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Tuesday, February 21, 2012

Cool Links: www.tribute-audio.nl

Hi!

Tribute is well known among tube amplifier builders for their high quality transformers. So it is about time that this company get's it's spot in the cool links section.

The company which is based in the Netherlands, is run by Pieter Treurniet. I met Pieter several times at the European Triode Festival to which he contributed with very interesting lectures and also with transformers for shootouts. Pieter is very passionate about transformer development and among the few people on the planet with profound theoretical knowledge and practical experience about transformer winding. He has no standard range of transformers. Each transformer is wound on order which means each one can be customized. This offers a flexibility which is missing from other transformer suppliers or can only be had at a large cost adder or if you order a certain quantity. Not so at tribute! You specify what you want and you will get it.

My preamps all use inductive volume controls driven by step down line output transformers. I always wanted an integrated solution, a step down transformer which can handle DC for single ended operation, with the secondary implemented as a 24 tap volume control. Since this is not available from other suppliers, at least not in the form which I would like to have it, I approached Pieter and asked if he could do such a transformer. Pieter agreed to calculate such a beast and wind them.

This is the result:


A pair of beautifully built single ended line output transformers with volume control secondaries. Primary and core air gap are sized to fit a 10Y or 801A tube. Pieter did first measurements and recommends to experiment with loading resistors between each tap. He found that the transformer operates without any ringing and excellent frequency response like this. Very promising!

Chassis material for the 10Y preamp with these transformers is already being made. I will present the making of that preamp in an upcoming article.

Best regards

Thomas

4 comments:

  1. Hallo Thomas,

    ein sehr interessantes Konzept! Kann es aber hier sein, dass die Last der treibenden Röhre abhängig von Eingangswiderstand der nächsten Stufe ist, der dann mit dem Quadrat des Übertragunsverhältnisses eingeht?

    Gruss,
    Bernd

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  2. Hallo Bernd,

    der Eingangswiderstand der folgenden Stufe geht immer in die Last der treibenden Röhre mit ein. Man sollte das aber so dimensionieren dass diese eine Größenordnung höher liegt und das so keine Rolle spielt. Hier wird der Ausgangswiderstand zudem geringer, je kleiner die gewählte Lautstärke. Da ist die folgende Eingangsimpedanz vernachlässigbar.

    Viele Grüße

    Thomas

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  3. Hallo Thomas,

    muss ich mir das dann in etwa wie einen SE-Ausgangstrafo vorstellen, der bei maximaler Lautstärke immer noch z.B. 4:1 übersetzt und dann leiser werdend 4:1/10, 4:1/100, usw.?

    Gruss,
    Bernd

    ReplyDelete
  4. Hallo Bernd,

    ja genau. Wobei ich den Trafo so gewählt habe, dass er bei maximaler Lautstärkestellung 1:1 hat. -6dB entspricht dann 2:1 (Ausgangsimpedanz ein viertel) -12db ist 4:1 (Ausgangsimpednaz ein sechzehntel, usw.

    Das ist allerdings bei der Lösung mit getrenntem Trafolautstärkesteller genauso, dass sich die Ausgangsimpedanz mit der Lautstärkestellung verändert.

    Gruß

    Thomas

    ReplyDelete