Thomas Mayer prefers inductive volume controls in his preamplifiers. For example by use of an autoformer as done in the ‘Meteor’ from Audio Consulting. This technology was already used by Western Electric and got reintroduced in the 70ies by Luxman. Due to the high cost this form of volume control pretty much vanished from the market. This method of level adjustment was also used in the past to adjust tweeters in speaker systems. Volume control by means of a resistive potentiometer has the disadvantage that the unused energy is simply wasted. An analogy would be a car engine with constant RPM. While the potentiometer would be similar to adjusting the speed by means of a brake, the autoformer would be the pendant of a gear box.

Back to the 10Y preamp. Here Thomas Mayer offers two variants. A combination of Lundahl line output transformers with autoformers from the American manufacturer intactaudio. Or –as used in the review preamp- a special made line output transformer from the dutch company Tribute who winds each transformer according to the customers specifications. In this case the primary and core air gap are chosen for the use with 10Y or 801A directly heated triodes. The secondary provides 24 taps for volume control. Both versions allow the setting of the volume in 2dB steps. Both versions have their merits and subtle differences in sound. The best would be to talk with Thomas Mayer directly to choose the right option for the own taste and existing components.

This preamplifier can be operated either with the mentioned 10Y or 801A tubes. Never heard of them? Both are directly heated transmitting tubes. Mayer has profound experience with these and is able to use them optimally. The use of these quite large tubes has nothing to do with Sigmund Freud. They are extremely linear devices which enable a reproduction with very low distortion. Their thoriated tungsten filaments offer a very transparent sound. But only if used correctly, i.e. by use of a carefully designed and laid out filament supply, which has to be DC. Any short cut in this area will be plainly audible.

The preamplifier is completely point to point wired with Teflon insulated silver wire, which is the standard by Mayer. If the option with silver transformers is chosen, this reminds very much of a famous Japanese manufacturer. Furthermore a lot of thought went into avoiding microphonics. These are an important topic with tube amplifiers (as well as transistor components). Mayer mounted the tube sockets on small vibration damped subchassis.

In our preamp you can see three elementary principles of Thomas Mayer’s designs: 1. The power supply. 2. The power supply. 3. The power supply. This somewhat simplified characterization is only one aspect of the philosophy. Disturbances from the mains supply are enemy nr 1! That’s why there is a lot of focus on a stable power supply.