[regal]

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

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

 

[ROBSCIX]

Do these measurments vary between stock to modded unit?

 

[mmerrill99]

Quote:

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:

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:

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:

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


 

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

 

[regal]

 
 
Quote:

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:

 
 
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:

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:

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.

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:

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:

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:

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