Decware is a small audio company that specializes in low-powered, hand-built tube amplification and pre-amplifiers based in East Peoria, Illinois, founded by Steve Deckert. They have a very simple business model. There are no distributors, no retailers - and according to Decware, they employ some of the most skilled, best paid audio craftsmen/gurus in the business. All point to point wiring, very little in the way of extraneous circuitry and ... a lifetime warranty. How many companies are offering lifetime warranties on anything? On top of that, if you buy a used Decware product, all you have to do is send it back to the Decware mothership, they'll look it over, and transfer the lifetime warranty to the new owner.
Anyway, enough with the preamble, now about the CSP2+. This is not the latest iteration of the Decware preamp. The current model is the CSP3. This model has seen a pretty significant jump in price from 895 for the CSP2+ to 1295 for the current one. Even at this price, it's still one of the best values in tube preamps on the market.
I'm pretty familiar with Decware products, having owned an older CSP preamp, as well as two Zen triode amps. So I knew what to expect ... as far as cosmetics, Decware products have sort of a funky, retro look about them that will probably be very polarizing. The Zen amp is downright utilitarian looking. I actually love the look of the Decware stuff. Some of it looks like it would be perfect for a "mad scientist" movie set.
I mentioned that I owned a CSP2 previously ... The CSP2+ improves upon the older CSP2 in a few ways. One thing is that all Decware preamps have adjustable gain pots for both channels, so you can customize the amount of gain your preamp has, as well as using this mechanism as a means of getting perfect balance between channels. The CSP had the trim pots on the inside of the chassis! Which meant, of course, turning the unit on it's side (while on, while playing music), taking the bottom off, and adjusting the channels on the fly... while being very careful NOT to touch the one capacitor on the inside of the unit. It is small, but gives a nasty shock, I found out. The CSP2+ has the trim pots on the outside of the unit, thankfully. No more electrocutions. The newer model's trim pots are also stepped attenuators, unlike the older one. I actually preferred the non-stepped approach, since it was easier to get more balanced, granular adjustments. The CSP2+ also has gain trim pots on the inputs as well (did I mention it has two inputs? handy for those of you who have more than one source). They input trim pots is supposed to make the amp compatible with all headphones (did I mention it's also a headphone amp?). Another handy feature is that there also a mono output jack, handy if you have a subwoofer to drive.
The CSP2+ uses fairly common, fairly inexpensive tubes, making tube rolling affordable. It uses 6922/6JD8/61NP tubes for both the input and output, and also 5U4 type tube rectification. I found that the preamp's sound can be changed most significantly by changing out the single input tube. I've tried a few different ones, but right now I'm using a Gold Lion 6922 that sounds great. As far as output tubes, the best ones I have found so far are Russian NOS 6H23n. These give the usually ultra-transparent Decware sound a bit of a smooth, warm sound. Not that I'm saying the CSP2+ is cold, analytic, or lean sounding. Really all it does is the proverbial "get out of the way and play music" sort of thing. It doesn't add nor subtract from the sound. Using this preamp is the clearest, cleanest sound I have ever heard from my system.
I decided on the CSP2+ because I needed a preamp with LOTS of gain to drive my Cary amp. Decware offers almost endless customizing possibilities, and one of them is adjustable from 0 all the way to 12 volts. This should be enough to drive just about anything.
To sum it up, if you are looking for a good, end game tube preamp, this should be the last one you will ever need to buy.