This thread is to provide a place to discuss modifications to and DIY solutions for building a cMP2 computer music player, as designed by cics.
See more info on the cMP2 hardware and software here:
cMP-Squared Main Audio Asylum Thread
and here:
cPlay Main Audio Asylum Thread
This setup is a sound-quality-first setup...specific hardware and software configuration, no networking, no other programs running on the computer, most of Windows removed or shut down, etc.
If you're into a super-convenient play-music-everywhere computer music server, this is NOT the system for you.
But if you want the best sound quality you can get from a computer (and don't mind wearing a hair-shirt to get it!), you need to check this out.
Interesting mods will include things like:
- Modified or scratch-built computer power supplies
- Motherboard modifications
- Sound card modifications
- Add-ons
- Alternative configurations (like Peter Daniels USB-DAC setup)
- Vibration, RF, & EMI control techniques
- AC power filtering
To kick things off, here's some modifying I did to my Juli@ sound card this weekend
See more info on the cMP2 hardware and software here:
cMP-Squared Main Audio Asylum Thread
and here:
cPlay Main Audio Asylum Thread
This setup is a sound-quality-first setup...specific hardware and software configuration, no networking, no other programs running on the computer, most of Windows removed or shut down, etc.
If you're into a super-convenient play-music-everywhere computer music server, this is NOT the system for you.
But if you want the best sound quality you can get from a computer (and don't mind wearing a hair-shirt to get it!), you need to check this out.
Interesting mods will include things like:
- Modified or scratch-built computer power supplies
- Motherboard modifications
- Sound card modifications
- Add-ons
- Alternative configurations (like Peter Daniels USB-DAC setup)
- Vibration, RF, & EMI control techniques
- AC power filtering
To kick things off, here's some modifying I did to my Juli@ sound card this weekend
Attachments
Now that the prices are coming down for Solid State Disks it
will be interesting to see how they perform.
One thing for sure - they're silent, and they are more efficient than even the small notebook hard drives.
The big trade off is lack of storage space though.
SUPER TALENT MasterDrive OX FTM16GL25H 2.5" 16GB $75.00
will be interesting to see how they perform.
One thing for sure - they're silent, and they are more efficient than even the small notebook hard drives.
The big trade off is lack of storage space though.
SUPER TALENT MasterDrive OX FTM16GL25H 2.5" 16GB $75.00
i'm using a CMP + CPLAY with a CICs optimized PC. Switched off upsampling in CPLAY as the DAC does it anyhow.
Motherboard mods :
- CPU Powersupply line, Common mode chokes and 1000uF added per line
Julie mods :
- Only using the digital part of the card
- Replaced the 3.3V regulator with a shunt regulator (better than batteries)
- IS2 out to external DAC
DAC setup currently :
- Twisted pears Sabre with batterie supply, I2S input
(This makes a huge change there)
- Luhndahl passiv out
- VREG mod with shunt regulator
currently waiting for my Counterpoint I/V to give it a try, this will be powered with a Jung style regulator.
Motherboard mods :
- CPU Powersupply line, Common mode chokes and 1000uF added per line
Julie mods :
- Only using the digital part of the card
- Replaced the 3.3V regulator with a shunt regulator (better than batteries)
- IS2 out to external DAC
DAC setup currently :
- Twisted pears Sabre with batterie supply, I2S input
(This makes a huge change there)
- Luhndahl passiv out
- VREG mod with shunt regulator
currently waiting for my Counterpoint I/V to give it a try, this will be powered with a Jung style regulator.
the VIA chip runs at 3.3V which is done with a cheap SMD regulator on the edge of the Julie card itself.
You simply unsolder that regulator and connect any shunt reg you want to to the solder joints and glue it to the back of the card.
There are several designs available in the forum, or if you are lazy just by them ready made.
the biggest advantage of the Julie is the design and the good drivers, it is so easy to mod. For I2S you do not need to fiddle around mit SMD soldering, simply connect it. However if you use the stock card, it is total crap especially the SDIF output.
You simply unsolder that regulator and connect any shunt reg you want to to the solder joints and glue it to the back of the card.
There are several designs available in the forum, or if you are lazy just by them ready made.
the biggest advantage of the Julie is the design and the good drivers, it is so easy to mod. For I2S you do not need to fiddle around mit SMD soldering, simply connect it. However if you use the stock card, it is total crap especially the SDIF output.
Re: Re: cMP2 DIY Mods...
Uh... I've looked at the schematic of your DAC and didn't catch that it's an I2S connection. It would make sense that it is, but the connection identifications are different than I've seen before, so I assumed it was something else.
Hmm... I have a Peter Daniel DAC sitting here doing nothing right now... I may have to hook that up myself.
I posted a compiliation of a lot of information on the Juli@ on the AA, bringing together information from a bunch of posts on different boards. I'll repost that here.
Greg in Mississippi
Peter Daniel said:In the light of the quote below, how about taking I2S from Julia@ and connecting directly to TDA1543 in my DAC? If that works well, I might finally get Julia@ myself for such a configuration
Uh... I've looked at the schematic of your DAC and didn't catch that it's an I2S connection. It would make sense that it is, but the connection identifications are different than I've seen before, so I assumed it was something else.
Hmm... I have a Peter Daniel DAC sitting here doing nothing right now... I may have to hook that up myself.
I posted a compiliation of a lot of information on the Juli@ on the AA, bringing together information from a bunch of posts on different boards. I'll repost that here.
Greg in Mississippi
Juli@ Follies
What prompted this is the imminent arrival (I hope) of an I2S-connected DAC. It's not a commercial product, but just a tweaked set of boards as used by one of the EQ modifiers. I'm hopeful that this DAC will work well driven by the Juli@ as it is based on the AK4399, a similar DAC to the AK4358 that's already used in the Juli@.
I needed to find the reset pin in the J3 header, one that I haven't found identified in previous posts on various forums in the past. So I pulled out my trusty meter and started poking around... and then wanted to confirm some of the other pins... and then find the +-12v pins... And then kept going... and this is what I found:
J3 connector signal pinout (note much of this is taken from the Head-Fi post http://www.head-fi.org/forums/f46/easy-i2s-juli-pci-sound-card-242285/):
J3 Pin 1 -> 1724 PSDOUT[0] ( I2S data out) -> AK4358 SDTI1 (I2S data in)
J3 Pin 5 -> 1724 PSYNC ( I2S Word Clock ) -> AK4358 LRCK (I2S Left/Right Word clock)
J3 Pin 7 -> 1724 PBCLK ( I2S bit clock out ) -> AK4358 BICK ( I2S bit clock in )
J3 Pin 9 - > Xilinx on the digital board -> AK4358 MCLK ( I2S Master Clock in )
J3 Pin 11 - > Xilinx & AK4114 on the digital board - > AK4358 PCN (Reset)
J1 connector power supply pinout (note much of this is taken from the Head-Fi post cited above and some is taken from this Asylum post http://www.audioasylum.com/cgi/t.mpl?f=pcaudio&m=35497):
J1 Pins 1 & 3 -> +12v
J1 Pins 7 & 9 > -12v
J1 Pin 2 -> +5v
J1 Pin 10 -> +3.3v
J1 Pins 4, 5, 6, 7 -> grounds
PCI power supply connections (note some of this is stated in this Asylum post http://www.audioasylum.com/cgi/t.mpl?f=pcaudio&m=35497 . Also, a good source for the PCI pinout is here http://pinouts.ru/Slots/PCI_pinout.shtml):
First of all, the Juli@ only uses the +5v and +-12 lines from the PCI bus. If you look carefully at the pins specified as 3.3v on the Juli@ edge connection, you'll see that the conductive fingers are not connected to the board. This simplifies hooking the Juli@ up to a separate power supply... here's the PS pins:
B1 - > -12v
A2 - > +12v
B5, A5, B6, A8, B61, A61, B62, A62 - > +5v
While there are a number of +5v pins that will need intercepting to inject the 5v from a separate power supply, it's a LOT easier than if you also had to connect up twelve +3.3v lines too!
Digital card power supply notes (note some of this is stated in this Asylum post http://www.audioasylum.com/cgi/t.mpl?f=pcaudio&m=35497):
U1 regulates 5v to 3.3v, with the first pin connected to ground, the second the output, and the third to the 5v bus. C1 & C3 are input filtering capacitors and C2 is the output filtering capacitor.
Also note these comments from a poster titled 'marcello' (from a post on this forum, sorry, I didn't dig it up to cite directly):
"Upgrading digital section:
Locate a good "audiophile"clock oscillator manufacturer. There are multiple offers available on the internet, varying from LC, Audiocom, etc. In NL, Audioart is making a VERY good clock but I'm not sure if they are selling it separately. If not I can intermediate.
I will come with my own clock this summer. 12V and the lowest noise and jitter you've heard of.
Two clocks are needed, one for 22.5792MHz and 1 for 24.576MHz. Replace the existing crystals (x1 and X2)with the corresponding clock oscillators. Power these external clock oscillators by a very good linear supply, or even a lead acid battery if the required voltage is 12Vdc.
Solder a 220uF/10V SG or SH OsCon capacitor from U6, AKM's 4114 chip AVDD pin 38 to ground. Best is to do this on the underside of the board, across BC25. Negative to the solder pad nearest to the "BC25" text.
Solder a 220uF/10V SG or SH OsCon capacitor across C8; positive to the pad towards text "C9", negative to pad towards text "C8".
These measures take care of the most basic limitations of the sound quality of the Juli@ card."
Analog card digital power supply notes:
U10 regulates +12v down to 5v for the digital chips on the analog card, with the same pinout as U1 above, G O I. C13 is the +12v input filter capacitor and C14 is the +5v output filtering capacitor.
Analog card analog power supply notes
U11 regulates +12v down to +9v, while U13 regulates -12v down to -9v. On U11, the tab is ground with the pin towards the of the card being the output and the pin towards the bottom the input. On U13, the tab is the -12v input with the pin towards the top of the card the output and the pin towards the bottom of the card the ground. C18 and C22 take care of input filtering for the +12v and -12v respectively, while C19 and C22 do the same for the +9v and -9v outputs.
Analog card analog circuitry notes
U22 and U23 are the output opamps, but I have to say given the size of those chips and the spacing between their pins, I'll never be replacing them. C70 and C73 are the output coupling caps, which I believe I could replace if I'm careful.
Separate Power Supply Voltage Insertion Points (note that this is inspired by and includes the information posted by Alfred in this post http://www.audioasylum.com/cgi/t.mpl?f=pcaudio&m=49122 ):
DVCC1 - 5v into both digital and analog cards (Note that the 5v is only used in the digital card by regulator U1, which make the 3.3v used by all the chips on the digital card. If you are inserting 3.3v as below and are only using the digital card, you don't need to insert 5v). But be aware that the analog card uses both the 5v and the 3.3v, along with +12v & -12v.
P3V3D1 - 3.3v out of U1 regulator. Can be used as an insertion point for 3.3v to both the digital and analog cards by removing U1
DGND1 - Digital card ground
AGND1 & AGND2 - Analog card grounds. Use 1 if you are using the balanced outs, 2 if you are using the RCAs
P12V1 - +12v into the analog card
NVA1 - -12v into the analog card
P5VA1 - 5v out of regulator U10, which regulates down the +12v rail
PVA1 - +9v out of regulator U11, which regulates down the +12v rail
C19 - The side of this capacitor away from the center of the board is also the +9v out of regulator Ull
C23 - The side of this capacitor away from the center of the board is the -9v out of regulator U13
R29 (open pad on my Juli@) - the side of this set of resistor pads away from the 'R29' is an insertion point for the +12v
R32 (open pads on my Juli@) - the side of this set of resistor pads towards the center of the board is an insertion point for -12v
My hope is to take the Juli@ farther than described in previous posts... ultimately including powering it from a separate set of linear power supplies. Even though I have a separate DAC card coming, I believe that the Juli@ is capable of much better performance than what one gets with a stock card powered from the computer's busses.
Here's my roadmap...
Phase I - Improve PS filtering by replacing the input and output caps on the two digital and two analog regulators and adding local PS line reservoir caps.
Phase II - Improve analog signal transfer by replacing the output coupling caps.
Phase III - Clean up the power supply by cutting the links to the motherboard's power buses and feed the card with separate linear analog & digital supplies.
Phase IV - Further improve the power by replacing the on-board chip regulators with upgraded discrete regulators.
I've completed the first two phases (pictures above) and have it burning in. It is sounding quite improved from the stock card.
Greg in Mississippi
What prompted this is the imminent arrival (I hope) of an I2S-connected DAC. It's not a commercial product, but just a tweaked set of boards as used by one of the EQ modifiers. I'm hopeful that this DAC will work well driven by the Juli@ as it is based on the AK4399, a similar DAC to the AK4358 that's already used in the Juli@.
I needed to find the reset pin in the J3 header, one that I haven't found identified in previous posts on various forums in the past. So I pulled out my trusty meter and started poking around... and then wanted to confirm some of the other pins... and then find the +-12v pins... And then kept going... and this is what I found:
J3 connector signal pinout (note much of this is taken from the Head-Fi post http://www.head-fi.org/forums/f46/easy-i2s-juli-pci-sound-card-242285/):
J3 Pin 1 -> 1724 PSDOUT[0] ( I2S data out) -> AK4358 SDTI1 (I2S data in)
J3 Pin 5 -> 1724 PSYNC ( I2S Word Clock ) -> AK4358 LRCK (I2S Left/Right Word clock)
J3 Pin 7 -> 1724 PBCLK ( I2S bit clock out ) -> AK4358 BICK ( I2S bit clock in )
J3 Pin 9 - > Xilinx on the digital board -> AK4358 MCLK ( I2S Master Clock in )
J3 Pin 11 - > Xilinx & AK4114 on the digital board - > AK4358 PCN (Reset)
J1 connector power supply pinout (note much of this is taken from the Head-Fi post cited above and some is taken from this Asylum post http://www.audioasylum.com/cgi/t.mpl?f=pcaudio&m=35497):
J1 Pins 1 & 3 -> +12v
J1 Pins 7 & 9 > -12v
J1 Pin 2 -> +5v
J1 Pin 10 -> +3.3v
J1 Pins 4, 5, 6, 7 -> grounds
PCI power supply connections (note some of this is stated in this Asylum post http://www.audioasylum.com/cgi/t.mpl?f=pcaudio&m=35497 . Also, a good source for the PCI pinout is here http://pinouts.ru/Slots/PCI_pinout.shtml):
First of all, the Juli@ only uses the +5v and +-12 lines from the PCI bus. If you look carefully at the pins specified as 3.3v on the Juli@ edge connection, you'll see that the conductive fingers are not connected to the board. This simplifies hooking the Juli@ up to a separate power supply... here's the PS pins:
B1 - > -12v
A2 - > +12v
B5, A5, B6, A8, B61, A61, B62, A62 - > +5v
While there are a number of +5v pins that will need intercepting to inject the 5v from a separate power supply, it's a LOT easier than if you also had to connect up twelve +3.3v lines too!
Digital card power supply notes (note some of this is stated in this Asylum post http://www.audioasylum.com/cgi/t.mpl?f=pcaudio&m=35497):
U1 regulates 5v to 3.3v, with the first pin connected to ground, the second the output, and the third to the 5v bus. C1 & C3 are input filtering capacitors and C2 is the output filtering capacitor.
Also note these comments from a poster titled 'marcello' (from a post on this forum, sorry, I didn't dig it up to cite directly):
"Upgrading digital section:
Locate a good "audiophile"clock oscillator manufacturer. There are multiple offers available on the internet, varying from LC, Audiocom, etc. In NL, Audioart is making a VERY good clock but I'm not sure if they are selling it separately. If not I can intermediate.
I will come with my own clock this summer. 12V and the lowest noise and jitter you've heard of.
Two clocks are needed, one for 22.5792MHz and 1 for 24.576MHz. Replace the existing crystals (x1 and X2)with the corresponding clock oscillators. Power these external clock oscillators by a very good linear supply, or even a lead acid battery if the required voltage is 12Vdc.
Solder a 220uF/10V SG or SH OsCon capacitor from U6, AKM's 4114 chip AVDD pin 38 to ground. Best is to do this on the underside of the board, across BC25. Negative to the solder pad nearest to the "BC25" text.
Solder a 220uF/10V SG or SH OsCon capacitor across C8; positive to the pad towards text "C9", negative to pad towards text "C8".
These measures take care of the most basic limitations of the sound quality of the Juli@ card."
Analog card digital power supply notes:
U10 regulates +12v down to 5v for the digital chips on the analog card, with the same pinout as U1 above, G O I. C13 is the +12v input filter capacitor and C14 is the +5v output filtering capacitor.
Analog card analog power supply notes
U11 regulates +12v down to +9v, while U13 regulates -12v down to -9v. On U11, the tab is ground with the pin towards the of the card being the output and the pin towards the bottom the input. On U13, the tab is the -12v input with the pin towards the top of the card the output and the pin towards the bottom of the card the ground. C18 and C22 take care of input filtering for the +12v and -12v respectively, while C19 and C22 do the same for the +9v and -9v outputs.
Analog card analog circuitry notes
U22 and U23 are the output opamps, but I have to say given the size of those chips and the spacing between their pins, I'll never be replacing them. C70 and C73 are the output coupling caps, which I believe I could replace if I'm careful.
Separate Power Supply Voltage Insertion Points (note that this is inspired by and includes the information posted by Alfred in this post http://www.audioasylum.com/cgi/t.mpl?f=pcaudio&m=49122 ):
DVCC1 - 5v into both digital and analog cards (Note that the 5v is only used in the digital card by regulator U1, which make the 3.3v used by all the chips on the digital card. If you are inserting 3.3v as below and are only using the digital card, you don't need to insert 5v). But be aware that the analog card uses both the 5v and the 3.3v, along with +12v & -12v.
P3V3D1 - 3.3v out of U1 regulator. Can be used as an insertion point for 3.3v to both the digital and analog cards by removing U1
DGND1 - Digital card ground
AGND1 & AGND2 - Analog card grounds. Use 1 if you are using the balanced outs, 2 if you are using the RCAs
P12V1 - +12v into the analog card
NVA1 - -12v into the analog card
P5VA1 - 5v out of regulator U10, which regulates down the +12v rail
PVA1 - +9v out of regulator U11, which regulates down the +12v rail
C19 - The side of this capacitor away from the center of the board is also the +9v out of regulator Ull
C23 - The side of this capacitor away from the center of the board is the -9v out of regulator U13
R29 (open pad on my Juli@) - the side of this set of resistor pads away from the 'R29' is an insertion point for the +12v
R32 (open pads on my Juli@) - the side of this set of resistor pads towards the center of the board is an insertion point for -12v
My hope is to take the Juli@ farther than described in previous posts... ultimately including powering it from a separate set of linear power supplies. Even though I have a separate DAC card coming, I believe that the Juli@ is capable of much better performance than what one gets with a stock card powered from the computer's busses.
Here's my roadmap...
Phase I - Improve PS filtering by replacing the input and output caps on the two digital and two analog regulators and adding local PS line reservoir caps.
Phase II - Improve analog signal transfer by replacing the output coupling caps.
Phase III - Clean up the power supply by cutting the links to the motherboard's power buses and feed the card with separate linear analog & digital supplies.
Phase IV - Further improve the power by replacing the on-board chip regulators with upgraded discrete regulators.
I've completed the first two phases (pictures above) and have it burning in. It is sounding quite improved from the stock card.
Greg in Mississippi
Re: Re: Re: cMP2 DIY Mods...
The attached pic shows connection between CS8412 and TDA1543 which is pure I2S. For USB version of a DAC it would be exactly the same.
All you need to do is cut those 3 traces and connect wires from Julia@ directly to TDA1543 pins, including ground.
Greg Stewart said:
The attached pic shows connection between CS8412 and TDA1543 which is pure I2S. For USB version of a DAC it would be exactly the same.
All you need to do is cut those 3 traces and connect wires from Julia@ directly to TDA1543 pins, including ground.
Attachments
Re: caps for juli@
Mark,
First, I've changed the configuration of the caps slightly from that shown in the pictures I posted above. Now all the caps between the computer voltage rails and the on-board regulators are BG Stds and the OsCons are only after the 3.3v regulator.
So here's what I did:
Digital Board
Input @ U1 reg:
Replace C1 & C3 with 1000uf/16v Black Gate Standards
Output @ U1 reg:
Replace C2 with 180uf/20v Oscon
PS Reservoirs @ chips:
Add 180uf/20v Oscon across BC25 & C9 (see details in my Juli@ details post above)
Analog Board
PS Reservoirs at raw +5v/+-12V input to board:
Added 1000uf/16v Black Gate Standards:
J1 Pins 1 or 3 (+12v)
J1 Pins 7 or 9 (-12v - note that the negative is to the rail and the positive to ground!)
J1 Pin 2 (+5v)
PS Reservoir at regulated +3.3v input to board:
Added 180uf/20v Oscon at J1 Pin 10 (+3.3v)
Input to regulators:
Replaced C13, C18, and C22 with 47uf/50v Black Gate N
Outputs from regulators:
Replaced C14, C16, and C46 with 220uf/6.3v Black Gate N
Replaced C19 and C23 with 33uf/16v Black Gate N
Analog Board Coupling:
Replaced C70 and C73 with 33uf/16v Black Gate N
Sorry for the delay in responding. Partly I've been very busy at work the last couple of weeks... And partly I wasn't sure about the sound of the mod. But I traced it down to another change I made in my system not long after I modified the Juli@... A few bad solder joints were causing the system to sound bad.
See here for details:
Audio Asylum Juli@ Mods Thread
With the solder joints in my volume control fixed, I'm getting the most analog-like sound from my cMP ever.
If you are using or considering trying the analog output of the Juli@, this is HIGHLY RECOMMENDED!
Greg in Mississippi
fzman said:
Mark,
First, I've changed the configuration of the caps slightly from that shown in the pictures I posted above. Now all the caps between the computer voltage rails and the on-board regulators are BG Stds and the OsCons are only after the 3.3v regulator.
So here's what I did:
Digital Board
Input @ U1 reg:
Replace C1 & C3 with 1000uf/16v Black Gate Standards
Output @ U1 reg:
Replace C2 with 180uf/20v Oscon
PS Reservoirs @ chips:
Add 180uf/20v Oscon across BC25 & C9 (see details in my Juli@ details post above)
Analog Board
PS Reservoirs at raw +5v/+-12V input to board:
Added 1000uf/16v Black Gate Standards:
J1 Pins 1 or 3 (+12v)
J1 Pins 7 or 9 (-12v - note that the negative is to the rail and the positive to ground!)
J1 Pin 2 (+5v)
PS Reservoir at regulated +3.3v input to board:
Added 180uf/20v Oscon at J1 Pin 10 (+3.3v)
Input to regulators:
Replaced C13, C18, and C22 with 47uf/50v Black Gate N
Outputs from regulators:
Replaced C14, C16, and C46 with 220uf/6.3v Black Gate N
Replaced C19 and C23 with 33uf/16v Black Gate N
Analog Board Coupling:
Replaced C70 and C73 with 33uf/16v Black Gate N
Sorry for the delay in responding. Partly I've been very busy at work the last couple of weeks... And partly I wasn't sure about the sound of the mod. But I traced it down to another change I made in my system not long after I modified the Juli@... A few bad solder joints were causing the system to sound bad.
See here for details:
Audio Asylum Juli@ Mods Thread
With the solder joints in my volume control fixed, I'm getting the most analog-like sound from my cMP ever.
If you are using or considering trying the analog output of the Juli@, this is HIGHLY RECOMMENDED!
Greg in Mississippi
Power Supply Follies...
I was happy to see Peter Daniel post the details of his linear-based hybrid power supply that he's using with his AoB & cMP computer music setups here:
Peter Daniel's Linear-based Computer PS Post
And for the lazy, here's what he said there:
His PS, along with Ryeland's from the Audio Asylum, were the inspirations for my experiments in linear-based hybrid PS's for computer audio. So far, I'd have to say they have been very successful.
Currently, my cMP has four separate linear-supplys...
+12v to feed a modified Pico-PSU for the ATX-24 connector on the motherboard
+12v to feed the motherboard P4 connector, which supplies the processor
+12v & +5v to power the LCD and USB (replacing one of cics's 'dirty' supplies)
+5v to power the laptop SATA harddrive (replacing the other of cics's 'dirty' supplies)
Comparing them to originally specified Antec Earthwatt 430 computer power supply (both stock and modified with additional caps on the outputs) and the Granite Digital supplies for the 'dirty' supplies, each provided a significant sound quality boost. I was and still am surprised that replacing the 'dirty' supplies made any different, much less as significant of one as it did, but going back and forth a few times convinced me to believe my ears.
My next project, in-process now, is to add a set of separate power supplies (+-12v, +5v, +3.3v) to power the Juli@ separate from the motherboard. This is a bit trickier as it requires cutting 10 power supply fingers on the Juli@'s PCI connector, but the sound quality lifts I got from the other supplies make this a 'MUST TRY' mod.
Greg in Mississippi
P.S. When I get time, I'll post a compilation of links to various cMP modification threads on the Asylum.
I was happy to see Peter Daniel post the details of his linear-based hybrid power supply that he's using with his AoB & cMP computer music setups here:
Peter Daniel's Linear-based Computer PS Post
And for the lazy, here's what he said there:
Peter Daniel said:
His PS, along with Ryeland's from the Audio Asylum, were the inspirations for my experiments in linear-based hybrid PS's for computer audio. So far, I'd have to say they have been very successful.
Currently, my cMP has four separate linear-supplys...
+12v to feed a modified Pico-PSU for the ATX-24 connector on the motherboard
+12v to feed the motherboard P4 connector, which supplies the processor
+12v & +5v to power the LCD and USB (replacing one of cics's 'dirty' supplies)
+5v to power the laptop SATA harddrive (replacing the other of cics's 'dirty' supplies)
Comparing them to originally specified Antec Earthwatt 430 computer power supply (both stock and modified with additional caps on the outputs) and the Granite Digital supplies for the 'dirty' supplies, each provided a significant sound quality boost. I was and still am surprised that replacing the 'dirty' supplies made any different, much less as significant of one as it did, but going back and forth a few times convinced me to believe my ears.
My next project, in-process now, is to add a set of separate power supplies (+-12v, +5v, +3.3v) to power the Juli@ separate from the motherboard. This is a bit trickier as it requires cutting 10 power supply fingers on the Juli@'s PCI connector, but the sound quality lifts I got from the other supplies make this a 'MUST TRY' mod.
Greg in Mississippi
P.S. When I get time, I'll post a compilation of links to various cMP modification threads on the Asylum.
Attachments
ASIO4all V2 Settings
Has anyone experimented with the best ASIO4all settings for use with Peter's USB NOS DAC?
In my rig I can't use hardware buffers without crackling. I use 2 buffers and played around with output latency compensation and feel its best around 500ms. Any other opinions would be welcome.
Has anyone experimented with the best ASIO4all settings for use with Peter's USB NOS DAC?
In my rig I can't use hardware buffers without crackling. I use 2 buffers and played around with output latency compensation and feel its best around 500ms. Any other opinions would be welcome.
Hi Greg and Peter, thanks for sharing your experiences and hoping ya'll are still following this thread.
I am currently gathering parts to build a cMP. All I have for now is a Lian-Li PC-C37B case and the E7200 cpu.
I will probably purchase a Earthwatts EA-430 to get things up and running. Knowing this recomended PSU is 430w makes me wonder if the picopsu-120 is adequate. Seeing Peter and you using it must mean it is.
Is the picopsu only reliable after optimizations and underclocking of the cpu and if so would there be any problems running cMP at the default setting prior to making the above changes?
Will Peter's ps be alright if the 150w version is used instesd of the 120w one?
http://www.mini-box.com/picoPSU-150-XT?sc=8&category=981
Brad
I am currently gathering parts to build a cMP. All I have for now is a Lian-Li PC-C37B case and the E7200 cpu.
I will probably purchase a Earthwatts EA-430 to get things up and running. Knowing this recomended PSU is 430w makes me wonder if the picopsu-120 is adequate. Seeing Peter and you using it must mean it is.
Is the picopsu only reliable after optimizations and underclocking of the cpu and if so would there be any problems running cMP at the default setting prior to making the above changes?
Will Peter's ps be alright if the 150w version is used instesd of the 120w one?
http://www.mini-box.com/picoPSU-150-XT?sc=8&category=981
Brad
I would get a PicoPSU, 90W is probably suffecient... I just built a home PC with an AMD Quad Cor, 3 HD's, 4GB DDR2, and a ATI 4850 and it only pulled 120W from the wall measured by a KillaWatt device... PicoPSU was a noticable noise floor reducer on my touchscreen jukebox PC... I used many of the same principles from the "art of computer transports" that cics wrote.... I am in the process of bringing in more ideas like small independent PSU's for the hard drives (2 , one SSD, one 200GB Laptop drive) ...
Has anyone tried cutting PCI traces and supplying a PCI card with its own independant PSU? I have an M-Audio Audiophile 192 that I wanted to try it out... I got a PCI riser to attempt it own but havent tried it yet...
Has anyone tried cutting PCI traces and supplying a PCI card with its own independant PSU? I have an M-Audio Audiophile 192 that I wanted to try it out... I got a PCI riser to attempt it own but havent tried it yet...
ecir38 said:
Brad,
This thread on the Audio Asylum list power measurements for use of a PicoPSU for the ATX24 connector (also known as P24):
http://www.audioasylum.com/cgi/t.mpl?f=pcaudio&m=55122
His findings and Peter D's use of a single raw DC PSU indicate that you are ok with one of his supplies for the PC, but ONLY if you are just using it to power the ATX24 and the P4. He also suggests that even a PicoPSU-60 should be sufficient.
In Peter's setup, the last time he published information on it, he was using one of his raw DC supplies for both the ATX24 and the P4. In my setup, I am using one supply apiece for each of these connections.
You should power the HDD (and USB and screen) from separate PSUs, at the very least the Granite Digital units or similar, but my experience is that good linear supplies make a useful sound quality improvement here too. Trying to power these off the PicoPSU alongside the ATx24 and P4 will likely challenge the 120 watt PicoPSU.
Do note Peter's mods to the PicoPSU... worthwhile.
The EA-430 is specified because a larger unit running at a lower level is supposed to provide lower ripple.
Let us know how you make out!
Greg in Mississippi
HaLo6 said:
I cut the traces on the Juli@ card and am powering it from 3 separate linear supplies, +- 18v for the output stage and two 11v supplies, one feeding a 5v regulator that then feeds the digital card and the 3.3v regulator on that card, one feeding the 5v regulator on the analog card.
You can see more info on this here:
http://www.audioasylum.com/cgi/t.mpl?f=pcaudio&m=48851
The regulators used were all Dexa discrete regulators (+-9v, 2 x +5v, +3.3v).
THIS WAS ONE OF THE TWO MOST SIGNIFICANT IMPROVEMENTS I MADE IN MODIFYING MY cMP2, RIGHT UP THERE WITH ADDING THE MODIFIED PicoPSU!
VERY well worthwhile.
I did it by cutting the traces on the card, not using a riser-card. Whether you want to do this will depend on the cost of your card (Juli@'s can be had for about $150), how important it is to be able to reverse the change (I make small cuts and can bridge them with solder) and whether it will fit on your motherboard (it would not with the risercards I had!).
Note that this is made a bit easier with the Juli@ as it only uses the +-12v and +5v supplies from the motherboard. That limits you to only having to cut 10 traces (there are 8 +5v supply connections). It derives +3.3v from the 5v input. If your card also uses the 3.3v from the motherboard, you'll have to cut 12 more traces!
Greg in Mississippi
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