ah yes, hehe i read that totally wrong the first time 
well good news! ive been fiddling around trying out some of your easier to implement suggestions and it seems much more stable now. in fact i've not yet been able to make it disconnect at all!
i've removed the inductors on the ground lines and hard wired them all together, added a 10ohm resistor to the base of the bc109 and a ceramic cap over the 100uF in the regulator circuit. the 10uH inductor is still in its current location as moving that was a little more work.
fingers crossed all my problems are now solved and i can start work on my enclosure
thanks so much for all your input. i reckon it was those inductors all along. maybe i should be on a physics degree rather than chemistry - it might serve me better in my hobbies
well good news! ive been fiddling around trying out some of your easier to implement suggestions and it seems much more stable now. in fact i've not yet been able to make it disconnect at all!
i've removed the inductors on the ground lines and hard wired them all together, added a 10ohm resistor to the base of the bc109 and a ceramic cap over the 100uF in the regulator circuit. the 10uH inductor is still in its current location as moving that was a little more work.
fingers crossed all my problems are now solved and i can start work on my enclosure
thanks so much for all your input. i reckon it was those inductors all along. maybe i should be on a physics degree rather than chemistry - it might serve me better in my hobbies
browner said:
I really like this type of information. It pinpoints the fault in your system
I will just take that comparision report as a record. I will try self-powered soon anyway though.
I did try 1543 and it is really good. sounds really relax and musical. the mids would match 1541 already.
I use schematic from the datasheet. with a little bit tweak as it shows only 2706 self powered and 2702 bus powered IIRC.
I've got few cases from my friends like yours when everything works properly again after pronounced dead at the first time. sounds like a resurrection to me.
I also built a aw-d3. It kind of works - if there is no other USB device attached to computer.
Whenever I plug in a USB hard drive, the PC will stop or fail to recognize the aw-d3.
First I suspected the USB 5v supply. So I use my own regulated 5v to power the PCM2706 through a relay. And the USB 5v is just acting as trigger for the relay. But it does not seem to help at all.
My Musiland MD10 USB DAC does not have this problem, it is very stable.
Any one has similar experience?
Whenever I plug in a USB hard drive, the PC will stop or fail to recognize the aw-d3.
First I suspected the USB 5v supply. So I use my own regulated 5v to power the PCM2706 through a relay. And the USB 5v is just acting as trigger for the relay. But it does not seem to help at all.
My Musiland MD10 USB DAC does not have this problem, it is very stable.
Any one has similar experience?
I've only just picked up my AW-D3 again to use it in a digital amp and I also get intermittent problems, (actually, I thought it was dead as XP reported it dead until I tried a diff laptop)
I wonder if it is a current issue i.e. lowish current from some PCs giving borderline operation of AW-D3 board? Is there any way to check the current reqs of this board?
I'm thinking of removing the Led. Is the 74HCU04 needed as a level shifter (3.3V to 5V) for SPDIF output?
Otherwise I'd remove it also!
I wonder if it is a current issue i.e. lowish current from some PCs giving borderline operation of AW-D3 board? Is there any way to check the current reqs of this board?
I'm thinking of removing the Led. Is the 74HCU04 needed as a level shifter (3.3V to 5V) for SPDIF output?
Otherwise I'd remove it also!
The USB spec requires that the DAC request the amount of current it requires from the host. As a bus-powered device, it should get 500 mA, which is plenty. According to datasheet, the PCM2706 draws less than 50 mA.
Since the problems are intermittent, I suspect L1. The intended purpose must be to separate grounds, but it may be hurting more than helping. I would try shorting it out and seeing if things improve.
There's also a lot of capacitance on the USB+5V line. The USB spec specifies inrush current and charge (100mA, 50uC), so some computers may actually adhere to the spec and disable ports when the inrush is exceeded. In this design there's almost 150 uF of capacitance (Q = CV = 750 uC) with JP3 closed. Fixing this requires either reducing the total capacitance (C19, C21, C23) to 10 uF, or redesigning the power network to do the proper sequencing.
Since the problems are intermittent, I suspect L1. The intended purpose must be to separate grounds, but it may be hurting more than helping. I would try shorting it out and seeing if things improve.
There's also a lot of capacitance on the USB+5V line. The USB spec specifies inrush current and charge (100mA, 50uC), so some computers may actually adhere to the spec and disable ports when the inrush is exceeded. In this design there's almost 150 uF of capacitance (Q = CV = 750 uC) with JP3 closed. Fixing this requires either reducing the total capacitance (C19, C21, C23) to 10 uF, or redesigning the power network to do the proper sequencing.
Thanks guys,
I'll do what you suggest - reduce capacitance & short L1 - I didn't know that the problems with this board had already been solved - where can I find the thread?
BTW, I count 7 * 47uF = 329uF total capacitance - 5 caps on the PCM2706 & 1 on the Optical out & 1 on the 74HCU chip. As I'm only interested in SPDIF or I2S I'll be removing optical out cap & 2 caps on the analog out lines of the PCM chip. Can I get rid of the 74HCU chip altogether?
This thread mostly talks about a seperate Power supply & it's issues, not the USB powered probs!
I'll be removing the LED anyway as I had to do the same for my USB external drive, the Seagate Freeagent drive, to stop intermittent problems on it. This worked, even though there is an external PS powering the disk!
I'll do what you suggest - reduce capacitance & short L1 - I didn't know that the problems with this board had already been solved - where can I find the thread?
BTW, I count 7 * 47uF = 329uF total capacitance - 5 caps on the PCM2706 & 1 on the Optical out & 1 on the 74HCU chip. As I'm only interested in SPDIF or I2S I'll be removing optical out cap & 2 caps on the analog out lines of the PCM chip. Can I get rid of the 74HCU chip altogether?
This thread mostly talks about a seperate Power supply & it's issues, not the USB powered probs!
I'll be removing the LED anyway as I had to do the same for my USB external drive, the Seagate Freeagent drive, to stop intermittent problems on it. This worked, even though there is an external PS powering the disk!
Hi JKeny,
Maybe you should get an external powered usb hub, this seems like an awful lot of work for what is apparently a very flaky usb port implementation in your pc/laptop.
Commercial products are tested to comply with standards and usually are pretty bullet proof. The amount of tinkering you've had to do to other devices is an indication of some sort of problem. I've not had any problem with USB drives, both HD and solid state, usb audio hardware, or any HID device on any machine I own including my now 8yr old Compaq laptop. (My two other machines are about 2 yrs old.)
Maybe you should get an external powered usb hub, this seems like an awful lot of work for what is apparently a very flaky usb port implementation in your pc/laptop.
Commercial products are tested to comply with standards and usually are pretty bullet proof. The amount of tinkering you've had to do to other devices is an indication of some sort of problem. I've not had any problem with USB drives, both HD and solid state, usb audio hardware, or any HID device on any machine I own including my now 8yr old Compaq laptop. (My two other machines are about 2 yrs old.)
I don't know if it's all the fault of my laptop - the Seagate Freeagent issue is a known problem & solution - I was just citing it as an example of borderline current draws causing problems.
Anyway, I'm going to take out the components as I only need the USB AW-D3 card for USB to SPDIF conversion to feed directly to my Panasonic SA-XR57 pure-digital amp.
Should be a killer combo, particularly as I've now discovered how much better audio sounds with the Linux Ubuntu distro (without any tweaks, so far)
Anyway, I'm going to take out the components as I only need the USB AW-D3 card for USB to SPDIF conversion to feed directly to my Panasonic SA-XR57 pure-digital amp.
Should be a killer combo, particularly as I've now discovered how much better audio sounds with the Linux Ubuntu distro (without any tweaks, so far)
Yep, that worked guys, I removed LED & left 4 caps in place plus I shorted L1, the inductor on the USB ground - don't know which did it but DAC works flawlessly now!
Now to download Ubuntustuduo-audio & get some high-end sound!
Edit: Oh one thing - what would be a good SPDIF output circuit for this board - I'm thinking of pulse transformer!
Now to download Ubuntustuduo-audio & get some high-end sound!
Edit: Oh one thing - what would be a good SPDIF output circuit for this board - I'm thinking of pulse transformer!
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.