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Reliability issues with VTL amps/pre-amps

I have a VTL ST-85 which I use mostly, in the triode mode. The left channel tubes have blown 5 times in a two year period. I had repairs and the tube compliment replaced by VTL during this time. After all the shipping costs, VTL replaced the last set of tubes for free and all is fine for now, but I'm worried it will blow again. No one at VTL has ever told me why they keep blowing. Has anyone had similar experiences with VTL? Is this type of problem common with their products?
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ryriken
164 posts
 
i have owned the same amp for 2 years with no problems, how old is your amp? Also does it have both triode and tetrode switch?What tubes do you use. I use NOS fatboy tubes from the 60's.Tell what tubes you use so i never use them in this amp, thanks. Ps How often do you bias the tubes...mine hols bias for at least 3 months or longer....
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albertporter
4,949 posts
 
I have two pair of VTL 750's, meaning I have 48 6550 tubes to contend with.

I have lost tubes and with that the large fuse behind the screw plug on the rear of the amp. No damage to the unit other than fuse and I'm into my 5th year with these.

I think VTL amps are among the most reliable and best sounding of all the big amps. If you want to keep them reliable be sure bias is right and tubes are suitable. I don't know about your ST-85, but the VTL 450, 750 and 1250 all run very reliably with Wing C 6550.
t_bone
1,182 posts
 
Hi. I am in my 7th or 8th year using my VTL MB450s (and I bought them used). They continue to be fine. Because I do not get enough hours on mine, I may not have the problems others have had, but so far, other than a couple of blown tubes after 4-5yrs, I have not had any issues. I use mine in triode almost exclusively.
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