Thanks for the feedback, folks, appreciated.
Czadco - where I've usually gotten clipping from the Eurorack is when I'm recording sounds with particularly low-end frequencies. I'm also interested in avoiding too many features, also because I find too many extra items confusing and unnecessary.
Pentd, to your questions - I mean a dedicated mixer which can interface with a computer. Not so much with any pre-amp stuff, although that could help. Currently, I'm using a simple four-track Eurorack, which is Behringer. It has no usb/firewire feature, I got it mainly for live work but use it for recording now that Tascam is faulty. The Tascam itself is a four-track multimixer, again without usb/etc. connections. So I've mainly been using gear not really designed to actually interface with a computer.
But, at least with the Tascam, I've had no serious issues. I had the line-out going straight into the audio-in jack in the back of the old desktop upright computer (the driver is called ACPI Uniprocessor PC, whatever that means, the system is Windows XP and the soundcard is called SoundMax Intergrated Digital Audio, which came with the computer) I've had since around 2004 or so, using whatever sound-card is in the computer. For years, this has been a perfectly satisfactory arrangement, despite not having a clue what I was doing and no one to tell me.
After having a closer look at the specs. of the Zoom I suggested, not what I really want. It's not that I have a problem with only two tracks to the computer, as it's for personal use, but upon reflection I decided I didn't like the whole stand-alone digital recording set-up. I used to own a digital eight-track, and I considered it a total waste of money for how I prefer to do things. Incidentally, I briefly considered getting a H4N to use as an interface, and still would like to get one for outdoor and on-site multi-tracking, but any ultimate editing would be on the computer.
To be honest, I've no idea why there would have been a difference between the Tascam and the Eurorack apart from the latter just not being able to take a wide enough sound range. Had a look at the Alesis you recommended and feel that something like the 6FX would be more to my needs - small and simple. I've done a bit of dicking around with the levels on both computer and mixer and have had more satisfactory results recently, but as mentioned to Pendt, there are lower frequencies I still can't get without clipping and popping. You may be right about calibrating settings, but outside of fiddling with levels I haven't found any other way to do that.