Those of you who have been reading about the Duelund-WRSE external crossover project know that pretty much everyone has wanted to use silver wound autotransformers in their Tannoy crossovers to provide the treble energy control (see below), including Paul Mills at Tannoy, Jignesh, Pambos, Frank, and of course, me.

The autotransformer in the Tannoy crossover allows the treble energy level of the tweeter to be adjusted over a range of -3 dB to +3 dB by selecting different taps on the autotransformer that increase or decrease the tweeter energy level in 1.5 dB steps from the crossover point.

After listening to the astonishing difference the Duelund Silver 6.8uF CAST capacitors (above) made in my crossovers, I've been wondering what sort of magic silver autotransformers might bring to the music emanating from my Westminsters.

Thanks to Jignesh and Frederik Carøe (Duelund), I (we) might actually find out the answer to that question, for in Jignesh's quest to build a complete set of Duelund silver CAST crossovers - input to output - for his Westminsters, he has worked closely with Frederik to build the first set of Duelund CAST silver autotransformers, one of which is shown below.

Frederik has started building me a set of the Duelund Silver CAST Autotransformers  to listen to in the Duelund-WRSE Project external crossovers, and I'll begin reporting on them here and at Positive Feedback Online as soon as they arrive.

Frederik mirrored the Duelund Silver CAST Autotransformers according to the transformers Jignesh sent from his crossovers, and while it is not visible in the photograph above, they are labeled at the top of the lead outs according to the convention in the circuit diagram.

Frederik told me, "We will actually copy client’s own transformers, to make sure they fit the speaker. So people can either send us their own autotransformers, or measure them and send the information."

I like the approach of measuring the specific autotransformers for a pair of loudspeakers, as that assures a custom optimized fit for every loudspeaker.

I'll keep you updated on this story as it develops!

Next up I'll have a follow on from David King about setting up Westminster Royals: "I have been doing a whole series of experiments based around Jim Smith’s book Get Better Sound ..."

More to come - thanks for stopping by!