difference between an active and a passive preamp?

I wouldn't necessarily consider a buffered device a band aid for passive-hostile systems. If you look at the designs of a Pass B-1, Burson-160, and Horn Shoppe Truth as examples, these buffered devices are anything but band-aids. They are also technically active devices as the buffers require a power supply, but in general they do not add gain to the system. The main purpose of the buffered output is to provide a consistent and low output impedance, generally under 100 ohms, but this could vary depending on the buffer design. Those using opamps or other solid state devices will tend to have very low output impedance, while tube buffers will in most cases have greater than 500 ohms, perhaps even over 1000 ohms.

IMO optimal dynamics can be achieved with both passive and active buffered preamps, my Lightspeed attenuator, Truth, and Silicon Arts Design preamps being examples in my system. However, system matching with a passive is a bit trickier than an active buffer (which if the output impedance is very low and due to the active circuitry may also provide the benefit of using longer interconnects). To really determine if your system is passive friendly and more importantly if you like the resulting sound, go to Arthur Salvatore's web site and read up on the Bolero test. This should give you a good idea if your source has enough output voltage to drive your amp. If so you might be ready to experiment a bit with resistive, magnetic, or LDR passives, as well as active buffers (preferably those with built in attenuation).

I could go on about how component specs can influence the sound, as can cable length and capacitance, but there is nothing like hearing it for yourself (although I think your system would benefit more from an active buffer). Lots of options out there at very reasonable prices to try both passive and/or active buffers. I know Ed Schilling offers a money back option on The Truth, and at $800 or so it is well worth a test drive. There are others that may offer trial periods as well. Take advantage of those opportunities to listen for yourself.

Although I have not heard the buffered passives Clio09 mentioned, the one's I have heard did not sound as transparent as the pure passive preamps. But this was a long time ago, and I don't even remember the brand of the buffered passives I auditioned. On my Bent Audio Tap X, I was thinking about putting in a Burson active buffer on the output of the Tap X, but this is akin to putting a transformer on a OTL amplifier. Seems ass backwards, but I've been known to do ass backwards stuff in the past.

My need for an active buffer with attenuator is due to a need to run long interconnects to an amp that sits in between my speakers. I have another set-up where I just use the Lightspeed with short interconnects to the amp and long speaker cables. Quite frankly, both units are very transparent. There are slight sonic differences, but nothing to split hairs over.

As for the TAP-X, IIRC the 6 input version John Chapman made has a board where the two sets of outputs can be operated with an active buffer by the flip of a switch. Quite a nice feature.

Yea, I know about active buffer option on the Tap X. John told me the active buffer degrades the sound of the Tap X and stopped including them on his later runs of the Tap X. I think the buffer was an opamp.

If you look at the designs of a Pass B-1, Burson-160, and Horn Shoppe Truth as examples, these buffered devices are anything but band-aids.

I think we're using the term differently. I didn't intend a pejorative. I meant it the other way: something that easily mends. In fact, based on your response, I must have made myself very difficult to understand in that whole post, so I'll rephrase. I'm not trying to find out how a passive is with my system. I have an older passive and I'm hooked on the direction it's taking me. It's already pretty clear that I would benefit from a buffer. In fact, Almarg was quite patient and helpful in another thread where I was struggling with this. Now, I'm just wondering what the active preamp crowd would say remains unprovided in a merely passive or buffered preamp that a traditional active preamp provides. On other words, I'm not just learning how configure my system; I'm attempting to learn the conversation.