Return-to-zero shift register FIRDAC

MarcelvdG · 2022-11-15 11:04 am

OK, see the attachment for the updated DAC layout and schematic, the schematic is an exact copy of version 9. The filter layout and schematics (version 6) are as in post #217, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7174367 and the BOM as in post #238, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7175493

NickKUK · 2022-11-15 11:34 am

I was thinking of bumping the tolerances on the voltage reference, output and filter.

MarcelvdG · 2022-11-15 11:44 am

I don't understand what you mean, looking up the meanings of bump didn't help. https://www.oxfordlearnersdictionaries.com/definition/english/bump_1?q=Bump

NickKUK · 2022-11-15 12:02 pm

MarcelvdG said:
I don't understand what you mean, looking up the meanings of bump didn't help. https://www.oxfordlearnersdictionaries.com/definition/english/bump_1?q=Bump

Sorry

ie use 0.1% instead of 1% and 0.1%/0.01% instead of 0.5%. Just for the more critical tolerances.

nautibuoy · 2022-11-15 12:08 pm

MarcelvdG said:
OK, see the attachment for the updated DAC layout and schematic,

Thanks Marcel, the costs are the same for the latest DAC PCB layout.

I'll start to get the GB organised later...

NickKUK · 2022-11-15 12:33 pm

@MarcelvdG in the BOM for the dac, the quantity for UFL is 1 but three parts (P4, P13, P14). Probably want updating to 3.

MarcelvdG · 2022-11-15 1:04 pm

Thanks for catching that!

nautibuoy · 2022-11-15 7:40 pm

GROUP BUY START-UP ANNOUNCEMENT

So let's get this Group Buy of PCBs to build Marcel's RTZ DAC formally underway; having experienced his protoype build I'm sure you'll not be disappointed with what you'll hear should you build one.

The group buy will be for unpopulated PCBs using Marcels's most recently posted gerber files. Assuming around 20 participants and that we all chip-in to provide two sets of PCBs free of charge to Marcel, I estimate a set of boards (DAC and filter) will be around $8-10 plus the shipping (at cost) for distribution once the PCBs are delivered to me. Of course the actual cost will vary depending on how many boards I actually order.

So let's start by giving people a little longer to sign-up; here's the list of those who've previously expressed an interest so that'll be our starting point. If you're on the list already, please adjust your requirements, if you're not please append your requirements to the list. I'll close the list Sunday November 27th after which I'll get a cost based on the number of boards required and start collecting down payments - I should add that I have no interest in making money from this exercise and everything will be at cost.

How does that sound to people?

OK, so here's the current list to get things started.

Marcel - 2xDAC, 2xFilter (FoC)
nautibuoy - 3xDAC, 3xFilter
pgour - 1xDAC, 1xFilter
Raj1 - 1xDAC, 1xFilter
rfbrw - 2xDAC, 4xFilter.
wealas - 1xDAC, 1xFilter
barryblue - 1xDAC, 1xFilter
randytsuch - 2xDAC, 2xFilter
Mich - 1xDAC, 1xFilter
Sonnymarrow - 2xDAC, 2xFilter
Twinkletoes - 1xDAC, 1xFilter
porcupinetrain - 1xDAC, 1xFilter
NickKUK - 1xDAC, 1xFilter
manniraj - 1xDAC, 1xFilter

porcupinetrain · 2022-11-16 5:37 am

nautibuoy said:
GROUP BUY START-UP ANNOUNCEMENT

So let's get this Group Buy of PCBs to build Marcel's RTZ DAC formally underway; having experienced his protoype build I'm sure you'll not be disappointed with what you'll hear should you build one.

The group buy will be for unpopulated PCBs using Marcels's most recently posted gerber files. Assuming around 20 participants and that we all chip-in to provide two sets of PCBs free of charge to Marcel, I estimate a set of boards (DAC and filter) will be around $8-10 plus the shipping (at cost) for distribution once the PCBs are delivered to me. Of course the actual cost will vary depending on how many boards I actually order.

So let's start by giving people a little longer to sign-up; here's the list of those who've previously expressed an interest so that'll be our starting point. If you're on the list already, please adjust your requirements, if you're not please append your requirements to the list. I'll close the list Sunday November 27th after which I'll get a cost based on the number of boards required and start collecting down payments - I should add that I have no interest in making money from this exercise and everything will be at cost.

How does that sound to people?

OK, so here's the current list to get things started.

Marcel - 2xDAC, 2xFilter (FoC)
nautibuoy - 3xDAC, 3xFilter
pgour - 1xDAC, 1xFilter
Raj1 - 1xDAC, 1xFilter
rfbrw - 2xDAC, 4xFilter.
wealas - 1xDAC, 1xFilter
barryblue - 1xDAC, 1xFilter
randytsuch - 2xDAC, 2xFilter
Mich - 1xDAC, 1xFilter
Sonnymarrow - 2xDAC, 2xFilter
Twinkletoes - 1xDAC, 1xFilter
porcupinetrain - 1xDAC, 1xFilter
NickKUK - 1xDAC, 1xFilter
manniraj - 1xDAC, 1xFilter

Many thanks once more for organizing this buy. Confirming that I am in for the following:

porcupinetrain - 1xDAC, 1xFilter

nautibuoy · 2022-11-16 6:25 am

You're welcome @porcupinetrain 😊

Let's keep and edit the original list of participants;

Marcel - 2xDAC, 2xFilter (FoC)
nautibuoy - 3xDAC, 3xFilter
pgour - 1xDAC, 1xFilter
Raj1 - 1xDAC, 1xFilter
rfbrw - 2xDAC, 4xFilter.
wealas - 1xDAC, 1xFilter
barryblue - 1xDAC, 1xFilter
randytsuch - 2xDAC, 2xFilter
Mich - 1xDAC, 1xFilter
Sonnymarrow - 2xDAC, 2xFilter
Twinkletoes - 1xDAC, 1xFilter
porcupinetrain - 1xDAC, 1xFilter
NickKUK - 1xDAC, 1xFilter
manniraj - 1xDAC, 1xFilter

Cestrian · 2022-11-16 8:49 am

Hi, I would also like to take part in the group buy please.

Cestrian - 1xDAC, 1xFilter

UK based.

Many thanks!

nautibuoy · 2022-11-16 9:03 am

Can we please try to keep the list contiguous...

Marcel - 2xDAC, 2xFilter (FoC)
nautibuoy - 3xDAC, 3xFilter
pgour - 1xDAC, 1xFilter
Raj1 - 1xDAC, 1xFilter
rfbrw - 2xDAC, 4xFilter.
wealas - 1xDAC, 1xFilter
barryblue - 1xDAC, 1xFilter
randytsuch - 2xDAC, 2xFilter
Mich - 1xDAC, 1xFilter
Sonnymarrow - 2xDAC, 2xFilter
Twinkletoes - 1xDAC, 1xFilter
porcupinetrain - 1xDAC, 1xFilter
NickKUK - 1xDAC, 1xFilter
manniraj - 1xDAC, 1xFilter
Cestrian - 1xDAC, 1xFilter

Twinkletoes · 2022-11-16 11:06 am

Posting to reconfirm my interest, requirements are unchanged.

Thanks for helping to organise this group buy Ray!

Marcel - 2xDAC, 2xFilter (FoC)
nautibuoy - 3xDAC, 3xFilter
pgour - 1xDAC, 1xFilter
Raj1 - 1xDAC, 1xFilter
rfbrw - 2xDAC, 4xFilter.
wealas - 1xDAC, 1xFilter
barryblue - 1xDAC, 1xFilter
randytsuch - 2xDAC, 2xFilter
Mich - 1xDAC, 1xFilter
Sonnymarrow - 2xDAC, 2xFilter
Twinkletoes - 1xDAC, 1xFilter
porcupinetrain - 1xDAC, 1xFilter
NickKUK - 1xDAC, 1xFilter
manniraj - 1xDAC, 1xFilter
Cestrian - 1xDAC, 1xFilter

MarcelvdG · 2022-11-16 5:02 pm

Just checking: you do all realize that it is a raw DSD DAC, so you need to add some sort of digital (hardware or software) sigma-delta modulator to play PCM, don't you?

NickKUK · 2022-11-16 6:09 pm

MarcelvdG said:
Just checking: you do all realize that it is a raw DSD DAC, so you need to add some sort of digital (hardware or software) sigma-delta modulator to play PCM, don't you?

Yup.
I intend to use a usb-i2s bridge capable of DSD, then use DSD-over-PCM to take my DSD stream from one of my mac minis. So, the dac will get a DSD stream. I have a balanced hybrid tube circlotron amp I’m developing that will then take the output

For me it’s the journey.. distracts me from my CTPO job

MarcelvdG · 2022-11-16 7:41 pm

I don't quite understand that, as the DAC requires raw (a.k.a. native) DSD rather than DSD over PCM.

NickKUK · 2022-11-16 7:43 pm

MarcelvdG said:
I don't quite understand that, as the DAC requires raw (a.k.a. native) DSD rather than DSD over PCM.

The output will have raw DSD

nautibuoy · 2022-11-16 7:55 pm

MarcelvdG said:
I don't quite understand that, as the DAC requires raw (a.k.a. native) DSD rather than DSD over PCM.

https://www.pcmag.com/encyclopedia/term/dop

randytsuch · 2022-11-16 8:02 pm

I saw nautibuoy used a JLSounds i2soverUSB board to generate DSD.

I have a HQ player PC that interfaces to a Pi running as a HQP NAA.
The Pi sends data to my diyinhk xmos board. That feeds DSD to my iancanada dac.
Thinking about picking up the JLSounds board too.
Pretty sure this will work ok.

Between the PC and SW costs, HQ Player is not cheap, so I'm glad I have that already. But there are other HW options out there that are much cheaper.

Randy

MarcelvdG · 2022-11-16 8:02 pm

So if I understand it correctly, Nick's USB-to-I2S bridge does the DoP-to-raw-DSD translation.

Return-to-zero shift register FIRDAC

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