F-1X and Noise Gate

[rv_bass]

I keep the treble at around 6 or 7 and the Deep switch engaged on my F-1X, which creates a bit of white noise when I boost the volume from the F-1X.  Is there a way to put a nose gate of sorts in the chain to reduce or eliminate the white noise?

[gtrguy]

You can always gate the noise. I am thinking the unit should not be putting out that much noise though. I would exercise the pots, clean the 1/4" inputs and outputs with a 9mm pistol cleaning brass brush, clean any internal switching jack 'points' with fine wet/dry 600 grit (or finer) sandpaper (use it dry), and try switching the tube, to see if it gets better.

[rv_bass]

Thanks for the reply, gtrguy.  I've done the pot and jack exercising, but I'll try the more extensive cleaning with sandpaper, etc. that you suggest and see how that goes. 

[StephenR]

Noisy preamp tube?

[rv_bass]

The tube is pretty new, but I’ll check it.  I’ll swap it out with another and see how it sounds.

[JimmyJ]

Could it be a gain structure thing?  Can you send more level into the F-1X inputs so you don't need to have the volume up so high?  Just a thought.

Jimmy J

[rv_bass]

Thanks, Jimmy and others for your suggestions. I'll check the output tomorrow and see if I can increase it with the gain trim pot.  I'll swap out tubes tomorrow as well as suggested by Stephen and gtrguy.  I did try the bass with my F-2B for comparison and don't seem to have the same noise issue with the F-2B.  I'll keep working on it.

[gtrguy]

New JJ tubes are always great. Sometimes a few tube brands will not fit into the metal shielding around the socket.

[rv_bass]

Thanks, gtrguy.   I worked through exercising the pots and jacks again today. 

I also exchanged tubes between the F-1X with the initial noise issue (affected F-1X) and a spare F-1X that I found in a closet that I had forgotten about (oops!). At first there was no reduction in noise level in the affected F-1X with either tube used, and the backup F-1X had no noise using either tube. Then when I put the original tube back in the affected F-1X, the noise was greatly reduced.  Maybe the act of swapping in and out the tube created better contact points for the tube in the affected F-1X.  Regardless, looks like the issue is resolved.
The affected F-1X had a Mesa - Russian 2, 12AX7-A tube that looked pretty new.  The backup F-1X had a Ruby 12AX7A tube that looked older. 

Results: things are back up and working.  Thanks for all the help everyone! 

[elwoodblue]

Great news,


 You'd be surprised how many amps that come through my friend's amp shop that
are just in need of pin retensioning and/or conact cleaning.


I should dig into my gear closet...wonder what I've forgotten bout 

[StephenR]

Sounds like we need to add "exercising the preamp tube socket contacts" to the troubleshooting techniques. Good to hear it was a simple fix and you rediscovered your spare F-1X in the process.