Hi Wargreymon,
I stopped experimenting with the TDA1541A for now.
The problem with the TDA1541A(S2) is that it sounds technically "correct" but fails to offer the level of involvement or capture artist emotion like analogue audio sources like vinyl or studio tape can.
The final SDV1-player is not based on a TDA1541A. The DAC chip was selected for lowest possible jitter contribution and easiest and most effective implementation of active jitter control.
Customers report that it equals or exceeds sound quality of vinyl.
I stopped experimenting with the TDA1541A for now.
The problem with the TDA1541A(S2) is that it sounds technically "correct" but fails to offer the level of involvement or capture artist emotion like analogue audio sources like vinyl or studio tape can.
The final SDV1-player is not based on a TDA1541A. The DAC chip was selected for lowest possible jitter contribution and easiest and most effective implementation of active jitter control.
Customers report that it equals or exceeds sound quality of vinyl.
Is this the Voff from the curve? It seems to suggest that an offset of slightly more than 0,050 - 0,060 volt? This is easily obtained with a current source. By the way I used 2SK30 CCS at 2 mA and the output drifted slowly up and down
eek.Can you explain that a little bit more?
Member
Joined 2006
So John is the final SDV1-player mentioned above same as the SD1 SD player on your site?
Yes.That also equal to Vout in left figure(第4図) of first picture because of vatual short.
Why, how do you use JFET?It seems to suggest that an offset of slightly more than 0,050 - 0,060 volt? This is easily obtained with a current source. By the way I used 2SK30 CCS at 2 mA and the output drifted slowly up and down
Typical external offset adjusting circuit is suitable in this situation.
see fig5 b
http://www.analog.com/static/imported-files/tutorials/MT-037.pdf
See right figure of first picture(第5図).
The glitch is caused by mismatch of transition timing of "bit1 Iout" and "bit2 Iout".
Then left figure(第4図).
If we assume the forward voltage of diode and Vbe of transistor in diode-transistor switch is equivalent,
the switch turnovers when Vsw exceeds Voff or falls less than Voff.
Therefore Voff affects the transition timing.
Imagine when Voff drops a little, what happens the timing in (第5図).
I used a JFET as CCS to dump 2 mA in the TDA1541, but I noticed that the result on the out pins is a very slow drift. This is with a passive I/V output.
Indeed with an opamp I never saw that because the opamp defines the zero at the input.
The drift is not from the 2SK30AGR JFET (wouldn't expect so.., never saw that), not temperature instable specially that one.
Hi Shinja,
Check Fig. 9 in this link:
Philips TDA1541A d/a converter - DutchAudioClassics.nl
Glitch current (largest glitch) equals 0.25 LSB. Therefore the TDA1541A needs no deglitcher.
The first CD player was introduced 31 years ago. Engineers had 31 years time for lowering THD to vanishing low levels and they sure did. The resulting sound quality is still flat, synthetic, uninvolving, distorted and emotionless compared to vinyl.
There even seems to be a come-back of vinyl because of this:
http://www.nytimes.com/2013/06/10/arts/music/vinyl-records-are-making-a-comeback.html?pagewanted=all
It's Alive! Vinyl Makes a Comeback | Postmodern Times by Eric Felten - WSJ.com
Check Fig. 9 in this link:
Philips TDA1541A d/a converter - DutchAudioClassics.nl
Glitch current (largest glitch) equals 0.25 LSB. Therefore the TDA1541A needs no deglitcher.
The first CD player was introduced 31 years ago. Engineers had 31 years time for lowering THD to vanishing low levels and they sure did. The resulting sound quality is still flat, synthetic, uninvolving, distorted and emotionless compared to vinyl.
There even seems to be a come-back of vinyl because of this:
http://www.nytimes.com/2013/06/10/arts/music/vinyl-records-are-making-a-comeback.html?pagewanted=all
It's Alive! Vinyl Makes a Comeback | Postmodern Times by Eric Felten - WSJ.com
We just need to move on from CD.
Higher sample rate PCM and DSD128 (5.6MHz) have proven subjectively to
replicate analog masters when copied very very well.
Direct download of a variety of formats are available.
Personally I would be putting your energy into a USB interfaced DAC that will
play all the current formats. The potential performance will leave 1541 a
long way behind. Having said that the 1541 is damn musical sounding
for red book replay - but time marches on. We have many options now.
T
yes,I knew it.
And Nakamichi must have known it too.
However Nakamichi might try to build ultimate DAC at that time,so they introduced a tweak like this.
1000p equipped not only special deglitching circuit which I wrote, but also linearlity correction sub-DAC and factory calibrated PROM individually.
TDA1541A have THD spec typical:0.0018% to max:0.0032% from datasheet.
This tweak may make worse chip to be better performance, or typical chip to catch S2 spec, I expect.
I see.
This tweak is unsuitable for passive IV circuit.
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Thanks, and to wlowes.
Many tda1541a designs I have seen have the -15v, and -5v regulators from a common input supply or the -15v feeds both the dac, and the op amp filter and IV.
I will have to look if there is a suitable voltage reference close to 15v.
Hi maxlorenz,
Hi maxlorenz,
By the way I saw the Youtube vids of your Tannoy Autograph clone speakers, impressive work!
Let's call it the mystery chip
Thank you very much. Your work is impressive too
That system has the scrambler-interpolator DAC, which I love, with integrated SD player/USB selector option--> TVC--> active crossover at 1Khz based on Pass' B1 buffer-->UCD 180/400 amps. I will try to post better videos soon.
I wish I could visit Netherland in the future and see the "products" in person...I'll bring the wine
Best wishes,
M.
I agree this is a huge problem at this point.
I have measure the noise content of the AC supply and then have take many steps to reduce it. Everything from dedicate lines, technical local earth grounds, isolation transformers, shielded/filtering power cords, power regenerator, separate AC line filters for ouput stages and digital sections.... Even the routing of the AC cords needs be considered to optimize noise level.
Each layer of isolation, filtering and then regeneration and more filtering has reduced the noise on the AC supply many fold. Earth grounding is over looked by most, implemented correctly it is the noise sink or a source of noise if not implemented correctly.
The results had been large decreases in the noise floor and large improvements in sonics. I have not measure the affect on jitter, but the fundimental idea of clean power and earth ground is essential in both the digital and analog domains. You can save a lot of effort elsewhere by getting that cleaned up.
Jk
I have measure the noise content of the AC supply and then have take many steps to reduce it. Everything from dedicate lines, technical local earth grounds, isolation transformers, shielded/filtering power cords, power regenerator, separate AC line filters for ouput stages and digital sections.... Even the routing of the AC cords needs be considered to optimize noise level.
Each layer of isolation, filtering and then regeneration and more filtering has reduced the noise on the AC supply many fold. Earth grounding is over looked by most, implemented correctly it is the noise sink or a source of noise if not implemented correctly.
The results had been large decreases in the noise floor and large improvements in sonics. I have not measure the affect on jitter, but the fundimental idea of clean power and earth ground is essential in both the digital and analog domains. You can save a lot of effort elsewhere by getting that cleaned up.
Jk
Follow all local electrical codes.... ( till you don't )
Gauge of wire to the service box from the the system and from the service box to earth ground should be over sized by many gauge sizes from standard. 12 foot copper clad grounding rod at minimum. I have 2 located near the service entrance. The second needs to be 12 feet away to be affective. Soil moisture and other soil conditions can affect your results. Use the best quality connectors. I used a cooper grease to improve and help seal the outdoor connections. But there is welding process that would be preferred, I used high quality clamps.
Then I have an isolation transformer near the gear and I have a third grounding electrode located near it as locally generated derived technical ground. All within my local codes.
As I did not have the gear to test jitter.... Find a place in the system that you can measure the baseline noise. Maybe as simple as the amp output with the preamp turned up...and no source playing. I also have two simple hand held AC noise meters. One for 120v and one for 240v. They were handy in verifying the filtering, but grounding improves AC supply filtering.
Then start your ground improvements.... You mileage may vary based on local conditions and noise in the Power Companies AC supply. But for the cost of 10 gauge wire & some 4 gauge, the ground electrodes and some of my own labor.... This vastly improved the baseline noise on the analog side and the sonics.
Even without a jitter tester, I think it's an easy stretch to imagine it improved the jitter as ECJohn notes, I simply did not have the test gear to base line that. By reducing noise on the ground and supplies. I also use AC filters and a power regenerator in addition to the isolation transformer. I isolate most of the different AC supplies going to each transformer with some level of line filtering. My amp runs on filtered 240v from the isolation transformer. Your choice on the other AC improvements , but the grounding was under 150$ US. The local technical ground can not be setup without an isolation transformer.
JohnK
Gauge of wire to the service box from the the system and from the service box to earth ground should be over sized by many gauge sizes from standard. 12 foot copper clad grounding rod at minimum. I have 2 located near the service entrance. The second needs to be 12 feet away to be affective. Soil moisture and other soil conditions can affect your results. Use the best quality connectors. I used a cooper grease to improve and help seal the outdoor connections. But there is welding process that would be preferred, I used high quality clamps.
Then I have an isolation transformer near the gear and I have a third grounding electrode located near it as locally generated derived technical ground. All within my local codes.
As I did not have the gear to test jitter.... Find a place in the system that you can measure the baseline noise. Maybe as simple as the amp output with the preamp turned up...and no source playing. I also have two simple hand held AC noise meters. One for 120v and one for 240v. They were handy in verifying the filtering, but grounding improves AC supply filtering.
Then start your ground improvements.... You mileage may vary based on local conditions and noise in the Power Companies AC supply. But for the cost of 10 gauge wire & some 4 gauge, the ground electrodes and some of my own labor.... This vastly improved the baseline noise on the analog side and the sonics.
Even without a jitter tester, I think it's an easy stretch to imagine it improved the jitter as ECJohn notes, I simply did not have the test gear to base line that. By reducing noise on the ground and supplies. I also use AC filters and a power regenerator in addition to the isolation transformer. I isolate most of the different AC supplies going to each transformer with some level of line filtering. My amp runs on filtered 240v from the isolation transformer. Your choice on the other AC improvements , but the grounding was under 150$ US. The local technical ground can not be setup without an isolation transformer.
JohnK
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