CM6631 usb audio interface .... any good?

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I believe the board I have is designed around the standard USB 2.0 specification for power. Surely it is, because the USB 2.0 ports on my ASUS EeePC are certainly not higher amperage than the standard. It follows that any standard USB 2.0 port is capable of powering the card I have.

Which begs the question; why do some of these CM6631A boards need an external power source, and some do not? I doubt it has anything to do with firmware. How could different firmware result in the chip drawing more power for the exact same function?

Firmware needs to a) enable the desired features and b) interface with the driver in such a manner that the features are available to the operating system. Full stop.

Not trying to be combative; simply inquisitive.
 
I believe the board I have is designed around the standard USB 2.0 specification for power. Surely it is, because the USB 2.0 ports on my ASUS EeePC are certainly not higher amperage than the standard. It follows that any standard USB 2.0 port is capable of powering the card I have.

Which begs the question; why do some of these CM6631A boards need an external power source, and some do not? I doubt it has anything to do with firmware. How could different firmware result in the chip drawing more power for the exact same function?

Firmware needs to a) enable the desired features and b) interface with the driver in such a manner that the features are available to the operating system. Full stop.

Not trying to be combative; simply inquisitive.


Well, if it is like this in my and many others' cases, I would guess that the firmware or the board limits the capabilities of the chip if powered weakly, so the jitter doesn't increase, the sound quality doesn't fall and other audio problems do not arise. Because if this wasn't because of the firmware or the chip controllers (differ on different boards), then the rates WOULD get displayed in the settings, but the audio simply wouldn't sound great. I didn't get inside the firmware or the chip yet, but this is my logical approach to this mystery :)

Think of this this way (simplification): if it wouldn't be the firmware or some other sort of a controller, 96KHz would be displayed as a selection, but the laser of the S/PDIF will only blink as much as the power (W of the USB = 5*amps) allows it to, so, simply speaking, it would blink at 64,698Hz, which would totally mess up the timing and the clock and will introduce a huge data loss, therefore the designers thought of this and introduced the limit to the output frequency by the variable of the external power connected or not. In your case, the board has no external power, so the board may be set up differently. If not a huge jitter, I'm pretty sure you'll get a significant data loss if the chip has not enough power.

Maybe it's about voltage, I'm not sure, but here is my theory ;)
 
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I believe the board I have is designed around the standard USB 2.0 specification for power. Surely it is, because the USB 2.0 ports on my ASUS EeePC are certainly not higher amperage than the standard. It follows that any standard USB 2.0 port is capable of powering the card I have.

Which begs the question; why do some of these CM6631A boards need an external power source, and some do not? I doubt it has anything to do with firmware. How could different firmware result in the chip drawing more power for the exact same function?

Firmware needs to a) enable the desired features and b) interface with the driver in such a manner that the features are available to the operating system. Full stop.

Not trying to be combative; simply inquisitive.

I have 3 ebay cards based on the CM6631, the Cmedia development card and a few cards of my own design. USB power has never been an issue. One ebay card I have-- in a very nice case --supports external power as an option. I expect the external PS option is for those who wish to use low noise supplies of their own design or will be using the device with a power limited host such as a tablet or phone.

The basic CM6631 + 2 external clocks draws < 200ma which is well within the capabilities of a USB2 port. An external Toslink will only add 10-15ma.

Regards,
George
 
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Try a USB 2.0 hub with external power.

Why?

My CM6631A board works perfectly directly connected to my EeePC. My board has no option for external power because it simply isn't necessary. It works at 192/24 on a standard USB 2.0 port.

That's the whole point of my posts. :yes:

Archimago said he couldn't get his to work at higher bitrates. Then suzzz said "...then asked the eBay seller and realised that it needs external power for higher rates and better sound quality..."

This sounded like complete BS to me, so I was simply stating that USB 2.0 is and should be plenty of amperage for a CM6631A.

Again, I have no issues with mine running off standard USB 2.0. Not sure what went wrong. Perhaps a language barrier?
 
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I have 3 ebay cards based on the CM6631, the Cmedia development card and a few cards of my own design. USB power has never been an issue. One ebay card I have-- in a very nice case --supports external power as an option. I expect the external PS option is for those who wish to use low noise supplies of their own design or will be using the device with a power limited host such as a tablet or phone.

The basic CM6631 + 2 external clocks draws < 200ma which is well within the capabilities of a USB2 port. An external Toslink will only add 10-15ma.

Regards,
George

Thank you. This confirms my theory. suzzz's ebay seller is high or something. There should be no reason whatsoever for an external power source with this chip, except perhaps purely personal choice.
 
Why?

My CM6631A board works perfectly directly connected to my EeePC. My board has no option for external power because it simply isn't necessary. It works at 192/24 on a standard USB 2.0 port.

That's the whole point of my posts. :yes:

...

Again, I have no issues with mine running off standard USB 2.0. Not sure what went wrong. Perhaps a language barrier?

I thought I was responding to Archimago, my mistake. I meant to say to Archimago to try external power for his problem.
 
I thought I was responding to Archimago, my mistake. I meant to say to Archimago to try external power for his problem.

Wow! You're right!

I tried external power before with the 108 firmware but did not work. However, 101 firmware with external 12V on the MacBook Pro opened up all the sampling rates to 24/192 for this CM6631A device!

How very odd since I thought Mac's were supposed to have pretty robust USB power. I've never needed the external power in Windows to get all the features to work!

Also, firmware 101 has a working ASIO on the PC side as well. Looks like I'll be sticking with this older firmware then...

Hopefully this is some kind of glitch in the firmware since I would love to not have to worry about the external power on the Mac eventually.

Addendum: I realized it's even more complicated! First the unit has to be unplugged from USB, then flip the switch to turn on with the external power plugged in, THEN plug into the USB port of the Mac. To make matters worse, it looks like only 1 of the 3 USB ports will consistently recognize the USB2 HD Audio! Bizarre!
 
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How very odd since I thought Mac's were supposed to have pretty robust USB power. I've never needed the external power in Windows to get all the features to work!

...

Hopefully this is some kind of glitch in the firmware since I would love to not have to worry about the external power on the Mac eventually.

I suspect different implementations of CM6631(A) have different power requirements. I'm not surprised to see that your problem is solved by adding external power. I came across multiple reports of CM6631 users having different types of problems and needed external power to resolve them. This is why when I choose a CM6631A product to buy, I chose one with a built-in sealed transformer and power supply. The additional benefit, although I cannot verify this, is that all of the reports I've read about adding external power results in improved audio quality.

As for computer USB power "robustness" or compliance, I'm not too sure about that. I believe they vary from motherboard to motherboard. I have too many experiences of not being able to use 2.5" USB HDD even supplied with _double_ power from double USB ports. There is a reason leading motherboard manufacturers now advertise the support for higher power in USB ports:
GIGABYTE 3x-usb-power
 
Hello all,

I'm trying to figure out what is the difference between plain 6631 and 6631A. Is there any confirmed format and performance issue between them? I can't find a 6631A board containing 12M, 45.1584M and 49.152M oscillators separately. Some plain 6631 boards have all crystals seaparately.
 
Hello all,

I'm trying to figure out what is the difference between plain 6631 and 6631A. Is there any confirmed format and performance issue between them? I can't find a 6631A board containing 12M, 45.1584M and 49.152M oscillators separately. Some plain 6631 boards have all crystals seaparately.

Try reading before asking. http://www.diyaudio.com/forums/digi...-audio-interface-any-good-17.html#post3358054

All the boards have 3 oscillators. I wonder if you have problems reading and seeing things ? :rolleyes:
 
Try reading before asking. http://www.diyaudio.com/forums/digi...-audio-interface-any-good-17.html#post3358054

All the boards have 3 oscillators. I wonder if you have problems reading and seeing things ? :rolleyes:

I did it but I couldn't find a particular answer within two pages of search results.

For example, description of 6631A item below tells about only two dedicated oscillators. 12M usb oscillator isn't well recognizable in photo.

24bit 192kHz USB to I2S SPDIF PCB CM6631 with Ultralow Noise 6 5UV Regulator | eBay

Thank you anyway, despite your naive rudeness.
 
For example, description of 6631A item below tells about only two dedicated oscillators. 12M usb oscillator isn't well recognizable in photo.

CM6631 data sheet states that "Only single 12MHz crystal input is required (embedded PLL function) or optional oscillator inputs for 49.152MHz and 45.158MHz". Perhaps that's why it's not necessary to advertise the mandatory presence of the 12MHz oscillator.
 
About my issues with ASIO:
- My unit came with firmware 0108 PID 0x0314.

I just got this cheap one on Taobao because it is the cheapest I found with i2s. It also has 0108/0314, which is 24bit, but I need 32bit for digital volume control. It has a very noisy regulator. XOs, esp 12Mhz, look low grade too.

- Using Windows XP I was able to switch between these two firmwares.

Yes me too, thanks to your instructions :

CM6631A Firmware 0101 VID 0x0D8C PID 0x0319:
https://docs.google.com/file/d/0B_6Y...it?usp=sharing

CM6631A Firmware 0108 VID 0x0D8C PID 0x0314:
https://docs.google.com/file/d/0B_6Y...it?usp=sharing

To be used with the flash update tool found in the CM6631 Firmware 2203 package VID 0x0D8C PID 0x0309 on Windows XP _ONLY_:
http://www.nutsaudio.com/driver/CM6631_Firmware.zip

Instructions:
- A Windows XP PC is needed (XP compatibility mode on newer Windows does not work - do not try it)
- Connect the CM6631(A) unit to a USB 2.0 port at the back of the PC, do not use the front ports even if available
- Run the flash update tool
- Erase firmware
- Unplug the CM6631(A) unit then reconnect it again
- Update using a new firmware hex file
- If a File Format Error or a Flash Error is shown, reconnect the unit again and flash it again

So now I have 32 bit with i2s and spdif, similar to the diyinhk cards.

I found that firmware 0101 PID 0x0319 can output to SPDIF via CMedia ASIO, but it will never passthrough DTS and AC3 :eek: because the unit shows up only as Speakers instead of SPDIF on Windows 7 x64.

Mine shows two channels in asio, both spkout, and it allows 32bit/192khz. The diyinhk cards show as spdfout, but it seems that functionally the ASIO works the same.

Firmware 0108 PID 0x0314, using current drivers, will not output to SPDIF via ASIO, but it can passthrough DTS and AC3 correctly. With this firmware, SPDIF, Speakers and Heaphones show up on Windows 7 x64 even though my unit does not have Speakers or Headphone output. DTS passthrough using both DirectSound in MPC-HC x64 or WASAPI in MPC-HC x32 + ReClock are tested to be working normally.

This showed 4 channels in ASIO, spkout and hdphout (or something like that) and was limited to 24 bit so it was not as good for me. It did not show any spdfout in the asio driver.

Thanks to tdtsai and everyone who helped. :)

My sincere thanks to all too ! I just need to improve the regulator and I'll be satisfied.
 
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I just got this cheap one on Taobao because it is the cheapest I found with i2s. It also has 0108/0314, which is 24bit, but I need 32bit for digital volume control. It has a very noisy regulator. XOs, esp 12Mhz, look low grade too.................
....................My sincere thanks to all too ! I just need to improve the regulator and I'll be satisfied.

Didn't you have two 6631 already at hand?
I thought to get I2S out of the 6631 it just needs to be flashed with the right firmware.
I ordered the exact board and wondered if I did the right thing.
Mine is gonna be hooked up to an AK4396 fed by A123 Batteries.
Can you recommed any XOs you tried? There are so many that claim 1ppm
accuracy but unless someone has tried them against alternatives it is
impossible to know what to get.
Have you tried running two of those boards from one XO to see if a four or
six way system can be build?
Routing to different sound devices after the digital crossover shouldn't be
to much of a problem with todays software options.

Greets,
Klaus
 
Hi,

I have four now - 2 cm6631 and 2 cm6631a. I have many dacs..... akm4399, es9018, dual ad1955, wm8741, cs4398... and more. I need more ears. :)

Good cheap parts are Fox Xpresso and Euroquartz xo91. PPM is not so important - this is the measure of stability. More important is phase noise, usually measured in ps, but for some very special clocks, it can be measured in fs. Crystek CCHD-957 has lowest phase noise for 45/49 clocks. Tent labs has lowest phase noise for 12mhz. Also, some NDK clocks have very low phase noise but they are special NDK and hard to find outside japan. But to get fs phase noise needs very low noise power supply, excellent pcb, design, etc. To route out lock to many devices needs a fanout buffer and a very good pcb.

my hifi uses a class-a line level crossover for bi-amping, so i don't need to use multiple cards for a pc/digital crossover.

I also have this as a usb/spdif to spdif/i2s :

http://myl8test.wordpress.com/audio/usbspdif-to-spdifi2s-and-asrc/
 
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The diyinhk cards show as spdfout, but it seems that functionally the ASIO works the same.

If it shows up in Windows as SPDIF device, it shows the "Supported Formats" tab (which contains options of DTS Audio and Dolby Digital and sample rates) in playback device properties, right? (When I was using 0101 PID 0319 this tab does not show up.)

Please tell me what is the value in Windows Device Manager -> USB2.0 High-Speed True HD Audio (i.e. the diyinhk device) -> Properties -> Details -> Hardware Ids

Thanks a lot!