First of all, silver is a relatively soft material, which will “self anneal” with time, and too much additional annealing makes it “over” soft. This generates a lot of problems for the cable manufacturing process resulting in a lower audio performance. Simply put, using “age annealing” means to find the best balance point when applied to silver cables. Copper, on the other hand, delivers its best audio performance in its high purity form. Applying annealing will oxidize it easily, which eventually lowers its purity. Therefore we did not apply any annealing to the copper used at the Overture transformers. But don’t worry, winding skills is another very important factor in making transformers, and all transformers in Overture are skillfully hand-made by ANJ. This is at least as significant a feature than the wire material.
Overture ain’t a cool Class A single-ended amplifier with a fancy triode at the end. Instead it’s a common Class AB push-pull design with fairly common EL-34s power pentodes that Mullard introduced in 1955. What’s the secret the Overture?
That’s what’s audiophiles keep constantly asking. At CES visitors praised the sound of the Overture as silky smooth, elegant yet with very clean and good dynamics. They thought that the circuit must be either Triode or Single-Ended design. Once we told them that they were listening to an EL34 Push-Pull circuitry, they were amazed about the quality level that can be retrieved from a pair of EL34. It was at that point we knew that we had reached our goal.
The 32W+32W output stage of the Overture is ultra-linear connected (ie. thanks to intermediate screed grid taps built into the primary of the OPT, part of the load is common to the screen grid and the plate). Is that the secret?
Speakers for the Overture
Clearly, the rated 32W output power surely is sufficient for majority of loudspeakers. Yet I constantly felt that the Overture would perform optimally (unveil its most important qualities) when it doesn’t have to work like a horse. Hence, sensitive, impedance friendly speakers. Tonally it would be essential to find a loudspeaker – neutral or less neutral – that would allow the Overture’s natural sound to come into sight, well, in a natural way. No show-speakers, please. And, of course, the Overture deserves to be paired with as high quality, wide-bandwidth loudspeakers as possible. If one can afford to invest more than a nurse’s annual salary in an amplifier, anything else would be sheer madness.