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PrimaLuna Dialogue Three Preamp Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 100 39.2%
  • 2. Not terrible (postman panther)

    Votes: 105 41.2%
  • 3. Fine (happy panther)

    Votes: 42 16.5%
  • 4. Great (golfing panther)

    Votes: 8 3.1%

  • Total voters
    255

amirm

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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.
PrimaLuna Prologue Three Tube Preamplifier Measurement.jpg

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:
PrimaLuna Prologue Three Tube Preamplifier Review.jpg


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.

Inputs5 Pair RCA +
1 Pair HT bypass
Outputs2 Pair RCA Preamp Outs
1 Pair RCA Fixed Tape Out
Gain12 dB
Freq. Response (+/- 3dB)10Hz - 130kHz
THDLess than 0.15% at 2 Volts
S/N Ratio>100 dB A-weighted @ 2 Volts










Input Sensitivity220mV
Input Impedance200k Ohms
Output Impedance2.5k Ohms
Power Consumption50 watts
Standard Tube Complement4 - 12AU7
2 - 5AR4
Dimensions (WxHxD)15.9" x 8.3" x 15.2"
Weight52.9 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):
Prima Luna Three Tube Preamplifier Measurement.png

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):
Prima Luna Three Tube Preamplifier THD vs Level Measurement.png


Prima Luna Three Tube Preamplifier 0.255 Measurement.png


Noise performance is surprisingly good for a tube preamp:
Prima Luna Three Tube Preamplifier SNR Measurement.png


Frequency response was excellent with small deviation between channels:
Prima Luna Three Tube Preamplifier frequency response Measurement.png


Crosstalk was poor for a "dual mono" configuration:
Prima Luna Three Tube Preamplifier crosstalk Measurement.png


Distortion is mostly frequency independent until you get to very low frequencies:
Prima Luna Three Tube Preamplifier THD vs frequency Measurement.png


Finally, channel balance was impressively good:
Prima Luna Three Tube Preamplifier Channel Match Measurement.png


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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Last edited:
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.

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