2. amps-preamps
  3. 1234221950

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?
tarraga

Showing 1 response by microstrip

microstrip
180 posts
 
If you look at VTL schematics you will see they are very simple and intrinsically reliable, operating the output tubes at low current. However they use a high anode voltage and the choice of output tubes is critical - if you take Albert Porter recommendation of Wing C 6550 you will have no problems!
Many cheap 6550 can not withstand these high voltages. Also, when tubes became tired replace them - do not wait until they break!
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