Coco BTJ-9000

I’m in the requirements gathering phase for that one.

Windproofing

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:grin:

Where the fuck are all the crocodile clips?

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First stage wired. Audio Note silver tantalum resistors at £39 a pop :sob:

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And the output stage:

Looks fantastic.

That really is a cost no option build. Didn’t even realise that the Sultan of Brunei was in to hi-fi.

It’s definitely a luxury version, but even this is not as high as you could go - silver inductors and transformers were too expensive.

I’ve read that someone who wound transformers said if there were anywhere to use silver then that would be the place. Why would that be? Do you agree with this?

Still, it’s reassuring to know that if I sold my car, I could afford 8 resistors :joy:

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No idea…

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Is that the Audi? Based on what webuyanycar offered me, you could swap it for 1 resistor.

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Lol. It is indeed. Man, you know how to wound :slight_smile:

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Heh, well they’re cheeky cunts - the fuel in the tank was wiry more!

How many miles has she done now? Still going well?

About 297000’ish Pete, still not missed a beat and pulls like a train.

Nuts really.

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Ah ffs, nice answer!

I saw the reply and thought there may be some in depth explanation on how this is not foo!

Appreciate the honesty.

I don’t know who wrote that or who wound the transformers but it’s stuck in my head ever since.

Yeah sorry! Can’t think of any reason why it should be so.

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Because Audio Note can then charge £10,000 for transformers if they are made of silver.

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You can use less silver for the same performance, or have more performance for the same quantity.

I think silver is slightly better at producing current from an electric field.

I may have just made this up in my head.

There was a debate going on in Another Place about silver interconnects where the techies debunked any possible advantage of silver’s slightly (6%) better conductivity. I think the killer blow was when someone said if you can hear 6% better conductivity then you’ll be able to hear a 6% shorter cable. Game Over.

But the situation with transformers is more complex of course. Cables aren’t typically constrained by space (we can make them as thin or as fat as we like) and they are essentially one-dimensional so, neglecting the connectors, everything (resistance, capacitance, inductance) scales linearly with length. In transformers the resistance of each winding scales linearly with its length. But the stray capacitance between it and the neighbouring winding, which can affect all-important resonances, doesn’t. Basically it scales as the outer area of the winding. This is constrained by the core dimensions, which have to be optimised for the nonlinearities of the material and for the geometry of leakage flux. The capacitance also depends on the thickness of the inter-winding insulation. This is often a great deal thinner than the windings themselves, so if we can save a small fraction of the winding volume (that’s volume, not length or area) by using silver instead of copper then we might be able to use that to increase by a large fraction the volume occupied by the insulation. It’s this range of different scalings (length vs area vs volume) combined with nonlinearities (particularly in the core material but also in, say, the insulation response to changing temperature) that makes interconnects easy to design and transformers very, very difficult.

I am no expert in transformer design, so this might all amount to nothing in practice. But I can at least see a way in which it might matter. Just my two penn’orth as usual.

VB

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