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Joachim Gerhard Filter Buffer for ES9022

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EUVL

EUVL

Member
Joined 2003
xen-audio.com
Here a screenshot of the data summary of the 07MFG 18mH as listed by Mouser.
The SRF is at 525kHZ, almost double that of the others.


Patrick
 

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enjoybiking

Member
Joined 2011
SRF

EUVL said:
Here a screenshot of the data summary of the 07MFG 18mH as listed by Mouser.
The SRF is at 525kHZ, almost double that of the others.


Patrick
Click to expand...

So SRF is pretty important. The below would also then be ? too far below spec? I could change out the coils in Summer. BUT if they will cause distortion... maybe I just wait. I can try a few...they would ship in just days, but I'm not ready with a board.

I would volunteer to sort and ship the proper coils for the USA, but it seems like 14 weeks to possibly get some. I have a great LCR meter.
I'll have Curryman's boards for USA folks too [they are handy for me even without the buffer you see...a good es9023 board with regulators and 50Mhz oscillator]. Happy to make this easier for folks this side of the pond -- good coils seem rare.


RL181S-183J-RC


Inductance: 18 mH Tolerance: 5 % Maximum DC Current: 21 mA Maximum DC Resistance: 17 Ohms Operating Temperature Range: - 55 C to + 105 C Self Resonant Frequency: 0.19 MHz Q Minimum: 100
 
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enjoybiking

Member
Joined 2011
SRF and what CAN we get?

EUVL said:
Here a screenshot of the data summary of the 07MFG 18mH as listed by Mouser.
The SRF is at 525kHZ, almost double that of the others.
Patrick
Click to expand...

I think of my deceased Father, in the 50s he ran a small town grocery store. Later when I was alive we'd go shopping, he'd have the newspaper ads along... and gripe "eggs are $0.38/dozen {USD} but they don't HAVE ANY".

I'll help with this situation but I can't buy 500 or 1 {the coils}. I have not tried direct contact with the maker [some of you probably HAVE].

I gather the 18MH coil forms a LPF at a very high Z-input to the FETs. I am not an ENGR. I cannot "see" if the buffer is unity or has gain, and I apologize for not reading the entire thread. I gather that SRF...could it have sub_harmonics? Not sure the issue with SRF. I think I understand low DCR always nice. Series R of the coil wire changes slopes? My mind thinks Acoustic Reality Crossover tweeter coil.

I will be sourcing Daniel's Es9023//JG buffer board to USA, to help the DIY cause{SO fun}, they will not cost much. I ordered them to have I2s es9023 boards around for my own mods and builds, if I like the JG buffer, well, the artwork will be there thanks to Daniel and Joachim.

- The other Patrick
 
Joachim Gerhard

Joachim Gerhard

Member
Joined 2009
suesskindaudio.de
The buffer is near unity gain. High self resonance of the coil helps to make the filter work
( drop aliasing products ) up to very high high frequencies where is not much energy any more. A low self resonance of the coil will change the slope of the filter. The coil looses inductance there, first there is a minumum ( actually an inductance maximum ) and then the coil gets capacitive so there is a rise in frequency. It simply does not work like a theoretically perfect coil any more over the resonance frequency.
First i had objections to use a ferrite coil but i testet the sound of the Faston compared to a very expensive Sowter coil and got a very satifying result. It sure does not sound hard or distorted. Quite the contrary, smooth and liquid and that was what i wanted.
I found the "untreated" ESS DAC a bit on the brittle side and that effect disapeared with my filter-buffer.
 
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EUVL

EUVL

Member
Joined 2003
xen-audio.com
By the time we deliver the 2nd batch JG Filter, Mouser would have them again in stock.
So I do not see an issue as far as our GB is concerned.
Failing that, we'll supply those who have boards from us.

Of course you are always free to organise GB for our board or whatever else other designs, assuming Joachim approves of those.
Please kindly start a new GB thread, in order to avoid confusion.

Disclaimer : the "Curryman PCB" has nothing to do with the xen Audio team, or the GB in this thread.


Best regards,
Patrick
 
G

GaryB

Member
Joined 2002
Paid Member
another inductor

Another place to get 18mh inductors with SRF in the 500khz range is from Coilcraft. They're located in the US and sell their parts direct. The model that I found is the RFB0807-183L, which you can read about at the following webpage Coilcraft RFB0807 Leaded Power Inductors

I haven't tried these myself, so this is purely at one's own risk. I have used Coilcraft common mode chokes for power supplies and their quality is good and they are easy to deal with.
Also note that these inductors aren't shielded, so care is needed in layout to insure that there isn't cross talk between inductors. The inductors on the Xen buffer are spaced fairly close together, so I don't know if this is an issue or not. But if one is building this from scratch then separating the inductors shouldn't be a big problem.

I have built a couple of versions of the JG buffer, both with the Fastron inductors. The first one that I built was done point to point without a circuit board and it sounds quite good. Yesterday, I soldered up the board that I got from the last group buy but haven't had a chance to listen to it yet. I can say that the SMD parts are really small and one needs a good magnifier and a steady hand to put it together.

---Gary
 
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enjoybiking

Member
Joined 2011
GBs etc..

EUVL said:
Of course you are always free to organise GB for our board or whatever else other designs, assuming Joachim approves of those.
Please kindly start a new GB thread, in order to avoid confusion.

Disclaimer : the "Curryman PCB" has nothing to do with the xen Audio team, or the GB in this thread.


Best regards,
Patrick
Click to expand...

Mostly ordered them to have for ME {because I have not mastered Eagle and need some ES9023 I2s assys}, if I get rid of any excess I won't do so here. I DID read in this thread about people with sourcing and grading problems, the coils... I'd be happy to help {it seemed to be suggested that is someone helped, things would go better, at least here in the States}. For instance the Coilcraft has 10% tolerance {and 56ohm? DCR, not sure 3x the DCR is...ideal, now that I have more understanding thanks again for the tech-brief}, they would need grading. I'll backorder some 07MFG and look around the planet. {I don't like building stuff that doesn't work like invented to be, unless I know it's better}. DIY is supposed to be FUN!
 
EUVL

EUVL

Member
Joined 2003
xen-audio.com
If you wish to discuss the technicalities of which inductor might be appropriate,may I suggest you post here :
http://www.diyaudio.com/forums/digital-line-level/151846-anybody-using-new-ess-vout-dac-es9022.html

If you wish to offer Fastron inductors to other members, perhaps this thread is more appropriate :
http://www.diyaudio.com/forums/group-buys/216993-fastron-inductor-group-buy-jg-filter-buffer.html

We had no problems ordering directly from the manufacturer, when they had stock.
And as already said, in the worst case people scubscribing for batch 2 PCBs will be catered for.


Patrick
 
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