Another LCR phono (aka BTJ-9000S)

Yep.

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How many chillies in it?

Do I need to lend you a Crosley to check it works or will you use the laptop & inverse RIAA as usual?

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Just the one, as usual :smiley:

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I’m very excited now - we’ve reached the badging stage :grinning:

This one’s going to be Coco San BTJ9000S.

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When! When! :astonished:

Got to find an excuse to go missing… :wink:

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Is Christmas going to come early?

Soon, soon! :grinning:

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Looking forward to seeing the finished item.
Hopping I can get to hear one of these soon.

You can have a quiet PSU, or a valve PSU… :wink:

Yup :+1:

If the supply is a simple one i.e. rectifier followed by CFEs* separated by resistors and/or chokes then it can be as quiet as you like whatever rectifier you use. Solid-state rectifiers are actually more prone to switching noise than valves, but it isn’t hard to deal with.

If you want a regulated supply with a low source impedance then it can indeed be tougher to make a quiet one using valves (voice of experience !) since it will almost certainly include an error amplifier, and valves tend to make noisier amplifiers in general than transistors. It can be done though. I’m working on a 250V/25mA supply which currently has ~20 microvolts RMS of broadband (20Hz-30kHz) noise and I’m hoping to tweak that down a little further. The supply has an output impedance of less than an ohm down into the sub 40Hz region. And it uses a gas-discharge reference ! To deliver an ohm at 40Hz using just a capacitor I’d need it to be 4000uF !

If you built the same supply using a high-power FET as the pass element you’d always be worried that any ‘little accident’ might blow the FET. They always seem to fail short-circuit which results in the full raw supply voltage being fed through to the audio valves. Fingers crossed they can take it for as long as it takes you to get to the Off switch …

VB

*Capacitor (F*****g Enormous)

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There is a disappointing lack of Numberwang! on this thread.

All I can add is it looks fantastic, and would mean a lot that a friend has designed and made it for Jim. I like Vannessa even more that Graeme has spent time inside her. There is uniqueness that hasn’t got a value.

Christ, I’m getting all sentimental ‘n’ shit. I’m off to watch detectorists.

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Have a box of kleenex ready.

Give him the wrong idea. That sort of thing and Vanessa will only end in tears.

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Rear panel. WBT silver connectors (£££Ouch!!!).

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No point in fitting foo connectors if Jims not going to use foo cable…

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If you want that engraved with inputs and output labels etc just pop it in the post :slight_smile:

I could have drilled the holes square too :stuck_out_tongue:

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