My DAC no longer working using digital inputs

I just purchased a lightly used Cambridge Audio Azure DacMagic-B. It came with no cables.

It was working fine using a USB connector from my Macbook as well as an IC from the CDP co-axial output jack to one or the other of the two digital input jacks on the DAC. Since I did not have a proper coaxial cable, for a couple of days I used a regular interconnect from the coax out on the CDP but replaced that today with a coaxial cable. The regular IC did work except the signal was cutting in and out. I did not have a proper coax cable until today otherwise I would have started with that.

When I put the coax cable into the system, that's when the DAC the problem started. Now, no matter what kind of IC I use from the CDP to the DAC, I can't get the digital inputs to work. The USB input continues to work fine.

My CDP is a Shanling T1000 SE. I've not been able to test using another CDP but I think that's the next step.

Any insights would be greatly appreciated. Should I suspect the DAC or the CDP or both? :)
are you unplugging everything else when trying the coax? start with that. also, what kind of format are you using from the mac? can the dacmagic handle that?
Thank you. I followed your excellent suggestion by unplugging the USB from the MAC to the DAC. I then plugged the co-axial cable from the CDP to the DAC and bingo, John Coltrane was in the room, making me a very happy man.

I have not yet plugged the USB cable back into the DAC for fear of messing things up. Since the DAC has a source button I assume that's OK. I will proceed with caution.

I am using iTunes to play Internet radio into the DAC. I have a trial of Amarra but can't tell much, if any difference with it on or off. Digital audio is a completely new activity for me but so far I find it very enjoyable. I have much to learn.

Thanks again.
Ps: When using Amarra sQ 2.0, please start iTunes first and then start Amarra sQ 2.0. This allows the correct connections to be made between iTunes and Amarra sQ. Please verify that Amarra sQ 2.0 was installed correctly. I had to install a 2nd time to get it to work correctly. This was my fault since I do NOT follow the instructions correctly. The first time the music was playing but was NOT playing through Amarra sQ.

Look at the Amarra screen to ensure the volume bars are showing. This means Amarra sQ 2.0 is working. If not, please review your Amarra sQ settings to ensure the DAC is connected, etc. Amarra recommends the volume on your amplifier be set to max BUT I do NOT feel comfortable doing that. I set my amplifier volume control where I like it and ADJUST the volume on Amarra sQ so that the yellow bars are just showing but not the red bars. You might have to experiment with the Amarra sQ settings to get it the way you like.
Thanks for your comments. I double-checked and Amarra 3.03 is running with iTunes.

I've been thinking about the issue of my pre-amp having but one set of line inputs and I think I'm better off plugging and unplugging the DAC and CDP depending on whether I want to input from iTunes or the CDP. It doesn't seem to make sense to me to run my CDP through the DAC or am I missing something? Would not the DAC in my CDP be better than in my modestly-priced Cambridge Audio DAC? Plus, the Shanling has tube outputs which sound better to me than the SS.
Ps: I agree that the DAC in your CDP is probably better than in your modestly-priced Cambridge Audio DAC (you should really test this to confirm).

I also agree that since your pre-amp has only one set of line inputs, you might be better off plugging and unplugging the DAC and CDP depending on whether you want to input from iTunes or the CDP. However, switching cables around is a pain.

Since your pre-amp only has one input source, you might consider buying a higher quality DAC so that the MAC and Shanling T1000 SE CDP can be plugged into the DAC.

I guess you could also replace your pre-amp that only has one set of line inputs with another pre-amp with multiple inputs so that the MAC can be wired to the DAC and the Shanling T1000 SE CDP can be wired to the pre-amp.

I do not like having to switch cables around to get it to work but you have to decide. Maybe you should call a Shanling dealer and ask about the right cable to use.
I've got a couple of issues.

I've finally determined that the digital input board on the DacMagic is malfunctioning intermittently. That's why the CDP has been cutting in and out. The USB board continues to work OK, so I can listen to iTunes. I don't think it pays to have the DAC repaired. The repair is likely to cost much more than I paid for the used DAC. I will say that iTunes played through this DAC sounds darn good.

One of our Audigon brothers sent me a link to an inexpensive switching box which would enable me to run regular ICs from the CDP into the box, and also run the ICs from the DAC into the box. Then I can use the switching box for the digital source rather than the DAC. I won't have to swap ICs and I also can utilize the tube outputs from the CDP, all into the single line inputs on my preamp.

I wanted to post an update which may be helpful to some of you guys and gals.

I just hooked up a small switching box - a passive pre-amp- I got from Schiit.
It's called the SYS, and it works great. It has two sets of input jacks and one set of outputs. It uses conventional IC's from both my DAC which is connected to iTunes via the USB cable, and my CDP. The SYS outputs go to my preamp's line inputs.

I don't have to swap cables to listen to one source or the other, I can use the tube outputs on my CDP, and all is well.