Just to confirm,
even if the analogue gain chips are fitted the board can still be used as digital only?
ie.
digital inputs -> dsp -> digital gain -> digital out
Thanks for your feedback!
I'll take a complete boardHave you decided on what op-amps to use ?
If I'm using opamps at all I kind of like the "LT 1361".
Another vote for CS3318! Just a reminder: Opamps are all on sockets. Swapping for all of them takes 1 minute
No, the volume takes place only on the analogue path. If you transfer audio digitally, you want to keep all of the resolution so that you can present to your DACs an optimally scaled signal. Isn't it what you're looking for?
We can talk more in detail about this if you wish, because it's indeed a tricky topic, sort of a brain-teaser.
I didn't think about it. Actually I'm not sure it's possible to add a poll within a thread, so I'd suggest we keep it simple and informal. As I said, it's just to help me in the process of ordering the chips and the PCB assembly. The CS3318 is by far the most expensive chip on the board: about USD 29 for a unit at Digikey, still USD 20 if you get 100 of them.
CS3318-CQZ Cirrus Logic Inc | 598-1180-ND | DigiKey
So far: analogue volume 2 vs. no analogue volume 0
I apologize but I'm afraid I don't understand your question. Each analogue out has indeed volume control - whether there's the chip (CS3318) installed or not. There's a master volume which is for all channels, and there's an individual volume for adjusting relative channel settings.
Thanks all for your feedback!
So that makes now Analogue volume 6 vs. no Analogue volume 0
I didn't expect this, given that one can add the chip anytime if he feels the need (provided he's not afraid of soldering small pitch SMD).
The analogue volume chip has another benefit beside performing volume in the analogue domain. Indeed, it lets you set the nominal output level and hence supply an appropriate signal to your amp. Without the chip, the nominal output level is 1 Vrms.
I read again your post and I saw the light this time
Now that I understood your question, yes I can confirm you're right: the board will perform nicely without the volume chip. The fact you're managing the signals to your loudspeakers elsewhere means that you have another way to control the master volume - so indeed you wouldn't need the expensive CS3318. Again, if you feel later the need of that chip because you've changed your system for example, you can just solder it on the board and it's automatically taken care of.
So that makes now Analogue volume 6 vs. no Analogue volume 0
I didn't expect this, given that one can add the chip anytime if he feels the need (provided he's not afraid of soldering small pitch SMD).
The analogue volume chip has another benefit beside performing volume in the analogue domain. Indeed, it lets you set the nominal output level and hence supply an appropriate signal to your amp. Without the chip, the nominal output level is 1 Vrms.
I read again your post and I saw the light this time
Now that I understood your question, yes I can confirm you're right: the board will perform nicely without the volume chip. The fact you're managing the signals to your loudspeakers elsewhere means that you have another way to control the master volume - so indeed you wouldn't need the expensive CS3318. Again, if you feel later the need of that chip because you've changed your system for example, you can just solder it on the board and it's automatically taken care of.
Thanks all for your feedback!
I read again your post and I saw the light this time
Now that I understood your question, yes I can confirm you're right: the board will perform nicely without the volume chip. The fact you're managing the signals to your loudspeakers elsewhere means that you have another way to control the master volume - so indeed you wouldn't need the expensive CS3318. Again, if you feel later the need of that chip because you've changed your system for example, you can just solder it on the board and it's automatically taken care of.
OK. Sorry for the confusion.
Thanks for clarification.
Wow I didn't understand that one neither yesterday
Yes sure, even with the analogue chip fitted you can use the board digital only. The analogue volume chip doesn't affect anything happening on the digital signal path. Sorry about the confusion.
CS3318 is actually controlled through SPI.
Both SPI and I2C are however available on the expansion ports.
At this stage there's no volume control for an external device, the main reason being that there's no standard for this: each chip has different addresses for the registers that hold the volume values, and these values are interpreted differently.
In a later release however if there's such a request, we can look at it and see how we can make it possible for a specific chip. Stay tuned
CS3318 is actually controlled through SPI.
Both SPI and I2C are however available on the expansion ports.
At this stage there's no volume control for an external device, the main reason being that there's no standard for this: each chip has different addresses for the registers that hold the volume values, and these values are interpreted differently.
In a later release however if there's such a request, we can look at it and see how we can make it possible for a specific chip. Stay tuned
when you say a later release you are talking about HW or SW?
I'm considering to go the same way as "qusp" with the "Ackodac's" but
maybe not for all channels so this is getting better and better (if it will work)
Will it be possible to adress 4 output-channels to I2S and the remaining 4
to the analog output section. Or is there signal sent both ways for all channels
at all times?
maybe not for all channels so this is getting better and better (if it will work)
Will it be possible to adress 4 output-channels to I2S and the remaining 4
to the analog output section. Or is there signal sent both ways for all channels
at all times?
I'm considering to go the same way as "qusp" with the "Ackodac's" but
maybe not for all channels so this is getting better and better (if it will work)
Will it be possible to adress 4 output-channels to I2S and the remaining 4
to the analog output section. Or is there signal sent both ways for all channels
at all times?
Here's a summary of what's available in terms of outputs.
Inside the DSP, there are 10 output channels internally.
- All channels 1 to 10 are on SPDIF outputs.
- Channels 1 to 8 are available also on analogue outs.
- There are 2 expansion ports with I2S. They are different but for now it's enough to know that one port can carry up to 6 channels, and the second port can carry up to 12 channels. You can assign to the I2S lines any channel 1 -> 10.