UA-25: SYMPTOM: Pops and clicks while recording

Tags: usb,ua-25,click,network,irq,pops
There are a few factors that could contribute to this issue such as IRQ conflicts, processor speeds or compatibility, and even network cards.

IRQ means "Interrupt Request". Devices can "interrupt" your processor and demand to take over current processes. Your processor usually says "No, I'm busy", and continues working. But a device may continue to send interrupt requests. In most devices, these interrupt requests will interrupt processes only for a moment and you won't notice it. But audio streaming requires totally interrupt-free operation, or you'll get click/pop sounds.

You can usually overcome IRQ Sharing conflicts by installing a PCMCIA USB adapter card. It will plug into the empty card slot on your laptop. Install the drivers, and Windows will usually assign a unique IRQ to the new USB card. You can now plug into the new card and enjoy uninterrupted audio. We recommend Orange Micro USB cards, but most cards using the VIA ver 5.0 USB Host Controller or better will do.

But be forewarned: Windows allocates IRQ's automatically. You cannot control what IRQ number it will assign. If Windows assigns a shared IRQ to your new USB card and you get pop/click, you'll need to contact your laptop manufacturer for advice on resetting the IQ scheme in the laptop.