M-audio Fast Track Pro(blem)
Posted on 16.07.2008
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I was begining to grow tired of the solution that was forced with the usage of laptop for mobile DJ gigs. "Solution" was split stereo where one mono line is set as master and routed to the PA and other is connected to my headphones for cueing. I will not comment the sound quality nor latency of builtin soundcard. Therefore I have obtained a FastTrackPro, good sound, low latency, rugged built, balanced outputs. It is great for the money i paid for it. (thus it lack at least 2 more stereo sound channels for my needs)

Everything was well, first gig done prefectly but while prepping for the second one, the card died for no reason. My DJ software was locked up, preventing the OS to reboot. That was the beginning of problems. That night during the gig, FTPro was shutting down every 30-45 minutes. We tried everything that we could, changed cables, transfered laptop to another power outlet, left laptop running off batteries, nothing helped. That was a wery frustrating evening. It has passed 4 months since then, in the meantime I've been struggling with this problem using every possible resource that has crossed my mind. I even molested local m-audio dealer shop to issue me another of their soundcards (firewire audiophile) in order to test if all cards behave the same way. Night after that problematic gig, I serched the internet for the sam problem and possibly a solution. The best lead I have found was this forum thread: FastTrackPro stops sending audio

First solution was to buy a 9V 1000mA DC power supply since the card has external power connector(usually it is just powered via USB 5V).

After that I made a USB cable that has only Data lines connected, no power lines(aka USBPowerCutter). This was also done to eliminate the ground loop buzz created by laptop's battery charger. This solution "confused" FTPro even more, it would take time after hotplugging it or wouldn't connect at all.

Next in the line was 1:1 audio transformer from Neutrik. Thiese galvanic separators are bulky and heavy. Altough usefull for eliminating ground loop buzz and protecting your equipment from ground loops I do not recommend to carry thiese around with you because of the weight. It did not help.

I made a 9V voltage regulator, with some relatively big capacitors to stabilise external power supply output. It helped a bit but nothing crucial. The card locked up few more times on the next dj set.

The FTPro has balanced outputs on only two channels(one stereo). I tried to connect the card to the amp that way and it helped a little bit. On the next gig it locked up only once while beeing connected to the numark mixer. Even if it did help the problem would be: I could not connect the card to the two stereo mixer channels because one stereo channel(unbalanced) would expose the FTPro to the problem.

5V regulator + power injection USB cable: I changed the 9V regulator to the 5V regulator and inserted output from the regulator into the USBPowerCutter cable. There was no +5V comming from the laptop. Still same problems again including the hotplug-detection-delay.

USB power regulation by using two 2,2mF polarised capacitors connected in paralel with +5 and GND from the laptop. Works like a charm. I've used it on EXIT fest 08. without any problems.

The image above is test version, you can see the gray/blue power lines connected to the capacitors and green/white data lines. Image below is same solution re-packed to fit casing.

This is how it looks wrapped-up:

While working on the final FTPro solution I made this prototype of 90deg bent usb plug to save desktop space around my laptop. It works well, sorry for not documenting the build process. I intend to make few more so (hopefully) I will post a separate newsitem regarding that build.

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