod category, like late-60's and early 70's muscle cars refitted with proper disk brakes, wheels for which (radial) tires are actually available, fuel injection, a decent sound system, and proper seat belts. The intention is to get the look of a vintage car without actually having to drive one in its original form.

To some extent, but the original models from the 1960s can be had for around half the price. They sound clean and measure respectably. Okay you've not got many watts so speaker choice is limited. A lot of people use them with the big Tannoy DCs and that works.

 

[anmpr1]

I was actually thinking of building a Tubes4hifi Dynaco st-120 before I came across Amir and ASR.

One builds a tube amplifier kit not because of any anticipation that its specs will compete with a modern SS design. That would never be a reasonable argument to make. You might, however, do it for fun, and a sense of accomplishment. Or perhaps you are just bored.

Also, please understand, that the 'ST-120' you mention has no real association, either electrically or otherwise, with whatever Dynaco made, back in the day. Other than it kind of looks like an old Dyna product.

That said, it is possible to build a Dynaco replica, with better parts than whatever David Hafler was selling, in the '60s. Below links to two outfit selling facsimile Dynaco amplifiers. They are about as close as you will find to a NOS Dynaco amp/kit.

First link is to a pre-built model. Second link for a kit.

GETDYNACO

The Amazing and Dramatic Vacuum Tube Stereo Experience with Vintage Vibe Audiophile / Hi-Fi / Stereophile Your Source for the Best Tube Amplifiers & Preamplifiers Analog Home Audio - Vacuum Tube Stereo Classic Two Channel Traditional Designs - Brand New - Custom Built - Hand Wired Dynaco /

www.getdynaco.com

Dynaco replacement parts & vacuum tube audio amplifier kits from Dynakit

Find the right Dynaco™ parts to restore, repair or upgrade your original Dynaco™ vacuum tube amplifier. We also offer an array of new "select" Dynakit™ classic vacuum tube amplifier kits based on the original legendary designs. Orders typically ship within 24 hours.

www.dynakitparts.com

 

[Sal1950]

This assumes that the recordings themselves are faithful to the original sound. Not a good assumption.

But they are what we have.
When mastered properly the CD is our gold standard.

Radford make proper valve amps and their prices are similar to those of these units.

personally I still don't see the point but if you were to put a pistol to my head and say 'Buy a tube amp' then it would be a Radford no question.

Have you or someone else measured them? Evidence please.

The early David Manley designed VTL amps were very good for tubes.
Back when I had the crave for tube power amps I bought mine based largely on
the Stereophile measured performance by John Atkinson. Driving my La Scala's from
around 80hz up they performed admirably for close to 20 years. I have no real idea how
todays VTL's designed.

"On the test bench, you could have been forgiven at first for thinking that this VTL was a solid-state design, the small-signal frequency response (1V into 4 ohms) extending from 2.2Hz to 77kHz (–3dB). Noise levels, too, were impressively low, measuring –90dB, unweighted, with the input shorted, this improving by just over 6dB when an A-weighting network was switched in circuit ahead of the meter. John Atkinson"

VTL 100W Compact monoblock power amplifier Specifications

Sidebar 1: Specifications

www.stereophile.com

 

[anmpr1]

The early David Manley designed VTL amps were very good for tubes. Back when I had the crave for tube power amps I bought mine based largely on the Stereophile measured performance by John Atkinson. Driving my La Scala's from around 80hz up they performed admirably for close to 20 years. I have no real idea how todays VTL's designed.

From my xperience, the problem is not so much with the tube amp, but rather with tubes. I've had Russian glass (I think most of those are owned by Electro Harmonix) with really poor reliability. Even rectifiers, which make a nice light show when they arc out.

Perhaps against popular opinion, my best luck has been with the Chinese brands. But people reactively want to look down on anything from that place. I don't understand that. Currently using a 6V6gt push pull amp sporting Marshall branded tubes (they look like black glass Shuguang) driving my LaScala II horns. They have worked fine, for a while.

Really, tube QC is a coin toss. Probably that's why NOS is in demand, but my wallet is not going there.

 

[Geert]

Perhaps the owner’s dog relieved himself on the unit while it was powering loudspeakers.

Wouldn't be surprised. Dogs have sensitive hearing.

 

[Sal1950]

From my xperience, the problem is not so much with the tube amp, but rather with tubes. I've had Russian glass (I think most of those are owned by Electro Harmonix) with really poor reliability. Even rectifiers, which make a nice light show when they arc out.

Your experience is much more recent than mine.
Back then my VTL Compact Mono 80s were running VTL branded Russian/Sovtek 5881 tubes (Chinese glass didn't exist at the time, very late 1980s) and I used the original set for close to 20 years. I talked to the gentleman that bought them from me who said one of the 5881's did go Chernobyl on him about a year later. But a new tube and fuse had him rocking again. Good amp designer & recording engineer was David Manley. RIP
My biggest issue was with the 12AT7 drivers going noisy.
As you know the La Scala's are just slightly sensitive (LOL) and highly revealing of any upstream
noise. Every year or two I'd start to hear that tube rush in one speaker or the other and have to
replace the input tube in the amp for that channel

 

[egellings]

Amir, thank you! I'm a life member of the bad-back club. So, as Class D amps get better and better, I'm skipping the tube stuff. I can't lift anything over 25 pounds. So, small subwoofers, bookshelf speakers that are under 25 lbs, and the like. It's just not worth the 3 months of PT if I over lift.

Can you get someone to help lift the heavier items? That's what I do when it becomes necessary. I wouldn't want to limit my audio equipment choices solely on my ability to lift them, which is limited due to old age. I'd get help for moving heavy pieces.