Measuring the Power Grid

[wil]

Yes, I know ... At this moment I would like to recover my ExactPower EP15A , one of the more clever power conditioner designs I have seen. https://www.soundstagenetwork.com/revequip/exactpower_ep15a.htm

The EP15A was simply an active corrector, adding or subtracting just what was needed to correct the actual mains system, using series feed-forward techniques. It was very effective and not expensive, unfortunately the company ceased production and service, and there is still no replacement for it. A good friend still owns mine but does not want to part with it!

Do you use any form of power conditioning?

 

[microstrip]

Micro,
What was your mains Voltage reading when it was low?

Around 216V - typically it is around 231- 233V.

Do you consider THD of 3% to be particularly high?

I do not have experience with absolute levels - but the european codes allow ut to 8% THD and 6% 5th harmonic - I should be happy!

And, can you hear the difference between 1.7 and 3%?

I do not have experience enough to answer such question. I could easily hear the effect of the PSAudio P10, but probably it also changes noise and amplitude, not just the distortion.

 

[microstrip]

Do you use any form of power conditioning?

I used in another house, never tried it in this one.

 

[wil]

Micro,
What was your mains Voltage reading when it was low?

Do you consider THD of 3% to be particularly high?
And, can you hear the difference between 1.7 and 3%?

Around 216V - typically it is around 231- 233V.



I do not have experience with absolute levels - but the european codes allow ut to 8% THD and 6% 5th harmonic - I should be happy!



I do not have experience enough to answer such question. I could easily hear the effect of the PSAudio P10, but probably it also changes noise and amplitude, not just the distortion.

The reason I ask is because you said your system was not sounding right and that you then measured 3% distortion.

Or was it the voltage drop (about 7%) that was affecting the sound quality? Or both?

Sorry for all the questions. Just trying to understand the correlation between the sq diminution and your measurements.

 

[microstrip]

The reason I ask is because you said your system was not sounding right and that you then measured 3% distortion.

Or was it the voltage drop (about 7%) that was affecting the sound quality? Or both?

Sorry for all the questions. Just trying to understand the correlation between the sq diminution and your measurements.

IMO it was the voltage drop - I am using the conrad johnson LP275m and I found that tube power amplifiers are very sensitive to voltage drop - although input and driver stages are regulated, output B+ and filaments are not regulated.

But 3% is just the limit for mains THD for hospitals and critical applications - I would be happy to have a lower value.

 

[treitz3]

Sensitive to voltage drop and overvoltage as well.

Tom

 

[Kingrex]

Rex, I'm not sure what you're saying here.

The fundamental is 50 Hz. Are you referring to the 250 Hz harmonics and are you saying it's particularly high? I have no idea as I don't know how to read this or what the Y coordinate refers to?

Yes, the 5th is the 250 hert with the spike as seen on the scope. I don't personally see much less than 3% in most houses. But that does not mean 0% might not be a lot better. Not sure if thats even possible.

 

[Holmz]

IMO it was the voltage drop - I am using the conrad johnson LP275m and I found that tube power amplifiers are very sensitive to voltage drop - although input and driver stages are regulated, output B+ and filaments are not regulated.

But 3% is just the limit for mains THD for hospitals and critical applications - I would be happy to have a lower value.

Maybe you need those to also be regulated?
Would that not be a viable solution to the problem?