# P20 voltage output setting
**URL:** https://forum.psaudio.com/t/p20-voltage-output-setting/12608
**Category:** Power Components
**Created:** [September 1, 2019, 10:51pm UTC](https://forum.psaudio.com/t/p20-voltage-output-setting/12608 "2019-09-01T22:51:19Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@hiendmmoe](https://forum.psaudio.com/u/hiendmmoe)
#### Post date: [September 1, 2019, 10:51pm UTC](https://forum.psaudio.com/t/p20-voltage-output-setting/12608/1 "2019-09-01T22:51:19Z")
When I set the voltage output level I’m getting a different reading at the ac receptacle. Using my voltage meter the voltage is off by 3 volts. To get an output reading at the receptacle of 120vt the setting
Is at 117vt. Is this normal? doesn’t sound like it should be.
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### Author:  [@MarADyr](https://forum.psaudio.com/u/MarADyr)
#### Post date: [September 3, 2019, 1:59pm UTC](https://forum.psaudio.com/t/p20-voltage-output-setting/12608/2 "2019-09-03T13:59:48Z")
I agree with your concern. However, a few questions first… Are you certain your voltage meter is accurate? Is it a Digital meter or an older Analog (with swinging needle)? Does it have fresh batteries? The “first rule” of testing to is ensure equipment is calibrated and in good shape.
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### Author:  [@RonP](https://forum.psaudio.com/u/RonP)
#### Post date: [September 3, 2019, 2:39pm UTC](https://forum.psaudio.com/t/p20-voltage-output-setting/12608/3 "2019-09-03T14:39:55Z")
You’re so right. I used to be in the business of measuring mass flow and density. Our density meters could detect differences to 0.0001gm/cc. I once got a call from a metrology lab complaining that our meter disagreed with the device they were using as reference. Turned out to be a car battery hygrometer!
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### Author:  [@jamesh](https://forum.psaudio.com/u/jamesh)
#### Post date: [September 3, 2019, 3:46pm UTC](https://forum.psaudio.com/t/p20-voltage-output-setting/12608/4 "2019-09-03T15:46:51Z")
Previous comments could certainly be valid. The volt meter that you’re using might not be 100% accurate. We do calibrate the P20’s oscilloscope, but if you’re certain the volt meter is accurate, you can re-calibrate the P20. Shoot me an email at [jamesh@psaudio.com](mailto:jamesh@psaudio.com) and I can walk you through this.