Hi looking for some advice I need a dac and found this on ebayAssembled AK4495 SEQ II2S DAC decoder board (upgrade version) 32BIT 768K
would this be a good project to start with and what else would I need .
I have been medically retired for the last six years (three spinal ops so far and awaiting another two)
so as you can understand money is on the tight side or can anyone recommend
anything else project wise I am not up to building boards yet just practicing soldering on a knackered old amp.
Regards Gerry
would this be a good project to start with and what else would I need .
I have been medically retired for the last six years (three spinal ops so far and awaiting another two)
so as you can understand money is on the tight side or can anyone recommend
anything else project wise I am not up to building boards yet just practicing soldering on a knackered old amp.
Regards Gerry
Have you read the AK4495 datasheet ?
What is your I2S audio source ? Does it feature a very high quality MCLK-out ?
In case you intend experimenting with the various AK4495 operating modes, how are you going to elaborate the SPI or I2C communication that's required ?
What is your I2S audio source ? Does it feature a very high quality MCLK-out ?
In case you intend experimenting with the various AK4495 operating modes, how are you going to elaborate the SPI or I2C communication that's required ?
The OP asked a perfectly legitimate question regarding getting started with a DIY Dac. I would also like to know is this a feasible project for a beginner to put together?
Jp
Jp
It depends what you mean by "a beginner". The project consisting of purchasing on eBay the assembled AK4495 DAC board, and exploiting it properly, is feasible at the condition that "the beginner" :
- is willing to read and understand the AK4495 datasheet
- is willing to read and understand the specification of all connectors on the eBay DAC board
- can base on a high quality I2S audio source as master delivering a high quality MCLK signal
- understands the difference between a I2S source as master, and a I2S source as slave
- can generate the required I2C or SPI transactions for selecting the various AK4495 operating modes and for adjusting the AK4495 output volume - he can do so using a PC as terminal and the Sparkfun "Bus Pirate" https://www.sparkfun.com/products/12942
In case "the beginner" doesn't have the required skills yet, he can try connecting an assembled PCM5102A DAC board acting as I2S slave, on a miniDSP miniStreamer acting as I2S master.
This time, no MCLK signal is required, as the PCM5102A will generate a MCLK internally thanks to its internal PLL.
This is a much simpler combination, that any beginner should be able to deal with.
Please note, the PCM5102A doesn't require I2C or SPI transactions.
As consequence, one cannot adjust the PCM5102A output volume.
You thus need to connect the PCM5102A DAC on a stereo power amplifier having its own volume control.
You better add a galvanic isolation on I2S using a ISO7240 chip.
This way there is a galvanic isolation barrier between the PC acting as USB Audio source (high-power switched-mode power supply conducting a lot of common mode noise), and the assembled PCM5102A DAC board that you should power using a 4 x NiMH rechargeable AA battery pack (4.8 Volt nominal) that you 2-pole disconnect from the battery charger when you listen to the audio.
In case you don't trust the stereo volume potentiometer and balance potentiometer sitting inside your power amplifier, you may rely on a digitally controlled volume consisting on switched resistors like in the PGA2311 chip. PGA2311 Volume Control
The PGA2311 requires a + 5 Volt and - 5 Volt high quality power supply. You may generate the two required voltages from the symmetric DC voltages that you may have in the power amplifier section, or in the preamplifier section.
The PGA2311 requires SPI transactions for adjusting the volume and the balance. You can do so using a PC as terminal and the Sparkfun "Bus Pirate" https://www.sparkfun.com/products/12942
You better add a galvanic isolation on SPI using a ISO7240 chip.
This way there is a galvanic isolation barrier between the PC acting as volume controller (high-power switched-mode power supply conducting a lot of common mode noise), and the PGA2311 volume controller.
Adjusting the volume using a PC console sending data to the PGA2311 will quickly get boring.
Soon or later, you'll want to replace the PC console method, by a proper remote control.
This is feasible using the SparkFun IR Control Kit https://www.sparkfun.com/products/13235.
You need an Arduino microcontroller board running a tailor-made Arduino program for reading the IR codes, and translating them into meaningful SPI transactions addressed to the PGA2311.
Sparkfun provides the beginning of an example program on their IR Control Kit webpage. This way you enter the Arduino world.
After completing everything that's above, you'll become a kind of "beginner", that's able to exploit the eBay assembled AK4495 DAC board.
- is willing to read and understand the AK4495 datasheet
- is willing to read and understand the specification of all connectors on the eBay DAC board
- can base on a high quality I2S audio source as master delivering a high quality MCLK signal
- understands the difference between a I2S source as master, and a I2S source as slave
- can generate the required I2C or SPI transactions for selecting the various AK4495 operating modes and for adjusting the AK4495 output volume - he can do so using a PC as terminal and the Sparkfun "Bus Pirate" https://www.sparkfun.com/products/12942
In case "the beginner" doesn't have the required skills yet, he can try connecting an assembled PCM5102A DAC board acting as I2S slave, on a miniDSP miniStreamer acting as I2S master.
This time, no MCLK signal is required, as the PCM5102A will generate a MCLK internally thanks to its internal PLL.
This is a much simpler combination, that any beginner should be able to deal with.
Please note, the PCM5102A doesn't require I2C or SPI transactions.
As consequence, one cannot adjust the PCM5102A output volume.
You thus need to connect the PCM5102A DAC on a stereo power amplifier having its own volume control.
You better add a galvanic isolation on I2S using a ISO7240 chip.
This way there is a galvanic isolation barrier between the PC acting as USB Audio source (high-power switched-mode power supply conducting a lot of common mode noise), and the assembled PCM5102A DAC board that you should power using a 4 x NiMH rechargeable AA battery pack (4.8 Volt nominal) that you 2-pole disconnect from the battery charger when you listen to the audio.
In case you don't trust the stereo volume potentiometer and balance potentiometer sitting inside your power amplifier, you may rely on a digitally controlled volume consisting on switched resistors like in the PGA2311 chip. PGA2311 Volume Control
The PGA2311 requires a + 5 Volt and - 5 Volt high quality power supply. You may generate the two required voltages from the symmetric DC voltages that you may have in the power amplifier section, or in the preamplifier section.
The PGA2311 requires SPI transactions for adjusting the volume and the balance. You can do so using a PC as terminal and the Sparkfun "Bus Pirate" https://www.sparkfun.com/products/12942
You better add a galvanic isolation on SPI using a ISO7240 chip.
This way there is a galvanic isolation barrier between the PC acting as volume controller (high-power switched-mode power supply conducting a lot of common mode noise), and the PGA2311 volume controller.
Adjusting the volume using a PC console sending data to the PGA2311 will quickly get boring.
Soon or later, you'll want to replace the PC console method, by a proper remote control.
This is feasible using the SparkFun IR Control Kit https://www.sparkfun.com/products/13235.
You need an Arduino microcontroller board running a tailor-made Arduino program for reading the IR codes, and translating them into meaningful SPI transactions addressed to the PGA2311.
Sparkfun provides the beginning of an example program on their IR Control Kit webpage. This way you enter the Arduino world.
After completing everything that's above, you'll become a kind of "beginner", that's able to exploit the eBay assembled AK4495 DAC board.
Therefore I sketched the above, simple & modular DAC project for you, basing on a assembled PCM5102A board. You should be able to step into this, don't you?
I am not sure if stef_tsf is trying to be helpful or sarcastic. If anyone out there can point to a simple diy project for a DAC that gets music from a computer to an amplifier it would be appreciated.
Jp
Jp
(From #4) Galvanic isolation does not guarantee the noise will be stopped, galvanic means there is no direct conduction path only, noise can still couple through the barrier unless special care with the layout is taken and often some form of filtering is also required...
I would look around at some of the very simple designs on here to begin with or a USB DAC from ebay or something like this..
http://pavouk.org/hw/audiosystem20/en_pcm5102dac.html
I would look around at some of the very simple designs on here to begin with or a USB DAC from ebay or something like this..
http://pavouk.org/hw/audiosystem20/en_pcm5102dac.html
I think steph_tsf couldn't explain it more complicated way 🙂 unless he's really sarcastic...
if cheap for beginners is the goal here than this is one of the cheaper one could find, simple 9V/15V trany and you are good to go, otherwise the one mentioned by OP is basically the same but requires external USB>I2S board connected through 5 line ribbon cable, at the end it would be more expensive so first option is better as all in one for decent money
of course in both cases this is only valid if you guys are planning to use PC as your source/player of music
if cheap for beginners is the goal here than this is one of the cheaper one could find, simple 9V/15V trany and you are good to go, otherwise the one mentioned by OP is basically the same but requires external USB>I2S board connected through 5 line ribbon cable, at the end it would be more expensive so first option is better as all in one for decent money
of course in both cases this is only valid if you guys are planning to use PC as your source/player of music
Marce, you are completely wrong. An isolation barrier equals a low value capacitor (say 100 pF roughly), while no isolation barrier equals a short circuit. For some reason, you don't want to recognize the essential différence. That's pathetic.
Marce, you are completely wrong. The hardware you are recommending is a not a USB DAC. It is a I2S DAC. For some reason, you don't want to recognize the essential différence. That's pathetic, again.
On top of this, the Pavouk's PCM5102 DAC that you recommend features the same schematic as the assembled PCM5102A DAC board that I recommend, easy to purchase on eBay. So, according to you, a beginner is willing to produce a PCB, purchase all SMD parts, and get them soldered. You are wrong again.
Not sarcastic. Didactic. Wanting to explain the difficulty of digital audio. High quality DACs integrated circuits are inexpensive nowadays, and they all require I2S audio at the input. Unfortunately a PC or a CD/DVD/Bluray doesn't output I2S Audio. Instead, a PC can output USB Audio, and a CD/DVD/Bluray player can output SPDIF or TOSLINK audio. Question: what to do with a simple inexpensive however high quality I2S DAC like the assembled PCM5102A DAC board that's available on eBay? Answer: add a high quality USB to I2S converter like the miniDSP miniStreamer (featuring a reputated XMOS USB2 Audio controller inside). Unfortunately, you face a problem: the PC ground gets connected to the Audio ground. The evil is the high power switch mode power supply of the PC, forcing current spikes to flow through the ground (conduction noise). You thus need an isolation barrier. And you still don't have a volume control, in case you want to bypass the oldschool volume potentiometer that's in your poweramp, or in your preamplifier. Etc etc. This is easy to understand. This is the foundation of homemade DACs. Sorry. Not my fault. In case you want to exploit the SPDIF or TOSLINK from a CD/DVD/Bluray player, you need a add a high quality SPDIF/TOSLINK to I2S converter. Same issues. Same complexity. Not my fault.
I fully agree. Nice finding. Such assembled USB2 AK4495 DAC board embeds a high quality USB2 to I2S converter basing on a XMOS chip. It is like you add a miniDSP miniStreamer. Is such assembled USB2 AK4495 DAC board coming with a Win7 driver or MacOS driver, enabling to take advantage of the numerous features of the AK4495, like the volume control, and the selection of the oversampling and reconstruction filter?
Not sure however, that such USB2 stereo soundcard does as good as the reputable Asus Xonar U7, that you can purchase for $120 on eBay, ready to use, with a proper Win7 driver (or MacOS driver).
Bear in mind that the Asus Xonar U7 outputs up to 8 audio channels, while the assembled USB2 AK4495 DAC board, only delivers stereo.
I vote for the Asus Xonar U7, connected to a Win7 PC running JRiver Media Center, that you persuade to send the stereo audio using ASIO to a stand-alone VST executable that you load at boot, such VST tailor-made using Flowstone, operating as stereo 4-way digital crossover, that's outputting eight audio channels using ASIO then USB2, to the Asus Xonar U7. And the Asus Xonar U7 has a big rotary encoder acting as volume control. This is a perfect newbee digital audio project. The use of the soldering iron, is typically, to remove the passive crossovers that you have in your speakers, replacing each passive crossover by a strong metal plate equipped with a 8-pole Speakon chassis. This way, all your speaker drivers become directly-driven by an array of power amplifiers. This is probably the best, and probably the most inexpensive multiway stereo system you can build.
Not sarcastic. Didactic. As I said.
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steph_tsf: Earlier in this thread you stressed the importance of a "high quality I2S audio source as master delivering a high quality MCLK" and "galvanic isolation on I2S using a ISO7240." Which is it? High quality MCLK or ISO7240, because you can't have both.
One of the worst things you can do to a clock is put it through an isolator. Have you looked at the ISO7240 specs? Skew, PWD, and jitter are all > 1 ns, PD > 20 ns.
One of the worst things you can do to a clock is put it through an isolator. Have you looked at the ISO7240 specs? Skew, PWD, and jitter are all > 1 ns, PD > 20 ns.
I agree with you on the principle. Have you noticed, there are more and more decent oversampled ADCs (AD1974), DACs (AD1933, AD1934, PCM5102A, TDA7801) and Codecs (AK4558EN, AD1928, AD1937, AD1938, AD1939) to be used as audio clock slaves, featuring an internal PLL exploiting the bit clock, and multiplying it for generating a high quality, local MCLK, bit clock and frame sync within the chip.
Has somebody measured the audio quality degradation caused by a ISO7240, in such particular context?
Are there more high quality ADCs, DACs or Codecs incorporating a jitter reduction mechanism?
I already spotted the ES9023 DAC.
In case there is a ISO7240 on a I2S thats conveying MCLK, bit clock, frame sync and data, and one wants a 132 dB DAC like the PCM1794A that's not incorporating the required jitter reduction mechanism, what re-clocking scheme would you advise?
I suggest a quartz-based 2x analog PLL on MCLK, loading a 22.5792 MHz or 24.5760 MHz quartz with varicaps, relying on a 2x divider (one flip-flop) for guaranteeing a 50% duty cycle. Are there practical examples?
In case there is a ISO7240 on I2S, only conveying bit clock, frame sync and data (no MCLK thus), and one wants a 132 dB DAC like the PCM1794A that's not incorporating the required jitter reduction mechanism, what re-clocking scheme would you advise?
I suggest a 2x 32 bits = 64 bits per frame setup, and a quartz-based 8x analog PLL on MCLK, loading a 22.5792 MHz or 24.5760 MHz quartz with varicaps. Are there practical examples?
Or perhaps, is is preferable to rely on a ASRC chip like the SRC4382 that's inside the miniDSP DIGI-FP, instead of relying on an analog quartz-based PLL?
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I said Galvionic isolation does not guarantee noise isolation, I am not wrong, also I dont go round calling people pathetic just because they post a wrong link... You are a pathetic as well read what you put about galvanic isolation,
Anyway bye cant hangaround here with such superior beings...
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