PrimaLuna Dialogue Three Preamp Review

[amirm]

This is a review and detailed measurements of the Prima Luna Dialogue Three tube preamplifier. It is on kind loan and cost US $2,599 when available in early 2000s.

The amp fit and finish seems excellent even after so many years. There seems to be microprocessor control for power on delay and input selection through rotary controller. Back panel impresses yet again with very high quality connectors:

Product is designed in Europe but manufactured in China as you can see from the torn sticker.

The amplifier is extremely heavy. At 52 pounds, that is one heck of lot of iron for a preamp!

Edit: specs are for different model. Will update tomorrow.

Inputs	5 Pair RCA + 1 Pair HT bypass
Outputs	2 Pair RCA Preamp Outs 1 Pair RCA Fixed Tape Out
Gain	12 dB
Freq. Response (+/- 3dB)	10Hz - 130kHz
THD	Less than 0.15% at 2 Volts
S/N Ratio	>100 dB A-weighted @ 2 Volts

Input Sensitivity	220mV
Input Impedance	200k Ohms
Output Impedance	2.5k Ohms
Power Consumption	50 watts
Standard Tube Complement	4 - 12AU7 2 - 5AR4
Dimensions (WxHxD)	15.9" x 8.3" x 15.2"
Weight	52.9 lbs

PrimaLuna Dialogue Three Measurements
I set the input to 2 volts and adjusted the volume control to get to same 2 volt output (about 3:00pm on the dial):

Good to see that the distortion level is within spec. Not so good is copious amount of it in the form of second and third harmonic. Performance can be substantially improved if you keep the input level much lower (but then again, you may not be able to get max power):

Noise performance is surprisingly good for a tube preamp:

Frequency response was excellent with small deviation between channels:

Crosstalk was poor for a "dual mono" configuration:

Distortion is mostly frequency independent until you get to very low frequencies:

Finally, channel balance was impressively good:

Conclusions
Rating it by modern solid state preamps, performance of the Three is abysmal. By tube standards though, it seems OK. I let you all opine what you think.

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[Hart]

Funny how some people embrace older inferior technology as superior. At some point I am sure someone will claim Edison cylinder records are the way to go. Probably a "warmer" sound.

 

[Sir Sanders Zingmore]

Performance can be substantially improved if you keep the input level much lower (but then again, you may not be able to get max power):

Not saying it’s great but just looking at one of their power amps. It only needs 880mV for full power, so you’d probably be comfortably in the lowest distortion range for this preamp.

PrimaLuna DiaLogue Premium power amplifier Specifications

Sidebar 1: Specifications Description: Push-pull stereo tube amplifier. Tube complement: six 12AU7, four EL34, KT88, or KT120. Output power: 25Wpc (14dBW) in Triode mode, 42Wpc (16.2dBW) in Ultralinear mode, with standard EL34 power tubes (see text). Frequency range: 12Hz75kHz. Input sensitivity...

www.stereophile.com

 

[renaudrenaud]

I wonder if the 60Hz bump is normal or a lack of power filtering. Seems huge.

 

[dfuller]

Well, it looks pretty much what I'd expect it to. These are not high feedback designs in the slightest. And you know what, for most people, this is going to be completely clean sounding. Most people I know would be hard pressed to hear distortion 50dB down, especially considering it falls off a cliff above H5.

I think you could in theory make some minor gains with higher quality tubes, those Chinese small signal tubes (Shuguangs, specifically) aren't great in terms of linearity or really any other spec (minus the incredibly beefy cathode coatings that genuinely do not care about cold starts in DC coupled cathode followers). Properly curve traced JJs or Psvanes or the like would probably do it.

The big 60hz spike is from the AC heaters. The fix is simple, float the heaters to about 60VDC above ground. That will kill any heater-cathode leakage.

 

[Billy Budapest]

I voted “not terrible” because I had to give kudos for the surprisingly decent noise performance.

 

[frabor]

Same here, not terrible since for tubes, it is not bad, and in top of that is Soooo Pretty with the big nichicons and the six tubes behind the grill. There is something in the looks of tube amp that is not matched by solid state.

In all fairness, for tube aficionados its a decent unit.

 

[DearSX]

Man getting a lot of stuff reviewed this week, thanks Amirm!

 

[Billy Budapest]

Same here, not terrible since for tubes, it is not bad, and in top of that is Soooo Pretty with the big nichicons and the six tubes behind the grill. There is something in the looks of tube amp that is not matched by solid state.

In all fairness, for tube aficionados its a decent unit.

The build quality of Primaluna gear is very high, too.

 

[gvl]

I never understood why you’d want to run a tube preamp. With power amps you could at least invoke the “soft clipping” argument if asked why it’s better, with preamps you just get higher distortion and noise.

 

[Ler0ck]

Thanks. I were correct, build quality decent mean same in sound quality.

 

[Ler0ck]

The build quality of Primaluna gear is very high, too.

I don’t think so when Octave still exist

 

[Blumlein 88]

I consider the pre performance of my Marantz pre/pro acceptable, but substandard vs what is possible for cheap. Yet it is better in every way than this unit. Like gvl, in my opinion tube pre's aren't good choices. They don't give you tube sound. I can understand liking them for reasons beyond sound. I've owned some and used them for a few years. Had a C-J PV-5 for a decade.

 

[AndreaT]

Orders of magnitude greater harmonic distortion than preamps/DACs offerings from Topping, S.M.S.L, Gustard…I am so glad I moved away from tubes more than two decades ago.

 

[CleanSound]

This may not be a good analogy, but let's give it a shot. With sports cars, you have the latest and high performing dual clutch transmission vs. stick shift manual. In terms of performance and technology, you simply cannot compare stick shift with dual clutch. Dual clutch will eat stick shift up for lunch.

But yet, there is a small group of people who wants stick shift to be saved. The Toyota Supra gave in to such demands and designed a stick shift transmission for an relatively older Supra model that's already in production.

This is the case with tube (and I also argue vinyl), it is OK to still like older and inferior technologies. So long, you don't make any ridiculous claims of how tube sounds better than solid state or vinyl sounds better than digital.

This PrimaLuna is honest with it's specs, it is made for that group of people who wants and appreciate the flaws of tube. And for tube standards, it seems to be OK. As such, I would give this amp a pass.

 

[Billy Budapest]

I don’t think so when Octave still exist

I do not understand what you mean.

 

[Ler0ck]

I do not understand what you mean.

Octave brand amp is solid build

 

[restorer-john]

What's HT Caution all about? A loop out of the selected source at line level?

 

[DavidMcRoy]

I consider the pre performance of my Marantz pre/pro acceptable, but substandard vs what is possible for cheap. Yet it is better in every way than this unit. Like gvl, in my opinion tube pre's aren't good choices. They don't give you tube sound. I can understand liking them for reasons beyond sound. I've owned some and used them for a few years. Had a C-J PV-5 for a decade.

They can give you "a" tube sound, maybe not the same kind you get with a power amp.

 

[polmuaddib]

What's HT Caution all about? A loop out of the selected source at line level?

View attachment 309303

I can't bother to look at he manual, but HT could stand for Home Theater, maybe... And Caution, because it is Unity Gain input, meaning volume control does not work.
Basically, it's a bypass input for using Audio Video Processor.