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Picked up on ebay a Philips 960 dac made in 1983. This is the one that uses the famous 1941a chip. This thing is built like a tank. It weighs 30lbs Hooked it up to my AudioNote transport and played a cd. Played fine for a few minutes and then started losing lock which is indicated by a lit up 44khs on the dac. Eventually wont play at all. If I turn everything off and let it sit for a while the whole process repeats. Any guesses what could be going on?
Alan
Follow Ups:
Hi,The 960 is a nice DAC. It will lock to SPDIF as it is "Sony/Philips Data Interchange Format" and was standardised by S&P long ago...
But at the age of this machine...
I rebuild a Marantz DA-12 which is a close relation more than 10 Years ago. This kind of DAC has gazillions of parts, many of which can go wrong.
There is no traditional SPDIF receiver Chip, instead you get discrete logic, two layers of PLL (one RC oscillator with fast PLL for fast locking, one LC oscillator with dead slow PLL for low jitter), opto-isolation between the digital section and and DAC/Analogue with reclocking after the opto isolators (yes, in the 80's, reads like todays super, super, super "if you have to ask you cannot afford it" DAC's, innit?).
If it has a major fault (like it seems yours has) not only do you need a service manual (try finding one), you also need a tech who understands this level of circuitry and finding intermittent faults in 30 year old gear (good luck, I know non in the UK and only one or two in germany).
And if you get these together expect to pay the tech for 10 Hours++ for a complete rebuild and any less than a total rebuild means it will go wrong agin in a few month.
BUT, if you can find the right tech and you are willing to pay what it takes to rebuild this unit (and yes, you can ask for SAA7220 Digital filter to be bypssed for non-OS if the tech is worth the 50 to 100 bucks per hour he will be charging) including the best parts you can now get for replacements...
You will have what in my not at all humble estimation is the best 44.1kHz SPDIF Solid State DAC any money can buy, possibly short of some esotheric Non-OS stuff with tubes and the latest Femto Clock etc. from various sources including my own designs...
Build is totally awsome, sound if well revived. Well, I'd still have an AMR CD-77 instead, but it would be close against my DP-777 (sorry, I cannot afford the big gear - coblers kids and all).
Ciao T
At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to untolerable pain. Really, what more could we need?
Edits: 08/17/15
Again depending on the transport being use this might work for you.
If a thing's worth doing, it's worth doing well
(Proverb)
Easy possible eason ; your Audio Note transport is S/Pdif. The DAC from 1983 isn't as S/Pdif wasn't a standard until 1992 (1998 for current version). Hence they won't lock together in a stable manner.NB: I have an old Sony transport which is pre-S/Pdif. It will lock to some later DACs but mostly not.
Edits: 08/16/15
But why does it lock initially for a few minutes before failing if what you say is true?
Alan
I would need to knnw far more than I do about the inner workings of S/Pdif to answer your question. However it is possible, for example, that a close but inaccurate synchronisation of components will not be acceptably stable over a period of time leading to an eventual loss of lock between them.
I can reproduce this situation by using different and out of synch clock signals for the DAC and for the source. The selected frequency for both is correct but not the timing in relation to each other. All will seem fine for a period but eventually and inevitably a glitch will occur. In your case this may manifest itself as a loss of lock.
Just surmising.
It sounds more like the DAC's power supply is only moving the signal as long as the capacitors allow the signal to progress. At some point they simply don't have enough charge In them for the circuit to work continuously !
(Now don't laugh too hard but I'm really not a technician,so this is only a non educated scenario on my part, but it sounds feasible given that initially things work)
I would look at PS caps too.
E
T
Overheating voltage regulator, bad caps, bad solder. All of these can cause the issue your getting.
I have an old Link DAC III here with a similar problem. After about 30 seconds the 5V regulator gets hot, and starts to drop out. I've traced it to
a bad cap on the upsampler.
Dan Santoni
not the 1541 chip? nitpicking a side....
Early Philips transports had issues with the spin motor. Take off the cover and load a disc and see if the spin motor starts up. May need changing ( they are cheap).
Also the transports had a switch to initiate the spin. IIRC it is at the rear of the tray . you'll see two wire leading out. Many times a shot of LPS 1 will cure it. Also make sue the tray hits that switch hard enough to trigger it, May have to change the belt to insure that.
Good luck
He,he,he..... I thought that Phillips DAC chip was a bit off as I have a pretty nice (not in use)
Consonance CD player that also uses that specific chip.
The transport of the Consonance seems. to be pretty mechanically sound after tightening the
tightening up the screws holding the transport posts to the chasis on the bottom of the player
I'm not sure how long it took for the looseness to occur ( or if it may have been an oversight
from when it left the plant in China, that became finally became slightly audible) I swear,, the
sound also appeared to improve a bit in micro detail retrieval after tightening these screws down. I think I slightly preferred the sound of the Consonance over the Auraliti until I gave it
a real DAC to use (the Hex)
Some days I still think the Auraliti could benefit from using a LPS with it , but the Hex sounds
So very nice most of the time, it becomes an issue I place on a "for further consideration" mental list !
As the title of the thread indicates, this is a DAC with... no spinning parts.
Yes, it is the 960 dac not the 630 cd player
Alan
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