Good Morning Baldin.
Your project looks very interesting as well, as the Aurora and the Octavia from Pit.
If i can put something on my wishing list..i would say...Balanced outputs for sure..and AES/EBU input and output...for me is even better than any toslink..This would be a must for people who want to implement multichannels systems..
Your project looks very interesting as well, as the Aurora and the Octavia from Pit.
If i can put something on my wishing list..i would say...Balanced outputs for sure..and AES/EBU input and output...for me is even better than any toslink..This would be a must for people who want to implement multichannels systems..
Hi Maurizio
Balanced input I might consider, but not output as this is intended as a build in part of either a 4 channel amp or an active speaker, where for both the distance btw. DSP and AMP is so short that it is not worth the effort.
For input it could make sense for long wiring to an active speaker. But it adds complexity and room needed for the board.
The later is important for the cost as I intend to go for a 4 layer PCB. 10x10 cm is really cheap, and everything larger gets expensive real fast.
AES/EBU, not really in the plans. For stereo I would think it is no better than TOS-Link / or coax SPDIF, at least for relative short (less than 10 m) distances.
And for handling multi channel, I think it only supports 5.1 as far as I know (correct me if I'm wrong), which is kind of a "dying standard", where 7.1 or ATMOS is much more interesting.
Sorry to disappoint in this area 😉
Balanced input I might consider, but not output as this is intended as a build in part of either a 4 channel amp or an active speaker, where for both the distance btw. DSP and AMP is so short that it is not worth the effort.
For input it could make sense for long wiring to an active speaker. But it adds complexity and room needed for the board.
The later is important for the cost as I intend to go for a 4 layer PCB. 10x10 cm is really cheap, and everything larger gets expensive real fast.
AES/EBU, not really in the plans. For stereo I would think it is no better than TOS-Link / or coax SPDIF, at least for relative short (less than 10 m) distances.
And for handling multi channel, I think it only supports 5.1 as far as I know (correct me if I'm wrong), which is kind of a "dying standard", where 7.1 or ATMOS is much more interesting.
Sorry to disappoint in this area 😉
Also now the title of the thread is becoming a bit misleading, as the plan is now 4 in 4 out, and not 8 out 😉
That does make sense to me actually. Ideally you probably wouldn't take a super long RCA to the speaker. Am I misremembering or were you still considering a breakoff board for the input connectors? 🙂
I'm also working on an ADAU1452 board, with 3 stereo DACs output. I'm using PGA chips for volume control (with an Attiny45).
Power supply board is separate, input via HDMI connector (LVDS receivers/transmitters) or TOSLINK. I'll run it at 24/96.
Layout is mostly done, I still need to change a few of the connectors throughout the PCB. I also put a latching relay so I can have a separate output for headphones (with EQ from DSP). Size is 100mm x 100mm, 4layers.
Hopefully I'm building it in a few months.
Power supply board is separate, input via HDMI connector (LVDS receivers/transmitters) or TOSLINK. I'll run it at 24/96.
Layout is mostly done, I still need to change a few of the connectors throughout the PCB. I also put a latching relay so I can have a separate output for headphones (with EQ from DSP). Size is 100mm x 100mm, 4layers.
Hopefully I'm building it in a few months.
Attachments
Cool stuff Trileru. So you are running only digital in?
What DACs?
4 layers, good. Do you use one overall common GND plane, or do you try to spilt analog and digital? .... I think I'll just use one overall common GND layer
What DACs?
4 layers, good. Do you use one overall common GND plane, or do you try to spilt analog and digital? .... I think I'll just use one overall common GND layer
ADC is separate but I can sync them.
I'm using CS4398, good enough for my needs.
Ground plane is split, on ADC PCB as well. I'll see how ADC behaves and if everything's fine I'll keep it the same for this board. ADC PCB is on its way already.
I'm using CS4398, good enough for my needs.
Ground plane is split, on ADC PCB as well. I'll see how ADC behaves and if everything's fine I'll keep it the same for this board. ADC PCB is on its way already.
Could copy Neutrality’s multi-channel volume attenuator (it’s posted here). However, when built in accordance with the design, it can get pretty expensive due to the multitude of thin-film resistors.
Volume control can be done in the ADAU using the onboard ADC and routed as you please, IIRC a 10K resistor, a 2K linear pot and a capacitor.
Last edited:
Never worked with SigmaDSP before. Can I use a button to switch between different EQ configurations for just two of the six channels output?
The general idea is that at lower volumes the DACs in the ADAU are not good, so instead you run them at "full volume" and attenuate after the DAC in the analog domain. At least that is what I meant in my earlier post. Doing multi-ganged volume is challenging in the analog domain and the best approach is probably a resistor network using high precision components.
The simpler solution for me was to use the PGA chips after DAC output, with an encoder. Made the most sense for me. Tho I'm sure there's "better" more involved/expensive solutions.
Yeah, that would be the gold standard I guess, in this case I'm talking about using the onboard Aux ADC's for control purposes, the ADAU1452,66 and 67 don't have onboard ADC's and DAC's for the audio path, ADAU1701 does and yes they're not great.
PS I do happen to have a few VCA's I pulled from a Soundcraft desk with a Sony broadcast interface.
In my case they are far and few, on my current ADAU1466 I'm using all that are available for signal level LED's although that could be done in the analogue domain.
Ah right, I was indeed thinking about the venerable ADAU1701. I have not paid much attention to hardare DSPs since I took a sharp turn into computer/software based DSP processing almost 10 years ago. What you give up with added latency you can easily gain with infinite headroom, as many FIR taps as you want (if you do FIR filtering) and ease of choosing and replacing/upgrading ADC/DACs. For a DIYer IHMO that is a better solution unless you have the chops to design and fab your own complete solution.
But back to hardware DSPs, just about when I tuned out of that market segment the ADAU1492 was just becoming available. I recall that it is heads and shoulders above the ADAU1701, so I am surprised that there have not been a slew of products using it now, and cheap enough to be affordable. Are there any?
I haven't gone down the PC route as mainly interested in the adau for live sound out and about. An adau14 system can be cobbled together with core board, pcm5102a / pcm1802 modules and a cypress programmer, 8x8ch for under $100, upto 20,000 taps capable.
You can get this kind of modules on ebay, for around 50$.
