So next question; do anyone know what's the easiest/laziest way to achieve a fully analog balanced in/out unit with the adau1452/1466? I've seen a lot of unbalanced DAC boards which is attachable, and one unit with integrated balanced out. I'm not very keen of designing my own PCBs if I don't have to. Is there any suitable ADC/DAC's that can be used with these boards as pretty much plug n play?
I'm trying to not get too deep into the rabbit hole here, heck, building a DSP is already pretty deep... 😀
I'm trying to not get too deep into the rabbit hole here, heck, building a DSP is already pretty deep... 😀
I expect you may be too far down the road with your DSP board by now, but the easiest overall solution for 8 x 8 balanced in and out (also unbalanced) is the miniDSP 8x8 kit board. It is reasonably priced when bought direct from miniDSP and the big problem of limited software can be got around by bypassing the onboard PIC and adding a Teensy (Arduino variant). I show how to do it in this thread: Getting more out of the miniDSP 8x8 kit
Sadly, one of the best products from miniDSP is out of stock and with no ETA.
Frank, also, incredible work bypassing the miniDSP software and using SigmaStudio instead! Congrats.
Frank, also, incredible work bypassing the miniDSP software and using SigmaStudio instead! Congrats.
Really a great work as mga2009 said, truly impressive! Unfortunately the miniDSP makes the project I'm onto a bit "useless", since it's purpose is to be a budget alternative to other DSP units in the €450 range.
My hope was to build a DSP cheaper than that, with better flexibility and stronger software with sigma, but I'm starting to think it's hard. I might just order the unbalanced version and try it to see how bad the noise is for my application 🙂
My hope was to build a DSP cheaper than that, with better flexibility and stronger software with sigma, but I'm starting to think it's hard. I might just order the unbalanced version and try it to see how bad the noise is for my application 🙂
Most likely the DSP for a start, very hard to buy these at the moment and expensive if found.
Thanks, I like a challenge 🙂 The project has come along quite nicely now, just waiting for a customised case to arrive from HiFi2000.
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What do you think of these kind of boards? They have i2s connection, but I'm not sure if it's working, what do you say? The 1466 seem to handle i2s but I'm not sure how to connect things correctly.
Balanced DAC
PCM1794A DAC Decoder Board Balanced HiFi Parallel Board 24Bit 192KHz Gold-plated | eBay
LRCLK
DATA
BCLK
MCLK (which I assume is master clock)
DGND (which I assume is common gnd)
ADAU1466 board
ADAU1466 Core Board Longer Delays for SIGMADSP Engineer Audio Maker DIYER | eBay
LRCLK
SDATA (which I assume is the same as regular signal-data)
BCLK
GND
What's missing here is the MCLK (masterclock), but is it necessary or should it be picked up somewhere else on the board? Or is it the same as SCLK (system clock)?
Or are these cards totally unsyncable?
Pin I/O for the 1466 board attached.
Balanced DAC
PCM1794A DAC Decoder Board Balanced HiFi Parallel Board 24Bit 192KHz Gold-plated | eBay
LRCLK
DATA
BCLK
MCLK (which I assume is master clock)
DGND (which I assume is common gnd)
ADAU1466 board
ADAU1466 Core Board Longer Delays for SIGMADSP Engineer Audio Maker DIYER | eBay
LRCLK
SDATA (which I assume is the same as regular signal-data)
BCLK
GND
What's missing here is the MCLK (masterclock), but is it necessary or should it be picked up somewhere else on the board? Or is it the same as SCLK (system clock)?
Or are these cards totally unsyncable?
Pin I/O for the 1466 board attached.
Attachments
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I also have this board - PCM1794A DAC Decoder Board Balanced HiFi Parallel Board 24Bit 192KHz Gold-plated.
But configuring this for multiple inputs illuded me. (perhaps someone would like to buy?)
I thought I would share my most recent experience, all balanced all good:
I bought what the ProAudio guys call “computer recording and audio interfaces”. It has included software that can be used to make a digital crossover, output this via (I am assuming) is a multi-channel DAC to multiple outputs, and eq each channel – Problem solved. Mine cost AUD520 delivered USB in (plus a lot of inputs) and 8 out - enough for 3-way & sub.
Computer Recording and Audio Interfaces | TASCAM - United States
Here are a lot from cheap to expensive
Audio Interfaces - Store DJ
I tired my Tascam with 2 x stereo amps, and it seems to work very well.
I welcome other experiences.
I am now building 3 x 2U enclosures to accommodate the TPA3251.
But configuring this for multiple inputs illuded me. (perhaps someone would like to buy?)
I thought I would share my most recent experience, all balanced all good:
I bought what the ProAudio guys call “computer recording and audio interfaces”. It has included software that can be used to make a digital crossover, output this via (I am assuming) is a multi-channel DAC to multiple outputs, and eq each channel – Problem solved. Mine cost AUD520 delivered USB in (plus a lot of inputs) and 8 out - enough for 3-way & sub.
Computer Recording and Audio Interfaces | TASCAM - United States
Here are a lot from cheap to expensive
Audio Interfaces - Store DJ
I tired my Tascam with 2 x stereo amps, and it seems to work very well.
I welcome other experiences.
I am now building 3 x 2U enclosures to accommodate the TPA3251.
I don't really understand what you mean by configuring it for multiple inputs? It does only receive L+R channel, which should be one data-pin from the adau board. If you want several outputs (which it must be since it's a DAC board and not a ADC board) you need one board per stereo channel. But all this is still in theory since I don't even know if the boards are compatible. If they are, this should apply.
Regarding your other experience, yes I find the sound cards of today very powerful. But I want the sigmastudio, and also have all the other possibilities with these cards since I'm planning a PA dsp unit and not one for headphones/mini-amp. Best case I can build a unit with 8-10band PEQ, 31 band GEQ, signal delay, limiter, crossover and feedback suppressor (if sigma supports it all?).
But thanks for your tip!
Hi Imbecillen,
Thanks for the reply. Looks like you have some fun. I will be following with interest.
I was going down the same track of having to buy multiple boards. But then how to get the music out of the PC after all the crossover and DSP. It was all too hard. Then I got talking to a mate who is a musician and he suggested the Tascam. It is a well know solution with the Pro Audio people.
My Tascam only has 8 outputs (1 more than I need). It can do all the crossover and DSP for each of the 8 channels. All in a nice 1U rack enclosure. There is a whole lot of Pro Audio software that does amazing things. But for now, I will stick to 2-way speakers a sub and the ability to eq each of the 8 outputs, via the Tascam software.
Thanks for the reply. Looks like you have some fun. I will be following with interest.
I was going down the same track of having to buy multiple boards. But then how to get the music out of the PC after all the crossover and DSP. It was all too hard. Then I got talking to a mate who is a musician and he suggested the Tascam. It is a well know solution with the Pro Audio people.
My Tascam only has 8 outputs (1 more than I need). It can do all the crossover and DSP for each of the 8 channels. All in a nice 1U rack enclosure. There is a whole lot of Pro Audio software that does amazing things. But for now, I will stick to 2-way speakers a sub and the ability to eq each of the 8 outputs, via the Tascam software.
Yeah I guess it all depends on what's your goal after all. My thought is to make a stand alone unit without the need of a computer (besides programming), and feed it with analog signal. But if you use it as a sound card I see why you took that route. 🙂
The PM1794A requires a master clock. For 192kHz sample rate a clock of 24.576 MHz is required which can be supplied by the master clock output of the ADAU1466 (CLKOUT, pin 23) with its MCLK_OUT register set for x8.
It looks like this pin is presented on pin 24 of the the top header in your posted diagram (1452 CLKO). Beware of course that this is a high frequency connection, so keep it as short as possible.
It is interesting that the PM1794A board has two DAC devices onboard operating in monaural mode in order to squeeze out the last 3dB of S/N available. Looks like they have made an effort!
Thank you for the pointer to the PMC1794A boards, their specification is significantly better than the CS42528 used on the miniDSP 8x8. I have a seperate miniDSP 2x4 taking the LFE channel from my AVR and sending it to four subs, each with different filtering in the DSP to flatten out the deep bass response around the room. I had thought about adding four more DACs to the 8x8 to pull it all into one unit and using a couple of the PMC1794A boards could be a good way to do it, where I'll use the additional DACs for teh al important front mains.
I've parked my miniDSP 8x8 to one side for now as one of the CODEC outputs seems to have died and chip shortages means a delay for a replacement. This has spurred me on to making my own version with higher quality and greater functionality. Briefly, my media room system is based on a Yamaha high end AVR, Linkwitz LXmini+2 for the mains and a custom LXmini for the centre. In addition, I have four active subs in the room corners for the LFE channel. These currently go via a miniDSP 2x4 so I can filter each one as determined by measurements and Multi-Sub-Optimiser. I have built an 8-channel power amplifier around Hypex modules with balanced inputs, the subs only have single ended RCA inputs.
Taking my cues from the above posts re the Midiworx ADAU1467 core board and the PCM1794A DACs, I have desiged a PCB with eight channels of PCM1794A DACs to drive the LXminis plus a couple of PCM5102A DACs for the four LFE channels. Main L & R inputs go through an AK5572 ADC board which I bought from Tomi (nihtila.com) as he has made a very nice job of it and I can't see the point to reinvent the wheel! I made an option to switch these inputs to take the balanced oputput from my phono stage in case I wish to bypass the AVR altogether for vinyl. Also provided is a direct digital input option. For these direct input options, volume will be controlled in the DSP. The centre and LFE channels go through a single ended PCM1802 ADC. There is a Teensy 4 with a TFT display and I/R remote input. Input and ouput trigger functionality is provided.
Here is a basic block diagram:
3D CAD of the board:
This fits in a HiFi2000 Galaxy case (330mmx170xxx40mm). Most parts mount straight to the board but due to back panel space limitations I had to use chassis mount 1/4" jacks for the balanced inputs, also a couple of chassis mount 3.5mm jacks for trigger in and out. Power supply generation is onboard, just requiring a +12V DC input.
The PCB is scheduled to arrive today and I'm reasonably confident it should all work once I've solderd the 500+ SMTs, etc. as have had all the elements running on the bench in a prototype lashup.
Happy to share more info if anyone is interested!
Taking my cues from the above posts re the Midiworx ADAU1467 core board and the PCM1794A DACs, I have desiged a PCB with eight channels of PCM1794A DACs to drive the LXminis plus a couple of PCM5102A DACs for the four LFE channels. Main L & R inputs go through an AK5572 ADC board which I bought from Tomi (nihtila.com) as he has made a very nice job of it and I can't see the point to reinvent the wheel! I made an option to switch these inputs to take the balanced oputput from my phono stage in case I wish to bypass the AVR altogether for vinyl. Also provided is a direct digital input option. For these direct input options, volume will be controlled in the DSP. The centre and LFE channels go through a single ended PCM1802 ADC. There is a Teensy 4 with a TFT display and I/R remote input. Input and ouput trigger functionality is provided.
Here is a basic block diagram:
3D CAD of the board:
This fits in a HiFi2000 Galaxy case (330mmx170xxx40mm). Most parts mount straight to the board but due to back panel space limitations I had to use chassis mount 1/4" jacks for the balanced inputs, also a couple of chassis mount 3.5mm jacks for trigger in and out. Power supply generation is onboard, just requiring a +12V DC input.
The PCB is scheduled to arrive today and I'm reasonably confident it should all work once I've solderd the 500+ SMTs, etc. as have had all the elements running on the bench in a prototype lashup.
Happy to share more info if anyone is interested!
Great work!!!
I did not got further then prototyping
your PCB looks great.
The Balanced out is done with the DSP?
Balanced output is done via the PCM1794. One device is used for each of the 8 channels. There are three dual opamps per channel, so three opamps for the Hot and three for the Cold differential outputs. It is a similar configuration as shown in the datasheet:
The I2S signals are fed to pairs of PCM1794A devices, both set to mono mode and one set for the left channel and one for the right channel. Linkwitz licensing does not allow me to publish crossover details in a public forum, but here is the prototype SigmaStudio top level design, including a few test tools such as signal generators and direct routing options:
Those who have a LXmini+2 licence will know that the sub has around 18dB peak lift compared to the woofer and tweeter so I have taken advantage of building my own post DAC stages to include an extra 18dB gain in the sub hardware channels in order not to require it in the DSP. This way I have kept an extra 18dB of dynamic range through the DSP.
The I2S signals are fed to pairs of PCM1794A devices, both set to mono mode and one set for the left channel and one for the right channel. Linkwitz licensing does not allow me to publish crossover details in a public forum, but here is the prototype SigmaStudio top level design, including a few test tools such as signal generators and direct routing options:
Those who have a LXmini+2 licence will know that the sub has around 18dB peak lift compared to the woofer and tweeter so I have taken advantage of building my own post DAC stages to include an extra 18dB gain in the sub hardware channels in order not to require it in the DSP. This way I have kept an extra 18dB of dynamic range through the DSP.
I should add, apart from the PCM1802 ADC which is limited to 96kHz, everything else is running at 192kHz sample rate. There are few things not shown in the proptotype SigmaStudio design, such as a a four stage tilt control (ala QUAD preamps) routing of the digital signals through the mixer, etc. so it is a definite work in progress!
Smart way of keeping the dynamic range better indeed!
I can see you spend a lot of time with it!
I used a TTGO T-Display for ir remote ect.
The datasheet of the pcm1974a is impressive
sounds like another project for me as well
I can see you spend a lot of time with it!
I used a TTGO T-Display for ir remote ect.
The datasheet of the pcm1974a is impressive
sounds like another project for me as well