Us-122l Logic Express Problem Options

[Jem]

Hi Guys, just found this board and had a search around and it seems a few people have US-122 and US-122L units so perhaps someone can help me with this problem (or at least replicate it!)

Firstly my hardware... I'm using Logic Express 7.2.3 on OS X 10.4.8 on a 2.0GHz Intel coreduo iMac with 2GB RAM. I've got a Tascam US-122L plugged into its own port on the back of the iMac.

I've been using it perfectly happily with Garageband for a few months but finally moved over to Logic Express and have been trying to reduce the latency by reducing the I/O Buffer Size and have run into biiiig problems!

With the size set at 512 (default) everything works but with a large latency
With the size set at 256 everything still works, better latency but still not good enough
With the size set at 128 everything falls apart! LE's cursor plays and pauses and plays and pauses etc... and no sound comes out (well, sometimes a bit of noise but mostly no sound).

It's not CPU loading as it happens even with 1 track, my CPU is sitting around 20% anyways so that's not the issue.

I took a look at the system.log log file (from the Console application under Applications/Utilities) and when I'm using 128 and LE is running, the following message appears every second in the console:

Jan 26 18:51:31 xxxxxx-xxxxxx-computer kernel[0]: USBF: 171139.681 AppleUSBEHCI[0x3a2d000]::UIMCreateBulkEndpoint: USB 2.0 Spec (5.8.3) converting MPS from 9 to 512

It looks to me that there's a (serious) driver issue with this unit. I've downloaded the latest firmware and drivers from Tascam - 1.02. I've unplugged every other USB device. Nothing seems to work.

What I want to know is can anybody either replicate this message and echo that it's unusable with anything less than 256 for a buffer size... OR has anyone got it working in LE without buffer problems? It could of course be something to do with my install but I can't for the life of me think what.

I've e-mailed Tascam but have read their support isn't exactly wonderful so I don't expect a reply any time soon. It's just annoying as it means I can't record a track while listening to the mix including the track being recorded as the latency is distracting. I was hoping to spend more money on instruments but I'm wondering if I should be scraping the US-122L and getting something that works with lower buffer sizes?

Please, please answer, I've posted on both apple boards and bigbluelounge and anyone would think, from the silence I've received that noone uses this combination??