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Old 2nd February 2011, 10:36 AM   #3581
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HI ecdesigns what solder you use ? very clean work

your diy resistor what power can take ? I will need 15ohm 25w , alternative ?

thanks manu
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Old 3rd February 2011, 01:46 PM   #3582
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Unhappy Synchronous reclocking with TDA1540

I completed a pcb with four 74AUC1G74 flip-flops (I need two DATA as TDA1540 is mono), all are supplied at about 2V, but it doesn't work. I'm only able to get the BCK 74 working (but only bypassing the 1K output resistor and connecting pin 3 directly to DACs). I tried to bypass both 2K2 and 1K resistors on DATA and WS signals, but that didn't help. Then I connected directly the two DATA signals and reclocked the WS only, but I only got noises with very distorted and low music. Thinking that one 74 could be dead I moved the WS on the other two (and also an external, flying, one) with no success. Connections are correct, I checked them so many times, and now I don't know what to think or to do. Maybe this circuitation is not compatible with the old 14 bit Philips chipsets (SAA7000), but since years I use the SAA7000 I2S output connected only via 100R resistors to the TDA1540 with no oversampling (SAA7030 removed).
Thank you for any suggestion.

Last edited by fralippo; 3rd February 2011 at 02:03 PM.
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Old 3rd February 2011, 03:14 PM   #3583
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Hi fvale,

Check if power supply is ok (2.4V), also check if signal levels are suitable to drive the TDA1540.

You may have damaged one or more reclockers by overheating or by applying too much force during soldering, these tiny chips are rather fragile.

If power supply and signal levels are ok and the circuits still don't work you may need to check exact moment of triggering in your application. If the reclockers are triggered on the wrong moment they don't sample the correct signal level. You may need to invert / delay the clock signal for the synchronous reclockers.

The clock signal on the reclockers should change when BCK, DATA, and WS signals are stable. The clock signal should not change during signal transitions of BCK, WS and DATA.
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Old 3rd February 2011, 04:11 PM   #3584
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Thank you EC for immediate support!
First of all my power supply (it's only dedicated to five 74AUC1G74s, one is also used to get my main 4MHz clock from a 8MHz oscillator) delivers 2.06V under load. May this be the problem? Tomorrow I will have to replace a zener diode to get 0.3V more.
I only have a simple handy multimeter that also work as a basic frequencymeter. What can I check with that? Thanks again.
I also thought about the possibility of flip-flop damage, but it's strange that four are dead. Problem should be elsewhere.
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Old 3rd February 2011, 08:02 PM   #3585
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Little update. I connected an external 2.5V power supply. It didn't help, even with a little higher tension. I also tried to feed pin 1 of reclockers with inverted signal from BCK 74 pin 5 instead of pin 3. No success :-(

Last edited by fralippo; 3rd February 2011 at 08:09 PM.
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Old 4th February 2011, 07:11 AM   #3586
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Hi fvale,

Quote:
I only have a simple handy multimeter that also work as a basic frequencymeter. What can I check with that?
You can check if clock signals are present (if the reclockers output a signal), but not much more. In order to spot and solve timing issues a suitable analogue oscilloscope is required.

I advise a (second hand) Hameg dual channel analogue scope (2 x 20 MHz or higher).

Have a look here:

Hameg Oscilloscopes | The Oscilloscope Shop

This one looks interesting:

HAMEG HM203-7 Oszilloskop Oscilloscope Oscilloscope 203 - eBay, Oszilloskope, Mess- Prüftechnik, Elektronik Elektrotechnik, Business Industrie. (Eindtijd 12-feb-11 14:03:32 CET)

Last edited by -ecdesigns-; 4th February 2011 at 07:14 AM.
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Old 4th February 2011, 09:17 AM   #3587
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Hello EC,

I knew that one day I had to buy an oscilloscope..... it was today! I just bought one at the link you suggested on ebay. They accepted my 110 Eur offer! Not bad!

Update: leaving only BCK on the smd 74 I connected a flying 74HC74 on WS. Again no success. I suspect all flip-flops to be ok.

With my tester I measured frequencies on flip-flop's pins 2 and 3. On BCK I can read 44.1Khz (????, I expected about 1MHz frequency with MCK ay about 4MHz) both at input and output. On WS I read 44.1Khz on input pin 2 but NO signal on pin 3. This happens both with smd or dip 74. Another think I noted is that on output pin 3 (again both smd and dip) I see a DCV respectively of 2V with smd and 5V with dip. This is flip-flip powering tension. Is this normal?

Many thanks!
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Old 8th February 2011, 01:17 PM   #3588
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Yesterday I tested another 3 74AUC reclockers with a different I2S source (Squeezebox receiver) and this time all works perfectly. I only had to bypass the 1k output resistor on WS.

Then I went back to the 14 bit Revox player. First of all I singularly checked all flip flops as frequency dividers: they all worked regularly. I made a further test, but results are the same of the first time. Only BCK can be reclocked succesfully.

Let's wait for the scope...
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Old 8th February 2011, 07:16 PM   #3589
a333bt is offline a333bt  Slovenia
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Quote:
Originally Posted by ernesternest View Post
THX! Looking forward to building it! And then to hearing it

Cheers Ernst
Hi ernesternest,

did you manage to build and tested mini regulators?

When you will once hear them, you will want to get rid of all standard LM... regulators.

Mine is now in Mk4 version and it is make quite big step in sound quality (more pure, ...).
I just want to taste them, since i am waiting list for final MK6 version.

Bostjan
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Old 9th February 2011, 08:23 AM   #3590
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Quote:
Originally Posted by a333bt View Post
Hi ernesternest,

did you manage to build and tested mini regulators?

When you will once hear them, you will want to get rid of all standard LM... regulators.

Mine is now in Mk4 version and it is make quite big step in sound quality (more pure, ...).
I just want to taste them, since i am waiting list for final MK6 version.

Bostjan
Bostjan,

I have parked this project for a while since my sparetime is currently very limited (preparing for building my own house) What I tried is to design a PCB for the regulators right after Johns pictures. Wanted to do this in Eagle, but stopped since I couldn't find all the footprints needed. To be honest, I have no plan how to carry on. PCB would be great, since parts are available. Currently I'm waiting for the semiconductors for MK6 outputstage. Will use Teddyregs and/or Salas shunts until I managed to make/get pcbs for the regs. i have some nice old CDPs, they are all waiting for these regs, since they are a real drop in replacement for the unwanted 7XXX regs.

Cheers Ernst
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