Hi all -
My question might seem basic, but I am new to audio tubes.
What are signs that the tubes on the BHK Preamplifier are starting to show their age? Basically, what audible characteristics can I expect to start hearing as they start to show signs of replacement. I don’t mean when they are at the point of obvious need, but more the beginning stages of degradation.
thanks in advance…
There will be an eventual dullness to the sound. One day you will realize the magic just isn’t there anymore. That is the time to replace the tubes.
Buy an extra set of tubes, then periodically swap the new tubes in for the existing tubes. At some point you will hear that the system sounds better with the new tubes swapped in.
Good advice!
Approximately how many hours on the BHK preamplifier and the BHK 300s?
2,500 hours on the preamplifier
Tube life depends on the types and brands of tubes too. For 12au7 tubes, GL and PSAVNE tubes typically last 2000 hours, after that the SQ would start fading in my experience.
Two brands stand out:
Aptos Ray Select advertised their 12au7 tubes last 10,000 hours. Well, mine have had 2000 hours, and they sounded better than new tubes.
Telefunken 12au7 NOS tubes, everyone says these last at least 10k hours. Mine was a part of tube rolling so there is no where near that yet.
In my experience when the tubes wear, which has happened after around two years of use,
I hear a small amount of distortion, low level but significant. When I replace the tubes that distortion disappears.