F1X hiss

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Author Message byoung Senior Member Username: byoung Post Number: 796 Registered: 12-2004 Posted on Monday, October 22, 2007 - 8:16 pm:    My newly acquired F1-X seems to be the culprit in some rather pronounced hissing (although I'll say that I'm hypersensitive). Bass plugged or unplugged, it hisses (seems to be more when plugged in, haven't had a chance to change the battery on my bass). Flipping the "deep" switch makes it more pronounced. The master volume, obviously, controls the hissing as well. I have another tube, which I might try, if anyone thinks it might help. Basically, I'm looking for an understanding about what causes hissing, since I'm a pretty decent troubleshooter. I didn't really have a chance to do a full control/experiment breakdown, but any hints would be appreciated. davehouck Moderator Username: davehouck Post Number: 5585 Registered: 5-2002 Posted on Monday, October 22, 2007 - 9:54 pm:    I found this, but it addresses hum rather than hiss. Still, checking the capacitors might be a good place to start. hieronymous Advanced Member Username: hieronymous Post Number: 223 Registered: 1-2005 Posted on Monday, October 22, 2007 - 11:30 pm:    How do you have controls set? My understanding is that "flat" is with the bass & treble at 2, and the midrange on 10. Normally one might expect having all the controls at 5 to be flat, but treble on 5 would be a significant boost. May not be the problem, but just thought I'd suggest it. byoung Senior Member Username: byoung Post Number: 807 Registered: 12-2004 Posted on Monday, October 29, 2007 - 6:02 pm:    Additional troubleshooting info: Hisses with a passive bass connected. Volume has no effect. Active bass (my Epic) hissing is volume dependent. Don't know if this is an Epic problem, but it was dead silent with just the Superfilter. I put a new battery in. Help! byoung Senior Member Username: byoung Post Number: 876 Registered: 12-2004 Posted on Wednesday, December 26, 2007 - 3:36 pm:    Still hissing away, and the new symptom is that it will have a sudden jump in volume occasionally. It sounds like it switches from passive to active inputs or something. Any thoughts? davehouck Moderator Username: davehouck Post Number: 5871 Registered: 5-2002 Posted on Wednesday, December 26, 2007 - 4:27 pm:    Inspect the connections around both inputs for any loose solder joints or any components that looked burned. jbybj Intermediate Member Username: jbybj Post Number: 122 Registered: 6-2006 Posted on Thursday, December 27, 2007 - 11:38 am:    One of the techs at my work will routinely resolder joints even if they look o.k., and has frequent success with that. In your first post you mentioned another tube, but I don't see any follow up on that tact. I would suggest forgetting about the other used tube laying around, and go plop down $15 on a new Groove tube gold series, see if that helps. Good luck. byoung Senior Member Username: byoung Post Number: 878 Registered: 12-2004 Posted on Thursday, December 27, 2007 - 2:49 pm:    Swapped tubes, and tried different wires, seems to have sorted itself (from the wiring change). Didn't have much time to really look at it, but it seems fixed for now. Bradley davehouck Moderator Username: davehouck Post Number: 5874 Registered: 5-2002 Posted on Thursday, December 27, 2007 - 5:22 pm:    Cool!