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

[iancanada]

Originally Posted by trung224

Hi Ian,

I want to ask a question about FIFOPi. The AK4499EQ or ES9028q2m support DSD data stream with fs = 48 kHz, therefore it need a 24.576 MHz clock for this playback. However when I read the datasheet of your FIFOPi, it only mentions DSD with clock frequency group 1 (5.6448 MHz, 22.5792 MHz). So I would like to know if your FIFOPi can proceed the DSD data with fs = 48 kHz

@trung224,

All DSD formats are the 44.1KHz group. DSD64,128,256,512 .... all of them are.

With FifoPi, you can play DSD at any frequency of 22.xxx, 45.xxxx, 90.xxxx MHz. However, to run at true sync mode, based on ESS data sheet, you will need the a 22.xxx MHz mclk. But the ES9028Q2M DAC was tested can go up to 45.xxx MHz at true sync mode.

I have never see a DSD with 48KHz family frequency. Just hope this helps.

Regards,
Ian

[trung224]

Thanks Ian for your answer,

DSD with fs = 48 kHz family is an Upsampling signal with Signalyst HQPlayer from 24/96 source. It is unorthodox way of DSD though. So it seems FiFoPi can only recognize DSD signal when it is fed with conventional DSD signal.

When will the group buy end? I am preparing to send the order form in the next 2 days

[32y0]

Originally Posted by AirAir

Yes, it is possible.

Originally Posted by ernesternest

As I have read, with Q3 you need to have only 3.3V, as there is no LDO anymore. So take care.

Thanks for the answers guys.

I read the part about the LDOs in the manual too. It says on page 2:

Uses pure 3.3V for a clean side DC power supply. All LDOs have been removed to allow direct operation with
a better 3.3V power solution via LifePO4 or ultra capacitor.

But further down in the manual on page 9 it says the following, implying that you can use higher voltages if R58 and R59 are not shorted:

With a 3.3V DC input on J5, the on-board LDOs are automatically bypassed internally because of the
dropout voltage is lower than the minimal dropout voltage (about 0.3V).
It is theoretically better to physically bypass on-board LDOs when using one of these supplies. You can solder a 0R
0805 jumper resistor or just a short piece of wire at positions R58, R59 which are located at bottom side of the FiFoPi.
CRITICALLY IMPORTANT NOTE: After you short R58 and R59, the ABSOLUTE MAXIMUM VOLTAGE you can
connect to J5 is 3.6V!!!! Any higher voltage means you will likely damage your FifoPi and clocks.

[gionag]

I can run the McFIFO with a 3.3 lifepo on the dc-input connector ?
maybe you can indicate what regulators are to be bypassed on the board and what are to be left alone.

On the mcdualXo i have already bypassed the local regulators to be able to feed direct 3.3v from batteries.

but on the mcfifo the silkscreen report 5-6 vdc on the input dc connector...

wondering if the concept of the fifopi power scheme apply also here.

thanks

[dddac]

Hi Ian,

Quick question for clarification as I am looking into running the clock side of FiFoPi directly from a 3,3V UC Conditioner

From the manual it was not so clear to me. Is the conditioner supplying the 3,3 Volt with the "charging PSU" still "connected" or is the 3,3V output just coming from the ultra caps only? And only when the ultra caps are not charged enough they get filled up automatically?

If this is the case:
Is there any experience from you or users, how long the FiFoPi clock side will run between charging cycles? (with the two 325F UCs)

[iancanada]

@dddac

The DC input to the UcConditioner has to be connected during power on.
With 2 3xxF UCs, it will last around 5 to 10 minutes before the voltage dropped from 3.3V to 3V for a 50mA output current. Unless using 3000F UC, you can not run them independently.

Regards,
Ian

[eduard]

Hello,
I read this here on this site.
BUT I can report that if you are just using 325F/350F UC pairs powering your USBBridge Signature, IF YOU CAN FIND THEM, you are in for a very nice surprise when you replace them with a 3000F Maxwell UC pair... using them took my setups to a new level. Sadly, Maxwell has discontinued units that large and they are getting extremely difficult to find. Does anyone have a good reputable source? I have some coming from a Chinese vendor on EBay, hoping they turn out to be good units and are as good as the ones I already have!

I will wait for Doede to report.

From what i read so far MY mind tells me if you wanna use these few hundreds or thousands F ultracaps you will need a fool proof circuit. Usually my DDDAC is on 24/7 but i assume it is not only me looking for a reliable solution.
These caps are made to '' contain a lot of juice '' and will show off no matter what causes the demand for energy.
Greetings, Eduard

[iancanada]

@Eduard

Yes, 3000F ultra capacitors really make difference. Fortunately I have a pair of Maxwell 3000F capacitor, I can not live without them.

Did you try

https://www.mouser.ca/ProductDetail/...Y5EyYHRg%3D%3D

and

https://www.mouser.ca/ProductDetail/...252BRGlA%3D%3D

Regards,
Ian

[eduard]

Hello Ian,
Once i know how i am going to upgrade my DDAC with parts that would benefit from ultracaps AND being sure about how to use these caps safely i will surely try big F number caps with the right voltage. The links take me to 2.7 and 2.9 volts DC rating while so far i just read about 3,3 volt.
Greetings, Eduard

[iancanada]

Ultra capacitors can not be over voltage. Unfortunately there is no any that is rated 3.3V or higher, so you have to use two of them at the same time.

Ian