Have you purchased the CCa tubes from the same source? They sound like something other than the "real deal", if you know what I mean.
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You did not mention what the amplifier is.
A few years ago I owned a prominent name brand amplifier that used 6922 tubes and after destroying several NOS Telefunkens and Amperex tubes, discovered the bias was in error by 300%.
Might check yours. Other option already mentioned that these could be faulty to begin with. Either way, something is beyond the norm.
Thank you both for the feedback. My amp is an Audion Silver Night MKII, a 7W SET amp. I've purchased the Siemens from two different sources, and the second source that I've used is honoring the warranty and replacing the tubes.
This amp is self-biasing, Albert. It has a single line input and a volume attenuator knob--a pseudo integrated, I guess you might call it.
I'm sending this current pair back today, and switching back to the stock tubes (Edicron...YAWN!) until I get the replacement pair of CCa's.
I should note that the fizzle/crackle of the tubes would probably not be so noticeable if I was using a less efficient speaker (our Klipsch La Scala's are 104dB), but we love them too much to switch. I just wish I could find some reliable tubes that I love as much as the CCa's.
Thank you both again,
You might try the Siemens E288CC. It's similar tonal balance, transparency and dynamics to the CCa but tougher to kill. I have had excellent luck with it in some circuits and not so great in others.
Aesthetix Io and Callisto neither one like the E288CC but one amp performed its best with them and a borrowed preamp responded very well too.
I could possibly loan you a couple. Is two what you need?
I loved them so much I bought a box of 50 NOS. If you don't like them you could just return them. If you do like them I know of a source with fair pricing.
Dekay is correct about the E288CC not being a direct sub. I have tried it in several circuits in place of 6922 with no problems but the suggestion to check with Audion is a good one.
If they say it won't damage the circuit, you have nothing to loose by giving them a try. Let me know via email if you want me to ship to you.