Left hand thumb
 

Working on tone and technique.
Here's a question:

Is it better to relax the left hand thumb and play with the fleshy part agaist the neck or is it better to employ the thumbtip like a claw?

Iv'e been trying the later and it seems really hard to get a good tone and it seems unnatural and makes my hand tired. Will this change over time?

I'd really like to get a tone like Brian Torff. Any suggestions would be great.

Relaxed is better for health reasons. I dunno about tone.

Check here for Chris Fitzgerald's video lesson on the left hand.

You will not be disappointed.

Possibly you are using the gripping force of your hand too much. You don't want to rely
entirely on your hand to get pressure on the strings. You need to also use your whole
arm. Using your thumb to provide much of the pressure is more appropriate to instruments
like electric bass, where the instrument itself offers no resistance to fretting or stopping
a note.

You don't want to "squeeze" the strings down to the fingerboard, but want to "pull" them down.
Of course you need to provide some force from the thumb, but it should be relaxed.

metaphor - Also make sure you are not standing to the side of the bass. You need to be
at least partly behind the bass so that you can pull back against the fingerboard.

GrowlerBox - excellent video, best I've seen.
Any idea what kind of bass that is?
I want one

Chris is a moderator on this forum, and there's a thread devoted to his YouTube videos here. He has discussed his bass(es) somewhere, but I'm sure he'd respond to a question on that thread.

John Clayton has a series of bass lessons also. Here are his left hand tips.

http://www.youtube.com/watch?v=EsQz3BnABHc

Wow, really great info. I love the videos. Thanks guys!
It's been a struggle. I've been playing for years with bad technique and little attention to tone. I feel like I'm having to relearn the instrument.

We're all relearning the instrument, every day.

It's probably one of Chris' New Standard La Scalas.