First time w/ Tubes - pings/noises normal?

I've been a very happy owner of hybrid tube/SS amp and pre from Vincent - SP20 Amp, and SA-T7. I have these currently paired w/ Rega RX-3's, which I like, but need more from a speaker; and a REL S5 sub, which is amazing. Music is coming from a Cambridge audio 851n network streamer.

Anyway, I love the warmth and tone of the sound i'm getting. After a few months of daily listening, i noticed that as the pre starts up, one of the channels will ping, and sometimes there's a static 'air' sound that can be heard. Then it goes away. Sometimes it will do a ping mid-listening. I had never heard this before, and assumed it was defect. I narrowed it to the preamp, as when I removed that from they system, it was all gone. I've also switched up all the cables, etc...  I sent it back for repair. The shop couldn't find a thing wrong, bench tested for a week, etc.. Couldn't reproduce what I heard somewhat regularly. They sent it back to me.. and it was still there.  I sent it  back again - and though they could not reproduce, they agreed to swap for a new one.

So i install the new pre, and 2 or 3 months of use, not a single ping. Then suddenly a few months in, starting to do the same thing.

I'm now wondering - is this just what happens to tube gear after it breaks in? Or something similar? Is there something else i'm missing here?


It is not normal for a tube preamp to do that. It sounds like you have a bad tube!
I've only heard low-level popping or crackling from some NOS tubes during the first few hours of burn-in. It doesn't sound right that a preamp would be making those noises. Especially since it was tested at the factory.
Also make sure your interconnects are tight and clean. I chased my tail for several weeks to isolate the source of some "noise" and it was ultimately caused by poor internal connection in one of the cable ends.  
That happened to me and it was a tube. It will get worst as time goes on. Change it out and see what happens.
Thanks for all the responses, I like going down the ‘change tube’ route and seeing what happens..!
Another potential source of noise - your volume potentiometer.  I once fiddled with tubes, sockets etc. for about a month before squirting some De-Oxit into the potentiometer and presto! noise was gone.
@p59teitel ,
That's a great tip! One that I often forget.