M2TECH Hiface USB->SPDIF 24/192Khz asynch

[GuidoR]

Originally Posted by jkeny

Ok, GuidoR, It's over to you - I showed you mine

yes, understood.
But you can argue from my avatar that speed is not my specialty
During this w.e., I promise, I'll work on it

Ciao

Guido

[jkeny]

No problem, GuidoR, your friend Vale told me that you are getting a Musiland unit also - I would be interested in your comparison with the M2Tech. I'm particularly interested in how the lack of USB cable on the M2Tech is giving it a sonic advantage. Can you try your HiFace with an extension USB cable?

[GuidoR]

Modding HiFace: how to

The board is very small, so only limited mods are possible.
Here the most important ones.
Taking out I2S: the points are on the following resistors:
MCLK -> R3
SCLK -> R5
LRCK -> R6
SDATA -> R7
In theory, it could be better to steal the signal upstream of the res, in case of long wires, downstream in case of short ones.
The "up" is the side near the DIT for R5 and R6, the opposite for R3 and R7.
In fact, due to the extremely small dimension of the 47R res (0603) is not advisable to attach wires directly on them, the risk of burning them (as I did ) is very high. (you can see from the pics that I replaced the 0603 with 0805, but due to the limited space one has to be mounted on edge).
DO NOT REMOVE THOSE RESISTORS!!!!
My solution, after some disasters , has been oriented to the better "mechanical" solution, in order to avoid any stress to the very fragile pads. Following the tracks from the resistors, you can see four vias that are connected, the other side, to the Xilinx chip (the one with the big green dot).
I ran copper wires (0,35mm - AWG 27), duly bent and tinned, applied some flux, lined them up on the legs of the chip and just a tip of a soldering iron - a magnifier is a must. The attentive reader can note that the connexions are mixed - upstream and downstream: it works just the same.
You can steal the ground connection from the second uninsulated pad on the side of the board (near the square one).

Replacing PS: the HiFace is fed by USB, so we can isolate the V input.
To make the change reversible, I disconnected the Vin pin by only lifting them, and connecting an insulated wire. The wire is fixed with a tie-wrap to improve the mech (and to avoid stress to the pads).

On the pics I have evidenced in red the vias and the contacts.

Enjoy (I did!!)

[GuidoR]

Originally Posted by jkeny

I'm particularly interested in how the lack of USB cable on the M2Tech is giving it a sonic advantage. Can you try your HiFace with an extension USB cable?

Hi Jkeny
Unfortunately I, from the very beginning, tried HiFace only with a cable extension (1m long) and I2s out, so no possible comparisons from me on this particular topic. As you can see from my last post (and after Vale's first attempt) I've further modded my HiFace replacing the USB PS with a shunt reg (ZenMod's Shiny or Salas Shunt, I'll decide tomorrow depending on the PCB I have on hand...).
BTW, you also excel in microsurgery, eh?

Guido

[jkeny]

Ah, Micro-surgery is fun
How much improvement did you note with each mod?
I found the external PS a significant upgrade but haven't had a chance to really evaluate I2S yet.

[jkeny]

Does anybody have a link to the clock/crystal shown in the above HiFace pic? I'm wondering what their specs are & where they might be purchased. I've searched for all the combinations of the letters that I can make out on the pic VEC C1009HC or NEC C10D9HC. Always looking for proven low jitter clocks at reasonable cost

[jkeny]

Ok, here's the start of the new clock install (micro-surgery is fun ):
- First pic is crystal removed with the smd Crystek clock beside it
- Second pic is the back of the smd clock with a small board cut from a matrix board - I had put solder on the clock pads as I had intended to solder to the board but I didn't use this method - instead I did this:
- Third pic - there are little grooves from the pads that go up the sides of the smd clock - here is a component lead cut-off soldered in the groove.
- I did this with all 4 pins (although I don't need pin 1 connected) & put the pins through the board from the top so I could solder the pins underneath to the copper side of the matrix off-cut board.
- Pic 4 - This gives a very solid & small structure. I soldered the out pin to the Xtalin (pin 12) where the original crystal had been.
- As a quick & dirty job I soldered the clock VDD to the 3.3V regulator Vout that goes to the Cypress USB chip; the clock gnd pin to the USB gnd at the USB socket.

- Plugged in USB cable but unit is now not recognised by the laptop . Not surprising really as I haven't changed the load cap that was on the crystal (I told you this was quick & dirty to see if I could get it working straight off). The other issue that may be causing it not to properly initialise is that there is a timing condition that an external clock has to meet for the Cypress to operate correctly. I will probably try to power the clock from a 3.3V battery as I originally intended & have this powered up before the Cypress chip.

[jkeny]

A better final picture - pin 1 (at bottom RH corner of pic) is not connected, it's just left floating in air.

I will be getting back to this later today & hopefully get it working

[jkeny]

Success
The clock needs 1-2mS to initialise so it needed to be powered up before the Cypress chip as I suspected. I re-did the clock - I'll post pics later.

How's the sound, I hear you ask . Obviously all this is on my own system so whatever the abbreviation is BUT

Bass is much more solid & powerful, mids & highs are more crystalline. What I use for listening is Herbie Hancock's River (The Joni Letters) recorded in WAV to disk from CD. As I said before, I'm using a modded Lepai amp (Tripath TA2020) with no caps on the input (because I'm using a transformer). So no caps from DAC o/p straight through to amp input.

My test is to get the brush strokes on the cymbals to sound like brush strokes on cymbals with texture, etc rather than a haze of sound - this gets me closer to it with some texture showing through, not all the way. I haven't heard a system yet that renders this properly so maybe it's in the recording. As for the rest of the album, the voices sound amazingly lifelike (Tina Turner, Corrine Bailey Rae, leonard Cohen, Joni herself, etc), the piano sounds perfect, Wayne Shorter's sax playing is a wonder on this album too & you can just about hear the spit in the mouthpiece

Anyway, I would recommend this mod to anyone - cheap too ($3 clock, $8 battery). A lot of the sonic improvement may well be providing a clean PS to the clock, something I couldn't do to the crystal to test it.

[okkyn]

Good job jkeny!!

However, I am a bit worried about mechanical stability of the clock...