Asynchronous I2S FIFO project, an ultimate weapon to fight the jitter

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sbelyo

Member
Joined 2004
I'm getting ready to assemble a Raspberry Pi-less stack with the following plus an Amanero board.

#35C StationPi SMT
#4B ESS Dual Mono II DAC and I/V board
#1D FifoPiQ7
#19D ReceiverPi DDC
#49B MonitorPi Pro
#50A GPIO extender
#7A Transformer I/V

Power:

#41C UcPure MkIII x2
#41F UcBalancer KIT x2

As I understand it, I connect a UcPure to each side of the StationPi. Is there more performance to be had by connecting the FifoPi clean side to the direct continuous output connector of a UcPure to keep the clocks powered all the time? If so, can I use the UcPure connected to the clean side or does it need a third UcPure all by itself?
 
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crm75

Member
Joined 2022
Batenet said:
I made a tweak i think works very well for SCPure.I use a small piece of Sorbothane under the clocks,from 0,1" thick sheet i put it through the connecting pins to ic-holder FifoPi Q7.Two sheets little bit bigger on top of clocks,press it down with HdmiPro. Creates both a floating and dampening effect.Forgot to mention another tweak,you can use coppertape and wrap around the clocks for extra shielding.Same tape for protection vegetables snails.look in gardening shop
Click to expand...
@Batenet, is everything ok with the sorbothane used for dampening vibrations for SC-Pure clocks? What duro did you get?
I would like to use some dampening material under and on top of the SC-Pure clocks and was thinking about sorbothane too.
Moongel seems to be a risky choice because I think it is not going to be ok at high temperatures.
Please, can you tell me where did you buy it? And how did you manage to use it on top of the clocks, HdmiPro has a cut right above the clocks. Maybe a photo would be relevant :)
Thank you!
 
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SimonJ

Member
Joined 2013
....VERY tough to answer as the DDDAC has so many mods and you can parallel the boards for a better sound etc. You cant really compare them like for like.

Doede is designing MK3 version right now too so I expect this to be even better. I have built 5 DDDACs if that helps e.g. its sounds WONDERFUL but so does Ian solution.

My super pimped 4 stack DDDAC with Andrea clock, super cap PSUs etc etc is the best I have ever heard and smashed hands down a Chord 10K DAC of my friend, we both agreed on that!
 
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Jaytor

Jaytor

Member
Joined 2019
I've been really getting into DIY over the past few years and have built several amplifiers, preamps, speakers, cables, and acoustic treatments. My goal is to get to a fully DIY system, so it's time to build a streamer/DAC.

I'm planning a fairly high-end configuration using Ian's modules and would like to get some feedback.

I had originally thought I would use a RPi mounted on the StationPi SMT, but from reading more of this thread, it seemed to make sense to separate the RPi and connect to the Ian stack through the ReceiverPi DDC.

Question: I had assumed these would connect via USB since this is an async transport, but I've seen mention about using HDMI. Is this I2S over an HDMI cable? Since I2S is a synchronous transport with the clock controlled by the source, how are buffer over/under runs avoided?

My plan is to include the FifoPi Q7 (with SC-Pure clocks), HdmiPi Pro II, dual mono DAC, and OPA861 on the stack.

I'm building a custom fabricated aluminum enclosure that will house a custom Toroidy Supreme Audio 400VA transformer (isolated using Sorbothane), a RPi 4 with display mounted to the front panel and separated from the rest of the circuits with an internal panel divider, a LinearPi with UcConditioner, and seven UcPure MkIII supplies to power all the boards, and a internal subchassis that will house the Ian Canada Stack. The subchassis will be its own sealed aluminum box (except for holes necessary for wiring) that will mount inside the main chassis with sorbothane isolation. The main chassis backpanel will have a cutout to allow access to the subchassis for external cable connections.

I haven’t decided whether to use an extender cable to mount the MonitorPi Pro to the front panel, or mount it so that it is only accessible from inside the chassis. Opinions?

Question: I believe that it is necessary to keep the MonitorPi Pro plugged in to provide control in a Pi-less stack. Is this the case?

I have room for seven UcPure supplies, so I need to figure out how to allocate them and the Linear Pi among the boards. These are two ideas, but I’m open to other suggestions.

Alternative 1:
LinearPi + UcConditioner for RPi
UCPure for StationPi SMT, ReceiverPi DDC and dirty side of FifoPi Q7.
UCPure for FifoPi Q7 clean side.
UCPure for HdmiPi Pro II
UCPure for ES9038Q2M DVCC/VCCA
UCPure for ES9038Q2M AVCC
2x UCPure for OPA861

Alternative 2:
Use SMPS for RPi (mounted inside front panel compartment)
LinearPi + UcConditioner for StationPi and ReceiverPi DDC
UCPure for dirty side of FifoPi Q7
UCPure for FifoPi Q7 clean side.
UCPure for HdmiPi Pro II
UCPure for ES9038Q2M DVCC/VCCA
UCPure for ES9038Q2M AVCC
2x UCPure for OPA861

Question: Am I correct in thinking that the DAC is most sensitive to the AVCC supply?

My transformer has enough independent secondaries for seven UcPures, but if combining one or more supplies with quad-pack 3000F caps makes sense, that’s another alternative. Four of my secondaries are lower current (2.5A) (I assumed I’d use 1.5A charging current with these), so two could be combined to get back up to higher current.
 
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sbelyo

Member
Joined 2004
sbelyo said:
I'm getting ready to assemble a Raspberry Pi-less stack with the following plus an Amanero board.

#35C StationPi SMT
#4B ESS Dual Mono II DAC and I/V board
#1D FifoPiQ7
#19D ReceiverPi DDC
#49B MonitorPi Pro
#50A GPIO extender
#7A Transformer I/V

Power:

#41C UcPure MkIII x2
#41F UcBalancer KIT x2

As I understand it, I connect a UcPure to each side of the StationPi. Is there more performance to be had by connecting the FifoPi clean side to the direct continuous output connector of a UcPure to keep the clocks powered all the time? If so, can I use the UcPure connected to the clean side or does it need a third UcPure all by itself?
Click to expand...
anyone have any insight on this?
 
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Spacejack

Member
Joined 2004
Jaytor said:
Question: I believe that it is necessary to keep the MonitorPi Pro plugged in to provide control in a Pi-less stack. Is this the case?
Click to expand...
You need it as it "remembers" the settings for ES9038Q2M. FifoPi Q7 has its own memory to store its settings, but ES9038Q2M does not have its own memory.

Jaytor said:
I had originally thought I would use a RPi mounted on the StationPi SMT, but from reading more of this thread, it seemed to make sense to separate the RPi and connect to the Ian stack through the ReceiverPi DDC.

Question: I had assumed these would connect via USB since this is an async transport, but I've seen mention about using HDMI. Is this I2S over an HDMI cable? Since I2S is a synchronous transport with the clock controlled by the source, how are buffer over/under runs avoided?
Click to expand...
I2S over HDMI is one option. I have used it in such a setup and have not noticed over/underruns. Both with Ian Canada components or with 3rd party Dacs with HDMI input. Another way to increase the distance between RPI and the rest of the stack is to use GPIO extension cable. Have used it like this and did not notice any significant degradation. Another more extravagant option is to use two FiFoPi Q7:
RPI -> FifoPi Q7 -> U.FL cables -> GPIO Input adapter -> FifoPi Q7 (with SC-PURE) -> DAC

GPU Input Adapter:
https://iancanada.ca/products/21b-i2s-dsd-input-adapter-for-fifopi-fully-finished



If you run ES9038Q2M in sync mode, then you do not need to power VCCA (at least, I do not have it connected at all). Then, you provide separate power to AVCC and DVCC. According to some measurements, DVCC spreads noise, and it should not share a power supply with other inputs.
 
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Spacejack

Member
Joined 2004
sbelyo said:
Is there more performance to be had by connecting the FifoPi clean side to the direct continuous output connector of a UcPure to keep the clocks powered all the time? If so, can I use the UcPure connected to the clean side or does it need a third UcPure all by itself?
Click to expand...
It is advisable to connect FiFoPi clean side to the direct continuous output (such that clocks are powered all the time) and power the DAC board through a switchable connector.
 
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Jaytor

Jaytor

Member
Joined 2019
Spacejack said:
You need it as it "remembers" the settings for ES9038Q2M. FifoPi Q7 has its own memory to store its settings, but ES9038Q2M does not have its own memory.


I2S over HDMI is one option. I have used it in such a setup and have not noticed over/underruns. Both with Ian Canada components or with 3rd party Dacs with HDMI input. Another way to increase the distance between RPI and the rest of the stack is to use GPIO extension cable. Have used it like this and did not notice any significant degradation. Another more extravagant option is to use two FiFoPi Q7:
RPI -> FifoPi Q7 -> U.FL cables -> GPIO Input adapter -> FifoPi Q7 (with SC-PURE) -> DAC

GPU Input Adapter:
https://iancanada.ca/products/21b-i2s-dsd-input-adapter-for-fifopi-fully-finished



If you run ES9038Q2M in sync mode, then you do not need to power VCCA (at least, I do not have it connected at all). Then, you provide separate power to AVCC and DVCC. According to some measurements, DVCC spreads noise, and it should not share a power supply with other inputs.
Click to expand...
Thanks for the info. Is there any advantage to using I2S over HDMI between the RPi and ReceiverPi DDC vs USB?
 
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Spacejack

Member
Joined 2004
With I2S over HDMI, you don't need the USB to I2S board (like amanero). You also skip additional conversion to USB and then from USB to I2S. This conversion to and back from USB does not help sound quality. To me, HDMI or pure I2S sounds better than USB. Others also mentioned that the sound quality directly from RPI is better than that of USB. Ian tried to explain it to me once, but I don't understand the technical reasoning.
 
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