Holy guacamole! "only" 240 clams, for a pair of TUBES?? Just how long can these tubes be expected to LAST (I'm reeeaaally hoping you say at LEAST a year or more)?
Well, yes, they should last at least a year. I don't know about the Svets, but the WE's are rated for around 10,000 hours. But if you think the $240 price tag is pricy, you don't wann'a go
there! The Svet's are aiming to be, at least structurally, a copy of the very popular WE's. In terms of sonics they sound different indeed on my amps. The Svets have a crystalline mid-range, striking in that effect...almost etched. The WE's give up a bit of that kind of sharply focused clarity for a better overall balance throughout the range (IMO and in my amps) reaching a bit more into the lower registers and delivering better detail there as well as in the highs. But that Svet midrange is pretty amazing...I was very impressed with them.
I forget how you got into 300B amps...was it you or someone else suggesting a Cary? This started out as a headphone amp thread....now if you are still looking at headphone amps that utilize tubes you don't have to worry as much about dropping that kind of coin on tubes, as most use smaller, less expensive tubes. If you are listening to your headphone amp to supplement your main system then I'm quite sure your tubes there will likely last you several years before having to change them. My MicroZotl takes 2 12AT7's and two 6SN7's. Total cost to retube is about $80 for some nice NOS stuff. You could spend more, and you could spend less depending on what you're satisfied with. Kind of like buying wine in a way. The tubes definitely have different flavors which can be more or less accentuated by the actuall circuit/component they are going into. There are tube amps that just use two tubes as well...even cheaper to retube, and not necessarily better or worse than amps using more tubes, bigger tubes or different tubes. Certainly they'll all sound different...but it is really up to you to decide which you prefer.
Marco
