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Old 25th March 2013, 10:47 AM   #4801
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Quote:
Originally Posted by studiostevus View Post
Nice find! May I ask what the price of these babies is? Also, is it spec'ed at -130db or did you measure? I can't find the datasheet on the Laptech page (don't know which one it is....
These are custom parts, both OCXO and crystal are 11.2896MHz.
-130dBc@10Hz for the OCXO was measured form the manufacturer before shipment, I published the measurement document in Ian's FIFO buffer thread, if i remember correct. The OCXO is very expensive, around 300 GBP without VAT and shipping.
You cannot find the Laptech sheet because it's a custom part; less than 10 ohm ESR and Q greater than 150K was measured by the manufacturer. It costs around 35 CAD excluding VAT and shipping for 5 pcs.
I'm working on a low phase noise oscillator using the Laptech crystal.


Quote:
As long as BCK is reclocked, it's probably indeed better to feed the cleanest clock signal to the reclocker and the multiplied clock signal to the source. The picture you show is of a 11mhz crystal though
About the BCK, I meant to feed it directly from the XO, without any reclocker, so 2.8224 or 5.6448MHz (32 or 64 bit words in NOS mode) for the TDA1541A, then a frequency multiplier for the source clock if it need higher frequency.
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Old 25th March 2013, 01:41 PM   #4802
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Thanks. It is a clear picture you paint.
Do I infer too much if I state, using you words:
"With conventional applications with low time resolution it has no advantages to use a TDA1543" --> with state of the art applications with high time resolution it has many advantages to use a TDA1543.
albert :-)

Quote:
Originally Posted by -ecdesigns- View Post
Hi triode_al,
If only I could simply share perceived sound quality of various prototypes. But even modern technology fails to offer this possibility over the internet.
[--]
TDA1541A is based on current mode logic too, but the on-chip circuits are more complex (DEM circuit), so DAC chip jitter contribution is likely to be higher. The advantage of the DEM logic is increased bit accuracy without (LASER) trimming, but without matching time resolution (that is degraded by this same DEM circuit), the DEM circuit has little added value.

These DAC chip properties only start to have a big impact when external circuits are approaching perfection (extreme low jitter, extreme high time resolution). With conventional applications with low time resolution it has no advantages to use a TDA1543.
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Old 25th March 2013, 07:52 PM   #4803
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Quote:
Originally Posted by dvb-projekt View Post
@ John

For a quick verification if everything is correct!

Click the image to open in full size.

Doei,
Oliver

Hi John,

i had integrated all changes above on my Red Baron test board. The 3.3V comes from one of my +5V SSLV Shunt modules (modified). It worked great!

Now the only question is, should we attenuate the BCK to your regarded 800mVpp with perhaps some TX2575 bulk foil resistors?

Best regards,
Oliver
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Old 26th March 2013, 04:49 AM   #4804
Ceglar is offline Ceglar  Australia
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.. and should we bias BCK to 1.2V even if we dont attenuate it...
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Old 26th March 2013, 09:16 AM   #4805
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Quote:
Originally Posted by dvb-projekt View Post
Hi John,
[--] , should we attenuate the BCK to your regarded 800mVpp with resistors?

Best regards,
Oliver
I just had a look at the TDA1543 datasheet, as it has the similar input schema, and there also BCK has this similar input configuration - no resistors in the signal.
just my 2
albert
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Old 27th March 2013, 01:34 PM   #4806
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Quote:
Originally Posted by Xpertv View Post
Is it necessary to add 2mA to TDA1541 outputs while I\U is provided by OpAmp? (Stock variant like NE5532\LM833) Or this is only for resistor I\U?
According to TDA1541 datasheet this is not required.

But if I/U is provided by opa-amp, accompaniment of 2 mA on output 1541 reduces the current through feedback resistor. This reduces the constant voltage on a opa-amp output (in ideal up to zero).
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Old 27th March 2013, 01:54 PM   #4807
oshifis is online now oshifis  Hungary
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From others experience, which has more sonic benefit:
a) Provide the 2mA bias to the TDA1541A output from a constant current source, and eliminate the coupling capacitor from the output of the opamp, or
b) Let it flow through the opamp feedback resistor, and use a good quality output coupling capacitor?
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Old 28th March 2013, 06:13 AM   #4808
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Quote:
Originally Posted by oshifis View Post
a) Provide the 2mA bias to the TDA1541A output from a constant current source, and eliminate the coupling capacitor from the output of the opamp, or
b) Let it flow through the opamp feedback resistor, and use a good quality output coupling capacitor?
Put or not to put the output capacitor - this is separate question. But I prefer variant 1.
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Old 28th March 2013, 10:22 PM   #4809
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just want to say that I will get my hand on one of the sd1 player real soon, will report back my impression. The comparison will be against a buffalo dac!
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Old 10th April 2013, 08:16 AM   #4810
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with state of the art applications with high time resolution it has many advantages to use a TDA1543

If this is true, what about TDA1545?

Should have an even better sound than 1543 without the DEM clock problems?

can we use the same mk7 output stage on a TDA1545? what about the -15v bias to the mosfet?
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