New tubes every year...or every five? ?

Hi Garfish, this is just a guess, but I think its probably the Sovtecs and not the SF. My experience has been, that Sovtecs seem to age rather quickly with exactly the sound-effects, which you describe and this not only in the Jadis, but also in the Beveridges of yore, a wonderful design by Roger Modjeski, which was killed and driven off the market by a hatchet review of H.Pearson in favour of the ARC SP8, in the SP 11 and 12.

Craig, Detlof's probably hit it the proverbial nail on the SOVhead. The current supply on (my) Jadis was quite stable and ample, hence no extraordinary tube wear. But replacement every 12??? That's expensive -- why not try another tube manuf. and if you feel the top end is soft by comparison -- don't worry: this could be cable or the machine... Just an idea.

Detlof Check out e-bay for tube testers. My audio buddy just bought one from a guy that restores and calibrates them. This past Sunday we went through about a quarter of my stash. What is most amazing to me is how the old tubes fared against the sovteks and newer tubes, all were MUCHO stronger. I have a bunch of amperex and the old Bugle Boy's and some Telefunkens, RCA's and Sylvanias. Only one of the old tubes was shorted. Two of them buried the meter! A few of these tubes were in my McIntosh MC-60's dating back to the mid 50's!! I also found out that the Svetlana 6550 output tubes I installed in my amp a year ago still tested strong with plenty of life. I estimate that they have about 1200 hours based on my use. It is a nice thing to know and you can keep your equipment running optimally. I say at the cost of tubes these days a tester is indispensible. I plan on purchasing one in the near future.

Detlof, my tube guru Andy Bouwman has some tube testers he keeps available for sale as well, and the prices were not high. I'll probably pick one up, although I can always send him my tubes for testing, since I buy from him.