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

Thanks Ian,

I have some problem yet with the PCM board, I should continue to test it,

Does the FGPA on it could support 5V clock injection :eek: ! I have to check with my other pcm board didn't test it yet ! The CDHH-957 45/49 work fine at full speed in normal I2S mode for the moment with clock board II at full speed (default setup) mode ! So my understanding from your answer is the PCM need full speed as well to play with 98 K XO !

Is it possible according to you to feed the PCM and the clock board II from the Battery management kit with a standalone A123 cell (by doubling the output wire and removing the embeded ldo of the pcm board to allow it to play at 3.2 V directly ?

No problem of ground loop like this, if the clock board and PCM board are sharing the same battery ?

Also : I heard most people can hear any difference when upsampling from 192 K Hz to 380 K with such old DAC chip, what is your experience with this please ?

Hi Eldam,

On my TDA1541A DAC, 4x or 8x up-sampling to 176.4K or 352.8K(need PCM board running at half speed mode) is better than NOS 44.1K. Otherwise, you will need a very good analog LPF for NOS application.

PCM board can share same battery will clock board. PCM board was designed to accepte 3.3V logic. Feeding with 5V clock to it might be OK but the jitter of output signals can be greater due to level clamping. So, I would go with 3.3V clock.

Regards
Ian
 
Thanks a lot Ian,

The 5V clock was just to know if I had broken the PCM board with the 5V overvoltage I putted ( my previous error) on the Clock with the 3.3V pins bridged by your strap (strap bridging appealing for 3.3 V instead 5V by J6 main PS input (on the clock board) !

Today I try the second PCM board + new XO to debug this simultaneous mode ! I believe the pcm board suffered from the last experience without knowing how exactly !

I 'll pm you to give the result as I told you already :)
best regards

Eldam
 
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I found the picture and the base band noise figure of this particular OCXO used in Agilent E5052B. Actually, someone is selling used parts on ebay. I borrowed the picture.
It looks like it has better close-in performance than DuCULoN, but DuCULoN is better at higher frequency and so is the noise floor. Interesting.

The E5052 uses a cross correlation technique to get very low noise measurements. It takes a while and two reference oscillators to work. There are other similar instruments. They can all measure really low noise.

If you are focused on close in noise for high frequencies you use two oscillators. This is the reference for this type of oscillator: Sorcerer | its in the same price range as the NDK and has performance about as good as you can get. For better close in PN you need to go to this type of product using a BVA crystal: http://www.oscilloquartz.com/files/1363164953-Br_ OCXO 8607.pdf figure $5-10K and 6 months to a year to get one. Actually variations in air temperature between your ears and the speaker will have more close in phase noise than any of these oscillators. You could try measuring it with a premium time interval analyzer. I would if I had some space to work with.
 
Regarding the battery. I cannot find the A123 one here.. but I can easily get one of those.

https://www.conrad.nl/nl/emmerich-u...-soldeerlip-lifepo4-33-v-2600-mah-250977.html

text is in Dutch, but you might get the point. Not sure about the quality of the brand / battery. The spec sheet in the bottom look more promising than the A123 systems' one
see: http://www.produktinfo.conrad.com/d...-EMMERICH_LIFEPO4_AKKU__ULT_26650_FP__ZLF.pdf

I got a mini charger (earlier linked a page or two ago i think), and i want to add this battery to that, using the battery management kit. Just not sure about the overvoltage of 3.6 possibly
 
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I just use one battery. I should try parallel but Ive not tried it. Works perfectly. They only stay at 3.6 for a v short time and maintain 3.3 almost the whole time. I tend to err on the safe side and rotate between a few batteries rather than let them run down, as that's what causes them to wear out quicker (or literally stop working!)
 
Here's another lifepo4 source which I've just ordered - price is for two batterys:

https://www.fasttech.com/products/1683800

and a good charger:

https://www.fasttech.com/products/2563800

Use promo code BLF for 5% discount. Free shipping as well.


Regarding the battery. I cannot find the A123 one here.. but I can easily get one of those.

https://www.conrad.nl/nl/emmerich-u...-soldeerlip-lifepo4-33-v-2600-mah-250977.html

text is in Dutch, but you might get the point. Not sure about the quality of the brand / battery. The spec sheet in the bottom look more promising than the A123 systems' one
see: http://www.produktinfo.conrad.com/d...-EMMERICH_LIFEPO4_AKKU__ULT_26650_FP__ZLF.pdf

I got a mini charger (earlier linked a page or two ago i think), and i want to add this battery to that, using the battery management kit. Just not sure about the overvoltage of 3.6 possibly
 
Hi Eldam,

On my TDA1541A DAC, 4x or 8x up-sampling to 176.4K or 352.8K(need PCM board running at half speed mode) is better than NOS 44.1K. Otherwise, you will need a very good analog LPF for NOS application.

PCM board can share same battery will clock board. PCM board was designed to accepte 3.3V logic. Feeding with 5V clock to it might be OK but the jitter of output signals can be greater due to level clamping. So, I would go with 3.3V clock.

Regards
Ian

Hi Ian,

Could you please explain the difference between a vcxo at 2.5v, 3.3v or 5v, is the output voltage constant or the same s the input voltage.

I fed a vcxo with 5v where the specs stated 2.5 or 3.3v and it actually worked 1st time round.

I replaced a can vcxo with orginally 5v feed with saw device rated at 2.5or 3.3v uing the same 5v supply line.

Cheers
 
Thanks! I'll pick one soon. The delivery costs of the A123 are quite large, so I'm doubting. Currently working with a 550mAh lifepo 3.2V to test the charger and board. The charger is a small one from Tindie, to be charged from USB. It's smart, maybe too smart since it won't start charging when connected to the management board.

One last question about the battery management board: To control the board, there this a switch using 5V voltage. Is there a way to use just a simple switch? :) (I prefer to use the board because of the fuse etc)
 
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Ihr Team von Lipopower Ltd.

Karl-Heinz Hofmann
Geschäftsleitung
Lipopower Ltd.
Tel. +49 (0) 9261/6260-50

Hi Gitaarwerk, this is a european firm where you can find all you need at reasonable cost.The A123 lifepo b-version is the latest model I know.(The green one)
The simplest 0.5Amp charger, about 15 euro, does the job already for two years in my setup with the fifo/managementboard combo. The 3Amp charger will kill the battery within a year.
One cell is more than enough for the dual clock and half the isolation board for I think 30 to 40 hours. Charging with the 0,5 amp one goes atomaticly after switching off the dac and fills the cell in about one hour!
Success, Ed.
 
Hello Ed,

Yes this is the adress of DVB Projekt and I believe it's certainly a much better adress for the cells A123 than the chineese one above (because A123 has a lot of counterfact cells on the markett, but how to know really!).

The only little charger I found at this adress are for LiPo only at this price. If I understood the doc I linked some posts ago about how loading a LiPoFe4, it it not so good for the A123 ! that's why I asked a link, maybe I'm mistaken !:( http://www.powerstream.com/LLLF.htm Could it be ok with a higher voltage charger than 3.65 V because it is only 0.5 A ?
 
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lifepo charger

Hello Ed,

Yes this is the adress of DVB Projekt and I believe it's certainly a much better adress for the cells A123 than the chineese one above (because A123 has a lot of counterfact cells on the markett, but how to know really!).

The only little charger I found at this adress are for LiPo only at this price. If I understood the doc I linked some posts ago about how loading a LiPoFe4, it it not so good for the A123 ! that's why I asked a link, maybe I'm mistaken !:( How to charge Lithium Iron Phosphate lithium ion battery packs including packs with high current and High Capacity. Could it be ok with a higher voltage charger than 3.65 V because it is only 0.5 A ?

Hi Eldam,

This 230 V Stecker-Lader max. 0.5A, für 1 LiFePO4-Zelle, Hohlbuchse, Lipop is the right charger, the one I use.
He says the thing is about 3.7V. So a litlle bit higher than 3.6 appears not be a problem. The 123 seems, because of it's build quality, a tollerant guy!
I started with a 3Amp charger of the same kind, and it killed a battery. But NOT by explodig or getting hot, it just died after about eight months or so. The max for this battery is about 2Amps. Sowith 0,5Amps you are on the very safe side. It charges my dual clock setup, after sixteen hours use every day, in about 65 minutes.

Regards, Ed
 
Ihr Team von Lipopower Ltd.

Karl-Heinz Hofmann
Geschäftsleitung
Lipopower Ltd.
Tel. +49 (0) 9261/6260-50

Hi Gitaarwerk, this is a european firm where you can find all you need at reasonable cost.The A123 lifepo b-version is the latest model I know.(The green one)
The simplest 0.5Amp charger, about 15 euro, does the job already for two years in my setup with the fifo/managementboard combo. The 3Amp charger will kill the battery within a year.
One cell is more than enough for the dual clock and half the isolation board for I think 30 to 40 hours. Charging with the 0,5 amp one goes atomaticly after switching off the dac and fills the cell in about one hour!
Success, Ed.

:( 25 euros of shipping for France and few grammes and we are neighbours: as important what what i want to buy... they are crazy, I give up this shop !
 
For me it was 15 euros.. Bit crazy just for 2 cells.
Im going to try the first 550mAh ones. They seem to work long enough for me. Not yet had any sound out of them. That'll be the next test.

The charging thing has kinda been solved I tjink. Apparently im missing a relay ;-)

Ive ordered some stuff from Mouser, nice company. Just didn't have the batteries there, but the clocks are ordered and a new set of u.fl socmets as I messed them up trying to solder it ;-)

Next weeken hopefully gotten everything connected. Just one clock is on backorder