Absolutely not and i will never do it, because i don't think i'm smarter than the Sony and Phillips engineers were when they admitted that they have to persuade the marketing department to pay for more components in a commercial system that needs to be sold so that they can pay their wages and make the owners rich, but even if i'd do it, the lm6172 still is amongst the best options for i/v stage because of its huge slew rate, high output power on low impedance loads , low thd at high frequencies and acceptable noise for only one tda1541 for both channels.
Dear Dreamth,
We are here (this forum; this planet) to learn and we learn through experience (experimentation) so do not dismiss options until you try them. Some of us do not tolerate the "sound" of opamps anymore. They suck the life of the music.
Simple (low noise; low capacitance low inductance) resistor is best for TDA1543 (no slew), as -EC- taught us with his honeycomb resistors, then for TDA1541A comes the expensive Tx, then the simple discrete solution which better have "Low Thermal Memory Distortion" (LTMD) circuit or use 2SK30A, about which Hephaïstos (ascended Master) found it shows lowest TMD.
The idea is enjoy the breath of music again.
Low THD and high slew rate means nothing if the sound is sterile...
Cheers,
M
PS: I am sure -EC- can invent something even better.
WOW! Should i join the Sforce, Dark Fader?Dear Dreamth,
We are here (this forum; this planet) to learn and we learn through experience (experimentation) so do not dismiss options until you try them. Some of us do not tolerate the "sound" of opamps anymore. They suck the life of the music.
Simple (low noise; low capacitance low inductance) resistor is best for TDA1543 (no slew), as -EC- taught us with his honeycomb resistors, then for TDA1541A comes the expensive Tx, then the simple discrete solution which better have "Low Thermal Memory Distortion" (LTMD) circuit or use 2SK30A, about which Hephaïstos (ascended Master) found it shows lowest TMD.
The idea is enjoy the breath of music again.
Low THD and high slew rate means nothing if the sound is sterile...
Cheers,
M
PS: I am sure -EC- can invent something even better.
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Experimentation is not a religion. You are able to excercise discerment, a high function of the Mind, after the experience. And one might learn something extra in the process...
But perhaps you prefer the religion of opamp and low THD.
Note that I am not attacking but proposing a strategy.
Best of lucks,
M.
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Well ... i'm not looking for thd lower than 70...90 db and i actually like -50...60 db thd , but that is not the point...I prefer valves or tape to create distortions.
It seems that lm6172 for tda1541 with oversampling and no active low pass filter works for me...
You can try that too...just for the sake of experimentation as you mentioned it!
It seems that lm6172 for tda1541 with oversampling and no active low pass filter works for me...
You can try that too...just for the sake of experimentation as you mentioned it!
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Hi again.
I made a low noise (LM4562) x100 amp and played your file through the Signed Magnitude TDA1541A. Very noisy and it is not the preamp, but a very rude measuring setup not optimized for noise reduction, that causes all the overlaying noise. But definitely a recognizable 1Khz.
If I speculate on what would happen the DAC could not resolve that, it would not IMHO result in even order harmonic distortion, but in raised noisefloor and lack of resolution.
I still am convinced it is the small differences between the two dac's inside the TDA1541A that is the reason.
Attachments
I also tried your files but with no luck.
All of the tracks except track 15 produced a - full scale DC at the output of the DAC. Track 15 only noise.
Amen!Dear Dreamth,
We are here (this forum; this planet) to learn and we learn through experience (experimentation) so do not dismiss options until you try them. Some of us do not tolerate the "sound" of opamps anymore. They suck the life of the music.
Simple (low noise; low capacitance low inductance) resistor is best for TDA1543 (no slew), as -EC- taught us with his honeycomb resistors, then for TDA1541A comes the expensive Tx, then the simple discrete solution which better have "Low Thermal Memory Distortion" (LTMD) circuit or use 2SK30A, about which Hephaïstos (ascended Master) found it shows lowest TMD.
The idea is enjoy the breath of music again.
Low THD and high slew rate means nothing if the sound is sterile...
Cheers,
M
PS: I am sure -EC- can invent something even better.
using lm4562 at 100x can explain the noise in the system and also the nonlinear measurement of short duty cycles spikes...It's possible that the lm4562 itself produce some of the spikes.
As you might not like op-amps either...better use a cascoded common base structure supplied by a very low noise power supply if you want to measure those spikes accurately.
It is ABSOLUTELY not noise from the opamp. I measured it about 1 - 2 mv out of the lm4562 x100 amp with shorted input ...And no spikes whatsoever.
I use a x1 probe into a scope with 5mV per division.
Please remember it is a DAC with absolutely no filters, so a lot of HF noise is expected!!
And I have never used a x100 amp when measuring distortion, why should I???
What spikes are you referring to?? I am not trying to measure spikes , but verify that the DAC actually have a resolution of at least 16 bits.
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Attachments
??
Sorry to hear what?
As far as I can see the DAC that I measure can easily resolve your file as well...
It is only drowned in a lot of noise because of no digital filters and no analog filters..
??
Sorry to hear what?
As far as I can see the DAC that I measure can easily resolve your file as well...
It is only drowned in a lot of noise because of no digital filters and no analog filters..
I did not use any filters either, so my feeling is still that things can be improved on your side.
You could for the purpose of this measurement place a cap parallel to your output resistor to get a better view on what’s happening.
But the noise of your 100x amp could also contribute to the noise.
Is this a low noise op amp that you used ?
Hans
Koldby,
What about the idea of placing a 22nF cap par. to the output resistor, that would suppress noise quite a bit, just for testing.
What I don’t understand is where all this noise comes from.
You could also feed the Dac with only digital zero, and try to find the source of this noise, an idea ?
Hans
What about the idea of placing a 22nF cap par. to the output resistor, that would suppress noise quite a bit, just for testing.
What I don’t understand is where all this noise comes from.
You could also feed the Dac with only digital zero, and try to find the source of this noise, an idea ?
Hans