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AC main power to high.
AC main power to high.
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Old 24th May 2016, 10:27 AM   #1
Guarnera is offline Guarnera  United States
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Default AC main power to high.

I just built a Tubelab SE amplifier, with 300B output tubes. It was designed to work with 3.5K output transformers, at 365 volts B+ voltage, with 120 volts AC main power.
However, my AC main power is up to 124 volts AC in the morning. And I've seen it get as low as 120.5 volts at night. This give me a swing of about plus 15 volts on my B+ voltage.
Maybe I'm being anal, but this really bothers me. Some suggested getting a regulated UPS. Then someone else said that a ups would introduce noise into the system.
I'm looking at the Tripp lite, Smart LCD 1500, regulated UPS. It says it protects against spikes and surges, Cleans up noise, and give a regulated 120 volts AC without using its batteries.
What is your opinion? Should I be worrying about the +/- 15 volts on my B+ voltage? Will a regulated ups help or hurt things?
I wish I could afford a PS Audio Perfect Wave AC power regenerator, but that's not in the cards right now. So what do you all think? Thank you all.
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Old 24th May 2016, 11:27 AM   #2
JonSnell Electronic is offline JonSnell Electronic  United Kingdom
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A good design will take into consideration changes in power voltages. The heater voltage has a 10% tolerance as will the HT. If it is an issue, redesign it to cope with the changes.
No need for a UPS.
Support for Fender, Marshall and all Valve Equipment; Audio Innovations, Audiorama FU29, Quad and Leak. www.jonsnell.co.uk
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Old 24th May 2016, 12:00 PM   #3
AndrewT is online now AndrewT  Scotland
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120.5 to 124 is only +2.9%

your mains probably has a tolerance of 6%
Do you hear any/many others shouting about variations in B+?
regards Andrew T.
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Old 24th May 2016, 12:21 PM   #4
AllenB is offline AllenB  Australia
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Originally Posted by Guarnera View Post
What is your opinion? Should I be worrying about the +/- 15 volts on my B+ voltage?
Worrying? Hardly, there are better things to worry about. Tubelab has this sorted.
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Old 1st June 2016, 10:01 PM   #5
Ken Newton is offline Ken Newton  United States
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A 'bucking transformer' is another possible solution. See the below linked informative page.

Bucking Xfmrs
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