# M2Tech HiFace Mods and Discussions



## 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....


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## 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.


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## 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.


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## 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.


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## mmerrill99

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## ROBSCIX

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


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## 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.


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## 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?


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## 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) ?


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## 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


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## regal

Here is Steve N's suggestion to fix the out of spec SPDIF output,  I'm going this route as it costs only $.50. The 470R resistor is a replacement for the stock 330R and the 1000R resistor is an addition.


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## regal

One last thing the 1.8V supply to the CPLD has to be tightly regulated their spect is +-1V.   This means a transformer and a linear or shunt reg,  meaning $'s and space,  no batteries will work here.
   
  I can see doing this part of the mod if you are building a good 5V power supply for the USB receiver,  then you could just add a small reg to drop to 1.8V.  Big question is it worth the $'s ?


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## mmerrill99

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## mmerrill99

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## regal

Quote: 





jkeny said:


> By all means fix the SPDIF out to be within spec but not because the attenuators are a bad idea as I don't believe they are or because the Hiface does not follow the DIT4192 application guidelines, as it does follow them exactly.


 

 Yes it does say Vio +2.7V to Vdd (max),  our Vdd is 5V+ but the Vio=3.3V so then output voltage is .8 VIO (in highlevel mode) and with the 2:1 pulse transformer we aren't even trying to meet SPDIF spec.  I hope you are right about the attenuators,  keep us posted.  I do think that a resistor divider (static pot) has more potential and is less expensive.  But opinions are like @-holes lets experiement and see what sounds best.


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## regal

Here is the calc STOCK:  5V-.4V= 3.6V,    transformer voltage reduction= 1/2*3.6= .1.8V.  Output SPDIF = 1.8V
   
  So doing Steve N's mod  3.6*470/(470+1000)*.5= 0.57V.   
   
  Output impedance Steve N Mod 470*1000/(470+100)/4= 75 ohms  (assuming output impedance of DIT is negligible.)
   
  Maybe is still a little high,  increase the 1000R to reduce further,  its the same principle as your attenuator idea just IMO more textbook and potentially better cause you don't have a wiper (read up on stepped attenuators vs potentiameters.)  Plus its cheaper!
   
   
  Anyone know the package size of the little 330R resistor in series between TX and the pulse transformer?  I can't find my calipers.


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## mmerrill99

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## regal

Quote: 





jkeny said:


> Is the VDD on the DIT4192  5V (from the USB PS) & not 3.3V?
> BTW, I believe that an independent, clean (battery) 3.3V supply to this Vio pin 7 could improve things more. So we would have three independent 3.3V supplies - one to the clocks, one to the CPLD clock handling output stage & one to the DIT4192 SPDIF generating output stage.


 


 Yes I meant Vio  (post edited)  Vio is 3.3V from your battery CPLD mod. 
   
  If they are fixed there should be no degredation.  So you're fixing it on the receiving end ,  I'm fixing it on the output side.  But its pretty similar.  You may want to try the resistor across the primary of the pulse transformer to determine the attenuation you need,  that way you only need to buy one attenuator (again I'm a cheap person.)


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## mmerrill99

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## regal

Bad news,
   
  If you guys are concerned about proper 75 ohm transmission,   the stock pulse transformer is incorrect:
   
http://www.murata-ps.com/data/magnetics/kmp_786.pdf
   
  See 78604/1C   .
   
  The DIT datasheet calls for a Scientific conversions SC982.04 which would have the proper 75 ohms on the output.
http://www.scientificonversion.com/catalog.html
   
   
  Don't know where we can buy these,  but me thinks the whole BNC 75 ohms quest is pointless with the stock pulse transformer.


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## mmerrill99

Quote: 





regal said:


> Bad news,
> 
> If you guys are concerned about proper 75 ohm transmission,   the stock pulse transformer is incorrect:
> 
> ...


 

 Yes Regal, this is what I was getting at in my post about the way I would do it - (in the methods below the signal level will be even higher, allowing for an even higher attenuator to be used.
   
  Use a 1:1 transformer Newava 22083, I think is a highly regarded one
  OR don't use an output transformer at all - these DIT4192 output driver (T+ & T-) lines are differential so galvanic isolation is still fine. I'm hoping they would be able to drive into one of these attenuators which would represent a mainly resistive 75R load
   
  A third way & possibly the best & premium way is from a post of John Swenson who states:
   
  Quote: 





> As a general purpose solution, I think the best approach would be a receiver that plugs in right on the output of the source with an adjustable input impedance that can be tuned to match the output as best as possible, followed by an amplifier and detector, which drives an LVDS transmitter, which goes over balanced cable to the receiver which is followed by an adjustable driver where the output level and impedance can be adjusted to get the best results out of the DAC receiver. With the input and output tuned to whatever equipment you have you would get close to as good as you can get.


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## regal

Jenky you're always blazing a new trail and I admire this.  I just follow the classic methods (which Hiface failed to do.)   Keep us posted, the best transformer is no transformer so I really like you're #2 option, I  just don't have the background to say if it will work or not.


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## ulfp

A few months back I modified my USB cable to give the HiFace fresh 5V power from battery. Perhaps some improvement, but not much. 
   
  Last Saturday I gathered the courage to "hack" my HiFace open for the 3.3V mod. I didn’t have the patient to wait for internet order, so I bought two 3.3V battery + charger from a local shop for $35.
   
  WOW, best $35 upgrade ever!!!  Even though I’m using fairly low-end gear (Compass with RCA), for sure the result is a very clear improvement. Better detail and overall clearer sound from low to high. But best of all, more natural musical touch to the sound.
   
  Thanks to jkeny for mod & pictures, and thanks to regal too (your recent posts in the other threads made me cross the line).
   
  Now I’m very tempted to order DAC-19 and C-2....
   
  My battery is 500mAh only. After approx 24h of use, voltage drop from 3.32 to 3.30. Anyone figured out the power consumption? How often do you need to recharge?


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## regal

Quote: 





ulfp said:


> A few months back I modified my USB cable to give the HiFace fresh 5V power from battery. Perhaps some improvement, but not much.
> 
> Last Saturday I gathered the courage to "hack" my HiFace open for the 3.3V mod. I didn’t have the patient to wait for internet order, so I bought two 3.3V battery + charger from a local shop for $35.
> 
> ...


 


 It sounds like you only did the clock mod?  I think the clocks use very little juice.  My 1500mAH battery lasted about 3 days (roughly)  but when they go they go fast then it is hard to recharge them.  Don't let the voltage go below 3V.  I have a feeling that the CPLD uses more mA's,  so you would need a bigger battery? (I haven't done that part yet.)


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## ulfp

Quote: 





regal said:


> It sounds like you only did the clock mod?  I think the clocks use very little juice.


 
   
  Yes, I did the clock mod.
   
  My 500mAH battery voltage is dropping faster now after 24h (about 24h effective playing over past 2 days). During first 24h, it was constant at 3.32V.
   
  Are you disconnecting the battery when not using the HiFace, or do you simply keep it powered all the time?
   
  Did anyone consider to put a few batteries in parallel to make them last longer, or is there some theory that parallel batteries would make it worse?


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## mmerrill99

Here's the transformer that is recommended by Jocko - Newava s22083 http://parts.digikey.ca/1/1/324876-transformer-isolation-dig-audio-s22083.html
  It's 1:1 so output stage has to be changed to bring down high level voltage
   
   
  Current consumption:
   
[size=10.0pt]Xilinx typically 30mA max,[/size]
   
[size=10.0pt]Cypress current consumption 85mA max[/size]
   
[size=10.0pt]Clock consumption 20mA?[/size]
   
[size=10.0pt]Total current consumption 115mA for 3.3V[/size]


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## regal

Quote: 





jkeny said:


> Here's the transformer that is recommended by Jocko - Newava s22083 http://parts.digikey.ca/1/1/324876-transformer-isolation-dig-audio-s22083.html
> It's 1:1 so output stage has to be changed to bring down high level voltage
> 
> 
> ...


 


 Nothing against Jocko but the datasheet doesn't show a 75 ohm secondary,   I emailed the manufacturer for clarification,  as we need to know what the impedance of the secondary is in order to spec the resistor divider ahead of it.
   
  I think we can make the stock pulse transformer work if we use a 150 ohm divider roughly 75ohm in series and 75 ohms across the primary,   the secondary impedance is so high that it won't matter in the calculation.


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## mmerrill99

Regal,
  I don't think you need a 75ohm secondary - just use a resistor divider to bring it down to 75ohm.
   
  Here's a schematic for double termination on primary & secondary & includes a 10db attenuator using the Newava 1:1 transformer


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## regal

Yes and we can use the same technique to "fix" the stock pulse transformer.
  
  Quote: 





jkeny said:


> Regal,
> I don't think you need a 75ohm secondary - just use a resistor divider to bring it down to 75ohm.
> 
> Here's a schematic for double termination on primary & secondary & includes a 10db attenuator using the Newava 1:1 transformer


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## mmerrill99

Quote: 





regal said:


> Yes and we can use the same technique to "fix" the stock pulse transformer.


 

 I'm not sure as I've seen somewhere that the stock one is so far off the 75ohm that it can't be successfully brought down to 75 ohm impedance - you might know more about this than me though?
   
  BTW, you'll need to correct that calculation on the last page 3.3V * 0.8 is correct for all digital lines on the DIT4192 EXCEPT T+ & T- line drivers which gives us the SPDIF signal where it's 3.3V - 0.7 I know this doesn't make much of a difference but for the sake of clarity if anybody is checking it!


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## regal

Quote: 





jkeny said:


> I'm not sure as I've seen somewhere that the stock one is so far off the 75ohm that it can't be successfully brought down to 75 ohm impedance - you might know more about this than me though?
> 
> BTW, you'll need to correct that calculation on the last page 3.3V * 0.8 is correct for all digital lines on the DIT4192 EXCEPT T+ & T- line drivers which gives us the SPDIF signal where it's 3.3V - 0.7 I know this doesn't make much of a difference but for the sake of clarity if anybody is checking it!


 


 Actually the datasheet says T+ is 5V-.4V,  Steve N's Mod comes out to right into the SPDIF spec (I edited the post.)
   
   
  As far as the 75 ohm,  this transformer is 4:1 impedance ratio,  so assuming that the secondary impedance is very high if in paralell with 75 ohms it would be negligable.  So we would want 75x4=300 on the primary side.  So to get this we would want 75 in series to and 225 across the primary to give the 75 ohms at the secondary and give the proper voltage divider(reduction.)   I'm not 100% on this
   (used to dealing with tube transformers) so I emailed the maker of the stock transformer and will report back.


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## regal

Here is a thread that explains how to get a proper 75ohm output from a transport (my last post is correct so I'm ordering from digikey):
   
http://www.head-fi.org/forum/thread/129132/adding-coaxial-s-pdif-to-the-m-audio-transit
   
   
  Also read this for the calculatios (series/parallel section)
   
http://en.wikipedia.org/wiki/Resistor


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## mmerrill99

Quote: 





regal said:


> Actually the datasheet says T+ is 5V-.4V,  Steve N's Mod comes out to right into the SPDIF spec (I edited the post.)


 Yes you're correct - phew, eventually we got there    
   


> As far as the 75 ohm,  this transformer is 4:1 impedance ratio,  so assuming that the secondary impedance is very high if in paralell with 75 ohms it would be negligable.  So we would want 75x4=300 on the primary side.  So to get this we would want 75 in series to and 225 across the primary to give the 75 ohms at the secondary and give the proper voltage divider(reduction.)   I'm not 100% on this
> (used to dealing with tube transformers) so I emailed the maker of the stock transformer and will report back.


 




  Quote: 





regal said:


> Here is a thread that explains how to get a proper 75ohm output from a transport (my last post is correct so I'm ordering from digikey):
> 
> http://www.head-fi.org/forum/thread/129132/adding-coaxial-s-pdif-to-the-m-audio-transit
> 
> ...


 


  Excellent, we only need the output driver impedance of DIT4192 & then we are good to go. For the output drivers, I've calculated it at 13.3ohms for High & 23.3ohms for Low so an average of 18ohms & maybe in the absence of actual measurements, these will do.
   
  This 18ohms needs to be taken into account in the calcs. Does this mean our 75R in series on the primary side becomes:
  75-18=57ohm?


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## regal

Quote: 





jkeny said:


> Excellent, we only need the output driver impedance of DIT4192 & then we are good to go. For the output drivers, I've calculated it at 13.3ohms for High & 23.3ohms for Low so an average of 18ohms & maybe in the absence of actual measurements, these will do.
> 
> This 18ohms needs to be taken into account in the calcs. Does this mean our 75R in series on the primary side becomes:
> 75-18=57ohm?


 


 I'm surprised I assumed that the DIT4192 with its drivers would have an output impedance under 1-2ohms,  the link I provided was for a transmitter that didn't have a driver/buffer.   Guess I need to look at the datasheet again (thanks btw almost placed a digikey order!)
   
  For a cheap but decent +5V PS here is one that folks can build on a radioshack breadboard:
http://hubpages.com/hub/zpedia
   
  I have one already built that I paid $5 for off ebay a few years ago,  I couldn't find it for sale anymore,  but there are LM317 boards on ebay that are probably of better quality.  For a transformer a 9-12V from digikey will work.
   
  To get the 1.8V I'm using this:  http://search.digikey.com/scripts/DkSearch/dksus.dll?WT.z_header=search_go&lang=en&site=us&keywords=MCP1700-1802E%2FTO-ND&x=24&y=14 after the +5V power.


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## mmerrill99

On a side note, I tried to do some testing yesterday with the Hiface output stage. I picked up a TASCAM MD-801R MinidisK professional recorder/player that was being thrown out to use for my testing as it has some nice digital readouts of SPDIF strength. I can'get a lock on the Hiface SPDIF out. The Tascam works with every other SPDIF source I throw at it. Any ideas what might be wrong? I've noticed this before in other situations but wasn't familiar with the equipment to make a judgement as to which was at fault. I think I got a  lock for a second when i was switching though the various settings on the Tascam as I heard music in the headphones plugged into it.
   
  Any experience of this?
   
  I know the Hiface is also non-standard in it's SPDIF coding output from this note I found on the Australia M2tech site:


> Some customers complained because of the lack of sampling frequency encoding in the S/PDIF stream of the present hiFace. The new model will have this fixed, for full compliance with the standard.


   
  This would hardly cause non-locking issues would it?
  I sent an email to Marco to ask about it & if it would be fixed for the Hiface too but apparently not! I have a follow up mail to him


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## regal

Well I can tell you that I discovered that my version has the DIT4192 set to low output,  so 0.4V before the pulse transformer and only 0.2V after it.  So they have been making changes.  They should have changed the output transformer to a 1:1 but didn't.


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## mmerrill99

Quote: 





regal said:


> Well I can tell you that I discovered that my version has the DIT4192 set to low output,  so 0.4V before the pulse transformer and only 0.2V after it.  So they have been making changes.  They should have changed the output transformer to a 1:1 but didn't.


 

 Are you sure? This seems very odd. What's the Vio voltage on pin 7? This is probably too low for a lock signal or would severely compromise the SPDIF receiver operation, I think?
  This is not my problem as I scoped the output & it's about 2Vpp


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## regal

Pin 7 Vio is 3.3 which is in spec.   Edit it looks like Steve N's mod of the 1k R across the transformer may have been too much of a load and damaged the DIT4192 TX drivers.  Luckily the DIT4192 is only $6 at digikey.


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## mmerrill99

Quote: 





regal said:


> Pin 7 Vio is 3.3 which is in spec.   Edit it looks like Steve N's mod of the 1k R across the transformer may have been too much of a load and damaged the DIT4192 TX drivers.  Luckily the DIT4192 is only $6 at digikey.


 

 Oops, that explains it - I don't envy you trying to unsolder & resolder that DIT4192 - it's tight in there!


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## regal

I have this low temp solder that makes removal easy,  the soldering back on is easy.
  Quote: 





jkeny said:


> Oops, that explains it - I don't envy you trying to unsolder & resolder that DIT4192 - it's tight in there!


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## ROBSCIX

Post some shots when you get the job done.


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## sleepy dan

Quote: 





regal said:


> Pin 7 Vio is 3.3 which is in spec.   Edit it looks like Steve N's mod of the 1k R across the transformer may have been too much of a load and damaged the DIT4192 TX drivers.  Luckily the DIT4192 is only $6 at digikey.


 

 1K + 470R is an easy load .... if the DIT is broke, the problem will be elsewhere.  
   
  By the way, Steve N's mod will divide the output by 3, followed by divide by 2 from the transformer .... is this what you're wanting?


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## regal

Steve N's mod will multiply by 2/3 then divide by 2 which gives .66V's which is closer to USB spec,   but it doesn't give a 75 ohm output.

  
  Quote: 





sleepy dan said:


> 1K + 470R is an easy load .... if the DIT is broke, the problem will be elsewhere.
> 
> By the way, Steve N's mod will divide the output by 3, followed by divide by 2 from the transformer .... is this what you're wanting?


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## mmerrill99

Quote: 





regal said:


> Steve N's mod will multiply by 2/3 then divide by 2 which gives .66V's which is closer to USB spec,   but it doesn't give a 75 ohm output.


 
  Then, I believe, it will do more harm than good! We need as close to 75ohm as we can get to avoid reflections! I'm off to do some more experiments & try to get the Hiface working into my minidisk recorder!


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## sleepy dan

You're right, I was viewing the resistors swapped round in my head.  About the Impedance .... 470R in parallel with 1K gives 320R on the primary side, close to the 300R you want.  Why not simply add an extra R in parallel with one of the others to bring it down to 75?
  
  Quote: 





regal said:


> Steve N's mod will multiply by 2/3 then divide by 2 which gives .66V's which is closer to USB spec,   but it doesn't give a 75 ohm output.


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## regal

Agreed,  but we need to agree on the output impedance of the DIT4192 and factor that in too.

  
  Quote: 





sleepy dan said:


> You're right, I was viewing the resistors swapped round in my head.  About the Impedance .... 470R in parallel with 1K gives 320R on the primary side, close to the 300R you want.  Why not simply add an extra R in parallel with one of the others to bring it down to 75?


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## ROBSCIX

I need to make out a shopping list for modding the power like you did Regal.  I think I may just pull the unit apart and mount it in a box as it will keep everything contained.


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## noinimod

I'm must confess i'm a total newbie at DIY, so i might be talking out of my ass here. I'm wondering, is it possible to use these sort of regulators to mod the hiface?
  http://www.paulhynesdesign.com/
  http://www.audio-gd.com/Pro/diy/PSU09/PSU09EN.htm


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## regal

The Z7803.3 on the hynesdesign page would be a possibility.  The audioGD only offers down to 5V but you need 3.3V.
   
  I would stick with the tent labs as it is more proven for powering clocks:  http://www.tentlabs.com/Components/Shuntcomp/index.html
   
  You would trade a possible degrade in SQ for convenience.
   
   
  Quote: 





noinimod said:


> I'm must confess i'm a total newbie at DIY, so i might be talking out of my ass here. I'm wondering, is it possible to use these sort of regulators to mod the hiface?
> http://www.paulhynesdesign.com/
> http://www.audio-gd.com/Pro/diy/PSU09/PSU09EN.htm


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## regal

I've checked 2 Hiface units now,  one brand new out of the box and they both output 0.2V RMC AC.  M2Tech is denying they changed anything but I believe the new version is programmed to have the DIT4192 set to low which would be .4 before the pulse transformer and 0.2V after it.  To correct the problem the transformer should be changed to a 1:1 ratio.
   
  Or maybe its my DMM,  its a Fluke 117 set to AC (true RMS).


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## mmerrill99

Quote: 





regal said:


> Agreed,  but we need to agree on the output impedance of the DIT4192 and factor that in too.


 
  Do we also need to take into account the DCR of the primary winding in the trafo? I don't know if this is already accounted for in the reflected impedance - Regal you will probably know better.


  
  Quote: 





regal said:


> I've checked 2 Hiface units now,  one brand new out of the box and they both output 0.2V RMC AC.  M2Tech is denying they changed anything but I believe the new version is programmed to have the DIT4192 set to low which would be .4 before the pulse transformer and 0.2V after it.  To correct the problem the transformer should be changed to a 1:1 ratio.
> 
> Or maybe its my DMM,  its a Fluke 117 set to AC (true RMS).


 
  I doubt M2tech have changed anything - particularly something this radical - Marco has stated that the output is 1.7Vpp. I see about 2Vpp on a scope.


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## regal

I think my fluke just doesn't read high frequency AC correctly.


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## regal

Here is the proper ground,  no audible difference,  unless you have a lot of soldering experience stick with the easier ground.


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## regal

Quote: 





jkeny said:


> Do we also need to take into account the DCR of the primary winding in the trafo? I don't know if this is already accounted for in the reflected impedance - Regal you will probably know better.


 

 The DCR of the transformer primary and secondary are negligable.


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## mmerrill99

Great, just checking 
   
  BTW, the jitter at the output of the Hiface has been measured at <10ps - a phenomenal result!!


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## regal

Last measurement I saw was 1 ns,  thats several order magnitude difference,  the 10ps number had to be after conversion to analog.
  
  Quote: 





jkeny said:


> Great, just checking
> 
> BTW, the jitter at the output of the Hiface has been measured at <10ps - a phenomenal result!!


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## ROBSCIX

Do these measurments vary between stock to modded unit?


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## mmerrill99

Quote: 





regal said:


> Last measurement I saw was 1 ns,  thats several order magnitude difference,  the 10ps number had to be after conversion to analog.


 
  Have you got a link to this 1ns measure? Here's the <10ps post which he says was measured at the SPDIF out of the Hiface - I trust this guy - he knows what he's doing http://www.diyaudio.com/forums/digital-source/168901-rf-attenuators-jitter-reducers-17.html#post2229547


  
  Quote: 





robscix said:


> Do these measurments vary between stock to modded unit?


 

 This is the stock hiface measurement - the battery powered one could only be better


----------



## Sebhelyesfarku

Can it cause problems if I supply the hiFace with 5V from a battery pack (with a butchered USB extender cable) and the voltage is changing between 5.3-4.9V? Or the regulators in the device take care of it.


----------



## mmerrill99

Quote: 





sebhelyesfarku said:


> Can it cause problems if I supply the hiFace with 5V from a battery pack (with a butchered USB extender cable) and the voltage is changing between 5.3-4.9V? Or the regulators in the device take care of it.


 

 The 5V supply directly powers the DIT4192 chip which is responsible for generating the SPDIF signal. This 5V isn't regulated, just de-coupled for this DIT chip. The chip has a recommended voltage range of 4.5 to 5.5V so you should be OK - just be careful you connect up in the correct manner otherwise you risk killing the Hiface!
   
  This voltage range should be OK as the input to the 1.8V & 3.3V regulators


----------



## hawaya

Is there improvement of SQ, if replace  Murata 78604 pulse trafo with Newava 22083, i am with 8412 receiver.
  Thank you.


----------



## regal

http://www.head-fi.org/forum/thread/446375/usb-24-192khz-m2tech-hiface/45#post_6063226

  
  Post #50 of the orginal Hiface thread.  970 ps of jitter measured.   The guy on Diyaudio is measuring jitter after DAC,  it is impossible for a transport to have 10ps of jitter,  it completely unheard of and utter nonsense.  If the Hiface really had only 10ps of jitter there would be no need to mod it.
   
   
  Quote: 





jkeny said:


> Have you got a link to this 1ns measure? Here's the <10ps post which he says was measured at the SPDIF out of the Hiface - I trust this guy - he knows what he's doing http://www.diyaudio.com/forums/digital-source/168901-rf-attenuators-jitter-reducers-17.html#post2229547
> 
> 
> 
> ...


----------



## regal

Quote: 





hawaya said:


> Is there improvement of SQ, if replace  Murata 78604 pulse trafo with Newava 22083, i am with 8412 receiver.
> Thank you.


 
  You would get 4Vp-p which would make the SPDIF high voltage problem even worse.  I ordered the correct transformer per the DIT datasheet,  I'll report if there is an improvement (it has a 75 ohm impedance secondary),  I think it was $15.


----------



## hawaya

Thank you Regal, i will wait for your report.


----------



## mmerrill99

Quote: 





regal said:


> You would get 4Vp-p which would make the SPDIF high voltage problem even worse.  I ordered the correct transformer per the DIT datasheet,  I'll report if there is an improvement (it has a 75 ohm impedance secondary),  I think it was $15.


 

 Hi Regal,
  I don't think the SPDIF high signal is really a problem, in fact for the Crystal 8412 receiver, it will be an advantage as these work better with high SPDIF signal. My idea in using the Newava 1:1 was yes to allow a higher SPDIF signal so as I could then use a higher attenuator & reap more of the reflection reduction benefits of this approach.
   
  So many different ways to skin a cat, I guess


----------



## mmerrill99

Quote: 





regal said:


> http://www.head-fi.org/forum/thread/446375/usb-24-192khz-m2tech-hiface/45#post_6063226
> 
> 
> Post #50 of the orginal Hiface thread.  970 ps of jitter measured.   The guy on Diyaudio is measuring jitter after DAC,  it is impossible for a transport to have 10ps of jitter,  it completely unheard of and utter nonsense.  If the Hiface really had only 10ps of jitter there would be no need to mod it.


 
  Maybe, you're right but I'll keep an open mind on the subject  As I said this guy knows what he's doing but I'm not expert enough to judge if he has made a mistake or not. I guess some detail on the where & how of the measurement would be useful but ..........


----------



## regal

Jkeny,
   
  the reflection attenuator idea has been around a while,  see the old Kenwood CDP 7090 CDP output here:
   
http://www.lampizator.eu/lampizator/TRANSPORT/CD_transport_DIY.html
   
  the 180R + 22R in parallel with the 75 gives makes a 75 ohm attenuator ((180+75/(180*75))+22)
   
   
  I'm pretty sure that the SteveN mod will do the same if you think about it.


----------



## mmerrill99

Quote: 





regal said:


> Jkeny,
> 
> the reflection attenuator idea has been around a while,  see the old Kenwood CDP 7090 CDP output here:
> 
> ...


 

 Yes, Regal, I know that BUT some people are getting the idea that the improvement in sound is due to the fact that the SPDIF signal is too high to start with & that this is causing sonic problems with the Hiface - I want to correct this notion before it gains currency because it is patently wrong.
   
  So please emphasise that it is the reflection reduction RATHER than the SPDIF signal reduction that is causing any benefit that may ensue.


----------



## regal

I agree,  but also feel that some recievers have "trouble" with the 2Vp-p SPDIF,  there is a spec to be followed,  I always think it best to follow spec and if that also reduces reflections even better.   I agree with you that the attenuator has to reduce the reflection,  there is no way it couldn't.
   
   
  BTW I got all my parts in,  I'll have linear regs for both the 5V+ and the 1.8V+.  I can safetly say that I am spending more than I had planned,  if you want to DIY to learn fine,  but don't think you save much money going the DIY route vs sending it to Jenky.
   
   
   
   
  Quote: 





jkeny said:


> Yes, Regal, I know that BUT some people are getting the idea that the improvement in sound is due to the fact that the SPDIF signal is too high to start with & that this is causing sonic problems with the Hiface - I want to correct this notion before it gains currency because it is patently wrong.
> 
> So please emphasise that it is the reflection reduction RATHER than the SPDIF signal reduction that is causing any benefit that may ensue.


----------



## mmerrill99

Quote: 





regal said:


> I agree,  but also feel that some recievers have "trouble" with the 2Vp-p SPDIF,  there is a spec to be followed,  I always think it best to follow spec and if that also reduces reflections even better.   I agree with you that the attenuator has to reduce the reflection,  there is no way it couldn't.


   
  Maybe, I don't know of any but there may be some. Also it cuts down the signal level by the dB amount of the attenuator *BUT it cuts down the reflections by twice this amount & this is the real benefit*. This is because the reflection has to pass through the attenuator twice before it gets back to the receiver where it can cause any damage. So if you have a 10dB attenuator in line the signal voltage gets reduced by 4 times BUT the reflections get reduced by 8 times. Have I done my conversions right?
   
   
  Quote: 





regal said:


> BTW I got all my parts in,  I'll have linear regs for both the 5V+ and the 1.8V+.  I can safetly say that I am spending more than I had planned,  if you want to DIY to learn fine,  but don't think you save much money going the DIY route vs sending it to Jenky.


 
 Ah but you are benefiting the audio community & advancing the cause


----------



## regal

-10dB would give approximately 1/3 Voltage the input V so the reflection would be about 1/6,  still enough that the reflection would not likely be picked up by the receiver.
   
   
  Another thing if we are doing these mods I think it makes sense for folks to open their DAC's and make sure the receiving end is 75 ohms,  its common practice for DAC makers to just throw on a BNC connector without the proper termination to the receiver.

  
  Quote: 





jkeny said:


>


----------



## mmerrill99

Quote: 





regal said:


> -10dB would give approximately 1/3 Voltage the input V so the reflection would be about 1/6,  still enough that the reflection would not likely be picked up by the receiver.
> 
> 
> Another thing if we are doing these mods I think it makes sense for folks to open their DAC's and make sure the receiving end is 75 ohms,  its common practice for DAC makers to just throw on a BNC connector without the proper termination to the receiver.


 
  Thanks for the correction - I thought I was off 
  Good advice, regal, but I wonder how many are up to the job of doing this, particularly the job of calculating the correct termination.
   
  BTW, I could have done with your input on that idiotic thread over on DIYA where I was being accused of casting a slur on e'ee designers precisely on this point - that a lot of SPDIF receiver circuits were improperly terminated. He maintained that a DMM could measure the input impedance & he claimed to be an e'ee??


----------



## regal

Quote: 





jkeny said:


> Thanks for the correction - I thought I was off
> Good advice, regal, but I wonder how many are up to the job of doing this, particularly the job of calculating the correct termination.
> 
> BTW, I could have done with your input on that idiotic thread over on DIYA where I was being accused of casting a slur on e'ee designers precisely on this point - that a lot of SPDIF receiver circuits were improperly terminated. He maintained that a DMM could measure the input impedance & he claimed to be an e'ee??


 


 He was probably fresh out of school with no bench or feild experience,  probably not a good school either.  I quit following the thread when he couldn't distinguish a question from a statement.
   
   
  What I've seen for termination at the input side of the DAC is almost always a 75 ohm resistor in paralell if no transformers are involved, should be pretty simple (not as convoluted as the transport output side.)


----------



## mmerrill99

Quote: 





regal said:


> He was probably fresh out of school with no bench or feild experience,  probably not a good school either.  I quit following the thread when he couldn't distinguish a question from a statement.
> 
> 
> What I've seen for termination at the input side of the DAC is almost always a 75 ohm resistor in paralell if no transformers are involved, should be pretty simple (not as convoluted as the transport output side.)


 

 Yes, full of the surety of his own opinion!
  OK, it sounds do-able so.
  How are the 1.8V & 5V mods going?


----------



## regal

Not good I built a great separate powersuply with umbilical cord and 5V & 1.8V but tried to fit the Hiface in a tiny separate box, The case I'm using is tiny and allows two 18650 battery holders to sit on top then I can plug it straight into my DAC with out a cable. But when I closed it up it put stress on the wires and one broke off and created a short, fried the DIT.  I'm going to put fuses inline with the batteries.  I need to find some very thin flexible wires.  The MCP regulator works great at supplying a 1.8V output from the 5V.  But I recommend ordering it in the SMD package to replace the silly stock buck regulator.
   
   
   
   
  When you use a spearate 5V power supply I imagine you still have to connect it to the USB ground?
  
  Quote: 





jkeny said:


> Yes, full of the surety of his own opinion!
> OK, it sounds do-able so.
> How are the 1.8V & 5V mods going?


----------



## mmerrill99

Quote: 





regal said:


> Not good I built a great separate powersuply with umbilical cord and 5V & 1.8V but tried to fit the Hiface in a tiny separate box, The case I'm using is tiny and allows two 18650 battery holders to sit on top then I can plug it straight into my DAC with out a cable. But when I closed it up it put stress on the wires and one broke off and created a short, fried the DIT.  I'm going to put fuses inline with the batteries.  I need to find some very thin flexible wires.  The MCP regulator works great at supplying a 1.8V output from the 5V.  But I recommend ordering it in the SMD package to replace the silly stock buck regulator.
> 
> 
> When you use a spearate 5V power supply I imagine you still have to connect it to the USB ground?


 
  Ah, sorry to hear that, Regal. The path of DIY is neither easy nor cheap, as you said before!
   
  Yes you still need to have the 5V ground connected to the USB ground.


----------



## punk_guy182

Hello all!
   
  I just spoke to Kingwa and according to him the BNC socket of the hiFace is not 75ohms but 50ohms. Would a 50ohms BNC attenuator have a better impact on sound quality after all?


----------



## ccschua

Just finish the mod to the hiface. I remove the inductor and connect the 3.3v supply to the right pad. Beside the inductor is a component. Is it ok to short the right pad of inductor with the left pad of the component next to the removed inductor.


----------



## mmerrill99

Yes, I've been wondering about this myself - it looks like it's not a 75ohm BNC connector (as it has white insulation around it's inner connector pin). I haven't really addressed this in my own head yet Matthieu. The correct approach is to really replace the whole output stage of the Hiface with true 75 ohm termination & then apply attenuators. I was intending to do something like this, bypassing (or removing) the SPIF transformer & output connectors for my own output stage configuration but I'm not at that point yet (so please don't ask me to do this for your device )
   
  So your question is very prescient - what's best to do with the current set-up? If you have a BNC Hiface then it is presumed that it is to feed a DAC with BNC input. This is assumed to be a 75ohm input but they are often not! So we are in a quandary of mistakes here. How best to work our way through them is the question?


----------



## mmerrill99

Quote: 





ccschua said:


> Just finish the mod to the hiface. I remove the inductor and connect the 3.3v supply to the right pad. Beside the inductor is a component. Is it ok to short the right pad of inductor with the left pad of the component next to the removed inductor.


 
 It would be better if you showed a HD pic of the parts you are talking about but if you mean the brown smd cap to the right of the inductor that you removed then yes, this is electrically connected to the inductor's right pad so you can short between them. But again you really need some pics to show if we are talking about the same thing? There is a HD shot on page 1 of this thread that shows the inductor & the smd capacitor to the right of it. From your pic it looks like you have already wired this up however - how does it sound?


----------



## punk_guy182

Quote: 





jkeny said:


> Yes, I've been wondering about this myself - it looks like it's not a 75ohm BNC connector (as it has white insulation around it's inner connector pin). I haven't really addressed this in my own head yet Matthieu. The correct approach is to really replace the whole output stage of the Hiface with true 75 ohm termination & then apply attenuators. I was intending to do something like this, bypassing (or removing) the SPIF transformer & output connectors for my own output stage configuration but I'm not at that point yet (so please don't ask me to do this for your device )
> 
> So your question is very prescient - what's best to do with the current set-up? If you have a BNC Hiface then it is presumed that it is to feed a DAC with BNC input. This is assumed to be a 75ohm input but they are often not! So we are in a quandary of mistakes here. How best to work our way through them is the question?


 

 Please let me know if you can find a way to make it 75ohms. The BNC socket on my DAC 75ohms and I'd like the hiface to match it.
  BTW, S/PDIF is a poorly implemented standard and I'd like to see another one replace it that is less vulnerable and better implemented on hardware.


----------



## ccschua

Hi,
   
  It works. I saw that Regal also shorted the link for easier connection. I apply solder paste thru out for easier working.
   
  Well sound wise it is slight improvement. again in hifi, noticeable improvement is something better than previous setup and it is better than without.
  
  Quote: 





jkeny said:


> It would be better if you showed a HD pic of the parts you are talking about but if you mean the brown smd cap to the right of the inductor that you removed then yes, this is electrically connected to the inductor's right pad so you can short between them. But again you really need some pics to show if we are talking about the same thing? There is a HD shot on page 1 of this thread that shows the inductor & the smd capacitor to the right of it.From your pic it looks like you have already wired this up however - how does it sound?


----------



## mmerrill99

Quote: 





ccschua said:


> Hi,
> 
> It works. I saw that Regal also shorted the link for easier connection. I apply solder paste thru out for easier working.
> 
> Well sound wise it is slight improvement. again in hifi, noticeable improvement is something better than previous setup and it is better than without.


 
  If it's only a slight improvement over stock, this wouldn't concur with Regal or my experience of this mod !


----------



## digger945

Quote: 





jkeny said:


> If it's only a slight improvement over stock, this wouldn't concur with Regal or my experience of this mod !


 

 Maybe you have much better listening gear than ccschua. Neither one of you have anything in your profiles.
   
  I wanted to ask, at what point on the leading edge does the recieving end of your dac trigger high? Somewhere in the 500 to 800mV range?
   
  Does the trigger point change if the spdif signal voltage is changed?


----------



## ccschua

my dac is audio-gd reference 1, Audiogd CIA-400, Dynaudio Focus 140. Cable is siltech paris and power by a richard company pro 400.
   
  very soon I will hook up the hiface with blackcat velose.
   
  I compare the hiface to audio-gd cd-7se and it is big difference.
   
  Should I consider the 5V mod? how shall isolate the USB 5V supply


----------



## mmerrill99

Quote: 





digger945 said:


> Maybe you have much better listening gear than ccschua. Neither one of you have anything in your profiles.
> 
> I wanted to ask, at what point on the leading edge does the recieving end of your dac trigger high? Somewhere in the 500 to 800mV range?
> 
> Does the trigger point change if the spdif signal voltage is changed?


 
  Good question - I haven't done the measurements myself - I neither have the equipments nor the expertise but I can direct you to plots from a scope & TDR of with & without attenuator on the output of the Hiface http://www.diyaudio.com/forums/digital-source/168901-rf-attenuators-jitter-reducers-8.html#post2226135


----------



## mmerrill99

Quote: 





ccschua said:


> my dac is audio-gd reference 1, Audiogd CIA-400, Dynaudio Focus 140. Cable is siltech paris and power by a richard company pro 400.
> 
> very soon I will hook up the hiface with blackcat velose.
> 
> ...


 
  So you are saying your modified Hiface is not as good as the audio-gd cd-7se?
  Are you also saying that there was only a minor improvement in it from the stock form of the Hiface?
   
  DIgger945 I don't think this has anything to do with my or Regal's system - it is about the relative difference between the stock & the modified Hiface *on his system* - there should be a very noticeable improvement as both I & Regal noted.
   
  The reason I don't have a system description on my sig is that it's in continual flux & is very modest, believe me.


----------



## digger945

Quote: 





jkeny said:


> So you are saying your modified Hiface is not as good as the audio-gd cd-7se?
> Are you also saying that there was only a minor improvement in it from the stock form of the Hiface?
> 
> DIgger945 I don't think this has anything to do with my or Regal's system - it is about the relative difference between the stock & the modified Hiface *on his system* - there should be a very noticeable improvement as both I & Regal noted.
> ...


 

 I don't have a high end system either, but good enough to tell the difference between transports pretty easily, for me anyway.
  I am sure that if you have a so-so amp/HPs then it should be very noticable.
   
  I would like to help out. I do have some equipment but the thing I lack most is time. My scope is not a phosphor, but a TDS-420 which should be more than adequate for testing.  One thing I am missing is a HiFace. Maybe if you guys want some testing done to your mods I can do that, slow as it would be through the mail. I can't really afford to purchase a HiFace right now, but keep looking for one on the FS forum anyway.
   
http://i333.photobucket.com/albums/m362/digger945/workarea001.jpg?t=1278276498
http://i333.photobucket.com/albums/m362/digger945/workarea003.jpg?t=1278276498
http://i333.photobucket.com/albums/m362/digger945/workarea002.jpg?t=1278276709


----------



## hawaya

The improvement with battery mod is very big over stock Hiface (first unit bought from friend, who bought from JKenny-3 Batteries+RCA JKenny modded Hiface), like Regal i fried my first unit(DIT chip,and some others), when i put 5v from spdif from my Audiosynthesis DAX ,with negative wire from my PC, then with the second Hiface my friend with solder skills
  put the transformer and 5v regulator(so i use positive and negative wire-galvanic sepparation).I use 3 batteries, one for clock, and two for the chip(in paralel), and also put the charger into DAX box.Everithing is fully automatic, i mean charging the batteries.(when i stop Dax, batteries starts charging). Direct coupling the usb cable and spdif, are also step forward to SQ.So my new transport(Hiface+Dax) beat my old combo Marantz Dv8300+Dax, and there is no more borring change the redbook CD's.From PC i played with J.River with wasapi.
   
  Here is some pictures:
   
http://hawaya.snimka.bg/details/dax-hiface.508491


----------



## digger945

Very nice work hawaya(how are ya?). Good to hear you like it.
   
  fwiw jkeny, I took some measurements of the Bridge and ~1.2V peak to peak on the scope reads about 450mVAC on my fluke.
   
  The musiland 02 shows ~670mV peak to peak on the scope and measures ~122mVAC on the meter.
   
   
  maybe this will give you a frame of reference to kinda work with while you're tuning the output up.


----------



## mmerrill99

Quote: 





digger945 said:


> Very nice work hawaya(how are ya?). Good to hear you like it.
> 
> fwiw jkeny, I took some measurements of the Bridge and ~1.2V peak to peak on the scope reads about 450mVAC on my fluke.
> 
> ...


 

 Thanks Digger,
  When you say the Bridge, do you mean the Halide? I've seen reports that this sounds better than the Hiface. I know you don't have a Hiface but how much better than the Musiland do you find the sound when using the Musiland as a transport only?
   
  Yes good work Hawaya!


----------



## digger945

http://www.head-fi.org/forum/thread/443786/musiland-monitor-02-us/720#post_6755628
   
  Yes, Halide Bridge. I want a HiFace but don't really need to spend right now. Maybe if I'm lucky and one shows up on agon or here cheap.


----------



## mmerrill99

Here's something that will probably interest a lot of readers - Dave Clarke from Positive Feedback is doing a round-up report on a number of these products - see this post on CA http://www.computeraudiophile.com/content/Halide-Design-Bridge-Review#comment-45366
   
  Quote: 





> I have now the Empirical Audio Off-Ramp 3 (with Ultraclock) powered by the Hynes DC PSU, a Sonicweld Diverter, the Stello U2, the Blue Circle Thingee, the M2Tech, the Halide Bridge, and coming soon the Audiophelio, Art Legato, and Lindemann units and a few others still in the works/under development.


 
   
  It should prove to be very interesting


----------



## digger945

Most interesting indeed. He had promised in CA some time ago(after much prodding) to do such a roundup and try to keep everyone informed and up to speed. Looks like the time has come.
   
  EDIT: I see the link is to the article I was referring to.


----------



## digger945

Heh, I couldn't agree more with MichiGoon about the Bridge. First impression was extreme disappointment. Everything sounded so foreign, most especially the stuff that I was most familiar with and had listened to almost exclusively for about 2 months before Canjam. Took me all of 3 weeks of daily listening to fully acclimate and adjust to the new sound.
      I said it somewhere else but it bears repeating. I spent every evening for 2 solid weeks tuning my Denon 2ks for the perfect bass response and level, without sacrificing anything else in any other area. I made some significant improvements, through luck and chance of course, just by trying different methods and materials and listening to the same track over and over. I did not recieve the Bridge until the same day I left for Canjam, and suffice it to say I was busy doing other stuff while I was there, so didn't really get to listen much to my stuff until I got home and setup again. Like MichiGoon on CA, most impressive is the bass. I have never heard the definition elsewhere. I won't vomit audiophool adjectives all over your thread, but bottom line is, I like it. I will eventually try a HiFace someday soon, simply because my audio creed is "try it and listen for yourself." Who knows, maybe because of what you're(and everyone else, you too Regal) doing here, there will be a modded version offered by M2tech, or an offspring company.
   
  Anyways, just thought you might like to know that I totally identified with MichiGoon when I read his post on CA.
  It's all good, and to me we are spoiled rotten with way too much stuff to listen to and try. We are so fortunate.


----------



## hawaya

Quote: 





digger945 said:


> Very nice work hawaya(how are ya?).


 

 Thank you Digger945,thank you JKenny, fine, BTW does the 1,8v mode improve SQ, and is there anybody who try to change pulse trafo?
  Thank's in advise.


----------



## regal

Some are saying that the Hiface is using a 50 ohm BNC,  it looks like an amphenol to me which is 75 ohm:
   
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=ARF1177-ND


----------



## regal

I called Fluke,  even though thier DMM's can measure AC frquency up to 50khz,  they can't measure AC voltage at those high frequencies,  confusing enough that I almost convinced my wife that I need to finally buy a scope 
   
  Quote: 





digger945 said:


> Very nice work hawaya(how are ya?). Good to hear you like it.
> 
> fwiw jkeny, I took some measurements of the Bridge and ~1.2V peak to peak on the scope reads about 450mVAC on my fluke.
> 
> ...


----------



## ccschua

As I have explained, the mod does give me improvement in most of the sound elements. I like it before the mod.
   
  I will zoom out the critical part and post the mod here.


----------



## mmerrill99

Quote: 





regal said:


> Some are saying that the Hiface is using a 50 ohm BNC,  it looks like an amphenol to me which is 75 ohm:
> 
> http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=ARF1177-ND


 
 Soory Regal, you are correct, I was incorrect, it seems.


----------



## regal

Unforunately  looked on the Amphenol sebsite and they have an identical version in 50 ohms,  so this isn't closed.
  
  Quote: 





jkeny said:


> Soory Regal, you are correct, I was incorrect, it seems.


----------



## punk_guy182

Quote: 





jkeny said:


> Soory Regal, you are correct, I was incorrect, it seems.


 

*UPDATE*: Marco has confirmed to me that they are using 75ohms parts for the hiface but his BNC socket is in fact 50ohms and *NOT *75ohms.


----------



## digger945

Quote: 





regal said:


> I called Fluke,  even though thier DMM's can measure AC frquency up to 50khz,  they can't measure AC voltage at those high frequencies,  confusing enough that I almost convinced my wife that I need to finally buy a scope


 


 I was using the 289 for those measurements(which according to the manual, should measure AC square waves to 1MHz, although the readout is RMS voltage), and the converters were not playing music so the waveform appears on the scope to be a constant 44.1khz bipolar square wave(as opposed to the random BMC when playing music, which makes it difficult to take measurements even for the scope, especially frequency/period and rise/fall times). If I did have a HiFace here to test, I would initially connect it directly to the scope input with an adapter, without using a coax.
   
  I did a lot of reading and shopping(and head scratching) before buying a scope, and purchased a super cheap Protek P-3502C analog for ~$45 on ebay to use while I was shopping for something a little better. I finally ended up with a Tek TDS-420 for ~$375 shipped just because I was at the right place and time bidding on ebay. There are lots of cheap scopes on ebay and you always take a chance, especially with all the sellers who claim "I have no way to test this blah blah blah buy at your own risk/no guarantees."  I still ask myself if it was worth it sometimes, but it is nice to put stuff on the scope and do testing(especially with power supplies) instead of just having to use something like spice and guessing or wondering if what you're doing is making a difference or not in reality. It has accelerated learning for me, and makes things fun. The feature I like most about the TDS line(and I think it's also available with other manufacturers) is the Autoset feature. Just hook up your signal or whatever and push one button and the scope puts everything in view on the screen. From there it doesn't take much adjusting to see what you want from your signal.
   
My apologies to your wife ...8-p


----------



## ccschua

isnt this 50ohm connect a clear case of mismatch. Looks to me too many reflection back to the transformer + reflection from down the line connector. Hope our fren JosephK can connect a 50ohm and 75ohm cable and voola, it can be confirmed, yes no?


----------



## punk_guy182

Dude, S/PDIF is just messed up!


----------



## DaveBSC

Quote: 





punk_guy182 said:


> Dude, S/PDIF is just messed up!


 

 No kidding. Unfortunately the other formats (with the exception of I2S) are all worse.


----------



## mmerrill99

Quote: 





ccschua said:


> isnt this 50ohm connect a clear case of mismatch. Looks to me too many reflection back to the transformer + reflection from down the line connector. Hope our fren JosephK can connect a 50ohm and 75ohm cable and voola, it can be confirmed, yes no?


 

 What 50 ohm connect? Did you not read what punk_guy said a couple of posts above yours? "Marco has confirmed to me that they are using 75ohms parts. I'd like to apologize to the community for saying that it wasn't the case."
   
  I also see that Kingwa from Audio_Gd is also incorrect in his statement about this & is basing his testing of his USB product on this wrong assumption!


----------



## punk_guy182

Quote: 





jkeny said:


> I also see that Kingwa from Audio_Gd is also incorrect in his statement about this & is basing his testing of his USB product on this wrong assumption!


 

 I just emailed him about the issue. It is sometimes difficult to understand what he writes in his emails.
  This is what he had to say in a previous email about Impedance and plugs:
   
  Quote: 





> I ever compare 50ohm and 75ohm and RCA , I spend a lot time to test and listen.
> The 75ohm is detail than 50ohm than RCA socket.
> The 50 ohm is not standard but it still keep 50ohm impedance.
> The RCA has not fix impedance, it some time maybe 30ohm, but after 1 min it maybe up to 100 ohm.
> The clear different on 75 ohm and 50 ohm is as the photo. You can see the axes on 75ohm is with plastic loop.


----------



## mmerrill99

Yep, if anybody can make sense of this perhaps it might be of interest? Even when it was said that he used a 50 ohm BNC connector because Hiface used one - it didn't make any logical sense then either!
   
  And I'm sorry if I shouldn't be talking about another manufacturer's product (seeing as I'm labelled as one myself) but he is directly comparing his product to the Hiface (even by the name?) so I think it's fair to question what this product is about?
   
  PS. sorry these posts should be over on the Audio_Gd USBface thread so as to keep this one on focus


----------



## digger945

jkeny,
  you got a PM.


----------



## Zorlac

Would any of you knowledgeable/experienced DIYers be willing to mod my Neko Audio D100 DAC's S/PDIF coax output and change it to a properly terminated 75 Ohm BNC? I will also need my hiFace modded to a properly terminated 75 Ohm BNC (sounds like Jkeny cant do this anymore because of legal reasons). I will pay for parts, labor and shipping.


----------



## punk_guy182

Quote:  





>





> I will also need my hiFace modded to a properly terminated 75 Ohm BNC (sounds like Jkeny cant do this anymore because of legal reasons). I will pay for parts, labor and shipping.


 

 Yeah the Hiface BNC socket is 50ohms and 75ohms would be better.


----------



## mmerrill99

Quote: 





zorlac said:


> Would any of you knowledgeable/experienced DIYers be willing to mod my Neko Audio D100 DAC's S/PDIF coax output and change it to a properly terminated 75 Ohm BNC? I will also need my hiFace modded to a properly terminated 75 Ohm BNC (sounds like Jkeny cant do this anymore because of legal reasons). I will pay for parts, labor and shipping.


 

 Ah yes, I can't have Hiface units sent to me any more!


----------



## mmerrill99

Quote: 





punk_guy182 said:


> Yeah the Hiface BNC socket is 50ohms and 75ohms would be better.


 
  Is this for sure? What is the evidence? It's better to give all the evidence rather than just make a statement - please spill the beans!


----------



## Sebhelyesfarku

The impedance of the BNC hiFace flip-flopped more in the last couple of days than a politician! MWUAHAHAHA


----------



## Bubu1

Quote: 





jkeny said:


> Ah yes, I can't have Hiface units sent to me any more!


 

 Really?  How unfortunate! Does this mean that you will no longer offer the modded units?   I'm really enjoying the boxed mod you did for me.  It is excellent and by far the best money I have spent on equipment yet!


----------



## mmerrill99

Quote: 





bubu1 said:


> Really?  How unfortunate! Does this mean that you will no longer offer the modded units?   I'm really enjoying the boxed mod you did for me.  It is excellent and by far the best money I have spent on equipment yet!


 
  I can provide modified Hiface units but only those that I buy - I can't receive boxes from outside EU for modification so I'm not doing the "send me your box for modification" service any more - I'm sure you understand this


----------



## punk_guy182

Ok guys I think I should have waited a bit before declaring that the BNC socket is 75 or 50 ohms. The feedback that I got will serve me as a lesson for next time.
  Nevertheless I got an email from Marco saying that they got their BNC sockets from Tyco.  It is listed on Tyco's website that the socket is 75ohms. Some manufacturers get it right and others don't I guess we would have to measure the impedance for the absolute truth.
   
  Peace!
   
http://www.tycoelectronics.com/catalog/products/en?q=1-1478031-0


----------



## ROBSCIX

I was wondering what some of the modders think of changing to optical output?
  As with anything else it has it's positives and negative aspects but I was wondering my optical is not offered as an output option?


----------



## punk_guy182

TOSlink or optical carries more jitter than any other digital signals.
  The advantage of TOSlink is that it is not vulnerable to interferences since it is not an electrical signal.


----------



## regal

And you don't have to worry about reflections, impedance mismatch, 50 ohm connects,  it adds up,  there are a lot of advantages to Toslink that people overlook.
  
  Quote: 





punk_guy182 said:


> TOSlink or optical carries more jitter than any other digital signals.
> The advantage of TOSlink is that it is not vulnerable to interferences since it is not an electrical signal.


----------



## DaveBSC

Quote: 





regal said:


> And you don't have to worry about reflections, impedance mismatch, 50 ohm connects,  it adds up,  there are a lot of advantages to Toslink that people overlook.


 

 True. The only trouble is I've never heard optical sound anything other than lousy. Optical is great at avoiding ground loops. I think its RF/EMI immunity is overrated. If your listening space is so noisy that a digital coax with a foil/braid shield isn't enough, you have other problems. Optical is a disaster for jitter control. Since nobody can agree on a damn standard connector for I2S, the best options we've got are AES/EBU and BNC.


----------



## ROBSCIX

Quote: 





regal said:


> And you don't have to worry about reflections, impedance mismatch, 50 ohm connects,  it adds up,  there are a lot of advantages to Toslink that people overlook.


 
   
  Yes, that is what I figured so that is why I asked for peoples opinions as to why they think it is not used with this unit.  There are pros and cons for any of these connection methods.  I think much of the issue come from companies using poor quality transmitters and receivers.
  Providing you have quality TX and RX, everything should work out great.  Maybe I will do some testing when I get some time.


----------



## mmerrill99

If you can find a quality TX & RX  for coax please tell - even more so for Toslink


----------



## DaveBSC

Well the EVO has Toslink, along with basically every other digital format ever used, so that's one way to go. Another issue with it is that supposedly Toslink isn't reliable above 24/96, which is why many DACs are limited to that when using it.


----------



## punk_guy182

I just wouldn't bother with TOSlink. S/PDIF outperforms TOSlink in so many ways.
  I would only choose TOSlink over S/PDIF when running a digital cable from PC motherboard to the DAC.


----------



## nattonrice

Do you mean bnc?


----------



## punk_guy182

Yes BNC is one of the 2 terminations possible with S/PDIF coaxial. I'd take BNC over RCA.


----------



## regal

The problem with the EVO is it will still have to be modded since the internal regulators aren't near the quality of what we are getting out of the Hiface mads.
  
  Quote: 





davebsc said:


> Well the EVO has Toslink, along with basically every other digital format ever used, so that's one way to go. Another issue with it is that supposedly Toslink isn't reliable above 24/96, which is why many DACs are limited to that when using it.


----------



## DaveBSC

Quote: 





regal said:


> The problem with the EVO is it will still have to be modded since the internal regulators aren't near the quality of what we are getting out of the Hiface mads.


 

 Right, but a modded EVO would give you the option to use Toslink or whatever digital connection you choose, without the need for any adapters. I'm curious how the modded Hiface would stack up against a DAC with built in 24/192 asynch USB like the W4S DAC-2. That would be an interesting experiment.


----------



## regal

Not really,  SS power supply, no galvanic isolation, no dedicated RBCD clock and you're stuck with a S-D DAC.  Not interesting to me at all.  
   
  The only USB protocol that is potentially superior to the modded Hiface is the Ayre because it hase galvanic isolation from the USB before the I2S output.
   
   
   
  Quote: 





davebsc said:


> Right, but a modded EVO would give you the option to use Toslink or whatever digital connection you choose, without the need for any adapters. I'm curious how the modded Hiface would stack up against a DAC with built in 24/192 asynch USB like the W4S DAC-2. That would be an interesting experiment.


----------



## mmerrill99

Anybody know diddly about the ST optical output included on the Evo. It seems a strange move as only EMM & Wadia DACs use it (but I guess the upcoming M2tech DACs will also). But apart from it being a different mechanical optical connector is there any sonic advantage to it?
   
  The only bit that I could find was from here: http://www.stereophile.com/cdplayers/189/index10.html
   
  Quote: 





> These are glass guys. Off-the-shelf integrated glass optical transmitters combine the driver circuitry and laser transmitter into one unit. But according to Wadia, such transmitters are intended for use in long-distance telecommunications; when used in short audio lengths, they overload the receiver and cause jitter. So Wadia designed a discrete glass optical transmitter tuned for shorter lengths which, they claim, _lowers_ jitter. They say the improvement can be heard in _any_ D/A converter with a glass-fiber input.


 
  This seems to indicate that a proprietary driver is need to avoid the high jitter of standard optical transmitters/receivers! Any ideas - is there a proprietary ST chip in the Evo?


----------



## DaveBSC

Are you sure it doesn't have galvanic isolation? I was looking at the 6moons preview, and they said all digital inputs other than Toslink are isolated. The DAC is the Sabre 9018 which isn't exactly a bad one. What is the Ayre using?


----------



## regal

I've received my new DIT chip and repaired my Hiface.   What are the thoughts on the external linear regulator +5V and +1.8V power supply?   I'm thinking that since it shares ground with the USB a big ground loop is immenant,   I'm thinking about forgoing this part of the mod?


----------



## regal

This 1.8V LDO regulato rMCP1700T-1802E/TT works fine with a 3.3V input from the batteries,  I'm thinking about forgeting about the +5V mod and just using this reg on the batteries for the 1.8V.  Jenky you may want to consider this as its only a $1 cost adder?
   
  I'm  going to start tonight,  any opinions appreciated.


----------



## Zorlac

Hey Regal, Jkeny, etc.
   
  I think it would be interesting for you guys to design and build your own USB converter. Have you ever considered this?  
   
  I dont mean this in a negative way, because I think your hiFace mods are incredible, but I would love to see a custom design from the ground up with your knowledge.


----------



## regal

Impossible,  it takes months to program an asynch converter,  huge expenses.  Its nothing like the PCM2707 USB recievers of old.
   
   
  Quote: 





zorlac said:


> Hey Regal, Jkeny, etc.
> 
> I think it would be interesting for you guys to design and build your own USB converter. Have you ever considered this?
> 
> I dont mean this in a negative way, because I think your hiFace mods are incredible, but I would love to see a custom design from the ground up with your knowledge.


----------



## mmerrill99

Yes Regal, I too am concerned about ground loops although maybe the galvanic isolation on the output of the Hiface mitigates this?
   
  I believe that the 5V PS is a worthwhile target as it powers the DIT4192 chip that generates the SPDIF signal! My experiments have shown that there is a sonic benefit of about 5% when compared to the sonic benefit of 95% for the 3.3V mod.
   
  I'm interested in your 1.8V experiments - I didn't do this as I reckoned that it was just powering the core logic of the Xilinx chip. I reasoned that the main benefit might be in removing the Hiface on-board 1.8V regulator & whatever noise it might be putting out. But, I'm open to being wrong & interested in the outcome of your experiments.
   
  When I look at regulators, the criteria I look for in digital circuits is the noise figure. looking at the MCP datasheet is not very encouraging - it's noise Vs freq plot is abysmal, up around 8/9 mV/SQRT Hz  at 0.01KHz. I think we need as low a noise figure at low Hz. I would prefer something like LT1763 at 20uV from 10Hz to 100KHz.


----------



## ROBSCIX

Quote: 





jkeny said:


> If you can find a quality TX & RX  for coax please tell - even more so for Toslink


 

 You don't like the quality of the current units on the HiFace?
  As for toslink, it seems that many attribute the issue with that connection to the TX and RX used.
  What is your opinion on that?


----------



## mmerrill99

Quote: 





robscix said:


> You don't like the quality of the current units on the HiFace?
> As for toslink, it seems that many attribute the issue with that connection to the TX and RX used.
> What is your opinion on that?


 
  I don't know about the Evo .
  That would seem to be the issue alright.


----------



## regal

Quote: 





jkeny said:


> Yes Regal, I too am concerned about ground loops although maybe the galvanic isolation on the output of the Hiface mitigates this?


 

 If you look at the stereophile measurements on transport jitter,  they all show a hump in jitter at 60hz,  this tells me the jitter is there from a ground loop issue before the pulse transformer and won't go away.


----------



## mmerrill99

Quote: 





regal said:


> If you look at the stereophile measurements on transport jitter,  they all show a hump in jitter at 60hz,  this tells me the jitter is there from a ground loop issue before the pulse transformer and won't go away.


 
  But what if you run a laptop on batteries as your source? I would expect this to kill the ground loop issue. So now we get into a specific computer for music playback which is no bad thing as I don't believe we should be using our general purpose computer as our music transport but rather a dedicated & optimised one.


----------



## regal

I am finally done with this project.  I ended up replacing the stock BNC because it didn't have the same connector as a true amphenol 75 ohm BNC.  I tried the linear power supply for +5V and 1.8V and heard no improvement so I removed the external powersupply to make it simple.  The battery holders are nice and the form factor is very small to allow hooking straight into the DAC.  The sound is really really phenomonal.


----------



## regal

thats an idea,  I'm not a laptop person so someone else will have to try,  definately worth looking into.  I'm moving back to building tube amps.  Desoldering/installing that DIT just about did me in for SS/digital projects for a while 
   
  I highly recommend anyone doing this mod to use flexible small wire,  they make it for the model train hobbiests.
   
   
  Quote: 





jkeny said:


> But what if you run a laptop on batteries as your source? I would expect this to kill the ground loop issue. So now we get into a specific computer for music playback which is no bad thing as I don't believe we should be using our general purpose computer as our music transport but rather a dedicated & optimised one.


----------



## mmerrill99

I'm not terribly surprised that you didn't notice any improvement with the 1.8V external supply for the reasons I gave above but I thought the 5V would have seen some benefits?
   
  Anyway, it's great that you are happy with the sound - it truly is high-end, I think you'll agree!
   
  You gave up the ideas of changing the output stage?
   
  Your next adventure, & this should appeal to you as an admitted  frugophile, is to try attenuators on the output!!


----------



## regal

Quote: 





jkeny said:


> You gave up the ideas of changing the output stage?


 


 I installed the SC pulse transformer per the AES paper here:
http://www.scientificonversion.com/AES1998.pdf


----------



## mmerrill99

Any change in sound with this xfmr?


----------



## regal

I can't honestly say, I  just changed everything at once.  They have a good reputation if you check out their website.
   
  I ordered a 9db minicircuit attenuator to try.


----------



## ccschua

Just wonder if anyone else can confirm if the mod hiface is already HIFI. meaning how does it compare to the highend transport like belt drive, cdm1, cdmpro , etc.


----------



## Sebhelyesfarku

Would it make sense to try BNC attenuator on an RCA hiFace/DAC? (with RCA-BNC converters). It would work the same way, decreasing the output level, no? Impedance, well, be damned!...


----------



## regal

better,  ground breaking,

  
  Quote: 





ccschua said:


> Just wonder if anyone else can confirm if the mod hiface is already HIFI. meaning how does it compare to the highend transport like belt drive, cdm1, cdmpro , etc.


----------



## ccschua

After I hook up the blackcat velose, it is more ground breaking.
   
  I am not sure if blackcat + attenuators helps again ?


----------



## mmerrill99

Quote: 





sebhelyesfarku said:


> Would it make sense to try BNC attenuator on an RCA hiFace/DAC? (with RCA-BNC converters). It would work the same way, decreasing the output level, no? Impedance, well, be damned!...


 

 PLEASE, It's NOT about reducing the output level - it's about reducing the reflections. The high output level is probably not a problem for 90% of DACs i.e. it doesn't over-drive them (some of them even prefer high levels). Yes the attenuators reduce the SPDIF output level & as a result doubly reduce reflections. So your conundrum is, will the extra reflections introduced by the RCA-BNC converter be eliminated & more by the attenuators - nobody knows. It's a $30 experiment, why not do it & let us know? You can always sell the attenuators & converter if it fails.


----------



## regal

I thought it was a $15 experiment, the one I bought was only $15 from minicicuits,   did I get the wrong one?  It was the 9dB version.
  Quote: 





jkeny said:


> It's a $30 experiment, why not do it & let us know? You can always sell the attenuators & converter if it fails.


----------



## punk_guy182

Quote: 





regal said:


> I thought it was a $15 experiment, the one I bought was only $15 from minicicuits,   did I get the wrong one?  It was the 9dB version.


 
  Where did you get this 9dB version?
  The only versions I see are: 3-6-10-15-20dB http://www.minicircuits.com/products/attenuators_coax_fixed.html


----------



## regal

http://www.minicircuits.com/cgi-bin/modelsearch?model=HAT-9&search_type=model
   
  I see its not rated for 75 ohms ,  dammit
  
  Quote: 





punk_guy182 said:


> Where did you get this 9dB version?
> The only versions I see are: 3-6-10-15-20dB http://www.minicircuits.com/products/attenuators_coax_fixed.html


----------



## punk_guy182

You have to pick the ones that are at the bottom of the page.
   
  [size=small]Attenuators, Coaxial (BNC)[/size] •  Precision 75 Ohm •  0.5 Watt •  3 to 20 dB, DC to 2000 MHz


----------



## regal

yea I caught that a day after they shipped the one I ordered wrong,  I guess it would be fine for someone using an RCA Hiface,   PM me if you want it.
  Quote: 





punk_guy182 said:


> You have to pick the ones that are at the bottom of the page.
> 
> [size=small]Attenuators, Coaxial (BNC)[/size] •  Precision 75 Ohm •  0.5 Watt •  3 to 20 dB, DC to 2000 MHz


----------



## mmerrill99

Quote: 





regal said:


> I thought it was a $15 experiment, the one I bought was only $15 from minicicuits,   did I get the wrong one?  It was the 9dB version.


 

 Yes, it's only $12 each - I'm suggesting buying two (75 ohm ones 
	

	
	
		
		

		
			





)!


----------



## regal

I tried the 50 ohm version and it really did improve the sound quite a bit.  This doesn;t surprise me as I think that the stock hiface BNC is 50 ohm,  you can tell by the size of the dielectric surounding the TX pin,  the stock hiiface BNC is no where close the dimensions of a true Amphenol 75ohm connector (Amphenol is a trusted brand.)  I suggestion anyone swap the hiface BNC for the Amphenol version, also the pulse transformer for the Scientific Conversion,  and last add the attenuator (75 ohm)  prior to investing in a $500 digital cable.  I'll never spend that much on a cable but it just makes sense to cover the basics first.


----------



## ccschua

Hi,
   
  can you post the link of the pulse transformer and also the steps taken to replace the pulse transformer and the Hiface 50ohm BNC plug.


----------



## wushuliu

So is it not possible/necessary to use this USB isolator recently mentioned for the Terakink X2, with the Hiface?
   
http://electronicsshop.dk/isoleret_usb.htm


----------



## regal

Quote: 





ccschua said:


> Hi,
> 
> can you post the link of the pulse transformer and also the steps taken to replace the pulse transformer and the Hiface 50ohm BNC plug.


 


 scientificconversions.com part #*SC982-04*  
   
  The 75 ohm BNC amphenol connector from digikey: *ARF1177-ND* 
   
* *
*Steps taken:  desolder and solder new parts in place*


----------



## regal

Quote: 





wushuliu said:


> So is it not possible/necessary to use this USB isolator recently mentioned for the Terakink X2, with the Hiface?
> 
> http://electronicsshop.dk/isoleret_usb.htm


 


 no not possible


----------



## xdanny

All right, I just got through ordering 2 attenuators for my BNC hiFace, one at each end of the cable.  I hope I got the right ones, they are the 10db version at the bottom of the page.  I will let everyone know once I test them.  
   
  I did post my impressions of the unit that jkeny modded for me.  Here is a link to that in case anyone is interested: 
  http://www.head-fi.org/forum/thread/446375/usb-24-192khz-m2tech-hiface/1440   post #1450
   
  Again, thank you John (jkeny) for an excellent job!  I am really happy he agreed to do it because I do lack the knowledge yet I'm constantly drooling over these diy threads and I "hate" all you guys who really understand this stuff... 
	

	
	
		
		

		
			




   
  Cheers!


----------



## regal

Quote: 





xdanny said:


> I do lack the knowledge yet I'm constantly drooling over these diy threads and I "hate" all you guys who really understand this stuff...
> 
> 
> 
> ...


 


 If you had high school physics you can understand the fundamentals, learn and apply ohms law inside and out that's 90% of it really,  the hard part is the mechanics of soldering to tiny pieces on a cheap PCB with old eyes and feeble hands.   Don't believe anyone without a Phd who claims to fully understand RFI , reflections and the like,  its an empirical science (trial and error) with the theory explaining the test results not the other way around.
   
   
  On another note I found if you discharge the batteries too far and they won't take a charge you can bring them back to life by switching the charger to 4.7V for a minute or less,  then putting them back on the 3.6V charger.  I find I have to disconnect the batteries when I'm done listening otherwise they continue to have current drawn even with the USB unplugged.


----------



## ccschua

happen to mine. Within 4 weeks of listening (about 1 hour each), the battery is flat. on hindsight, I charge it to 4.7 V and I just discharge it using a 10W 10ohm resistor and within secs, it drops to 3.2V.


----------



## regal

Quote: 





ccschua said:


> happen to mine. Within 4 weeks of listening (about 1 hour each), the battery is flat. on hindsight, I charge it to 4.7 V and I just discharge it using a 10W 10ohm resistor and within secs, it drops to 3.2V.


 

 Next time just charge on 4.7V for a minute then switch to 3.6V you will get better battery life (although when we discharged them too far their life was compromised somewhat regardless.)


----------



## keyboard

I don't k now whether jkeny would be interested in testing the Digital Interface,I don't have a hi-face so there is no way I can compare the two.


----------



## FauDrei

In that regard I find JKeny's switch solution quite good:
   

 When it is switched on one battery powers the clocks (slow drain), other the chip (fast drain) and the blue led is reminding you it is working.
  
 When you switch it off - the batteries are connected in parallel and, if no charger is connected, the batteries even out - the slow drain battery "recharges" fast drain battery.

 This way I manage to listen for a week (2-3h per day) before recharge is needed. Of course, you have to remember to switch it off after your listening and aforementioned led comes in very useful in reminding you of that.
  
 If charger is connected, when you switch it off the charger recharges both batteries and stops charging once both batteries are full. It is really (semi) automatic mode because you do not have to think about recharging batteries - you only have to remember to switch it off once your listening is done.

 This is most elegant way of dealing with battery powered hiFace, but I still prefer one "big" recharge per week instead of many "small" recharges daily. YMMV.
   
  Otherwise, good to know how to revive excessively drained batteries (if/when I manage to forget to switch it off), thanks guys.


----------



## regal

Yes Jenky has a good implementation,  I bought the battery holders,  just have to remember to remove the batteries when done, I wanted to have the batteries separate from the charger just because I'm a paranoid individual and murphies law always strikes me 
   
  I had to put in a separate order for a dam 64 cent jam nut from digikey to hold the hiface from both sides of the case.  If you order from digikey make sure you pick up part number 1-1634816-0    so you don't pay $5 to ship a 64 cent nut that no hardware stores carry locally!


----------



## Sebhelyesfarku

What would be the *simplest* way to get the 4.5-5.5V range for USB from two LiFePO4 accus (2x3-3.4V = 6-6.8V)? I mean without regulators, complex PCBs, whatever. For e.g. with a simple resistor? Obviously I'm clueless about electronics


----------



## ccschua

Hi FauDrei,
   
  just wonder if you have compared the modded hiface with other dedicated cd transport ?


----------



## i_djoel2000

hi, all..i heard usb input has higher jitter than coaxial/optical input. can someone tell me the audible difference of the higher/lower jitter? is this why they're building m2tech?
   
  sorry for the noob question


----------



## regal

Quote: 





i_djoel2000 said:


> hi, all..i heard usb input has higher jitter than coaxial/optical input. can someone tell me the audible difference of the higher/lower jitter? is this why they're building m2tech?
> 
> sorry for the noob question


 

 wrong thread


----------



## mmerrill99

Quote: 





keyboard said:


> I don't k now whether jkeny would be interested in testing the Digital Interface,I don't have a hi-face so there is no way I can compare the two.


 

 Digital interface of what?


----------



## mmerrill99

Quote: 





regal said:


> I tried the 50 ohm version and it really did improve the sound quite a bit.  This doesn;t surprise me as I think that the stock hiface BNC is 50 ohm,  you can tell by the size of the dielectric surounding the TX pin,  the stock hiiface BNC is no where close the dimensions of a true Amphenol 75ohm connector (Amphenol is a trusted brand.)  I suggestion anyone swap the hiface BNC for the Amphenol version, also the pulse transformer for the Scientific Conversion,  and last add the attenuator (75 ohm)  prior to investing in a $500 digital cable.  I'll never spend that much on a cable but it just makes sense to cover the basics first.


 
  I don't think the dialectric around the TX pin is a visual identifier of a 50ohm connector - this only applies to the female RX part where a dialectric ring inside the ground shield is a sign of a 50ohm part.
   
  I posted about this in another thread because I had bought 75ohm Huber & Suhner 75 ohm attenuators & I thought I had been duped because they looked like this: note the white insulation ring - this is a 50ohm connection at this end anyway. This image is taken from their web-site & is also on their datasheet. Joseph K checked his & also confirmed that they were also like this. I emailed H&S but because I didn't buy them from their official distributor @ €45,each,  they won't deal with my request for technical information about this part. They are saying I should look for my money back even though these are genuine H&S 75ohm attenuators. A bit arrogant & not very forthcoming which make me they are think they are hiding smething. 
   
  So you see it's not just cheap parts that are suspect even the reputable H&S seem to have it wrong although I don't know why they would do this?
  
  You can see now why I recommend minicircuits - firstly they are $12 parts compared to what $60 for H&S. Secondly their 75 ohm part looks like it's really 75ohm.


----------



## FauDrei

ccschua said:


> Hi FauDrei,
> 
> just wonder if you have compared the modded hiface with other dedicated cd transport ?


 

 Well, stock hiFace was already in most aspects better than my Marantz (CD63SE), but that's not saying much.
   
  Recently I brought my modded hiFace and DB-510 to my friend's place and it trashed his old Sony <something> ES into his Benchmark DAC1 USB (that I don't like).
   
  O, ya... Benchmark's USB input? Bah, Sony CD player through SPDIF was better. Especially with Oyaide digital cable.


----------



## keyboard

Quote: 





jkeny said:


> Digital interface of what?


 


 audio-gd's Digital Interface.


----------



## keyboard

The digital interface bu audio gd.


----------



## mmerrill99

Quote: 





keyboard said:


> The digital interface bu audio gd.


 

 I don't have a Audio-gd USBface so I don't think so - anyway, is that not what audio-gd are doing themselves & publishing their findings?


----------



## keyboard

The findings are not published,the test user results will be published.you should have applied for being a test user.


----------



## mmerrill99

I didn't see that option anywhere!


----------



## keyboard

That was on their website,not there anymore.


----------



## regal

Quote: 





jkeny said:


> I don't think the dialectric around the TX pin is a visual identifier of a 50ohm connector - this only applies to the female RX part where a dialectric ring inside the ground shield is a sign of a 50ohm part.


 


 If [size=x-small]Mr. He Qinghua [/size] (Audiogd) identified it as a 50 ohm BNC odds are good that it is IMHO.  It cost me $8 and 15 minutes with the soldeing iron to replace it.


----------



## mmerrill99

Quote: 





regal said:


> If [size=x-small]Mr. He Qinghua [/size] (Audiogd) identified it as a 50 ohm BNC odds are good that it is IMHO.  It cost me $8 and 15 minutes with the soldeing iron to replace it.


 
  As you said yourself, he's not infallible, none of us are, especially not the pope who claims infallibility 
	

	
	
		
		

		
			




   
  Most people don't own a soldering iron or want to invalidate their warranty!


----------



## tomasino

Hi jkenny, i would like to try doing you "battery mod" myself. I looked to all you photos and description of that. I´m total noob in electrotechnics and soldering, so i´m sorry for maybe little bit stupid questions.
  For me battery mod for clocks seems clear. Mainly from Regal´s picture: http://www.head-fi.org/forum/thread/446375/usb-24-192khz-m2tech-hiface/1320#post_6718773
   
  But problematic for me is understanding what must i exactly do to complete battery power mod for rest of board. I´m attaching you image with description. First of all i must remove regulator on top. Next step is not clear for me. I marked two soldering points at bottom of board. Are these two right soldering points for battery conection or i´m wrong? I issued from you description, but not sure if i understand it right:
   
_"The 3.3V external +ve supply can be connected to the square connection point at the bottom of the pic (just to the left of the W4 letters) & the -ve (ground) external 3.3V supply to the round pad to the left of this."_


----------



## tomasino

Hi jkenny, i would like to try you "battery mod" myself. I´m looked at all your description and pictures at head-fi even at diyaudio. Unfortunatelly i´m total electrotechnics and soldering noob. So i´m sorry for maybe little bit stupid questions.
  Battery mod for clocks seem very clear for me. Mainly from Regal´s picture: http://www.head-fi.org/forum/thread/446375/usb-24-192khz-m2tech-hiface/1320#post_6718740
   
  But i have problem with understanding what exactly must be done if i want to complete external power for rest of hiface board. I know first step is removing regulator marked at top of your picture. But second step is not clear to me.
  I´m attaching your picture of mod. I marked two soldering points for external power. Are these two points right or am i wrong? I issued from you description: _"The 3.3V external +ve supply can be connected to the square connection point at the bottom of the pic (just to the left of the W4 letters) & the -ve (ground) external 3.3V supply to the round pad to the left of this."_
   

   
  Thank you for your help
   
  Thomas


----------



## mmerrill99

Hi Thomas, I would just do the clock mod - it gets you 90% of the way there & is the easiest also. The rest is difficult for not as big a return. 
   
  If you really want to go ahead then just remove the 3.3V regulator circled in yellow at the top of the picture & provide the external 3.3V supplies to the points you have identified at the bottom of the pic.


----------



## ccschua

can I know what Thomas indicated "external + and - supply" are actually going into the 3.3V regulator ?
   
  Which means just ground the enable pin, remove the regulator (optional) and supply 'another' 3.3V to the regulator right


----------



## mmerrill99

Quote: 





ccschua said:


> can I know what Thomas indicated "external + and - supply" are actually going into the 3.3V regulator ?
> 
> Which means just ground the enable pin, remove the regulator (optional) and supply 'another' 3.3V to the regulator right


 

 Yes those annotated connection points are +3.3V & ground connection points.
  You will find grounding the enable pin to be quiet difficult - easier to remove the reg altogether BUT I'm suggesting NOT to do this at all, just do the clock mod as Regal has shown.


----------



## regal

If you decide to remove the regulator you will be going past a point of no return.  This PCB is thin and cheap,  it taks a lot of flux and heat to remove the regulator and probably will pull a trace or two up with it.  Be careful,  its easy to blow up the DIT which takes special solder and tips to remove and replace.


----------



## GreenLeo

Any chance to see the photo of the final version of Regal's mod?  Just want to look at the 75 ohm BNC connector and the new regulator used in the mod.


----------



## regal

Quote: 





greenleo said:


> Any chance to see the photo of the final version of Regal's mod?  Just want to look at the 75 ohm BNC connector and the new regulator used in the mod.


 


 I took the regulator out,  running a separate +5V B= just sets up a big ground loop that causes more harm then good.   The connector is self explainitor except TX+ and TX- are reversed,  you'll understand when you order the part.


----------



## hawaya

Hello again JKenny, Regal,
   
  My question is can i remove a pulse  trafo from Hiface, if i use a clean 5V (is this safe for unit)?
   
http://hawaya.snimka.bg/details/dax-hiface.508491.19312896,
   
  Thanks in advance.


----------



## regal

its safe but not neccesarily smart,  your "clean" 5V just made a big ground loop. I removed the separate 5v+ because it degraded the SQ in my setup. The Texas Instruments DIT4192 datasheet calls for an SC pulse transformer and I assume they know more than us.  Unitl Adum or whomever makes a 480mBS USB isolator and we can galvanically isolate the hiface from the computer I would stick with the pulse transformer.  
  
  Quote: 





hawaya said:


> Hello again JKenny, Regal,
> 
> My question is can i remove a pulse  trafo from Hiface, if i use a clean 5V (is this safe for unit)?
> 
> ...


----------



## hawaya

Thanks Regal,
   
  What do you suggest, to remove the trafo with 5v (I use both positive and negative wire), and switch to dirty computer 5v from usb cable?
   
  Regards


----------



## regal

You still have the ground of the PC connected otherwise it won't work right,  you can't isolate the Hiface from the computer,  so the external 5V+ just makes a big ground loop,  we are stuck with the dirty USB 5V+ for now.
   
  Quote: 





hawaya said:


> Thanks Regal,
> 
> What do you suggest, to remove the trafo with 5v (I use both positive and negative wire), and switch to dirty computer 5v from usb cable?
> 
> Regards


----------



## hawaya

So 5v from computer, the SQ is better? And what if i use 5v from battery?


----------



## mmerrill99

I modified the 5V supply to remove it from the USB input of the Hiface & supplied externally - I get no ground loop hum or noise! 
   
  OT. Here's a brilliant idea - a LiFePO4 battery supply for audio - only costs $1,000 to upgrade your equipment. Some people athttp://www.computeraudiophile.com/content/Updated-Battery-technology-RWA think it's a great idea. Now why didn't I think of that 
	

	
	
		
		

		
		
	


	




(charging $1,000 instead of €50, I mean 
	

	
	
		
		

		
		
	


	




)


----------



## Zorlac

Hey Jkeny...have you ever looked into using double-conversion online UPS power? I started reading up on these and apparently they output perfect sinewave power at all times. Would this essentially be the same as battery power to the amp, DAC, etc.? I will probably buy one regardless at some point.


----------



## mmerrill99

So far I haven't heard or been told of any commercial or DIY regulator or PS that beats these batteries for sonics. There may be but I haven't heard about them!


----------



## hawaya

Thanks Jkenny, i don't have any hum too with external 5v, but is there any improvement with oscillators, i have with the second device one  small, and one big, or should i use other brand oscillator, with low ppm?


----------



## mmerrill99

I meant to say that my 5V was not from a battery & i still don't seem to have a ground loop but I'll investigate further.
   
  I've stayed out of the oscillator discussions by & large but I really don't get it. Can I ask you this, what oscillator are you thinking of to replace the smaller osc.? How do you know the replacement one is lower jitter? Are there any specs for the "bad" oscillator - what is it's jitter spec? How does a change of PS make a "bad" oscillator into a "good" sounding one?
   
  Have any of these questions been addressed?


----------



## hawaya

Don't get me wrong, i just ask you because you have large experience, with both type, for me the large improvement in SQ came with your 3,3v battery mode.


----------



## mmerrill99

I'm not being confrontational or attacking you - I just had to answer your question honestly - I think there might be a rush to judgement based on very flimsy evidence i.e. I don't even know if there is any consensus that all units with "small" clocks sound bad? Surely this sort of evidence needs to be established first? These are just my thoughts on the matter - I'm undecided about it but think these questions need to be asked/answered.


----------



## FallenAngel

While I do enjoy seeing a nice discussion on modding gear, it strikes me as very funny to see the length people will go to mod a $150 USB to S/PDIF converter.


----------



## sleepy dan

Quote: 





fallenangel said:


> While I do enjoy seeing a nice discussion on modding gear, it strikes me as very funny to see the length people will go to mod a $150 USB to S/PDIF converter.


 

 Why?


----------



## hawaya

Quote: 





fallenangel said:


> While I do enjoy seeing a nice discussion on modding gear, it strikes me as very funny to see the length people will go to mod a $150 USB to S/PDIF converter.


 

 Because may be , the future is in the computers as source?


----------



## FallenAngel

No doubt there is bad gear out there and yes, it's likely that computers as source are much more common now.  I simply find it funny to what lengths people mod gear, this sounds like the Honda Civic of computer audio. 
	

	
	
		
		

		
		
	


	



   
  No offense, I realize my comment probably came off worse than intended.  The perspective in my mind is "it's JUST a transport converter" and plays a minor role in comparison to the rest of the system.  Since there was some mention of "audiophile USB cables", that certainly puts things into perspective on where the S/PDIF converter stands in terms of "overall importance".  Some may disagree, this is simply my take on it.  I will no doubt try something like this in the future, for now, I'm happy using a modded sound card as transport (X-Fi XtremeMusic with S/PDIF signal taken at output buffer, sent through a pulse transformer and connected to a BNC jack via 75R coax).


----------



## mmerrill99

Quote: 





fallenangel said:


> ................ for now, I'm happy using a modded sound card as transport (X-Fi XtremeMusic with S/PDIF signal taken at output buffer, sent through a pulse transformer and connected to a BNC jack via 75R coax).


 

 And what's the difference between modding a (ahem!)  sound card & this (apart from the superior quality of this compared to an modded X-Fi). Jeez, some guys are hilarious


----------



## Zorlac

I suspect FallenAngel has a X-Fi to benefit from PC games that support EAX and OpenAL. The thing is that those standards are pretty much dead for all modern games. Hardware sound is dead in fact. Game makers are now using software engines. Moving away from a sound card (i.e. X-Fi) to the hiFace was the best computer sound upgrade I have done yet...in fact, I was so blown away that I too got addicted to this thread and decided to buy a Jkeny modded unit.


----------



## mmerrill99

Is FallenAngel just trying to be devil's advocate - sorry for the bad joke - Just had to say that


----------



## FallenAngel

[size=medium]A little playing devil's advocate, perhaps offering a little perspective.   Some go nuts with opamp changes, some spend more on cables than headphones and amplification while some others seem to mod all hell out of things.  
   
  I use the X-Fi as it offers hardware acceleration but much more importantly, it allows for 3D-CMSS, a great benefit for gaming.  It also happens to be a decent bit-perfect (and now transformer coupled) transport.   The reason I modified it is because it barely cost me $15 to add a pulse transformer and a BNC jack, which is what I wanted.
   
  As for "superior quality", I can't comment as I haven't heard this one yet.  For computer transports, I've used a couple of different PCM270x-based converters, an EMU0404PCI, an ESI Juli@, of course an older Chaintech AV710, and this X-Fi.  Truth be told, I haven't noticed enough difference between them to stress over this.  The EMU0404 was my favorite S/PDIF transport, though still no match for hard-wired I2S from the Juli@ going to my Buffalo32 DAC. 
   
  I think in a few months, I'll have a nice DAC built and can play more with transports, this HiFace will be something to try.  For now, perspective is what's important for me; and transport is less important than headphones, amplification and DAC.  Though certainly more important than cables. ​[/size]


----------



## regal

FallenAngel,  I never messed with transport using my Emu0404 PCI for 4 years,  didn't believe a big difference could be heard.
   
  This battery powered Hiface is a huge upgrade over the 0404,  I mean real big,  much bigger than changing from an amp's gain stage from 6SN7GTB to VT-231's.  You can make out words and emotional cues in voices like never before,  intrumental tone is just right.
   
  Just a little perspective ,  you have your head buried in the sand as I did because you have never heard a $20k transport.


----------



## FallenAngel

That's easily possible, I've went to my share of meets and listened to tons of gear, but transport has never been a huge focus of mine so compared to some of the others, I'm probably completely ignorant (as I chose not to pursue transport upgrades much).  I can accept that and look forward to hearing a better transport once I get a decent DAC up and running (minimized my setup when I moved a few months ago).
   
  Just a quick question, how is the charging circuit on that lipo cell?  Once I finally get settled (hopefully in a new condo with a decent workshop), I totally plan to mess with one of these.


----------



## regal

I just use the $8 charger that I linked earlier.   I believe that soon all the big dogs will be using LiPO4 batteries for their clocks,  first person to patent a charging circuit for audio clocks with 2 banks that relay back and forth will be a Rich man.


----------



## FallenAngel

Well, there are certainly options with lipo chargers out there and the batteries are relatively cheap in the grand scheme of things.  Can't imagine this being too hard.  Lots of portable amps use lipo batteries these days anyway, nobody says anything has to be as specific as "charging circuit for audio clock".


----------



## regal

Quote: 





fallenangel said:


> Well, there are certainly options with lipo chargers out there and the batteries are relatively cheap in the grand scheme of things.  Can't imagine this being too hard.  Lots of portable amps use lipo batteries these days anyway, nobody says anything has to be as specific as "charging circuit for audio clock".


 

 Take a look at how AudioNote patented the use of a step-up transformer in their DAC's,  all it takes is a good lawyer.


----------



## sleepy dan

Quote: 





regal said:


> I just use the $8 charger that I linked earlier.   I believe that soon all the big dogs will be using LiPO4 batteries for their clocks,  first person to patent a charging circuit for audio clocks with 2 banks that relay back and forth will be a Rich man.


 

 I use a charger I built using the LT3652 (suggested to me by jkeny).  There's a  3.3V circuit in it's datasheet. Does the job nicely and is pretty intelligent.


----------



## regal

I did a comparison of the A123 batteries and two different no name Chinese LiFePo4 batteries,   I can't hear any differences,  but the A123's definitely hold a charge longer (even though it is rated lower.)
   
  I've really hit a road block/brain block with the case.  It just seems there is no small case that fits under 2 18650 battery holders available commercially.  And I can't figure out how to make a suitable mount to hold the USB side,  the chassis is always the least favorite part of anything I build.
   
  I think for modders the Evo is probably going to be a better platform to start from,  I doubt any SQ improvement but ergonomically easier to work with.


----------



## upstateguy

Quote: 





fallenangel said:


> <snip>  *I think in a few months, I'll have a nice DAC built *and can play more with transports, this HiFace will be something to try.
> <snip>​


 

 OT:  What are you building that's better than your Buffalo 32?
   
  USG


----------



## ccschua

I did a slight ugly way.
   
  with the hiface siting on flat, I drill a 2mm hole to bring out the wire and terminate that wire to female RCA. I wrap this wire to the hiface with tape (and with that, I hold the casing back).  I wrap the battery and wire with tape and terminate it with male RCA. I did the female RCA to the charger and with that I can swap easily.
   
  some mey prefer phone jack.


  
  Quote: 





regal said:


> I did a comparison of the A123 batteries and two different no name Chinese LiFePo4 batteries,   I can't hear any differences,  but the A123's definitely hold a charge longer (even though it is rated lower.)
> 
> I've really hit a road block/brain block with the case.  It just seems there is no small case that fits under 2 18650 battery holders available commercially.  And I can't figure out how to make a suitable mount to hold the USB side,  the chassis is always the least favorite part of anything I build.
> 
> I think for modders the Evo is probably going to be a better platform to start from,  I doubt any SQ improvement but ergonomically easier to work with.


----------



## flu_fighter

Have you tried these? seems like the dimensions might be suitable.

http://cgi.ebay.com/5-x-Box-18650-Rechargeable-CELL-Battery-Holder-Storage-/320567344976?pt=LH_DefaultDomain_2#ht_4971wt_902
   
  Quote: 





regal said:


> I did a comparison of the A123 batteries and two different no name Chinese LiFePo4 batteries,   I can't hear any differences,  but the A123's definitely hold a charge longer (even though it is rated lower.)
> 
> I've really hit a road block/brain block with the case.  It just seems there is no small case that fits under 2 18650 battery holders available commercially.  And I can't figure out how to make a suitable mount to hold the USB side,  the chassis is always the least favorite part of anything I build.
> 
> I think for modders the Evo is probably going to be a better platform to start from,  I doubt any SQ improvement but ergonomically easier to work with.


----------



## b2890x

First post in these glorious forums. Hello to all from Dresden. Reading so much positive feedback about jkenys 3.3 V mod i want to do myself -  I wonder if it is possible to use the 3.3 V output of an PC power supply (ATX) because i dont want to mess around with these batteries? As stationary device that would be optimal. Any suggestions about that? Best regards-


----------



## qusp

why would you do that? the idea is to AVOID the noise caused from sharing ground and power supply with the PC via the USB cable, why bother modding if you are just going to use a PC power supply? seems to be pretty pointless to me, switching power supplies are generally BAD for audio and you would just be replacing what you removed
   
  regal, check the candlepower forums, a guy there has made quite rugged battery holders for mountain bike riding, they use the A123 and similar for their headlights for night riding.. i'll search out the link for you, he has single ones


----------



## b2890x

Oh ok i didn't thought that all the reported improvements in audio quality are caused by isolating the noise of the USB power supply. If thats the only reason then you are right and there seems no other reasonable power supply.
   
  Quote: 





qusp said:


> why would you do that? the idea is to AVOID the noise caused from sharing ground and power supply with the PC via the USB cable, why bother modding if you are just going to use a PC power supply? seems to be pretty pointless to me, switching power supplies are generally BAD for audio and you would just be replacing what you removed


----------



## GreenLeo

QUSP is indeed right for the reason that JKeny's mod increases the SQ of the device.  It's pretty well posted in head-fi's forums and other forums.


----------



## motorica.net

Hi guys
   
  I want to replace the rca connector on my m2tech with bnc connector.
  How hard it will be ?
   
  Thanks
  David


----------



## regal

You have to use alot of solder wick but it is doeable if you have a strong iron and steady hands.    Note the polarity on real BNC connectors are reverse of the stock 50 ohm Hiface so you will have to cross the leads (use heatshrink.)


----------



## motorica.net

Where can i obtain m2tech stock 50ohm bnc connector ?
   
  Does it worth the effort , or should i use an adapter /
   
  Thanks regal


----------



## regal

Quote: 





motorica.net said:


> Where can i obtain m2tech stock 50ohm bnc connector ?
> 
> Does it worth the effort , or should i use an adapter /
> 
> Thanks regal


 

 Probably off the street in Singapore?  
  Few good ones to look at:
   
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=A99517-ND 
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=ARF1704-ND 
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=991-1018-ND


----------



## thread

Where the heck do you buy the Hiface these days anyway? I'm looking around, and can't even find any for sale.


----------



## Lil' Knight

Did you check it here? 
http://www.tweekgeek.com/_e/Portable_Computer_Audio/product/HiFace/M2Tech_HiFace.htm


----------



## thread

Yep, I had actually found Tweek Geek just after that post. Is that the only place it's for sale on the internet?


----------



## cursto

I used the attentuators with my Hiface to great success. I ended up with 10db at Hiface end and 15db at the DAC end. What I noticed most was a deeper soundstage, more "air" around instruments and a more relaxed sound from my DAC. Brushes and cymbals took on a much more realistic sound, a lot closer to analog.Then i went completely craxy and mounted my Hiface inside my DAC connecting it directly to pcb, thus eliminating the RCA/BNC/Cable dilemma!!! So....    now I have 3 attentuators I'm not using. A 6db, a 10db, and a 15db.
If anyone can use them and wants to have them, send me a PM.


----------



## thread

Anyone know how these devices fair on the Mac? Are there issues? I've started a thread here.
   
  http://www.head-fi.org/forum/thread/531980/m2tech-mac-driver


----------



## gameguytw

1.DIY MOD First time

   
  2.DIY MOD SECOND TIME

   
  M2tech Hiface DIY MODer From Taiwan(Country on the Earth)


----------



## tranhieu

^Great post! very informative and detailed! This will automatically go to my diy archive for further reference!


----------



## Takaji

@gameguytw

Can you provide any details on the second mod you did? I want to identify what some of those boards are that you used... what are the dual crystal boards achieving?
Any information would be appreciated.


----------



## upstateguy

@gameguytw
   
  Great job.  
	

	
	
		
		

		
			




   
  Could you describe the things you've done for those of us who are not so electronically inclined.
   
  Thanks
   
  USG


----------



## torkis

@gameguytw:
   
  The first mod why was unsuccesful? The Adum4160 module is not works with HiFace?


----------

