M2TECH Hiface USB->SPDIF 24/192Khz asynch - Page 13 - diyAudio
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Old 26th December 2009, 04:18 PM   #121
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Doesn't work on Vista 64bit. That I can tell for sure!
Perhaps it only works on XP or on 32bit operating systems?

I don't really mind since I only use it with Foobar (with KS), but over at HeadFi there are reports that the M2Tech people are working on a DS/WASAPI driver.
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Old 5th January 2010, 02:28 PM   #122
jkeny is offline jkeny  Ireland
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OK, here's some final bits of info that I've picked up about the HiFace before I mod it - please correct any point that you might think might be wrong:

Regulators:
- These 3.3V & 1.8V chips are step down DC-DC converters TPS62203 which use a 1MHz fixed freq PWM for operation - I believe these have to go for best sound particularly as the 3.3V supplies both IO banks of CPLD with power as well as the clocks PS. The 1.8V is supplied to the CPLD's core. Pin 3 of these 5 legged chips is an enable pin which is enabled at high. It might be possible to lift this pin (very tight layout!) & connect to ground to disable these chips?

Clocks:
These are MEC clocks but I can't find a datasheet for these particular IDs. smd MEC clocks that I can get locally from Radionics have a jitter spec of 10ps (I know this single figure is almost meaningless but at least it's not 500ps ). These clocks feed into pins 43 & 44 of the CPLD and MCLK is generated & output to the DIT4192 along with SDATA. So part of the CPLD is being used as a clock MUX & buffer - for best sound it's important to provide it with clean 3.3V & 1.8V supplies. The CPLD then outputs MCLK & SDATA to the DIT

DIT4192:
- requires 5V pin 19 so external 5V supply needed
- works at 128x for 176.4 and 192kHz speeds, 256x for 88.2 and 96kHz, 512x for 44.1 and 48kHz based on pins 4&5 (CLK0, CLK1) being set.
- it is operated in master mode based on pin 14 (M/S) set high? So both SYNC (R6) & SLCK (R5) are outputs
- operates in 24 bit I2S based on pin 9 (FMT0) is high & pin 10 (FMT1) is low


So here are the mods I intend & the stages of implementation:
- Tap out I2S from the attached points in the pic (red points show the points for tapping the signals downstream from the resistors)- I'll be using short leads to a local DAC so I'm hoping I can arrange a plug-in connection for this DAC. I'll be listening to this configuration for a while to get an idea of the sound but knowing me I'll want to go straight to the next stage.
- Supply an external clean 5V supply in place of the USB 5V - evaluate
- Supply an external clean 3.3V supply to the two audio clocks - evaluate
- Supply a separate clean 3.3V supply to the CPLD - evaluate
- Supply a clean 1.8V supply to the CPLD - evaluate
Attached Images
File Type: jpg 3.3V Power Supplies.JPG (403.5 KB, 1777 views)
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Old 5th January 2010, 06:39 PM   #123
Gluca is offline Gluca  Italy
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jkeny

where are those red points? I see two red squares and 3 red circles (one carries the 3.3v?)

I will just supply a clean 5V and tap the I2S.
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Old 5th January 2010, 11:05 PM   #124
jkeny is offline jkeny  Ireland
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Quote:
Originally Posted by Gluca View Post
jkeny

where are those red points? I see two red squares and 3 red circles (one carries the 3.3v?)

I will just supply a clean 5V and tap the I2S.
Here you go:
Attached Images
File Type: jpg 3.3V Power Supplies.JPG (407.6 KB, 1652 views)
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Old 6th January 2010, 10:06 AM   #125
Gluca is offline Gluca  Italy
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Old 8th January 2010, 09:20 PM   #126
jkeny is offline jkeny  Ireland
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Report:
- I tapped out I2S & listened - about the same as my modded Musiland but maybe a bit warmer in the mids & highs - not sure about this as I didn't have A/B to compare
- modded a USB cable & added 5V feed from a transformer - not that noticeable a change in sound - maybe my 5V source isn't that clean - will experiment here
- removed the clock PS series inductor & fed a clean 3.3V from LiFePO4 battery - noticeable improvement in sound - much better resolution of instrument timbre & subtle sounds such as the snare drum & cymbal brushing on Herbie Hancock's The River (my test record) - Corrine Bailey Rae now sounds quiet good singing the River or maybe I'm just got into it after listening to the album for so long. This really is a big step up in SQ - not surprising that a cleaner PS feed to the clocks will improve matters. I suspect that this feed could even be improved by isolating the clock's ground from the USB dirty ground - I will be trying an experiment along these lines. Can I simply run the clock from the battery +/- & feed it's output to the unit without reference to the units ground? Just checking before I make a mistake.

Anyway, I believe this unit has more to give as I suspect the switching down-converters are hashing the sound somewhat.

I haven't put a scope on the supplies yet as I want to do some listening - pics & scope measurements to follow!
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Old 8th January 2010, 11:50 PM   #127
jkeny is offline jkeny  Ireland
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Here's some pics (but my camera has developed a fault & I don't know if I can get any more pics)
- ESS DAC is a small, easy & good sounding DAC
- I used DIP8 sockets for both plug & socket
- DIP8 socket is glued to the top of the Xilinx CPLS on the HiFace & pins point up. Thin varnish insulated wires are soldered to the 4 pins on one side of the DIP8 & ground is connected to the 4 pins of the other side. The I2S wires are soldered to the bottom of the board.
- The ESS DAC board plugs into the Hiface at right angles (it could probably be done directly on top of the HiFace).
- The third pic shows the connections - LiFePO4 battery PS to the ESS DAC - you can just see the red & black wires running into the USB connector for external 5V supply - the output is through transformers to a TA2020 amplifier also running on batteries.
- My laptop is a Dell Inspiron 6000 but I have no batteries for it anymore so I'm running it from the laptop charger without the ground connected. I reckon it would sound even better running on batteries.
Attached Images
File Type: jpg DAC + modded HiFace.JPG (322.6 KB, 1589 views)
File Type: jpg ESS DAC underside I2S socket.JPG (253.7 KB, 1351 views)
File Type: jpg HiFace + Connected ESS DAC.JPG (437.9 KB, 1349 views)
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Old 9th January 2010, 12:01 AM   #128
jkeny is offline jkeny  Ireland
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- Next pic shows the clock inductor removed from the pads marked in red & sitting on bluetak. You can see the I2S wires more clearly here going through the vias & soldered to the connection points previously shown.
- an external +3.3V (again from battery) was connected to the pad closest to C1 & battery neg connected to ground
Attached Images
File Type: jpg HiFace I2S socket + clock inductor removed.JPG (280.8 KB, 842 views)
File Type: jpg P1000729.JPG (440.3 KB, 1393 views)
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Old 9th January 2010, 05:58 PM   #129
Salsero is offline Salsero  United States
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Is all of this issue with kernel streaming, etc... only applicable to USB1.1? With the higher bandwidth of USB2.0, is it still an issue? Is there a more advanced version than USB2.0?
Cheers
Salsero
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Old 10th January 2010, 01:31 PM   #130
jkeny is offline jkeny  Ireland
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Finished most of the potential mods to this unit - here's my experience/impressions:
- The clean 3.3V supply to the clock is a must do - it clears up the sound substantially
- After I did this I put a scope on the existing 3.3V on-board - pic below - looked like 40mV peaks @ 80KHz?
- I took off the 3.3V switching down-converter & supplied 3.3V from battery to the rest of the board - another jump in clarity - not surprising as this supplies the PS to the CPLD IO banks & the clock is Muxed & buffered there.
- The only switching converter left on board is 1.8V & removing it may not have too much benefit as it supplies the core logic to the CPLD (apart from removing whatever hash this puts on the ground plane which may be no bad thing)

This is the best audio I've had in my system to date - I reckon it would compete well against the best. The weakest link now, I reckon, is the fact that there's no way to galvanically isolate the USB 2.0 signal so the quality of the sound depends on the computer (& PS) feeding it.

Time to shift it to my main listening area and out of the work-room & do a bit of listening before I tackle the Musiland or maybe the Squeezebox receiver
Attached Images
File Type: jpg 3.3V from HiFace - Laptop Dell supply.jpg (275.5 KB, 735 views)
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