Start up noise

[mhardyman]

During the first twenty minutes of firing these amps up, one of them has a propensity for snap, crackle, pop and white noise until I tap the 5670 driver.  My setup consists of the new Bottlehead V1.1 with the soft start.  The drivers are GE Five Star 5670s and the 300Bs are TJ 300B/n mesh plate.

I'm thinking some sort of contact enhancer on the tube pins as these guys are 50 years old at best.  All of the tubes test well and are relatively balanced. I also fired up the Dremel with the tiny wire brush to remove mung from the driver pins.  It has helped but it has not made the problem disappear.

It just gets annoying to flick one with a finger to make it behave...

Thoughts?

[2wo]

Pop the tubes in and out of the sockets 10 or 12 times to try to clean them as well, while you are at it swap the tubes between the amps to see if the noise follows  the tube. If it doesn't reheat the connections to the socket. Let us know if that works...John 

[mhardyman]

Been there done that.  The DeoxIT Gold finally arrived and seems to have lessened the situation.  The noise does follow the tube, however.  Bummer about that as these Five Stars are very nice drivers.   

[Grainger49]

Sounds like the problem is mostly the tube itself.  Bummer because the five star can be really nice tubes.

There are are "tooth cleaners" (branded Gum) that look like small bottle brushes that you can use with the DeoxIt to clean the tube sockets more thoroughly (buy at the drug store).  I bought a tube socket cleaning kit 15-20 years ago, with four different sized brushes, that I use but I don't think it is sold any more.  The tooth cleaners look like they are just the right size for a standard 9-pin miniature socket.

[coca]

I tend to clean all new tubes before I install them in a piece of audio equipment, especially NOS tubes. I made up a gig with cup style octal and 9pin sockets, and work the tubes in and out spraying a solvent in the socket, then drying the tube really good.

Bernie.

[Paul Joppa]

It could also be cathode-forming issues since these tubes have been sitting around a long time. Give them 100 hours or so of operation and see if the problem resolves itself.

[shelby1420]

It could also be cathode-forming issues since these tubes have been sitting around a long time. Give them 100 hours or so of operation and see if the problem resolves itself.

Interesting, when I heard this re my issues upon completing the soft start mod, I simply could not get my head around why this should make any difference at all, time or not, but it did.............pops, snaps etc --waited it out and let the tubes adjust and have had the last 5 months( every day for 3 hours) of dead silent listening without any issues at all..................

[mhardyman]

As I have already passed 100 hours easily and the issue has not lessened very much, I went ahead and rummaged around to find another 5670 to plug in.  As luck would have it, this is a GE White Five Star 5670 NIB NOS testing out at 43/26 & 44/26.  Straight out of the box it sounds beautiful and not a trace of noise.

Setting the other tube aside and marking the box as troublesome.  Will still keep it as it may be a good fit in something else...

Thanks for all the cleaning ideas and conjectures.  This particular addictive hobby is endlessly fascinating to me.