Graeme-
To go further afield...
I have minimal experience with Ashdown. I listened to a player testing a combo against a Super Redhead at Bass NW a few months ago. The guy played both upright and electric through it and the Ashdown sounded more warm and natural. I would say it had better bottom and low mids where the SWR sounded like it had a smiley EQ applied to it. I believe he bought the Ashdown, and I know I would have under the circumstances.
I haven't seen any TE gear around here in quite a while, so that's a tough comparison. Certainly, you should be able to find some stock at a local shop there to hear it for yourself?
I would say that you should be careful going from a 4x10 to a 1x15 or 1x12. Most 4x10 cabs spec out to have the same or better low end response compared to a larger speaker. What you may be experiencing is too tight a bottom such that the sound quality isn't what you want. I suspect that your combo has a tube preamp, so you might experiment with pushing the preamp stage a bit harder and backing off on the main volume (or the reverse) and see if you end up with a tone that you like better. If it isn't warm enough, you might see about inserting some sort of tube pedal or preamp to warm it up. For example, I sometimes play an F-1X into the effects return of my SWR to replace the preamp stage with the warmer Alembic version.
In my experience, buying on recommendations other than your own ears usually results in reselling and buying something else. It's also true that the tone you enjoy solo in the shop or your home may not be what you want on a gig. One important concern is that bass frequencies suck mucho power. When you turn up that 250w amp to gig volumes, you may not have the juice for the low end response that you want.
Go out and see bands playing where you want to play and see what they are using. Pay attention to what's going on when you hear something you like. If the place is large enough to have a soundman controlling the house mix, then see if you can chat with him about what works and what doesn't. In those venues, things that you think sound good may have little or nothing to do with the stage amp.
As much as I enjoy the simplicity of a combo (and hate lugging gear, since I get to carry the PA as well), I am leaning toward the component setup at the moment. If I were starting from scratch today, I'd start with a good power amp (stewart 2.1?) with a ton of headroom. The power amp should be a permanent item that has minimal impact on tone unless it breaks. It's money that you won't have to spend over and over as you switch rigs. Then it's a matter of playing with cabinets and preamps to find what you're looking for. An F-1X or Bass Pod XT would be my current preamp choices, and I'd go with the BPXT if I had to choose just one. It's more versatile for what I need to do. For cabinets, I'd try to stay small with a Schroeder 1212. If space weren't an issue, I might try one of the more audiophile 2x12 cabinets. The ideal modular rig would add a 1210 to the 1212. Other than Schroeder, I might go Bag End to stay compact. I'd run the bass into the BPXT and send the direct out to the F-1X. Each pre would feed one side of the power amp full range. I'd have to experiment to see which pre should feed which speaker.
Well, too much info as usual...Sorry!
-Bob
