Crackling Sound on TASCAM US122-L

trippin13

New member
Hi,

I've just setup Guitar Rig 3 with Cubase 4 and Tascam US122-L (digital interface) and I've been having issues with slight sound crackling in the background. This occurs while playing the guitar, during playback and recording as well.

I've purchased dedicated USB card for Tascam and set latency to "normal" (as it was crackling even more in low latency setting) but everytime I use software I get slight sound issues.

Tried it all under XP and Vista but still same problem. I've updated the firmware and driver for Tascam still only slight improvement.

Any ideas what could be causing the crackling?

Thanks
 
Hey bud, I dug around a bit.

I think the issue is that our computers aren't issuing enough current to the device. I know it happens for me during loud parts of music. I turned down the overall volume (in Xp... Control Panel -> Sounds and Audio device and set the volume in the Volume Tab) Try playing around you'll notice you get pops and cracks when you increase the volume.

Other people have suggested getting an externally powered usb hub to power this sucker, I'll stick with the volume trick for now, since you can crank up you externally powered speakers. I took a look at the specifications for Tascam US122L, the maximum current intake is 500mA so be careful if you're going for externally powered hubs... I'm sure most usb hubs provide some means to prevent frying usb devices, but I'm not too bright in that area. Advice given to me is "don't buy a cheap usb hub"

Hope that helps.

Paul
Kaiyoti
 
yep I've tried putting in dedicated usb card ... didn't really do much my motherboard is pretty good anyway ...

but funny thing is it does seem to relate to volume and stronger signal so I reckon it is a latency issue or even a bad driver issue ... I used 1.12 and updated firmware but no luck.

my volume is pretty low overall so this still causes issue for me because I am monitoring on my headphones I am recording with a mic as well so it will pickup any sound in the room, can't rely on speakers... I've tried various settings without any luck so far ... mainly happens with vst instruments such as guitar rig 3 when I play low notes or many notes in small time span ... it's just a small static crackling but it gets recorded I checked all my jacks, cables etc...

I am running Core 2 Duo, 2GB ram , clean vista install ... the latency cracks least on "normal" setting of 16ms ... everything else is much worse

any ideas welcome ...
 
Hi, I am having the same issues with mine. It shows up at any volume but it's just a little harder to hear when it's loud. Did you guys figure out any solutions to this problem or what is causing it. It is very aggravating.
 
I just read this that someone posted....bought this in Jan. 2008 to record guitar tracks onto my macbook (Garageband). I didn't like it for some of the reasons stated: notably, the recording levels were hard to manage (signal would easily spike), and there were crackles frequently. However, I loaded the latest driver--updated since my purchase--and it seems fine now. I use it to record our band (we mic guitar, bass, vocals, and 3 mics on drums through a Yamaha mixer, with the monitor channel mixing into the Tascam, then to the computer). The signal is good, low noise, no crackles.
 
yeah I've updated to 1.12 straight away got a bit better result but I still have crackling especially at higher volumes ... it's totally random even doh cpu usage is around 15% with vst instruments ...
 
I just downloaded the new drivers too. But I haven't been able to check it out yet. I am going to try tonight. I'll let you know if it works. Also when you are plugged in via USB check to see how much power the Tascam is taking. Mine said it was requesting around 480mA and my USB supports 500mA so I was in the limit but it was close. I found this post online, maybe it will help you...

Go to device manager in WIndows XP and see the properties of the USB Root Hubs,
you can see which device is attached and how much current strength it demands.

One USB Root Hub can provide max 500mA and the Tascam needs the full amount !!
Some onboard USB's do not provide that reliably


Yes that's German, okay...well,it means "Properties of USB-Root Hub"
and can be found in the XP device manager.

Try different combinations with your USB devices until you got the US-122 alone at it's own port.
Check Device Manger to get sure.

You may try the famous "Asio4All" driver which provides an alternative ASIO Interface to the applications.
and is under permanent development for improvement.
Some people made it work by using this one instead.
Try with and without hardware buffer in the ASIO4All control panel.

http://www.asio4all.com

All the best..and good luck.

Good luck
 
So I tried the Tascam again. No luck still crackles. It is only when I play and more noticable when I play quiet. My usb port is fine and my cpu is only at 20% when running the program. I guess I have to keep looking. Maybe I will call the company. Laters
 
I also have what sounds like this problem. I figured out that the crackling only occurs when the input signal is just loud enough to trigger the LEDs.

Tried updating the firmware which made no difference.

I read on this forum that the US-122L is quite power hungry so I tried using a D-Link powered USB hub (like this one: http://www.amazon.co.uk/D-Link-DUB-...2?ie=UTF8&s=electronics&qid=1279752382&sr=8-2) and what do you know it seems to have fixed the problem!

Haven't tested it for any length of time but thought you'd appreciate a solution which worked for me.
 
I also have what sounds like this problem. I figured out that the crackling only occurs when the input signal is just loud enough to trigger the LEDs.

This is what I believe also. The crackling can be reproduced with the unit simply plugged into a USB hub (no computer) and listening on the headphones while making sounds into the microphone. Whenever the LED lights up, there is a crackle.

I believe that this is due to design flaws, made-in-China construction, and poor quality control.

I have the unit disassembled on my desk, and have been debugging the problem.

The first thing I noticed was that one of the capacitors on the edge of the circuit board was badly mashed. It looks like the case had been pressed into it forcefully. I suspect this was one of the overseas assembly people, who then neglected to replace the part. They just bent it and got the case to fit. I replaced the cap with a similar valued one that I had in my box. There is also a transistor with badly bent legs. It looks as if an assembly person ran out of transistors of that type and pulled it out of a trash bin. Tsk, tsk!

Using an audio probe, I have discovered that the crackle is quite epidemic throughout the circuit board. When the level LEDs light up, the switching crackle can be heard at random test points all over the circuit.

For instance, the crackle does make its way to the +/- inputs on the NJM4580 op-amps in the input stage. However, I don't hear it on the output pins: the op-amp's power supply rejection is doing its job! At that point in the circuit, I can hear crystal-clear audio with no crackle. So it is somewhere later in the chain and possibly the bifurcated legs of the signal chain could be picking it up independently. (I don't care if it is heard in the monitor circuit, if it's not in the recorded samples.)

I've had some luck in somewhat diminishing the noise by placing an extra cap across the power pins of a particular op-amp IC.

I think the problem may be best attacked by trying to squash the noise at is source, which is likely the LED circuit. The LEDs are driven by the very tiny surface-mounted transistors: Q105 and Q205 (left, right). The collector voltage of these varies directly with the LED behavior, and the trace can be followed from the collector to a resistor and then the LED. I'm going to experiment with sticking a power supply bypass capacitor into that circuit, to try to iron out the spike that occurs when the LED activates.
 
LED-originated crackling: "solved"!

Hi again everyone,

I'm pleased to report that I solved the crackling issue in my USB-122L. It is indeed the VU meter LED circuits that are causing this.

What I have done is installed some jumpers on the circuit board which cause the LEDs to always be on. (I.e. their meaning has changed: they indicate "power on", :D)

Poof, the crackling noise is gone, just clear audio.

The stupid LEDs are idiot lights anyway that are only really good for checking that there is signal from an input. Nobody is going to sit there adjusting their volume based on what the LED is doing. You're not even looking at the unit when recording. Your software (and ears) tell you you have clipped. So there is no real loss of functionality from this hack.

What I did was pull the bases of transistors Q105 and Q205 (left and right) to a negative voltage (-6.8V). The most convenient points for obtaining this voltage were pins 4 (-VCC) of op-amps U300 and U308.

I took a snapshot which I will try to attach. You can see the board powered up with the LEDs lit, and if you look closely, you can find the jumpers. One of them is partially obstructed by the phantom LED base: you can see the connection to the tiny transistor's base only.

So if you have the same LED-related crackling with a US-122L, here is one way to go.

Cheers ...
 

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