2. amps-preamps
  3. 158704-127647

signs that tubes need to be replaced

I have a pair of Cary Audio Six pacs which i bought used about a year ago. They mate well with my tube preamp and i couldn't be more pleased with the setup i have.  I dont know the number of hours on the EL 34s that came with the amps. The previous owner may have replaced them at one time since they look like they were sourced from Tubeco.I have them biased at the recommended 220 ma. and put about 300 hrs/yr on them. Question is, what should I be looking for (sonically) besides obvious tube failure that would signify the tubes are nearing the end of their useful life? Will inability to maintain bias be any indication?

Thanks,
J.Chip
128x128jchiappinelli

Showing 2 responses by decooney

decooney
1,896 posts
 

The same exact same Ruby EL34-BSTR (formerly Shuguang Factory made for Ruby batches), same tubes in the Cary SixPacs were also used in my Cary V12R amp.

Don’t underestimate these particular -bstr tubes due to the lower price point. These amps were designed and voiced with them and actually sounded fantastic! Similar reports over the years from friends with same amps. Grab ’em if you can find them, supply was kinda drying up on the BSTR version Ruby’s for a while. Did a search today, fewer carrying them as before. Look for the -bstr version. Snatch up three quads.. good luck.




decooney
1,896 posts
 
@jchiappinelli 
Look here for additional signs...
https://www.thetubestore.com/how-to-tell-if-your-tube-is-bad

@oddiofyl 
Interested in your update after you fully burn in the Genelex GL KT77s in your QS amps.  I'm recommending them to a friend for his QS mono 60 apmps in place of the stock JJ KT88s.  
More to discover