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BU-1 moans.
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Old 11th May 2012, 04:52 AM   #1
PlasticIsGood is offline PlasticIsGood  United Kingdom
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Default BU-1 moans.

Pursuing my fascination with Ken, the DP770 with the Sony 20152 DAC, I chanced on a purportedly dead CDP102 with what I assumed would be the definitive, authentic version of the same audio circuit.

Actually, but for a layout skimp in Ken's sample-and-hold section and the mystery of the missing crystal, it's the Sony that departs most from their own datasheet, having 5532 opamps and no Murata filters. But that's another story that I'll get back to when I've compared them. For now, it's amusing to think that the datasheet circuit is deliberately second-rate.

The big shock was the state of the mechanical bits. It's apparent that the 102 wasn't a Sony flagship. The lightweight case is plain painted steel without the gorgeous plastic laminated covering of the 101. The fascia is a lowly grade of polystyrene and the innovative touch-pad membrane does nothing for its looks or function. The cosmetics haven't survived the rubbish heap very well, but structurally it's near-perfect. Unlike many more heavily-engineered machines, its strength to weight ratio favours survival.

After disinfecting the outside and drying the machine out for a day, I checked it was safe and then switched it on. As expected, it lit up and after a momentary death-rattle the processor gave up and all that remained was stillness and a single decimal point on the display. So as usual I loaded a copy of Tchaichovsky's 6th in preparation for burial in the garden, next to the BMW engine with Libyan sand in its float bowl.

As it happens I was reading Mooly's advice on resuscitating a CDM12, so I had laser sled on my mind when I opened up the 102, top and bottom which is handy.

Crikey. I guess this is the kind of engineering that makes grown men cry. The plastic is first rate, but I have to admit there's not much of it. Occupying over half the width and nearly the whole length and depth of the case, supported by steelwork on both sides, is a total tour-de-force of aluminium alloy, steel, and iron. Makes the rest of the player look very cheap.

Thoroughbred machines have an ecological structure. As your eye zooms in, successive levels of detail appear at regular intervals. It's an epic story of development, like you can see the way the design team was organised, and how each level preferred a different size of screw.

The top clamp and sash-driven drawer sled get a motor each. Which of these drops the platter I haven't yet worked out. The spindle is driven by a surprisingly small but perfectly formed mystery device, which I guess is a naked Hall effect motor. The laser sled is slung on twin steel rails between a pair of monumental linear motors.

Slathered over the rails was a layer of what looked like automotive grease, contaminated with black slime that I guess is dissolved plastic. I wiped this off and polished the rails in situ with cotton string. To clean the last inch or so I needed to move the sled. It was stiff and I worried I might strip the teeth off a gear somewhere. But it hasn't got gears so, with nothing much to loose, I pushed harder.

The next second was a blur. I'd forgot to turn it off. A click from somewhere strangely distant, lights, a faint whirring, rapped fingers, deathly silence, can't find the off button, and then this dreadful moaning...

do do dooo do

do do doooo do


Welcome back, Base Unit Number One.

Thanks Mooly.
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Old 12th May 2012, 07:31 AM   #2
Mooly is offline Mooly  United Kingdom
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BU-1 moans.
Pleased the write up helped

I vaguely remember these players and worked on a few at the time. Even the portable Sony D50mk1 had a Hall effect motor, and that had no filters too (think that had a 20152 DAC but with TLO72's).

All good stuff at the time.
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Old 24th July 2012, 06:16 PM   #3
kenny33012 is offline kenny33012  United States
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Do you intend to scrap this cdp 102? I have one, all in working order except for one of the plastic suspension parts (Sony calls the "insulators). They are located on the underside of the transport, two to the front, one holds up the back. One of mine seems to have gone missing in action. The retaining scew and spring were trapped by the sled's magnets (fortunately). The upshot is that my cdp102 will play, but only upside down.
If you intend to part this out, please let me know! I'd like to be able to use the thing right-side-up again!
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Old 25th July 2012, 03:23 AM   #4
PlasticIsGood is offline PlasticIsGood  United Kingdom
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Hi kenny33012

I'll probably keep it for a while, and maybe forever, I'm afraid. The BU-1 is beautiful and I love it. If I do decide to sell, I'll let you know, but it will be as a complete machine in perfect working order.

Working upside-down is a good party trick, but I know it gets annoying after a while. Sorry.

The three suspension poles are all the same length, unlike the springs, which is a strange design decision. Perhaps you could make one? In the manual it looks quite simple. Tubes are everywhere!
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