eBay stuff (Part 2)

Sure, but I’m not talking about SQ, I’m talking about safety and longevity.

I had absolutely no problem with Cayin products many people were astonished at the build quality.

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I had a Cayin CS-55A Integrated which I p/x’d for the Luxman and it was a superb amp with outstanding build and sound.

I wouldn’t hesitate to buy a Cayin again if I was ever mad enough to get rif of the Luxman :grinning:

You can just use a 2x12V transformer to subtract 24V from our “240ish” voltage for little money or effort. Since most electronics use switching power supplies it makes no difference, but with valve kit it’s usually linear power supplies, and for sure you don’t want to be 10% over on the voltage.

Rather than mess around making a bucking transformer I just bought a 240>220 step down, it was only around £80 for a decent rated one.

It did make a big difference to the heat generated by the Line Magnetic amp I had, prior to the step down the power transformer would get very hot.

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With a step-down the common part of the winding is normally doing very little - the current flowing into the load pretty much balances the current flowing out of the mains (I’m assuming it’s an autotransformer).

If you’ve got a 230V:115V step-down then it’s only half the winding that’s coasting, which is OK I guess. But if you’ve got a 240V:220V then eleven twelfths of the copper that you’ve paid for is idling, which seems like a lot to me. It’ll be bigger and heavier than necessary too.

There are some interesting fault-mode questions with bucking transformers though. If the load should go dead short (not at all likely in a valve amp, unless the fault happens before the mains transformer) then the full mains will be applied across the 20V secondary which will then try to step that up to 2880V on the primary !. The ends of the winding will be clamped to the mains, but the winding’s intrinsic impedance (due to strays) may allow significant voltages to be generated across turns far from the ends - maybe enough to blow the insulation. You will also have put a fuse in the primary circuit. But what happens if that fuse ‘nuisance’ trips ? Now the secondary looks more like an inductor than a transformer and it may drop more than the nominal 20V. In terms of voltage the transformer action still takes place though, so again we may risk the primary insulation. This is the effect whch can blow output transformers if you run valve amps into no load.

I find 2x9V tends to work better. I normally over-spec the bucking transformer so since it’s running slightly below its nominal load it will generate slightly more than its nominal voltage. 9.5-10V gives just the drop-down I’m looking for (here, at least, where the mains is close to 240V).

Yeah my mains is usually closer to 250V than 240, hence the 12s

When we were in Selby it never dropped below 250VAC and once hit 267VAC - well outside even the generously lax standard. Probably explains why valves in the chifi tended to be short-lived… :grimacing:

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Spot of woofer bigness, anyone?

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What do we think they are worth / will go for?

The sb 10000 cost £10,000 in 79/80.
No idea what the 6000 would fetch 2nd hand.

https://youtu.be/aMSQja37sUY

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Wooah how much damage is that nowadays

Breathy female vocal demo alert…

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£65,000

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:see_no_evil:

Endgame. And if you can squeeze a bit more off it’s a bargain given the way prices are skyrocketing.

I had a pair of the Technics SB 7000, they were fun. I sold them to a guy who was going to mount them into a gourmet burger Van in east London somewhere!.

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https://www.hifido.co.jp/sold/17-12649-66854-00.html

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Is the SL-1000R an SP-10R with tonearm or something different?

500,000 Yen = £3,200 :+1:

although I suspect shipping could be spendy… then duty, then VAT, but possibly around £5k?