Welcome to the Machine …. PrimaLuna DiaLogue Premium Integrated Amplifier 2012 (Part 4)

Almost forgot to describe one of the most obvious changes in the DiaLogue Premium design … the use of 6 x 12au7 tubes …. Lots to tell you about this.

One + One = Two, but Two + One =THREE … 3 x 12AU7 per channel

So far we have used one 12AU7 tube per channel as phase shifter and driver for the power tubes. In this situation each leg of the push-pull output stage is driven by only one triode.

That configuration is powerful enough to reasonably drive 1 – 2 power tubes. But … It is a known fact that an output stage benefits greatly from a “powerful” drive. The stronger the better, although there are limits to this of course.

For example in military transmitters, the output stage is often driven by a driver stage which already can supply half the power of the entire amplifier. So a 100Watt transmitter could have a 50Watt driver stage. Just to drive the power tubes …

The extra 12AU7 tube in this new Dialogue Premium design allows for a far more powerful driver stage. Suddenly we can use now for each half of the power amp one full 12AU7, and the two triodes in this tube can be put in parallel. This reduces the impedance of the driver stage by half.

This creates the situation that the power tubes are driven from a 50% lower impedance, which results in a double current supply capacity of the signal drive for the power tubes, which has positive effects on a few key parameters:

1. The bandwidth of the driver stage becomes twice as wide, increasing the entire bandwidth of the amplifier significantly,
2. The linearity of the driver stage becomes twice as linear, reducing the dynamic distortion of the amplifier significantly,
3. The linearity of the power stage is further increased, which results again in a reduction of the dynamic distortion of the amplifier.

This results in:

Less phase-shift in the extreme high frequency range, reason why the amp is more stable and the harmonics of the instruments are reproduced in a more accurate way.

The amplifier has less phase-shift in the extreme low frequency range, so the amp can supply more energy and deliver a tighter bass.

The feedback has less phase-shift to compensate, which makes again the amplifier more stable.

The power tubes are driven with more control, which results in a more dynamic stable output signal.

The static distortion, as measured with a tone on a distortion meter, will not decline significantly. Just a little. But the dynamic distortion, which the human ear perceives as unpleasant distortion, is significantly reduced. It makes the amp sound cleaner.

About hermanvandendungen

Almost 40 years of being with and in the world of high-end audio equipment. As distributor of Krell, Sonus Faber, Cello, Conrad-Johnnson and many more, initiator of brands like Kiseki, Cogelco, AH!, PrimaLuna, Mystère and maybe more to follow.
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10 Responses to Welcome to the Machine …. PrimaLuna DiaLogue Premium Integrated Amplifier 2012 (Part 4)

  1. Chris says:

    I could have sworn that I saw a power rating somewhere in the posts. But for the life of me I can’t find it. Can you restate what is probably right in front of me somewhere? As well as when the US market will get it, and the approximate US price.


    • hermanvandendungen says:

      Hi Chris!

      I will add powers specs soon to the blog, but you can say between 35 and 45 Watts depending what tube used. These powerratings don’t say the full truth as you might think “not more” while in most cases a PrimaLuna amp is powerfull enough to drive most speakers. The Integrated is supposed to land in USA end of May. Retail will start at US $ 3249.- with EL34 tubes.

      Best regards,


  2. Loris says:

    Hi Herman,
    nice to meet You again over the net.

    • hermanvandendungen says:

      Hi Loris!

      That’s a long time ago :-). Nice seeing you again.

      Ladies and Gentlemen, Loris is the long time AH! Njoe Tjoeb client who wrote us in the early days of PrimaLuna:

      PrimaLuna > believe it or not … I discovered a small town located 50Km north of Milano called Primaluna!!! Please get yourself a map from Italy. You’ll find PrimaLuna town near the upper-right corner. It is located 50Km north of Milano near the lake of Como. This should eliminate every doubt regarding “italian” origin of PrimaLuna name. I’ve read the “history” section of the PrimaLuna village web site and found the following (literally translated):

      One probable interpretation of the name of the village comes from latin “Primum Lumen”, which means “First Light” of Christianism, since the very first evidence of Christianism in this region dates 495 Annus Domini. “First Light” translates into “Prima Luce” in Italian and this seems very interesting to me: PrimaLuce (FirstLight) is the first light that we, hi-fi lovers with small budgets, can se in this world of darkness populated by way too expensive esoteric gears …..<

      And this very same text is now already for 10 years on the backside of all PrimaLuna manuals printed!

      Thank you Loris! What's next 🙂

      Best regards,


  3. Mark Boccaccio says:

    Hi Herman- it seems the stupid doctors have decided it’s time to stamp a “use by” date on my body, giving me a rather meager shelf life. I currently am saturating myself with all forms of music in this race against time. It all sounds killer; from Imogean Heap to Miles Davis, Terge Rypdal to the Kronos Quartet.

    I am using a PrimaLuna tandem of their Classic tube CD player, feeding a DiaLogue Premium integrated amp, fitted with matched Tungsol K120’s, driving a pair of Martin Logan EM-ESL electrostatic hybrids, supplemented with a pair of “top of the line” SVS 13.5″ Sealed Subwoofers. My question: Is there another set of tube configurations that will surprise and delight me?

    And Herman, as you know, I must insist on being surprised and delighted. Thanking you for any of your always measured and thoughful suggestions ….

    Mark Boccaccio

  4. James Christie says:

    Hi, I am using KT120s with this amp and they sound just divine. I was thinking of thinking of playing with the 12AU7s. Which of these tubes most affect the sound, or do I need to change all? I was considering Gold Lions

  5. Having read this I believed it was very informative. I appreciate you
    taking the time and energy to put this information together.
    I once again find myself spending way too much time both reading
    and leaving comments. But so what, it was still worthwhile!

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