I recently bought a Sansamp Programmable BDDI (well call this the SAPBDDI for short hmm, not very short, is it maybe Ill just say Sansamp) and this has distracted me from more meaningful engagements (like cyber-loitering around TalkBass). Here is what Ive learned so far. Im running this with a Thunderfunk 550, Accugroove Tri112 and dbx160A compressor. I've (per the Sansamp manual) put the dbx160A in the pre-EQ loop, and the Sansamp in the post-EQ loop (less noisy that way, as I tried the other combinations). (1) the preprogrammed 'fat tube' sound is very addictive ... I've put my Ritter Roya on passive humbucker mode, and really love the tubey sound. It doesn't quite get that overdrive 'squeak' that you can hear with real tubes, but otherwise, it's pretty nice. The Thunderfunk is warm, but the Sansamp adds a little something extra which I'm still trying to figure out. Anyway, for this alone it is worth its modest price. (2) the manual says it is low noise, but I'm spoiled by the Thunderfunk, which is even lower noise. So in comparison, the Sansamp adds some noise ... not much, but noticable. That said, the footswitches (which the manual says are custom) are completely noiseless, and have a nice feel when hand operated. You can always take the Sansamp out of the loop with a step on the footswitch, and its noise drops to zero. (3) My signal chain then appears to be (counting what I think is going on inside the Sansamp): Bass >> dbx160A >> TFB EQ >> Sansamp Tube Emulation >> Sansamp EQ >> Sansamp Out Level >> TFB Power Section >> Tri112L So how to control Sansamp noise. First, never boost the line out level (at least not in this configuration). Boosting will only add noise. Second, do put the Sansamp after the preamp-EQ section, and keep the preamp gain low. Third, if you are going for a vintage sound (Im using my Variax 700 Bass on vintage Jazz / flatwound setting) then turn the treble EQ down on the Sansamp. This will cut way down on the annoying high frequency digital noise which is from the Sansamp, not the TFB (definitely). If you need the higher frequencies (for slap as they say) then turn the level and presence down, or conversely, just live with it if you want that distorted tube sound. You need to fiddle with the settings for each different bass you input, but there always seems (IMHO) to be a setting where the sound is tube modulated the way I would like, yet where the Sansamp noise is acceptable. BTW ... the Variax Bass sounds are very much improved by the Sansamp! (3) the 'lazy pot' feature of the footswitches is brilliant. You step on a switch to change settings, and the old setting turns off instantly, but the new setting fades up over a few seconds. The gives you time to drop the volume on your bass pot if the new setting it too loud. (4) It's definitely worth it to have 3 switchable sounds. And the 3 footswitch package is actually a more practical shape for the Sansamp. Well worth the price differential over the non-programmable. I've not used a real tube amp, so don't know what I'm comparing to. But if this is close to the sound, I can see why musicians are willing to put up with the expense and weight of tube amps. My guess is that the Sansamp provides better tone that a tube preamp like, e.g., the Demeter, or GrooveTube, because it is a mic-ed speaker emulation that captures the tube-speaker interactions.