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Post by cedarchoper58 on Jul 16, 2022 20:00:55 GMT -5
Does any one know when and what the wall votages were and changed from the 50's on ward? also what was it like in the 80's thks
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Post by Jim D. on Jul 17, 2022 10:07:25 GMT -5
After WW II the nominal voltage was 117, although parts of the US were still as low 112. In the mid 1960's the nominal voltage rose to 120. Utilities deliver 240 Volts single phase, and there is 120 on each phase. (one black and the white neutral = 120 Volts-two blacks and the neutral = 240 Volts) Today's electrical equipment is typically rated for plus or minus 10% 120 volts. My outlets are at 122 Volts and that's fine and even preferable to being under 120 within reason.
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stl80
Wholenote
Posts: 216
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Post by stl80 on Jul 17, 2022 13:37:33 GMT -5
120, 121, whatever it takes. Jim
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Post by cedarchoper58 on Jul 19, 2022 16:52:40 GMT -5
i have been measuring my wall voltage and it goes from 118.3vac at 5pm to 124.3 in the evenings that is a 6VAC swing daily. For many years my wall voltage has stayed around 123-124VAC This 6V swing is new here. i calculated makes my bias drop about 4ma and my plates around 18vdc can this effect the sound of my amp i seems to me it sounds like it has less drive at 118.3VAC
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pdf64
Wholenote
Posts: 557
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Post by pdf64 on Jul 19, 2022 19:05:54 GMT -5
To some degree, the mains voltage variance certainly affects amp performance.
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Post by cedarchoper58 on Jul 19, 2022 20:03:46 GMT -5
To some degree, the mains voltage variance certainly affects amp performance. I rebiased my amp 3 weeks ago and i always check the wall voltage and it was 123.4VAC now that it is running around 118VAC if i rebias then when it goes back up what are the odds ill burn up my tubes. My amp sounds kinda weak at 118VAC biased for 123.4VAC as i crank it on 7 and crank a tube scramer and wha and play a lot of SRV-Hendrix-Trower-Skynyrd-Led Zeppelin and lots of classic rock. The power grid here in Texas must be the issue. I have never had the voltage drop bellpw 123VAC and it drives me nuts having my amp weaker sounding
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pdf64
Wholenote
Posts: 557
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Post by pdf64 on Jul 20, 2022 4:25:55 GMT -5
It depends on the amp design and how hot you set the bias. As the mains voltage goes up, the valves run hotter. Would biasing hotter when the mains voltage is low really improve the amp’s tone / response? Test that for yourself maybe, but it seems to me that the amp’s more likely to sound weaker because it is weaker, less power output due to the lower voltage. Rather than sounding weaker because the idle dissipation is a bit lower. It’s a good idea to bear in mind that the power company are working to a pretty wide tolerance, it would need to go above 129V before they see it as their problem.
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