USB vs. line-in

[khoffcran]

Hello again, my little international fraternity of tech-savvy, music-loving friends. I've yet again encountered some static interference (despite using a fresh USB cable, checking various sockets, avoiding hub use, shutting down all other programs etc. etc.).

I suspect, as all of you do, this is somehow a USB issue. (Analog TT / ART USB V2 A-D interface / USB 2.0 cable into iMac5,1 (2006 dual Intel, OS 10.4.11)).

So, what's your collective opinion on USB vs. line-in? The ART allows the RCA to 1/8" option, and it's the one situation during which I have not yet encountered any problem. Is there a loss of fidelity, and if so, is it significant or merely marginal? My early experiments reveal no obvious problems.

Thanks yet again,

Keith H, NJ / USA

[waxcylinder]

Keith,

it really depends on the quality of the ADC (soundcard) in your ART USB device versus the quality of the soundcard in your computer. In my case my external Edirol is definitely superior to my desktops onboard soundcard - but I don't get static from my USB connections (he says while frantically touching wood with one hand and grabbing his lucky rabbit' foot {not so lucky for the rabbit ...} in the other). I would recommend some recording and listening tests

You could try cleaning the USB connectors with alcohol and drying them - try (gently) wiggling the USB plug in it's socket. Also are you sure that you have no external stuff causing interference (tramsportable/mobile phones, fluorescent lights etc.). My recordings are very sensitive to the routing of the power lead from the transformer to my ART pre-amp.

WC

[khoffcran]

Hmmm. It occurs to me that I never encountered this problem when I first started doing this stuff about four years ago. (I kind of let it go for a while). Since then, I've added a wireless router from Verizon, my TV/Internet/phone provider. (I don't know how it works in the UK, but I imagine you have something similar. You don't just have a choice between BBC1 and 2 and one independent channel anymore, right?) That router sits within a foot of the USB sockets. Potential problem?

Keith H, NJ / USA

[waxcylinder]

Potential problem?

Quit possibly, such devices can interfere with each other. There was a letter in the Radio Times (or my paper - can't remember which) this week where some lady had long had problems with her TV signal until one day she re-organized her room and moved the base-unit of her transportable phone away from where it previously sat next to hetr TV digibox. After that fortuitous move her interference vanished.

Having said that, my Edirol soundcard and my passive switch both sit right next to my WiFi router and they all sit bang next to my FM tuner - and the ART preamp sits on top of my PC's system box. The really critical piece of "plumbing" is as I said in my earlier post the power lead to the pre-amp. Even with all that close proximity I get very little "noise". I do make sure that I have an old-fashioned incandescent bulb in my Anglepoise desk lamp though rather than one of these modern flooryessent low-energy jobbies ...

WC

[billw58]

In my experience the A/D converters in Macs are very good - quiet and accurate. I'd suggest a little A/B experiment. Record the same LP track with the USB connection (assuming you can get a clear recording) and with the analog connection. Line them up one under the other, apply the Amplify effect to each track so they're the same volume, go to Preferences > Tracks and set the Solo button behaviour to "Simple". Now you can play them and switch between the tracks.

As for cleaning the USB sockets, is there an electronics supplier nearby that carries the Caig DeoxIT products?

-- Bill

[Irish]

Is your Art USB device powered from the mains or the USB socket?

I recently got an Art USB Phono Plus V2, which I'm guessing is what you have, and I have had no problems with it. However, I did notice that the noise floor was about 20dB higher when the device was USB-powered than when it was mains-powered (-50dB vs -70dB).

In either case, I couldn't hear any noise on the recording, but I could see every hard disk access on the Audacity recording meters when the Art was USB-powered. The routing of the audio cable from the turntable to the Art also made a difference. I would suggest powering the Art from the mains, if you are not already doing so, and keeping the turntable and the Art away from everything else as far as possible.

POL

[khoffcran]

Thanks All - Will do. Will check.

Keith H NJ / USA