[ROBSCIX]

It seem that information related directly to modding these devices is vast but scattered all over other threads, some related and some not.
I started this thread to allow people to have a place to discuss modding this unit and possible theory for future moddding such as S/Pdif
signal modificatio ideas or USB based mods.  Hopefully this can be a great place to find information and discuss current mods and ideas for future ones.
So let's here your ideas, musings or theories....

 

[slim.a]

Hi ROBSCIX,
 
This is indeed a good subject. While I don't have as much technical knowledge about the modding as some others here, I can say that when I listened to the battery powered hiface (modified by jkeny), it was a real and big improvement over the stock model. Here is a link to my review.

 

[ROBSCIX]

These units seem to get great reviews from their owners and can be improved a great deal with some modifications.  It would be nice to get all the ideas and insights into modding these units in one main location for those looking for it.

 

[mmerrill99]

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[mmerrill99]

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[mmerrill99]

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[mmerrill99]

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[mmerrill99]

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[ROBSCIX]

Great stuff, thanks for the contribution.  Now if people ask a question that has been covered they can just be pointed to the first page, if they happened to miss it.
 

 

[mmerrill99]

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[ROBSCIX]

Thanks for the attenuator ideas and info.  Now I have to run more tests!

 

[punk_guy182]

Yeah that's pretty cool stuff! I posted this earlier on an another thread but if anyone can find an attenuator that has both Male in and out plugs please let me know. I'd like to try this without my high end Oyaide DB-510 S/PDIF cable to hear what it sounds like.
Those precision 75ohms T-Pad attenuators are a real deal! I haven't tested them but so far, I like what I read. 
 
Thanks Jkeny, Jocko Homo and Joseph K.

 

[punk_guy182]

Look whatI found guys: http://ca.digikey.com/1/3/bnc-attenuators-75-ohm
I think that it is possible afterall to DIY a BNC Male to Male T-Pad attenuator.
 
What do you think jkeny?

 

[regal]

I start posting the datasheets as this is where any good modding begins
 
CPLD:
http://www.xilinx.com/support/documentation/data_sheets/ds311.pdf
 
Cypress Chip:
http://www.keil.com/dd/docs/datashts/cypress/cy7c68xxx_ds.pdf
 
SPDIF Transmitter
http://focus.ti.com.cn/cn/lit/ds/sbos229b/sbos229b.pdf
 
 
Now after reviewing the datasheets,  we see where hiface made a shortcut. Vio for the SPDIF transmiter is 3.3V vs the datasheet called for 2.7V.
They followed the TX to pulse transformer output to the letter of the datasheet.  But this may not be correct according to SteveN.  Are these the reasons the SPDIF output doesn't follow specs? 
 
Should we fix this before we add an attenuator which always degrades signal quality (same reason people spend $500 on stepped attenuators) ?
 
 

 

[regal]

Case
 
SerPac 113,BK  (digikey) Edit (this is a PITA,  need a case that's 2 3/4" long internal dimension)
18650 Battery Holders BK-18650-pc2 (digikey)  buy 2
 
http://www.szwholesale.com/18650-32vrechargeable-battery1865032v-p-1139.html     - 18650 LiFePO4 Batteries
 
http://www.szwholesale.com/universal-charger-18650-16340-lion-nimh-nicd-battery-p-3241.html     -Charger
 
Get some 24 guage wire from radio shack and an additional nut identical size/shape to the one on the highface BNC out.
I can't speak for the RCA out Hiface as far as casing.
 
Jenky is right that LiFePO4 batteries are no longer all the same as when they were first introduced a few years ago,  however this budget transport I'm perfectly comfortable with the $4 specials,  these batteries charge to 3.4V and I can't measure an output impedance, your decision and not worth debating.
 
http://visforvoltage.org/forum/4581-testing-lifepo4-battery039s-quality