Cambridge CD1 2 box player...where's the dacs? pics

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Just picked up a vintage Cambridge CD1(i) 2 box player that has me scratching my head. :confused: I looked inside to see what DACs were used(the little info I found says 1541(a)). Thought maybe the older 1540's might even be used. This unit seems to be hand assembled , with most of the electro caps bypassed with wima's and even the voltage regs have them mounted directly to the pin outs. I remove the shielding over the main board , only to find the place were the DACs should be(?) are empty. I see reciever chips(saa72xx)and such , but nothing familair to me that Philips made in that era(early 80's).I also count 3 clocks. The data appears to go out of the main unit via embillical cord(one for data , one for power) to the top box. This contains 2 boards that make up the 'conversion filters' and ,I suppose , the output stage. 7 small relays switch on/off when one or all of the filter selectors are lit. Perhaps I am missing something: :scratch: I included some pics and will be greatful for any info
 

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The second and thrid posts are of the digital circuit boards that are under the shielding , ,and that is pretty much it. There is another small board mounted vertically on the front panel , but no DAC chips ,at least known to me. I'll post that pic here.
 

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The CD1 used 3 X TDA1541 dacs and a bespoke filter design if memory serves me right, all the work of Stan Curtis I believe.
The integrated components you mention are circuitry that has been 'potted' to keep out prying eyes of those at the time (80's) who would copy any and every innovation and claim it as their own!
I think you will find that the laser assembly is a special design also in that the whole shebang is mounted on an ingenious suspension system which required special hand castings to be made.
The whole machine is, as you claim, very 'handmade'. It needed to be as it sold in low volumes and Stan had his hands in the assembly of most of the machines and I believe his wife was also involved in the project to!
Hope this helps.

Gary.
 
GJF said:
The CD1 used 3 X TDA1541 dacs and a bespoke filter design if memory serves me right, all the work of Stan Curtis I believe.
The integrated components you mention are circuitry that has been 'potted' to keep out prying eyes of those at the time (80's) who would copy any and every innovation and claim it as their own!
I think you will find that the laser assembly is a special design also in that the whole shebang is mounted on an ingenious suspension system which required special hand castings to be made.
The whole machine is, as you claim, very 'handmade'. It needed to be as it sold in low volumes and Stan had his hands in the assembly of most of the machines and I believe his wife was also involved in the project to!
Hope this helps.

Gary.


Gary,
Yes , you are most correct. The 2 output boards have 'STAN CURTIS' imprinted on the underside. DOGPILE.COM found me some info , which stated , as you said , 3 1541 dacs(per channel??) with 16X oversampling . All these are encapsulated(potted) to prevent what you mentioned. The conversion fillter selection is most interesting , and I would like to find out more about how it functions. And you are also correct about the elaborate transport system , with it's unique suspension setup. Any idea what this thing sold for back then? I must say that this player sounds very different than all my other vintage Philips based designs. Thank-you for the information.
 
Back in 1986 this would have cost around £1500!

I'm not surprised in that it sounds different, in its time it was way, way advanced against the then state-of-the-art.
Most Japan made players were sold on the promise of more bits and more oversampling but failed to achieve any of the claims made whilst the CD1 used some original thinking in running in what I think was paralleled dual differential mode.
Hence the number of dacs per channel which possibly accounts for some of the price because at the time they were new and expensive.
 
AFAIK the first one was thrown together over a Christmas break, Stan B&Eing RadioSpares to get much-needed components (joking), Stan also casting much of the transport metalwork himself because no subcontractor was found wanting to do this (true).


homemade said:

The conversion fillter selection is most interesting , and I would like to find out more about how it functions.

If you have a 192kHz ADC you can do frequency sweeps and impulse response measurements. That should tell a lot.


W
 
This machine blows all the modern so called modern high end wannabes out of the water. A closed doors test was done last year in britain with all the highest end expensive cd players and Stan was invited to bring in his machine. No comparison it blew away all the overpriced and overhyped crap out there.
 
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Should actually be 3 x 1540 (not 1541)

There was a MKII which used loads of DACs but it wasnt really released.

I'd love to try one. There's an extra module too that displays and counts read errors and was good for judging different types of CD pressing with those gold discs apparently having fewer errors.
 
I bought a couple of amplifiers from a chap demonstrating a CD1.

There was one track that I knew and his system played an "extra" note in one channel I had never heard before.

Repeated the exercise at home, no extra note. Arcam Delta 70.2 seemed not to have the resolution to reveal it.
Bought a Sugden two box CD player. There was the missing note again.
 
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