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Old 13th December 2012, 09:42 PM   #18911
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Quote:
Originally Posted by 6h5c View Post
Looks o.k. to me, it should work this way... Did you also connect a GND wire from the Flea to the decoder?

Maybe C522 and 523 should be removed. It's the last thing I can think of. Especially that 10nF is quite a capacitive load.
I connected the clock as in the diagram but it did not work

The ground wire of the clock was connected and the DAC worked nicely but only not on the Decoder

May be you are right I will try to remove C522 C523 as well as R521 (I think I need to remove R521 otherwise CR OUT will have clock signal via R521). With this arrangement Pin 14 CR OUT will be totally isolated i.e. free from any connection and the clock signal goes directly to Pin 13 CR IN. I hope it will work.
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Old 14th December 2012, 11:11 AM   #18912
6h5c is offline 6h5c  Netherlands
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Ok, hope that will work...
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Old 15th December 2012, 05:08 PM   #18913
mickie is offline mickie  Germany
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Hi,
i'm using the 63 as a transport (internal is dac disconnected) and i ran into some trouble clocking the decoder (alone) as well.
What i found is the following:
-removing all parts (c521,c522,c523, etc) and feed the clock signal straight in did NOT work. CRIN obviously needs a series resistor to the clock signal, i took what i had at hand, 100R. 390R seemed a bit high to me.
-removing R521 also caused the player to fail, the decoder seems to need a connection between CRIN and CROUT, i took 500kohm

What worked when i clocked the dac and the decoder from the same clock, was indeed a series-capacitor of 10pF.

Mickie
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Old 15th December 2012, 06:47 PM   #18914
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Quote:
Originally Posted by mickie View Post
Hi,
i'm using the 63 as a transport (internal is dac disconnected) and i ran into some trouble clocking the decoder (alone) as well.
What i found is the following:
-removing all parts (c521,c522,c523, etc) and feed the clock signal straight in did NOT work. CRIN obviously needs a series resistor to the clock signal, i took what i had at hand, 100R. 390R seemed a bit high to me.
-removing R521 also caused the player to fail, the decoder seems to need a connection between CRIN and CROUT, i took 500kohm

What worked when i clocked the dac and the decoder from the same clock, was indeed a series-capacitor of 10pF.

Mickie
@Mickie: Am my understand is correct that I should remove everything connected to CR IN and CR OUT and then connect the clock signal to CR IN using a 10p cap in series ??
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Old 15th December 2012, 08:18 PM   #18915
mickie is offline mickie  Germany
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..sorry, i was a bit unclear. I think you can / should leave everything in place, just lift the 390R (clock out from the dac is now disconnected) solder a 10pF the the clock cable and connect it to the 390R resistor. This is basically you original configuration but you have bypassed the dac and therfore have cleaner signal. Anyway this should work. You can experiment with removing the other small caps later.
Mickie
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Old 15th December 2012, 10:06 PM   #18916
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Originally Posted by mickie View Post
..sorry, i was a bit unclear. I think you can / should leave everything in place, just lift the 390R (clock out from the dac is now disconnected) solder a 10pF the the clock cable and connect it to the 390R resistor. This is basically you original configuration but you have bypassed the dac and therfore have cleaner signal. Anyway this should work. You can experiment with removing the other small caps later.
Mickie
Thanks Mickie. Is this what you mean as shown in the diagram ?
I connect the clock as in the diagram but it did not work.
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Old 16th December 2012, 11:26 AM   #18917
mickie is offline mickie  Germany
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Right.
Unfortunately i don't know why the clock-signal can't be fed straight into CRIN by removing all other parts (C521,522,523, R521, U193) -as you can do with the dac- and what those caps/resistors actually do.
Maybe the SAA7345 needs a bufferd clock-signal when its synchronously reclocked.

You may also do some considerations about the connection-cables you use; while a shielded coax for the dac is highly recommended, it adds some capacitance to your 10pF cap (i used a silver mica, btw.) which is not wanted.
Anyway, reclocking the decoder seems tricky.

Maybe someone else out there can offer a more elegant solution?

EDIT: I'm sorry i skipped your comment that its not working for you this way - it definitely has to, thats strange.....hmmmmm.
What i can think of, is the fact that there are issues with the ribbon cable (from mainbord to drive pcb). Connections can fail when the cable is often removed/reconnected. Symptoms can be very similar to a bad clock-connection.....so please check

Regards,
Mickie

Last edited by mickie; 16th December 2012 at 11:42 AM.
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Old 16th December 2012, 01:18 PM   #18918
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Default Clocking Decoder

Thanks Mickie for your valuable comments and as you said theoretically speaking feeding a clock signal via the 10p cap should work but unfortunately it did not. Anyway I will try other ways and connections and see if I can resolve the problem.
BTW when you have the independent clock signal feeding to the decoder what are the improvements you observed ? Do you think it is worthy to carry out this mod ?
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Old 16th December 2012, 03:17 PM   #18919
mickie is offline mickie  Germany
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Originally Posted by higlander View Post
Do you think it is worthy to carry out this mod ?
..well, not if you spend days resolving issues.

I did it out of curiosity and because i felt uncomfortable looping the low jitter clock-signal through the dac...

It's audible, yes, but as you can't feed the signal - clean, with a shielded cable - straight forward to the decoder, and, in addition to that, have to consider cable capacitances, HF-noise beeing emitted and picked up, etc., benefits of this mod are easily "reversed" i'm afraid.

I don't know which clock you are using, but there are some that offer a buffered (also divided by 2 or 4) frequency output - that might be a different story.

On the CD67 for example, a "parallel" reclocking of dac and decoder from the same clock is not a problem, but it uses a different decoder-chip.

I think at this point its better to put everything back together as it was and reclock the dac only (for now).

Reclocking the servo-chip / transport is probably more effective.

Regards,
Mickie

PS: Everbody please feel free to correct or complete my statements.

Last edited by mickie; 16th December 2012 at 03:38 PM.
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Old 16th December 2012, 06:51 PM   #18920
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Quote:
Originally Posted by mickie View Post
..well, not if you spend days resolving issues.

I did it out of curiosity and because i felt uncomfortable looping the low jitter clock-signal through the dac...

It's audible, yes, but as you can't feed the signal - clean, with a shielded cable - straight forward to the decoder, and, in addition to that, have to consider cable capacitances, HF-noise beeing emitted and picked up, etc., benefits of this mod are easily "reversed" i'm afraid.

I don't know which clock you are using, but there are some that offer a buffered (also divided by 2 or 4) frequency output - that might be a different story.

On the CD67 for example, a "parallel" reclocking of dac and decoder from the same clock is not a problem, but it uses a different decoder-chip.

I think at this point its better to put everything back together as it was and reclock the dac only (for now).

Reclocking the servo-chip / transport is probably more effective.

Regards,
Mickie

PS: Everbody please feel free to correct or complete my statements.
Thanks Mickie again for the reply.
Actually I have used 2 independent clocks - one for the servo and the other for the DAC. Clocking the Decoder is the last mod I would like to try but if it does not work I will leave it. My clock to the DAC has no buffer and I can only tap the signal out in parallel with the DAC signal - that may have caused the problem
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