P10 thd out is high when i turn on the amplifier

Hi, my inout voltage swing quite a lot, from 247-253v. THD in is aroun 0.8-1%. When all the sources are idling, thd out is 0.1%. The issue is when i turn on the amplifier, THD out will goes higher to 1-2%, and eventually drop back to 0.3-0.4%. However, i usually get 3-4% THD out when i am blasting the music(consume 80-120w).

May i know is this normal?

I would say no, not normal - since I have never experienced the THD out being higher than the THD in.

Also, the voltage regulation should be better, based on my experience. There appears to be too much of a delta between you inbound and corrected voltage.


Welcome to the forum.

i study a bit from the forum. play a bit with the phse tune. when i try to regulate the volatge out to 220v, the thd out reading is lower. it’s really confuse me now

This looks good/nominal.

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Firstly, with no load at all I don’t think you can rely on any of the incoming/outgoing THD values. However, once there’s some load you should get much lower THD Out than In (PSA quote that THD should be down to around 0.1% or about 10% of incoming). I also don’t think the unit should be trying to convert 250V down to 220 V. I think the regen boards have had their day and need to be replaced.

the first two photo is voltage out set at 230v. Thd out is high when I blasting music. The last with THD out 0.2% is I try to regulate the voltage to 220v, phase tune 0. No matter how loud the amp, the thd still constant at 0.2%

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The 1st (230v) photo and the 2nd (220V) photos are clearly inconsistent. When I played with phase tune it had very strange results. I’ve been waiting two months for some refurbished regen boards. Obviously I’m in the UK, where are you?

The voltage should be stable at 220v or 230v without any fluctuations?

I am in Malaysia

Voltage isn’t 100% stable, it’ll probably vary by about a volt. Years ago I often saw incoming voltage at about 243 and I’d set required output voltage at 240. Now we typically get lower voltage ins, between say 233 and 238 so I now set required output voltage to 238. It rarely outputs 238 but will vary between 237 and just under 238. If you’re regularly seeing 250v in and believe what it says what’s the reason to set it at 220? I love malaysia, I’ve spent about 18 months in Indonesia and about a year in Malaysia, loved it!

I live in a condiminum and with shared power line with others. The volatge swing from 247-252. I tried to set the output to 240v, 230v and any in between, the THD out is not favourable. At last i only manage to get THD out at 0.2% when i try set the output voltage at 220v.

This is a really good result though…understood/correct?