S/PDIF through Edirol UA-25

I record my hardware synths over S/PDIF through the UA-25. This works well for tracking audio at very high quality and zero hum, noise, EMI or RFI.

But I have one annoying problem. When I enable the digital input on the UA-25 it turns off the USB input from the DAW. Which is to say I cannot record audio via S/PDIF and listen to the previously-recorded tracks at the same time!

I have just ordered a new mic pre with A/D converter and S/PDIF out. This will be very cool, but unfortunately I cannot use it with the UA-25. Kind of hard to sing along when you can't hear the song!

To the question, then: is this just a quirk of the UA-25, or a general limitation of low-end converters? Are you able to monitor your previous tracks while recording a new track via S/PDIF on the converter you're using?

Thanks for the quick reply.

Yeh, the whole idea of using the digital input is to bypass the UA-25's A/D converter, skipping an unnecessary conversion, and also bypassing the UA-25's wimpy analog circuits. All the UA-25 does is serve as an S/PDIF-to-USB interface.

I take the output from my outboard synth, run it through an RCA-to-optical converter, and from there into the UA-25's digital input.

When I press the switch on the UA-25 that enables the digital input, that kills the output from the DAW so that I cannot monitor the existing tracks while I'm recording.

Since I record everything as MIDI initially and only commit to audio after I'm happy with the sequence, not being able to hear the mix during recording is usually not a problem. But now I want to bring my vocals in digitally, too, and not being able to hear the mix is a showstopper. I don't want to run the audio output from the preamp into the UA-25 audio input, since - as you pointed out - that would defeat the purpose.

It looks like I may need a better converter, or at least a different one. Based solely on price and appearance, the FA66 looks to be identical to the UA-25, the only difference being firewire instead of USB. Are you saying that you have personally used your digital input on the FA66 for live tracking?

And what made you dump the UA-25 in the first place?

CJ,

I believe he wants to record the audio sounds of his hardware synth. I'm sorry I can't help you on this bitflipper except to maybe suggest to contact M-Audio and ask them about that, or maybe go to their support site and write them an e-mail. I for one am switching to another company mainly due to M-Audio's lack of driver support. They are not bad at responding e-mails though. Peace.

Yeh, the whole idea of using the digital input is to bypass the UA-25's A/D converter, skipping an unnecessary conversion, and also bypassing the UA-25's wimpy analog circuits. All the UA-25 does is serve as an S/PDIF-to-USB interface.

I take the output from my outboard synth, run it through an RCA-to-optical converter, and from there into the UA-25's digital input.

From what I can understand this is how he wants to do it. He only does MIDI for composing and then records audio when he feels happy about the arrangement. Hopefully he will schime in to correct us/me .

You're exactly right, Junski. The diagram clearly shows that the USB input is taken out of the circuit when the digital input is enabled.

My question is: is this the norm for outboard converters, or is there another model that will allow the USB input to be monitored while recording via the S/PDIF input?

I think my solution will be to add a second converter, use it for audio output. Solves the problem and provides two more input channels. My built-in sound card isn't an option, I intentionally ordered the computer with the crappiest audio option because I knew I wouldn't be using it.