Tube 6K4P lifetime ?

[Marcin]

I'm impressed of sound from simple chinese headphone amp based on two TI NE5532P OP AMPs and two chinese 6K4 tubes. I plan to make a home replacement stock for tubes and here is question for russian (and not only) members : what is lifetime of standard USSR 6K4P tube ? I know that 6K4P-EW (long life version) is ~ 5000 hours.

[gekaufman]

Life span should be quite long, as the B+ is very low on those amps.

Most of those amps will also accept USA made 6AK5 or 5654 tubes, still very inexpensive and easy to locate for under $5 each. As a general rule the quality control of Chinese tubes is poor, while most of the 6AK5's were made in the "golden age of tubes" and were of very high quality. If you can't locate them I can ship some to AVICC for you.

I believe that the European version was EF95.

Best of all is the Western Electric 403A or 6AK5, Typically about $20-25 each.

[Bator]

[Marcin]

Thank you guys ! Now I know much more about them. I will take a look around for replacements and see what I can get

[KattiMini]

Hi....the 6F31 tubes had a slight murmur (practically like ground commotion) and was heard when sound was quieted, yet during playback it isn't perceptible in any way. After certain hours it has settled down in my framework and could be because of my mind blocking it out. That being said, I actually remain by my outcomes for the 6F31.

The 6K4P Nevz (standard) tubes I attempted and referenced were bought from a nearby dealer. I likewise have the 6K4P-EV (long life variant) from a similar dealer you have recently bought from however these are yet to be tested. Their time of production shows 1978, while the standard ones are from the last part of the 80s.