Noise when recording from USB preamp

Hello,

I recently bought a Technolink TC-756USB Phono Preamp to save my records and tapes to my computer (Dell Inspiron 15 laptop with Windows 10). However, when I tried to save the music from my tape deck and my turntable using Audacity I found a high pitched noise in the background of the recordings. Here is what I’ve tried so far to fix it:

  1. Recording with both the tape deck and record player with the preamp and computer plugged into their adapters
  2. Recording with different combinations of the laptop on battery power and preamp powered by its adapter and laptop powered with its adapter and preamp on USB power. Then I tried the above without the tape deck or record player plugged into the preamp. Then tried it just with the preamp running on USB power and the laptop on battery power (i.e., nothing plugged into the wall and nothing else plugged into the preamp or computer)
  3. Grounding the preamp to the laptop
  4. Changing out the preamp’s USB cable and making sure it is tight at both ends
  5. Recording with the preamp and a desktop computer
  6. Plugging the preamp into a powered USB hub and then into the laptop
  7. Downloading the preamp’s OEM device driver
  8. Connecting my turntable to the preamp and then used the preamp’s analogue outputs to connect to receiver/speakers and in this instance, I did not notice any noise. However, if I went turntable to preamp and then preamp’s analogue outputs to receiver/speakers AND the preamp’s USB output to my computer, I got the noise while recording on my laptop and a high-pitched whine in my receiver/speakers when the laptop was recording.
  9. When I tried to listen to just the preamp using the listen tab in the Windows sound manager, I still hear the noise

I’ve been in contact with the preamp’s customer service and he’s been very responsive, but we haven’t figured it out yet. He’s sending a transformer adaptor for the preamp to see if that makes a difference. The only other things I can think to try would be a USB isolator (anyone have luck with these?) or seeing if the preamp is defective. I attached a sample of the noise

I know this is not an issue with Audacity, but I wanted to post here to see if anyone has any suggestions.

Thanks in advance!

Goodness!

I get three problems and I’m not even breathing hard.
Screen Shot 2017-05-10 at 18.09.57.png
See the bottom blue line doesn’t match “0” on the left scale? That’s DC offset. There is something very seriously wrong that allows the battery system to leak into the audio. Once you fix that, the bottom track has normal “frying mosquitoes” whine and we have a new tool to deal with that.

But.

The top track which sounds roughly the same, isn’t, and doesn’t respond to the repair. It’s a screechy-whine problem I’ve never heard before.

I think it’s three strikes. You will spend most of your time struggling with the unit and no time enjoying the sound. Just to make this worse, many of these problems are a dance between the USB audio device and the computer. The computer maker may have cut corners on the USB service and could be causing some of these problems. Can you try another computer?

Koz

People here like the ART USB adapters. I didn’t do it that way and the forum link is broken, so maybe someone will pop in and give us the info.

Koz

http://artproaudio.com/turntable_preamps/product/usb_phono_plus-ps/

WC

  1. Connecting my turntable to the preamp and then used the preamp’s analogue outputs to connect to receiver/speakers and in this instance, I did not notice any noise. However, if I went turntable to preamp and then preamp’s analogue outputs to receiver/speakers AND the preamp’s USB output to my computer, I got the noise while recording on my laptop and a high-pitched whine in my receiver/speakers when the laptop was recording.

Usually high-pitch whine with a USB device is caused by noise on 5V USB power from the computer. (And then you never know if the computer’s power is unusually noisy or if the interface is unusually susceptible to noise.) But, since your interface uses an external power supply I’m not sure why the USB power would even be connected internally.

It would be worth trying a different computer.

The [u]DC offset[/u] is definitely a hardware problem. You can’t directly hear it and It can be removed, but it does limit the amount of signal (or gain) that you can get without clipping.

The DC offset is definitely a hardware problem. You can’t directly hear it

You can’t hear it, but it makes audio editing a complete nightmare. Every edit has a pop or click. It’s a land mine. You don’t see anything until you step on it.

I blew the whistle because I’ve never heard/seen that many different problems in one system before. That’s a red flag.

Not all computers lend themselves to sound production.

Koz

Thank you all for your help. I’m still learning as I go with this so it’s really great information.

I tried the preamp on a desktop and got a similar sound, but I’m not convinced that specific desktop is any better for sound recording than this laptop. I’m planning on asking a few friends if I can test the preamp on their computers. I still can’t tell if the noise is coming from the preamp, the computer, or a mix of both.

I was looking at the ART USB preamp, but went with the Technolink because it had inputs that can be used for a tape deck. If I ended up getting an ART USB preamp, does anyone have any recommendations for ways to digitize tapes? At this point, I’m thinking getting a computer with a stereo line in might be the best option to avoid USBs all together.

I’m thinking getting a computer with a stereo line in might be the best option to avoid USBs all together.

If you can. The last Mac I bought—intentionally—was an older model that still had Stereo Line-In and Stereo Line-Out.

The next more modern model removed Stereo Line-In. I know of no current model laptops that still have analog Stereo Line-In.

You can buy large desktop Windows machines with full soundcards. That does work, but nobody is throwing awards at those for high quality. Built-in soundcards are living in a hot, hostile, super electrically noisy environment with a mandate to be cheap. If you build your own desktop, they warn you to mount the soundcard as far as possible away from the video card.

The last high quality audio connections I know of on a normal production machine appear a Mac Mini.
Screen Shot 2017-05-13 at 9.12.46.png
In general, any machine with a single audio socket need not apply. Those are for headsets or headphones. Any connection labeled Mic-In can have problems. They’re usually mono, not stereo and can have problems with high volume Line connections.

Good luck.

Koz

You can adapt high volume stereo to a machine easily with a Behringer UCA-202 (or one of the cousins). That’s one with my analog sound mixer.

They make a UFO-202 which will switch between Phono (for an analog turntable) and Stereo Line, but jury’s out on how well they work with a known noisy computer.

Koz

Thank you Koz!

As a follow up, I tried the preamp on a friend’s desktop who does a lot more audio recording than me. We still got the noise on his computer. He also lent me a tascam us-428 and I did not get any noise when I tried recording with that on my laptop. I also checked for DC offset and both L and R were at the center line. At this point it seems like the noise and DC offset were both from the preamp’s ADC.

My understanding is that the ART device should be perfectly capable of doing that. All you would need to do is to use the button on the front to switch it to “Line” rather than “Phono”. This will bypass the phono pre-amp and will take the line-level output from your tape deck/cassette deck which should be line-level signals.

Effectively you are just using the ART this way as an external USB ADC soundcard.

WC