M2Tech HiFace 24/192 USB->S/PDIF penstyle interface

roscoeiii · « **Reply #140 on:** 3 Jul 2010, 04:34 pm »

Has anyone tried this with other digital coax cables to see if this trick works for any digital coax cable?

jkeny · « **Reply #141 on:** 3 Jul 2010, 04:49 pm »

Quote from: roscoeiii on 3 Jul 2010, 04:34 pm

Has anyone tried this with other digital coax cables to see if this trick works for any digital coax cable?

It's not that it works for some SPDIF cables & not for others - it's more a case that it will be more noticeable a sonic difference on some than others. This also depends on the DAC being used.

So there are a number of variables to take into consideration & that is why I introduced it for experimenting, hopefully by a number of people to get some consensus & feel for attenuation Vs sound Vs cable Vs DAC.

Have you downloaded the track & listened? How does it sound to you?

jkeny · « **Reply #142 on:** 4 Jul 2010, 12:22 pm »

22 downloads of this Nat King Cole track now! Guys, if your not going to use it to evaluate your system & post your evaluation here please don't download it

It is meant as a tool for evaluating the effect (if any) of attenuators in your system not as a free download. I have now cut down the track so as it's no longer a full song!

jkeny · « **Reply #143 on:** 6 Jul 2010, 05:11 pm »

Hal, how are your experiments going?

29 downloads & only Hal reporting

HAL · « **Reply #144 on:** 6 Jul 2010, 06:26 pm »

Tried the 10dB pad with the RCA version HiFace. It does not change sound quality as much as the BNC version HiFace, which is a bit odd.

I did find that the 6dB pad with the BNC version does not get the same effect as the 10dB version. The 10dB pad is where the sibilant problem goes away.

I guess the next experiment needs to be with the o'scope and a 75 ohm pad. Feed the S/PDIF signal down the line from the HiFace with the attenuator at the o'scope end with the termination at the scope BNC via a "T". Look at the data eye pattern. Best idea I can think of to see what might be changing.

oneinthepipe · « **Reply #145 on:** 6 Jul 2010, 09:23 pm »

I tried the -10db attenuator and found a reduction in sibilance. Brushes, in particular were much more defined. I think that there is much more mid-range definition generally, especially in vocals.

I conferred with jkeny and have since ordered (2) -6db attenuators to use on each end of the BNC cable.

I have been very busy and haven't have much chance for extended listening, but I will report when I have an opportunity to compare the various combinations of and positions of the attenuators.

oneinthepipe · « **Reply #146 on:** 6 Jul 2010, 09:25 pm »

Does anyone know if (2) HiFace adapters can be used with a single computer at the same time?

jkeny · « **Reply #147 on:** 6 Jul 2010, 09:31 pm »

Quote from: HAL on 6 Jul 2010, 06:26 pm

Tried the 10dB pad with the RCA version HiFace. It does not change sound quality as much as the BNC version HiFace, which is a bit odd.

Maybe there are stronger reflections from bigger impedance mismatch which need more attenuation to diminish?

Quote

I did find that the 6dB pad with the BNC version does not get the same effect as the 10dB version. The 10dB pad is where the sibilant problem goes away.

You could try a 6dB at each end of the cable? You just don't want to attenuate too much that it causes the SPDIF receiver problems or fails to lock.

Quote

I guess the next experiment needs to be with the o'scope and a 75 ohm pad. Feed the S/PDIF signal down the line from the HiFace with the attenuator at the o'scope end with the termination at the scope BNC via a "T". Look at the data eye pattern. Best idea I can think of to see what might be changing.

This sounds like a DIY TDR from Diyhifi.org

HAL · « **Reply #148 on:** 7 Jul 2010, 02:30 am »

Well, I think I have found a setup that gives the same effect, but is easier to implement.

I have the RCA version HiFace conneced directly to the DAC with an RCA(m) to RCA(m) adaptor from Radio Shack. I used a 15' USB cable and it sounds as good as the BNC setup with the 10dB pad. This is with my DAC, so not sure how this will react with other systems.

The second stage is a powered two port USB hub that I will run off a regulated battery supply. This should do a nice job of isolating the PC power noise and put the power right at the HiFace.

Will get the connectors at Radio Shack tomorrow to start the project. I already have the USB cable, battery and 5VDC regulator.

jkeny · « **Reply #149 on:** 7 Jul 2010, 07:28 am »

Quote from: HAL on 7 Jul 2010, 02:30 am

Well, I think I have found a setup that gives the same effect, but is easier to implement.

I have the RCA version HiFace conneced directly to the DAC with an RCA(m) to RCA(m) adaptor from Radio Shack. I used a 15' USB cable and it sounds as good as the BNC setup with the 10dB pad. This is with my DAC, so not sure how this will react with other systems.

That's interesting! I would like to see the waveform or eye pattern for this one Vs the in-line attenuator

Quote

The second stage is a powered two port USB hub that I will run off a regulated battery supply. This should do a nice job of isolating the PC power noise and put the power right at the HiFace.

Will get the connectors at Radio Shack tomorrow to start the project. I already have the USB cable, battery and 5VDC regulator.

Now you are getting into the area of modifying the power to the Hiface, something I know a little about

. What you are proposing will improve the Hiface sound by about 5%. I have done more radical mods to the Hiface PS which improves it by 95% - the DIY guide starts here http://www.head-fi.org/forum/thread/498151/m2tech-hiface-mods-and-discussions#post_6724767

HAL · « **Reply #150 on:** 8 Jul 2010, 11:27 am »

Have read some of that thread. Very interesting but to small for me to work on.

Picked up the DC power connector for the USB 2 port hub and will work on the power supply this weekend if things go well. Already have a 12VDC/5AH SLA battery to use for the regulated 5VDC supply.

coops · « **Reply #151 on:** 8 Jul 2010, 07:43 pm »

The new M2Tech Evo is starting to become available, you can use lithium or alkaline or a linear power supply.

HAL · « **Reply #152 on:** 8 Jul 2010, 10:35 pm »

I looked at the M2Tech website, but did not see any info on the Evo. Any other links to the info?

ted_b · « **Reply #153 on:** 8 Jul 2010, 10:47 pm »

Quote from: HAL on 8 Jul 2010, 10:35 pm

I looked at the M2Tech website, but did not see any info on the Evo. Any other links to the info?

http://www.m2tech-hiface.com.au/index.php/hiface-evo

HAL · « **Reply #154 on:** 8 Jul 2010, 10:56 pm »

Thanks! It even has I2S Bus output!

HAL · « **Reply #155 on:** 9 Jul 2010, 12:06 am »

I have the BNC "T" adaptor with a 75 ohm terminator to attach to the O'scope input. Not sure if a 100MHz scope will be fast enough to capture the eye pattern or the leading edge transient to look for reflections.

Will give it a try.

jkeny · « **Reply #156 on:** 9 Jul 2010, 12:13 am »

Quote from: HAL on 9 Jul 2010, 12:06 am

I have the BNC "T" adaptor with a 75 ohm terminator to attach to the O'scope input. Not sure if a 100MHz scope will be fast enough to capture the eye pattern or the leading edge transient to look for reflections.

Will give it a try.

Cool. looking forward to any results you might get.

oneinthepipe · « **Reply #157 on:** 9 Jul 2010, 02:19 am »

Just had a chance for a quick listen, but a -6db attenuator on each end is sounding good.

oneinthepipe · « **Reply #158 on:** 9 Jul 2010, 02:20 am »

Quote from: coops on 8 Jul 2010, 07:43 pm

The new M2Tech Evo is starting to become available, you can use lithium or alkaline or a linear power supply.

Anyone have an idea about pricing?

mgalusha · « **Reply #159 on:** 9 Jul 2010, 02:43 am »

Quote from: oneinthepipe on 9 Jul 2010, 02:20 am

Anyone have an idea about pricing?

Looks like $365.