Hi I have an pcm2706 dac with an tda1543 output section. Im using a 230v ac -> 12vdc regulated supply -> then two regulated supplys using lm317 for two 5 volt rails. One for the pcm2706 section and one for the tda1543 section.
So to the problem. When other electrical equipment turn on and off the dac some times halts in windows, this meaning foobar output stops and I have to start the song again. Although not critical, this really is annoying. Im assuming this is a problem with noize on my AC. Is there anything to do with my supplies, or before the supply's, that will prevent this problem ? Some kind of spike protector on the AC inlet or something like that ?
So to the problem. When other electrical equipment turn on and off the dac some times halts in windows, this meaning foobar output stops and I have to start the song again. Although not critical, this really is annoying. Im assuming this is a problem with noize on my AC. Is there anything to do with my supplies, or before the supply's, that will prevent this problem ? Some kind of spike protector on the AC inlet or something like that ?
Maybe a transformer with better isolation?
I read someplace that toroids are worse than conventional transformers because they have a wider bandwidth and therefore pass more electrical noise. In case that is relevant.
If the battery solves the problem, could you power the DAC stuff off the 5V from the USB port, using a DC-DC converter followed by some little linear regulators?
There could be some grounding issues since you've got electrical continuity between all the grounds in your audio system through to the computer. I'd be more comfortable with an S/PDIF link to provide electrical isolation - optical or transformer - between the USB output critter and the DAC.
I read someplace that toroids are worse than conventional transformers because they have a wider bandwidth and therefore pass more electrical noise. In case that is relevant.
If the battery solves the problem, could you power the DAC stuff off the 5V from the USB port, using a DC-DC converter followed by some little linear regulators?
There could be some grounding issues since you've got electrical continuity between all the grounds in your audio system through to the computer. I'd be more comfortable with an S/PDIF link to provide electrical isolation - optical or transformer - between the USB output critter and the DAC.
The usb bus, is realy noizy not good for audio use, might be workable with some filtering as you suggeste. Im not using usb ground, for the reasons you mention. Only thing powered by the usb on the dac is a light diode, usb ground is not connected.
I'w though of changing the transformer, currently Im using one from Block-Trafo.de model FL6/12
http://www.block-trafo.de/fileadmin/productpdf/FL.pdf
Any suggestions for a more sutable replacement?
Come to think of it there might be an other reason for the problem. Maby my AC mains just is filled with noize, maby its wiered in a wird way or something, and the problem is not with the dac supply and can not be fixed there. So I think Im gonna try a simple filter on the ac mains input of the dac to se if it helps.
I'w though of changing the transformer, currently Im using one from Block-Trafo.de model FL6/12
http://www.block-trafo.de/fileadmin/productpdf/FL.pdf
Any suggestions for a more sutable replacement?
Come to think of it there might be an other reason for the problem. Maby my AC mains just is filled with noize, maby its wiered in a wird way or something, and the problem is not with the dac supply and can not be fixed there. So I think Im gonna try a simple filter on the ac mains input of the dac to se if it helps.
No USB ground? Don't the USB signals need that as a reference? Or do you have the USB signals coupled through transformers or optocouplers?
I'd try whatever transformers are lying around and see what (if anything) makes things better or worse. Your transformer is a "UI" core, which sounds like it should give good isolation (windings presumably on opposite sides, not one over the other like an EI). But there's no pin for grounding the core or an electrostatic shield, which might help things.
I'd try whatever transformers are lying around and see what (if anything) makes things better or worse. Your transformer is a "UI" core, which sounds like it should give good isolation (windings presumably on opposite sides, not one over the other like an EI). But there's no pin for grounding the core or an electrostatic shield, which might help things.
I have the same problem with my AW-D3 usb dac from Audio Workshop.
I use an AT psu to provide 12v to a modded T-Amp and 5v to the TDA 1543. The Burr Brown chip is powered by the usb, a bit too noisy for listening.
When it stops, foobar has to be closed and the usb unplugged before starting again.
Have tried the following and it still stops when the fridge or washing machine turns on/off.
Use the Burr Brown dac so the AT psu only powers the T-Amp.
As above but using a laptop running on battery.
Plug the dac straight into the PC without usb cable.
Any ideas? (I checked the grounds, all there.)
I use an AT psu to provide 12v to a modded T-Amp and 5v to the TDA 1543. The Burr Brown chip is powered by the usb, a bit too noisy for listening.
When it stops, foobar has to be closed and the usb unplugged before starting again.
Have tried the following and it still stops when the fridge or washing machine turns on/off.
Use the Burr Brown dac so the AT psu only powers the T-Amp.
As above but using a laptop running on battery.
Plug the dac straight into the PC without usb cable.
Any ideas? (I checked the grounds, all there.)
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