Fender Twin Reverb '72

jimbones Joined: Nov 21, 2012 Posts: 151 Montreal	Posted on Jul 30 2015 10:59 AM Hi all - I just got my hands on a Fender Twin Reverb '72 in excellent shape. It appears that the plug was converted to a 3-pronged plug and my question is about the ground switch. It's a 3-way toggle and seems to make a audible hum and cuts the volume way down when in the left or right position. The sound/volume is perfect when in the middle position. What's the reason behind this? — The Men in Gray Suits (Montreal, Canada) Facebook: The Men in Gray Suits Instagram: The Men in Gray Suits Top
Badger Joined: Nov 16, 2013 Posts: 4536 Wisconsin	Posted on Jul 30 2015 02:56 PM jimbones wrote: Hi all - I just got my hands on a Fender Twin Reverb '72 in excellent shape. It appears that the plug was converted to a 3-pronged plug and my question is about the ground switch. It's a 3-way toggle and seems to make a audible hum and cuts the volume way down when in the left or right position. The sound/volume is perfect when in the middle position. What's the reason behind this? If the update was done to install a properly grounded 3-prong plug then there is no need for the ground-path changing toggle, which was to overcome old plug polarity issues - something that is not an issue with a 3-prong when going into a properly functioning outlet. Leave the switch in the middle, forget it's there and surf on. Caveat: Notice my liberal use of the word 'properly' - I know roadhouses in this neck of the woods that are still wired to kill you if you don't carry a multimeter... — Wes SoCal ex-pat with a snow shovel DISCLAIMER: The above is opinion/suggestion only & should not be used for mission planning/navigation, tweaking of instruments, beverage selection, or wardrobe choices. Top
jimbones Joined: Nov 21, 2012 Posts: 151 Montreal	Posted on Jul 30 2015 03:19 PM YES! That's what I'm doing... "set and forget". I was just curious as to what it was about that switch that made the amp cut in volume and produce that nasty hum.... — The Men in Gray Suits (Montreal, Canada) Facebook: The Men in Gray Suits Instagram: The Men in Gray Suits Top
Brian Joined: Feb 25, 2006 Posts: 19194 Des Moines, Iowa, USA	Posted on Jul 30 2015 03:52 PM I'm not an expert but I think whoever changed your plug to 3 prong should have also taken that toggle switch out of the circuit. As Wes mentioned, this is only useful for 2 prong plugs. — Site dude - S3 Agent #202 Need help with the site? SG101 FAQ - Send me a private message - Email me "It starts... when it begins" -- Ralf Kilauea Top
Badger Joined: Nov 16, 2013 Posts: 4536 Wisconsin	Posted on Jul 30 2015 03:58 PM Brian wrote: I'm not an expert but I think whoever changed your plug to 3 prong should have also taken that toggle switch out of the circuit. As Wes mentioned, this is only useful for 2 prong plugs. Yep, my tech would've made that switch into ornamentation. — Wes SoCal ex-pat with a snow shovel DISCLAIMER: The above is opinion/suggestion only & should not be used for mission planning/navigation, tweaking of instruments, beverage selection, or wardrobe choices. Top

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Fender Twin Reverb '72