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Old 31st January 2009, 04:11 PM   #2491
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Hi Builder Brad,


Quote:
I have just updated the charge transfer schematic to show the connections for transformers without the centre tap - is this the correct way to connect these?
You need to use a rectifier bridge (requires 4 rectifier diodes).


Quote:
after about 5 minutes of playback the right channel starts to distort
This is probably caused by tolerances, as the DAC chip heats-up, the voltage across the internal diodes (digital input circuit) drops. This can be solved by lowering the series resistor value, you could try 2K2 or lower.
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Old 31st January 2009, 04:28 PM   #2492
Telstar is offline Telstar  Italy
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Quote:
Originally posted by -ecdesigns-

The derived 16.9344 clock with higher jitter is only used to clock the CD player, NOT the DAC chip. The DAC chip receives a (ultra) low jitter clock, derived from the 11.2896 MHz master clock.

Hello John,

May I ask you why you chose this frequency for your master clock? Wouldnt higher be better?
Availability?
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"The total harmonic distortion is not a measure of the degree of distastefulness to the listener and it is recommended that its use should be discontinued." D. Masa, 1938
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Old 31st January 2009, 04:29 PM   #2493
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Hi gaetan8888,


Quote:
How can we use a DIR9001 in your DI4 dac ?
The SPDIF receiver, used together with the master clock / tracker module, needs to run in slave clock mode, it seems this mode isn't supported by the DIR9001.
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Old 31st January 2009, 04:51 PM   #2494
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Hi Telstar,


Quote:
May I ask you why you chose this frequency for your master clock? Wouldnt higher be better?
Availability?

I planned to support 44.1 KHz sample rate only, I used 11.2896 MHz because of availability of required crystal.

Then I ran into troubles with my satellite receiver that outputs 48 KHz sample rate.

Today this problem was fixed.

My brother successfully completed the firmware for the new multi-rate master clock / tracker module.

This micro controller-based multi-rate tracker / master clock module automatically detects and tracks 44.1 KHz, 48 KHz, 88.2 KHz, and 96 KHz sample rates. It uses 2 crystals (11.2896 and 12.288 MHz), and a programmable clock divider to support these sample rates.

So I now have a highly effective source jitter blocker that accepts 44.1, 48, 88.2, and 96 KHz sample rates. These sample rates are supported by Toslink, and are within TDA1541A / TDA1543 bit clock specs.
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Old 31st January 2009, 06:43 PM   #2495
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THANK-YOU JOHN,

"You need to use a rectifier bridge (requires 4 rectifier diodes)"

I thought that your schematic was giving half wave rectification - providing plenty of time for the mosfets to switch and transfer the charge - looking at the details again I can see that the centre tapped transformer is also connected up for full wave rectification.

congratulations on you solution, regards the sample rate input firmware.
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Old 31st January 2009, 09:39 PM   #2496
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Quote:
Originally posted by -ecdesigns-
Hi gaetan8888,

The SPDIF receiver, used together with the master clock / tracker module, needs to run in slave clock mode, it seems this mode isn't supported by the DIR9001.

Hello John

I can not have the CS8412 or CS8414 here arround and buying them from out of Canada would cost way too much with the shipping.

But I can have the AK4114, AK4116, AK4117, WM8804 (very low jitter), DIR9001 (very low jitter), or maby the CS8416.

Do I really need to use the receiver master with a clock/tracker module and in slave mode ?

Maby I could do could do a simplier version of the DI4 with one of the receiver that I can have ?

Thank

Bye

Gaetan
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Old 1st February 2009, 12:22 AM   #2497
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Hi John,

You need to use a rectifier bridge (requires 4 rectifier diodes).


I had prepared such a circuit with a full bridge rectifier that I intended to use.
To return to your original circuit we only need to remove D3, D4 and add the jumper.
This way we can use a transformer with center tap or a single winding.
I also worked on a pcb for this circuit. I still need to ajust the footprints for various capacitors to use.
I would appreciate you check it out, if it would be usefull to others on this thread.
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Old 1st February 2009, 08:51 AM   #2498
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Hi gaetan8888,


Quote:
But I can have the AK4114, AK4116, AK4117, WM8804 (very low jitter), DIR9001 (very low jitter), or maby the CS8416.
Both AK4114, and WM8804 support slave-clock mode and seem to be suitable. I use the CS8416, it's placed on a module, so I could easily swap between various SPDIF receiver chips.


Quote:
Do I really need to use the receiver master with a clock/tracker module and in slave mode ?
Depends on the sound quality you want to achieve, I tried many different solutions. I started with a CS8412 in master mode (coax and RS422 twisted pair), and experimented with direct I2S (DATA, CLOCK and WS signals transmitted using 3 x RS422 twisted-pair).

Next I tried USB / direct I2S, using an asynchronous reclocker (USBDI2S module), later an USB / Toslink combination module was designed (UTOS1 & 2), I2S signals from USB were routed through high-speed opto-couplers, and SPDIF was routed through Toslink. Asynchronous reclockers were used to attenuate source jitter. During these experiments, the advantages of full galvanic insulation became clear.

Then I experimented with running a SPDIF receiver in slave-clock mode, directly feeding the crystal oscillator signal to the DAC chips. This was a big improvement, but the lack of synchronization between both source and master clock produced audible cliks, best audible when playing-back sine waves.

In order to solve the synchronization issue, I then experimented with a VCXO / PLL circuit, this circuit was first used in both DI4T and DI4MJ, and it was integrated on the mainboard. The clicks were gone, but still sound quality wasn't optimal.

So I decided to replace the analogue PLL with a micro controller-based frequency tracker that only performs corrections with 2 second intervals. This solution works fine, and I designed a PCB that holds master clock, tracker and clock buffers.

In order to expand the functionality of this tracker circuit, a multi-sample rate support was added, so the tracker could be used with popular sample rates. It would also be possible to support 176.4 and 192 KHz, using the same 2 crystals. This possible option will be included in the new design. In that case the tracker could automatically detect and track 44.1, 48, 88.2, 96, 176.4, and 192 KHz.
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Old 1st February 2009, 02:11 PM   #2499
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Quote:
Originally posted by Jean-Charles
Hi John,

You need to use a rectifier bridge (requires 4 rectifier diodes).


I had prepared such a circuit with a full bridge rectifier that I intended to use.
To return to your original circuit we only need to remove D3, D4 and add the jumper.
This way we can use a transformer with center tap or a single winding.
I also worked on a pcb for this circuit. I still need to ajust the footprints for various capacitors to use.
I would appreciate you check it out, if it would be usefull to others on this thread.
I don't know what hapenned, the pdf file did not follow.
I try again, hoping it will work.
Attached Files
File Type: pdf charge-transfer.pdf (14.2 KB, 252 views)
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Old 2nd February 2009, 12:24 AM   #2500
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Quote:
Originally posted by -ecdesigns-
Hi gaetan8888,

Both AK4114, and WM8804 support slave-clock mode and seem to be suitable. I use the CS8416, it's placed on a module, so I could easily swap between various SPDIF receiver chips.

Depends on the sound quality you want to achieve, I tried many different solutions. I started with a CS8412 in master mode (coax and RS422 twisted pair), and experimented with direct I2S (DATA, CLOCK and WS signals transmitted using 3 x RS422 twisted-pair).
...

Hello John

I would like to keep it as simple as possible and I'm limited in my budget, at least I have the four TDA1541 chip.

I just done a search in the forum and found in your thread a sync reclock post and schematic;

http://www.diyaudio.com/forums/showt...60#post1317660

And the schematic link;

http://www.diyaudio.com/forums/attac...amp=1191570449

Any littles mod suggestions on this schematic ?

How about using it for the DI4 dac ?

Thank you

Bye

Gaetan
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