Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Topic started by: danilo on September 08, 2012, 05:50:33 AM
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My venerable Foreplay has been working well.. for years.
But recently has developed a hisss (with no music playing).
Could be aging tubes, but the current ones JJ's (my fave ones) have 'maybe' 24 hours run time on them.
Venerable 4play has ..ALL.. the mods except for the "snubber' Because (oddly) it Never actually needed that one (no hisss or at least barely audible ) .. until now.
What is the technique (circuit?) for adding a wall wart Heater power to the tubes.. I have a 12v 2 amp unit handy.
Also... What is the downside to removing the heater duty /load from the wee Transformer?
Will this Up the available Volts to the rest of the Gizmo?? and if So.. How do I mitigate that??
Sorry for all the questions but my carefully hoarded info disapeared with a Hard drive fail.. sigh.
thanks
dan
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Wall warts and snubbers are for 120Hz hum, not hiss. My hunch is that the JJs having only 24 hrs of burn time is the cause of the hiss. Let them burn in another 50 hours or so and see if the hiss goes away. If not, try a different brand of tube.
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OK yer the "doc" Will try your suggestion...Obviously :-).
Thank you.
Only odd, confusing me bit, is that the Hisss (buzzz? Virtually the Same sound as on My Fender Bassman, though it Could be Hummm ?? I'm not yet clear on the various nuisance noises) wasn't there when these valves were fresh out of their boxes. Or at least I didn't notice it.
Pesky 4play sounds satisfyingly 'fine' when with music :-)
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Buzz has a hard "zzz" sound to it. Hiss is "ssssss" like shushing someone.
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Excuse my Bungling .
Yess! it is Hummm/ Buzzzz on careful listen, this time.
So I will need Wall Wart for the heaters and or a snubber circuit.
IF such still exists. perhaps on someone's hard drive?
thank you
dan
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If it ran without buzzing for years and now it buzzes it is most likely that there is simply a solder joint that has come loose and needs to be reflowed. I would start by going over the solder joints, particularly around the RCA jacks and the ground buss connections.
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Excellent thought! I will reflow the rascals.