Maybe somebody wants to help him

Post by **joerg** » Sat Oct 31, 2009 7:31 pm

http://charlotte.craigslist.org/ele/1412790088.html

GX3 · Post by **GX3** » Sat Oct 31, 2009 8:04 pm

Just sent him an email telling him to check us out.

Post by **ttocs** » Sat Oct 31, 2009 8:12 pm

why would he be switching from floating ground to common with out changing the wiring?

Post by **joerg** » Sat Oct 31, 2009 8:13 pm

GX3 wrote:Just sent him an email telling him to check us out.

Could have thought of that myself

Post by **mhyde71** » Sat Oct 31, 2009 8:35 pm

ttocs wrote:why would he be switching from floating ground to common with out changing the wiring?

what wiring needs to / or should be changed when selecting the different selections? I, when i first installed the 275's, had switch to one setting, and heard a lil engine whine...flipped it over to the other selection and it was gone... what is it i would be changing as i make different selction choices?

pls thx
m

Post by **ttocs** » Sun Nov 01, 2009 6:10 am

common ground means that all the speakers use one, common ground. Floating ground means each speaker has its own. Some systems back in the day used commmon ground wiring but I have not seen it used anywhere since the days of these amps.

The noise you heard, was it just standard alt noise or did it sound more like an electronic sounding motorboat?

Post by **mhyde71** » Sun Nov 01, 2009 7:49 am

^^^^^ TBH I dont recall... think more like alt whine...IIRC ^^^^^^

Post by **Eric D** » Sun Nov 01, 2009 9:10 am

ttocs wrote:common ground means that all the speakers use one, common ground. Floating ground means each speaker has its own. Some systems back in the day used commmon ground wiring but I have not seen it used anywhere since the days of these amps.

The noise you heard, was it just standard alt noise or did it sound more like an electronic sounding motorboat?

That is not what this switch is for. If you common ground wire a PG amp it will blow up. This switch is to isolate the reference ground of the preamp section so it can float with the RCA line in, or to connect the reference ground to the amplifiers power supply ground. You wire the amp up like Matt said, and then try both settings for the least noise.

Post by **smgreen20** » Sun Nov 01, 2009 9:38 am

ttocs wrote:common ground means that all the speakers use one, common ground.

That's sorta like the powered eq boosters of yesteryear. 5 speaker wires, 4 pos and 1 neg.

Post by **ttocs** » Sun Nov 01, 2009 11:08 am

exactly, they were popular mainly for thier ease in install but I do not think they had any sonic improvement.

and for those that do not know, you have a good chance of blowing any floating ground amp that is wired into a common ground speaker schematic. The amp will often start to make a noise that is referred to as "motor boat noise" because of the sound while it slowly kills the amp.

There were alot of cars in the 70s and 80s that had common ground configerations but I have not seen it for a longtime, thankfully......