From my Talkbass ramblings at 4AM this morning:
OK, after night one with the Pyramids my attitude towards them is cautiously optimistic. They are VERY different from the TI strings. They've gotten a bit more consistent from string to string, but there is still a progressive sense of tension and brightness going from the E string to the G string. The G string is much twangier than the others. The E string could be considered a lot more dead sounding. However, if I worked it as a feature rather than a bug, I could get very different tones by playing in different parts of the neck. It did take a while to dial in the tone, so that there was sufficient low end but without the sound being muddy. I run each pickup in the bass through an Alembic SF2 channel and an F2B channel. The F2B on both channels was run with the bass at about 11 o'clock, the mids about 1 and the treble at 12. Bright switch off. The SF2 added some very deep lows on the neck pickup and the other channel I played with depending on the sound I wanted. I also experimented a lot with the onboard filters and could go from a pretty bright twangy sound to a much thicker, deeper tone. Some of it was almost upright-like in the lower registers of the E and A string.
One thing that I seemed to notice, but I'm not sure if it was all about the string, is that it seemed like the lack of the TI boxy mids allowed the guitars to have more space in the mix. Also, it seemed like the onboard filters worked a bit better with the Pyramids, especially playing with the different Q amounts.
Physically, they're more work to play and I did have to tighten the truss rod a fair amount to get the neck to go back to where I'm used to it. With the TIs, the truss rod was pretty loose.
As far as comparing to the 60s tone from recordings of the Guild/Alembics I've heard, the Pyramids sound and feel a lot closer. I can hear how those tones were achieved. The TIs are similar, but there are some aspects that are pretty different, once you start playing with them and the way they interact with tone controls. There are still some differences, but they have a clarity that the TIs don't seem to have.
We'll see if I feel the same way after tomorrow.