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In Reply to: RE: cMP - the open source high-end Memory Player posted by cics on December 30, 2007 at 04:42:01
It is my sound card (please see: http://www.yystation.net/show.asp?id=213). It uses VT1723 I/O chipset and the datasheet is here (http://www.datasheets.org.uk/VT1724*-datasheet.html). It uses 3.3v@150mA. In the SQ210A+ sound card, VT1723's power is fed by a MT1117 which regulate the PCI 5v to 3.3v.
SQ210A+ uses the same chipset VT1723 as Juli@ sound card. The experts here desolder the 1117 regulator: http://www.audioasylum.com/forums/pcaudio/messages/4/49122.html).
I do the same to my SQ210A+ sound card. When I turn on the 3.3v power supply before turning on the computer, the red light on the sound card light up, which suggests that the chipset VT1723 is working. However, after I turn on the computer, the red light on the sound card goes away.
Any idea?
P.S.
1. someone in other forums suggests that the ground should not be interfered. What does that mean?
2. I intend to feed the 3.3v by superteddyreg with input 12v and output 3.3v. The multi-meter reads 3.3v when I turn on the power supply for superteddyreg and the light on the sound card glows. The light disappears immediately after I turn on the PC.
Follow Ups:
Hopefully you have resolved you issue in the time it took for someone to respond to you here.
But if not, here's some thoughts...
1. You say the red light on the sound card goes off when you turn on the computer. Does the voltage provided by the SuperTeddyReg stay at 3.3v when this happens?
2. I’m not sure what others are saying about 'the ground should not be interfered', but I assume you have connected both the 3.3v & the ground from the SuperTeddyReg to the appropriate pads where you removed the 1117 regulator, correct. The ground must be connected for the circuit to operate.
3. Post pix, especially one with an overall closeup of your sound card and another of the mod area. That will help understand what's happening.
Greg in Mississippi
Everything matters!
Thank you very much, Greg!!! Here comes my pic:-
Tentlab clock + flea clock power supply and transformer
Superteddyreg and transformer
My sound card: SQ210A+
Close up to show how the SUperteddyreg is connected to SQ210A+
In the last pic, you can see the twisted wires (red and black) at the bottom right corner of the sound card. The connection is:-
Red wire, i.e. +3.3v from superteddyreg --> output pad of 1117 reg (desoldered) on the sound card PCB
Black wire, i.e. ground from superteddy --> ground pad of 1117 reg (desoldered) on the sound card PCB
Someone suggests that because the ground of the superteddyreg is not connected to the ground of my sound card (i.e. pin 50 or 51 of the gold finger, see: http://en.wikipedia.org/wiki/Conventional_PCI), the circuit does not work.
Therefore, I plan to add the connection between the black wire (already soldered to the ground pad of 1117 on the sound card PCB to pin 50. Any idea?
Thank you very much!!! (again ^.^)
P.S. I use I2S output by desoldering the DAC chip (AK4936 or something like that).
Dear Greg,
The addition connection is as follows:-
Does it work?
Thank you!!!
I know the cause now. It is because the 1117 regulator is 1117-ADJ, instead of 1117-3.3. In case of 1117-ADJ, how should I connect the external 3.3v to the sound card PCB?
Ok, that makes more sense now.
This drawing from the MT1117 datasheet showw the different circuits for the fixed versus the adjustable.
You need to find the voltage-setting resistors (R1 & R2 on this drawing) on your soundcard board. They should be very close to where the MT1117 was. Remove the resistor on the soundcard that corresponds to R2 on the drawing. Then attach the ground wire from the SuperTeddyReg to the ground pad where that resistor was.
It won't hurt to leave the resistor that corresponds to R1 on the soundcard. And where you connected the 3.3v wire from the SuperTeddyReg should still be ok.
You should not need the connection you made to the PCI finger.
Try this and let us know how it works.
Greg in Mississippi
P.S. I'm glad you caught this. I was scratching my head trying to see what you did wrong and couldn't find anything!
Everything matters!
Hi Greg,
Thank you for your tips. The independent 3.3v power supply has been successfully installed as follows:-
R1 and R2 must be removed!!!
And the pics are as follows:-
The modification I have made:-
1. Remove the ak4396 DAC and tap I2S signals therefrom
2. Remove all the unused cap., opamp on the upper part of my sound card, which are for DAC only.
3. Change all the cap. on the lower part of my sound card to Black Gate
4. Remove the 49.152MHz clock and install flea + tentlab combo (see http://cynicalaudio.blogspot.com/2011/05/shigaclone-clock.html)
5. Install Superteddyreg
I would say that the modifications bring huge improvement to the sound quality. The sense of presence and depth of the sound stage is better than a CD transport for sure.
Thank you again, Greg!!!
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