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Building the ultimate NOS DAC using TDA1541A
Building the ultimate NOS DAC using TDA1541A
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Old 29th December 2018, 09:33 AM   #6811
batteryman is offline batteryman  United Kingdom
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Quote:
Originally Posted by lcsaszar View Post
And do you also hear some noise in one or both channels for a few minutes after initial turn-on?
I use Nichicon UKL very low leakage 100uf caps and there is noise for less than 10seconds when first powered up.
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Old 29th December 2018, 09:44 AM   #6812
batteryman is offline batteryman  United Kingdom
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Quote:
Originally Posted by rfbrw View Post
Writing as one of those fools that observes datasheets, I wonder, does the performance loss of the TDA1541A scale with amount by which one violates compliance.
What violation are you referring to? Dem clock frequency.

If you stick to the datasheets you'll hear what Philips want you to which is a compromise to keep 99% of consumers happy and get good magazine reviews.

It makes sense to me that high frequency dem clocking is at the least going to pollute the power supplies in addition to what the digital signals do, and having tried 50Hz dem clocking, I like the result.

I also like 100R passive I/V + transformer output. 100R may contravene the output compliance but only at DC because the transformer primary impedance is reduced by the load resistance on the secondary (by the square of the step-up ratio), so reduces the AC impedance.
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Old 29th December 2018, 10:09 AM   #6813
lcsaszar is offline lcsaszar  Hungary
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Datasheets are for equipment manufacturers not for us lunatic DIY experimenters
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Old 29th December 2018, 10:45 AM   #6814
rfbrw is offline rfbrw
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Quote:
Originally Posted by batteryman View Post
What violation are you referring to? Dem clock frequency.

If you stick to the datasheets you'll hear what Philips want you to which is a compromise to keep 99% of consumers happy and get good magazine reviews.
That speaks more to limited knowledge of the variety of designs based around the TDA1541A.

Quote:
It makes sense to me that high frequency dem clocking is at the least going to pollute the power supplies in addition to what the digital signals do, and having tried 50Hz dem clocking, I like the result.
I am indifferent to dem reclocking.

Quote:
I also like 100R passive I/V + transformer output. 100R may contravene the output compliance but only at DC because the transformer primary impedance is reduced by the load resistance on the secondary (by the square of the step-up ratio), so reduces the AC impedance.
Does not change anything. The violation remains.
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Old 29th December 2018, 10:48 AM   #6815
rfbrw is offline rfbrw
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Quote:
Originally Posted by lcsaszar View Post
Datasheets are for equipment manufacturers not for us lunatic DIY experimenters
Try getting the pinout or the configuration data without them.
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Old 29th December 2018, 12:54 PM   #6816
lcsaszar is offline lcsaszar  Hungary
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Old 29th December 2018, 12:58 PM   #6817
sthcoaster is offline sthcoaster  United Kingdom
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Building the ultimate NOS DAC using TDA1541A
Quote:
Originally Posted by lcsaszar View Post
And do you also hear some noise in one or both channels for a few minutes after initial turn-on?
Not that I've noticed. But because of the tube output in my DAC I always turn it on first and it will be on for quite a few seconds before everything else is power up and I'm pressing play.

Quote:
Originally Posted by batteryman View Post
I use Nichicon UKL very low leakage 100uf caps and there is noise for less than 10seconds when first powered up.
The KY is at least a factor of ten higher leakage. Seems to be fine as far as this noise issue goes. This is my working rig and I plan to use better spec caps in my final 2x tda1541a DAC.
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Old 29th December 2018, 01:19 PM   #6818
sthcoaster is offline sthcoaster  United Kingdom
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Building the ultimate NOS DAC using TDA1541A
Quote:
Originally Posted by batteryman View Post
Have you check the new dem clock frequency? I use 1uf on pins 16/17, with 10k to -15 from both pins and dem is about 50Hz. (not sure whether any difference would be audible).

Simultaneous operation + stopped clock you will find, makes a big difference to sq.
I don't have the capacity to check DEM frequency. I'm just playing follow the leader

Next time I get the urge I will try your configuration.

Yes, I'm looking forward to getting simultaneous operation etc. but that will be another couple of months yet.

Last edited by sthcoaster; 29th December 2018 at 01:21 PM.
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Old 29th December 2018, 01:51 PM   #6819
sumotan is offline sumotan  Indonesia
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I tried the 50hz thingy on my AyA Ds dac with 100uf Pana FC caps.
It sounded pretty natural but upon further listening, I notice the pace of the music
that Im very familiar with have slowed down a little & slam has weaken, sound of instruments have become larger as well. No sure if it is the FC caps. Im running direct I2S coonection from my SD Trans 384.

Cheers
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Old 31st December 2018, 02:23 AM   #6820
978HK is offline 978HK  Antarctica
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Quote:
Originally Posted by rfbrw View Post
Writing as one of those fools that observes datasheets, I wonder, does the performance loss of the TDA1541A scale with amount by which one violates compliance.
DC voltage output compliance for lowest distortion.

As to the resultant performance 'loss', an increase in 2H which may or may not be complimentary in an overall system context. More violation, greater imbalance in 2H to 3H ratio, and also higher overall THD.

It's a compromise, so variation in subjective opinion based on experiences comes without surprise.

Overall lower THD vs a more complimentary even to odd harmonic spectra within that now overall increased level of THD - marketing dept wins, datasheet recommends for lowest overall THD.

Last edited by 978HK; 31st December 2018 at 02:40 AM.
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