Well, I have never contributed to a "Mega Thread" before..... but since I just bought a walkabout amp head, I figure; its a good time for a thread revival.
Currently, I am using the WA amp head with a double bass (just purchased the amp from classifieds). Here is the positive; It feels like the timing (or attack?) can be adjusted using the volume knobs to make the sound response (?), the same as the upright bass. This may sound odd to electric players, but my experience with a Little Mark II and the DB caused problems because the sound seemed to jump out of the amp much quicker than the natural bass. It kind of threw the timing of the band off. The LMII also seemed to be a sustain killer, slower songs, with half notes, were painful. The notes from the WA have a more natural sound, more of an of ext. of the bass, than a separate amp.
So far, the WA is creamy. It had the Mesa stock tubes inside and I switched them with some old 12ax7's from a 1960 Hammond chord organ. I am not sure of the make of the tubes but, the plates are significantly longer than the Soviet Mesa tubes. This made a noticeable difference, not as loud, but very smooth, no harshness at all. I will try the Groove tubes 12ax7c next, just to compare.
I am also using an Ampeg BXT 15 speaker with the WA. They have a different sound compared to regular Ampeg speakers, more scooped middles, I think Victor Wooten had something to do with these. Any way, the combo sounds good.
Double basses are very difficult to amplify, This amp is new to me, I hope it will work out for the best.