US-1641 Digital Noise Issue

[therecluse26]

My Tascam US-1641 has been having this issue on and off for the past year or so, and it's finally gotten to the point where it's unusable... every time I power it on or connect it through USB, a rhythmic crackling occurs through every output (making me think this is some sort of clocking issue). It sounds like loud digital noise, but it the rhythm/intensity changes every time I reboot the box. I have messed with the clock source on both the computer and the interface, and double checked all of the sample rates and so forth, but to no avail. I've also flashed/updated the firmware several times, plus reinstalled the drivers, but it hasn't helped in the long term... it inevitably always comes back after an interface reboot or two.

I know for a fact through running many tests that the problem doesn't lie in preamps/A-D conversion (recorded 16 simultaneous channels while this problem was occuring and only showed silence) or D-A conversion (the same problem happens using an external converter via S/PDIF).

What do I do? Does it sound like a hardware problem related to the internal clock, or what? I will say that whenever I've updated the firmware and/or reinstalled drivers, it does seem to fix the problem for a very short amount of time, so maybe this is a firmware or driver issue? I'm not 100% sure. All I know, is that this is REALLY affecting my ability to do real paying work and it's bottlenecking my business currently, and Tascam's official support has been everything BUT helpful... this REALLY sucks.

Please help... I'll buy you a drink if you can help me figure this out!

[CHECK THE ATTACHMENT TO HEAR WHAT I'M HEARING]
(apologies for the aimless rambling. my brain's scrambled from this)

 

[Billaboard]

Based on listening to the sound, I'd first look for some sort of feedback issue. The gradual build up and the slight "whooping" noise as it starts make me think this.

If it happens when you just have the usb cable connected, and no other external gear except for headphones, I'd suspect the usb cable, or some weird problem in the computer.

I mainly use a Tascam FW1884 and only have lesser, older, Tascam usb units, so I am assuming there is no setting within the 1641 to route output to input via the converters.

 

[therecluse26]

Based on listening to the sound, I'd first look for some sort of feedback issue. The gradual build up and the slight "whooping" noise as it starts make me think this.

If it happens when you just have the usb cable connected, and no other external gear except for headphones, I'd suspect the usb cable, or some weird problem in the computer.

I mainly use a Tascam FW1884 and only have lesser, older, Tascam usb units, so I am assuming there is no setting within the 1641 to route output to input via the converters.

Thanks for the response!

Yeah, I've tried multiple cables, so that's not the source, I'm thinking. I'm thinking it may have something to do with the drivers, since the problem briefly gets resolved every time I reinstall them and flash the firmware on the box itself.

How would you suggest I track down the source of the problem if it is a feedback issue? Is there a way to trace/alter the signal flow internally? Unfortunately there's no frontend software to this that I'm aware of..

I'm actually thinking that the gradual build-up might just be happening because it's booting up and the amps are activating, however it's not a tube-driven circuit so I could be wrong on that.

 

[Billaboard]

If it is the drivers, the place to go is to http://www.usbaudio.com/ . They wrote the drivers.
I had a problem with a US-122L. After I got desperate because Tascam didn't reply, I emailed them, and got a very terse, succinct reply which was right to the point, and was the key to solving the problem. Their site gives the support email address.

Is the unit connected to a PC running Windows 7? There appear to be several weird things that happen when you open the control panel audio settings in that OS. Your problem doesn't sound as if it is related to that, but it might be worth trying disabling the 1641 in the Windows audio areas of the control panel and just use asio.

I can't really help with the 1641 itself because I've never used one, but I would still look for some sort of feedback. Are the faint whoops audible as the noise fades in on the original of the sound that you posted? They might just be an artifact caused by the encoding of the uploaded file.

What OS and audio applications are you using? As above, the OS might have an effect

 

[therecluse26]

If it is the drivers, the place to go is to http://www.usbaudio.com/ . They wrote the drivers.
I had a problem with a US-122L. After I got desperate because Tascam didn't reply, I emailed them, and got a very terse, succinct reply which was right to the point, and was the key to solving the problem. Their site gives the support email address.

Is the unit connected to a PC running Windows 7? There appear to be several weird things that happen when you open the control panel audio settings in that OS. Your problem doesn't sound as if it is related to that, but it might be worth trying disabling the 1641 in the Windows audio areas of the control panel and just use asio.

I can't really help with the 1641 itself because I've never used one, but I would still look for some sort of feedback. Are the faint whoops audible as the noise fades in on the original of the sound that you posted? They might just be an artifact caused by the encoding of the uploaded file.

What OS and audio applications are you using? As above, the OS might have an effect

Thank you very much for that usbaudio information! I'll send them an email about it. I'm currently running OSX 10.6 with Logic Pro 9. This issue happens regardless of if Logic is running or not though, so I doubt it has anything to do with interfacing w/my DAW .

 

[Billaboard]

Ah, right. I did think you might be running with Apple hardware, and all my experience is with Microsoft, plus a small amount of work with Linux.

I am not sure whether the same usbaudio people write the OSX drivers. As far as I know, Tascam just get someone like Frontier Design to design the hardware and someone else to write the drivers.

I'd better opt out of this now, except to say again that I'd still vote for some sort of feedback issue.

 

[therecluse26]

Ah, right. I did think you might be running with Apple hardware, and all my experience is with Microsoft, plus a small amount of work with Linux.

I am not sure whether the same usbaudio people write the OSX drivers. As far as I know, Tascam just get someone like Frontier Design to design the hardware and someone else to write the drivers.

I'd better opt out of this now, except to say again that I'd still vote for some sort of feedback issue.

No, I really appreciate all the feedback! You've been infinitely more helpful than anyone at taSCAM. You should get a job with them as a support supervisor.

I just wonder.. is there really any kind of feedback that would come in the form of digital noise? I've never heard anything like that outside of a clocking error, but every time I change the clocking settings (i.e. the master/slave settings and sample rates), it changes nothing.