To get more information contact me at: webmaster audiodesignguide. In this configuration the output signal is too low to drive any amplifier so I have design for the ADN-K the better output stage. The DAC board follows the original design but has been inserted a jump to switch the phase of output signal.
In any vacuum tube stage the signal on the anode is in out phase with the grid signal so the jump is necessary to get a correct in phase output. After some test has been decided to use shunt regulator to increase the sonic performances so a Salas regulator has been used for the DAC section. Quang Hao have created a group buy on diyAudio to reduce the production cost of these pcb. Any board have the same size All these pcb boards has been created only for DIY so no commercial use is allowed.
About wire forget the teflon! A very good quality stranded tinned copper wire could be buy directly from E-Z-HOOK that carries an extensive line of fine stranded and extra flexible wire. DAC BOARD On the pcb layout is visible the jump for the digital phase inverter as described in the introduction and n o other regulation are necessary. A little post shunt regulators using the TL has been inserted to separate all the power supply like suggested in the datasheet of AD and CS The original DAC end have no capacitor on output because in this case this filter is created by the output transformers band.
The files to produce this pcb was lost so Vito Flamminio have created new files from images and schematic here. The relay will short the output to ground during the switch on and switch off phase to prevent dc peak on the outputs. The ECC will give an higher output level because the amplification factor is 24 instead of 17 and the internal resistance is quite the same. Using the the voltage gain of this stage is The power supply for the vacuum tube stage is quite the same of original DAC End.
It use a no feedback regulator inspired to the Virtual Battery invented many years ago by Technics. To get the best sonic performances I suggest to use a Jensen electrolytic on output but any other audio grade cap.
For the filaments has been used a slow turn power supply using a common LM to get a long life time of tubes. Follow the measurement on the prototype of the output stage using the Jan Philips, distortion is less than 0. Follows in the same conditions the frequency response without sound card errors compensation.
Follows the measurement of the DAC board on AD output with a filter composed by a 10nF capacitor in parallel to the ohm resistor, the sampling frequency 44KHz is at dB. The high frequency cut-off is the result of this formula. Some photos sent by Quang Hao.Reader Alex H. It lacks coherence and most of all, presence. I think it's safe to say that many of the people who are attracted to the NOS implementation are also attracted to analog playback and perhaps tube-based amplification and high sensitivity speakers.
Think Tone. The scuttlebutt running mainly underground is that NOS can deliver the digital goods for vinyl lovers. If you know of one or more that I missed, let me know in the comments section and I'll add 'em. Does not employ upsampling but it does employ oversampling. This is really a subject that demands its own post but your 1 is confusing upsampling with oversampling. Oversampling adds additional interpolated data based on existing data points whereas u psampling 'pads' the existing data to reach some arbitrary higher sample rate.
Basically, oversampling is just type of upsampling where resulting digital signal has sampling rate that is integer multiple of the original digital signal. For example 8X oversampling of kHz digital signal is actually upsampling from kHz to kHz. Of course, in DAC implementation they are intended for different goal but that's another story. If answer is NO then literal interpretation of term could lead to confusion don't you think? But in its original use, NOS means no up, down or over sampling and also typically means no digital filters.
Extensive testing and listening tell us that up-sampling and sample-rate conversion do more harm than good, as does negative feedback. Consequently, no form of sample-rate conversion is ever employed. Without too much hyperbole, I could almost cut and paste in here the thoughts expressed in my very first paragraph about what makes vinyl special -- the DAC-9 seemed to do the very same things right, if not, in the end, to quite the same degree.
It had a certain liquidity and tonal rightness that ultimately made music more enjoyable. Pop and rock, or any recordings that live in the middle of the dynamic spectrum, generally sounded fantastic, alive, and vital.
I would appear though the same general impression is shared by others. In both cases the Vertex treatment is applied inside the cases on the circuit boards to tackle problems at source, stopping contamination from spreading. Delta-sigma module using 1-bit conversion must up sample the data stream at least times to execute digital to analog conversion.Certainly it applied ten years ago in the case of the Philips engineers working on the development of the Compact Disc system.
Given a specification that had included a bit data word length, they had duly developed a bit DAC chip, the TDA, only then to be informed that the CD standard decided upon after Sony joined forces with the Dutch company would involve bit data words. Thank goodness! Philips having already committed the bit design to silicon, they would not have a bit DAC ready in time for the medium's launch in the Fall of They were thus faced with the problem of squeezing four times the resolution from their existing bit DAC.
The result was an ingenious digital filter that combined 4x-oversampling and noise-shaping—the latter is effectively a digital feedback loop, the error produced when the filtered digital data are truncated to 14 bits being fed back to the beginning—to give a digital system with full bit resolution. Philips's true bit DAC chip, the TDA, followed inbut the seeds of ingenuity had obviously been sown: if the combination of oversampling and noise-shaping can increase the resolution of a DAC using too few bits, then why not go all the way and implement a system that used a simple 1-bit DAC and make up for the shortfall in resolution by taking the oversampling, noise-shaping process to the limit?
I discussed the design of the system in detail in June Vol. The data words are then fed to a 1-bit DAC, with the bit error fed back in a noise-shaping loop. But unlike multibit systems, this "Bitstream" DAC is inherently linear and monotonic over its entire range—the reasons why were given in Peter Mitchell's "Industry Update" in January Vol.
I was told by Philips last year that the Bitstream DAC was therefore intended to be used in low-cost and portable players, the company saying that they would remain with their TDbased chip set for high-performance players.
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Lampization of the TDA chip
Please give us the opportunity to resolve any problem. IC is not recommended OPA OPA other cold op amp, op amp need to buy an independent Materials in one step, a detailed single-material below the three main IC is a good test of disassemble IC, these IC is discontinued, are removed from the CD, the rest of the whole new pieces of low-l part of the selection of the United Kingdom WEL resistance, so that the output of some detail.
The actual use of Panasonic is also good, you can choose. Picture of the capacitor is all resistance, shipping will change with the blue British WEL resistance, probably 10 The output capacitor has been replaced by Panasonic U capacitor, if that is not enough burning, you can choose a better mix of other Regulator is also the focus, with a new 7 on the LM LM and LM, the beginning and the joint use of wow Tian proofing, anti-feel that the small.
The layout of the IC directly affects the sound, which is the third version of the image. Returns Policy: All sales come with us day warranty. Contact us: If you have any questions,Please contact with us via eBay message or our customer service e-mail. Excluding Weekends and Public Holidays Feedback: Dear buyers, we appreciate your business, if you are satisfied with our service, please leave us a positive feedback.For Audiophile-sounding DAC for almost no money.
To get a great sounding DAC its important to choose a DAC chip with lots of potential and ignore most of the datasheet specs. Going back to the s most DAC chips were just that - DACs and had neither on-board digital nor analog filters using opamps. Both of these kinds of filters have the potential to screw up the sound so you do not want them on the chip where its impossible to bypass them.
Analog Devices have had great designs too, the most recent being AD Of the audio chips I've mentioned, all are out of current production so if you want to have a viable manufactured product you have to look beyond audio to find your chip.
Hobbyists though aren't constrained by production volumes and so have rarely had it so good with the wide choice of recycled devices on the secondary market. Take in the realm of amps their in-car offerings TDA for example - I have a design for an amp using it here : Hi end chipamp.
In regard to the tech behind the chips, the TDA takes some beating as it continuously recalibrates itself on the fly so doesn't require the usual extreme resistor matching achieved in other manufacturer's offerings by laser trimming. Its also absurdly cheap as the chips are recycled from old 'Soundblaster' PC cards. So oversampling 4X was used as a way to gain a couple of bits from the DAC through averaging out 4 faster samples to create one slower one.
When the TDA was eventually introduced a couple of years later with 16bit performance, Philips could have deleted the digital filter SAA but to do so would necessitate a much more complex analog filter to keep out the inherent ultrasonic images produced by any DAC. So Philips stuck with the digital filter because the analog challenges were immense.
DIYers who've embraced NOS generally say no anti-image filtering is needed, some go further and say its detrimental to the sound. The short answer - for those who don't want to navigate that long thread - is - I found the filtered DAC to have not only a sweeter HF but, and this was most surprising, a much more 'holographic' presentation overall.
By which I mean the acoustic space of the recording seems to become 3D.
TDA1541A TDA1541 DAC Data Converter DIY Kit (CS8414 & AD797)
This latter feature is most subjectively alluring, once you've heard this kind of sound you really can't go back. I associate it with a reduced noisefloor electrically meaning that very low-level cues in the recording aren't getting garbled.
Passive filters like the one I designed aren't at all commonly found in commercial DACs which to me is quite surprising. Nowadays inductors seem to be the Cinderella components, EEs typically think designing with them is some kind of black art.
The only DAC I know of with a more complex filter than mine is the Zanden and this has a rather different design objective from my own. Having determined to my satisfaction that fairly steep, aggressive filtering of DAC images was an essential component of a top sound quality DAC this rather sets me on a different path from almost all commercial and DIY DACs.
Not being at all scared of being a lone explorer I looked into ways to get around the need for inductors. Active filters are a standard item in most DACs, generally they're implemented with opamps. But opamps don't sound particularly great and they sound even worse when fed ultrasonic frequencies, liberally available at the output of DACs.
I have built a few DACs with active filters made out of discrete transistors, these sounded very good but the steepness factor I was able to achieve wasn't particularly high. A Q of about 10 was about as far as I was able to take my Sallen-Key based design in practical terms. Even this relatively low Q needs careful selection of capacitor values with an LCR meter.
So if we have to select caps to get the filter response we need, why not inductors? When inductors are cheap and you're making a few DACs a solution is to buy a lot more than you need and to sort them out into bins and use all inductors from the same or adjacent bins, adjusting capacitors in combination to get a nice flat response.
This is the way I've been building LC filters over the past few years - as I've not found a better solution that's how this DAC is getting built. What makes these inductors stand out is they're relatively flat in their losses over the audio band. I've tried cheaper ones Sumida is in general cheaper but for some reason the one I tried had 4X higher losses at 20kHz than at 1kHz.
Frequency dependent losses translate into high frequency droop and such losses are very hard to simulate in LTSpice my simulator of choice. There is a more 'hair-shirt' way to build high Q inductors and that's from ferrite beads. I have built and characterized a ferrite bead filter - the Q obtainable is really excellent, far higher than achievable with COTS parts. But each bead does not contribute much inductance, typically 1uH.
DIR9001+TDA1541A Classic NOS DAC
So to build a uH inductor takes beads in a string, rather impractical. One way to deal with this is to scale the working impedance of the filter.
For an audio band low pass filter, a rule of thumb is that the working impedance in ohms is the inductance in uH divided by User Name Stay logged in? I'm a long time lurker but this is my first post. The seller's description for power supply requirements is as follows: "Power needs 3 way 1 pair of dual 15 can be up to 22V 2 single 7V up to 11V the whole machine free debugging" I think I figured out the 2 x 7V winding green and yellow pair of twisted leads connections as pictured.
But I don't know how to configure the 2 x 15V windings blue and white pairs for connection to the 3-terminal connectors. Thanks in advance! Find More Posts by je Originally Posted by je I don't know how to configure the 2 x 15V windings blue and white pairs for connection to the 3-terminal connectors. Measure resistance on the Multimeter, one blue should have zero resistance with one of the whites. Yes, I've verified via DVM that the pair of blue windings are not connected to the white pair.
I connected the windings in series with the CT connected to ground center terminal with the single blue and white on the outer terminals. Did I get this right? Thanks again! What is this component? I presume it should be mounted in the area marked "L", since I've mounted everything on the PCB board except this.
This is the first time I encountered it. Originally Posted by weissi. Last edited by rayma; 2nd April at PM.蘇嘉研 -- TB xmos USB + TB tda1541 DAC + TB audio note kit one 300B + energy c100
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