I recently had a blind opportunity to hear the effect of poor mains power. My NCore 400 had started sounding harsh in the mids and brittle in the hi end over the last month. My class A/B mosfet amp started suffering harsh mids. My Stereomour single ended triode showed no performance change in this period. Last weekend cf bulbs started flickering out and on. My power provider came yesterday and found bad supply to the house (buried cables failing at splice points). Immediately all amps were back to sweetness! I believe this may show that mains power will have very different effects on the different amp designs.
shouldnt have a huge effect if home loads were lightly stressed. assuming poor /corroded connection, but it really depends what the actual fault was.
IMO no data /results can be taken from here due to variable nature of brown outs E.g.other loads that may / may not of been present at the time. Buy a big ol variac and test under more controlled conditions.
Last edited:
Several years ago I had a CRT TV that appeared dim. When I took it to a repair shop twice they couldn't find a fault. I measured my line voltage at 108 VAC. Power company move the distribution transformer closer to my house and problem solved. I live in an area with old infrastructure and my house was at the end of the line. Since it was summer, all of the AC units caused a voltage drop.
I wouldn't call 60% power poor. More like seriously crap or no power at all.
Most 220/230V rated devices will not work at all at voltage like that.
Fortunately I never saw under 220V for our 230V line.
If voltage changes 10%, then it is out of spec. So no wonder something doesn't work 60% below rated.
Last edited:
Tube equipment will by affected by low line voltage, i.e. a drop of more than 10% will take 6.3VAC down to 5.6VAC
I have a big Variac for the lab in the summer when the voltage can get reduced by JCP&L. More often,it goes out completely.
For our production line, summer power outages or low line voltage are a huge issue. In July and August we move our first shift to start around 5:00 a.m. when the temps get high.
It seems that since it was the buried line to my house that my house as a whole was acting as it's own end of a line. That would make my problem crop up when I was creating more demand. Thanks.
You know, regulated switching power supplies would prevent all that. they would just draw more current from mains as the voltage drops.
(Was it me or Evan? He's further to the south. My big variac was bought from an audiophile who used it to dial up his window air-conditioner!)
Low power tubes don't suffer that much from lowish filament voltage and can even have lower noise, but power output tubes (think kW ham radio linear amplifiers) aren't happy in this situation.
Ericj response
The ncore supplies are smps so what I was hearing would have to be attributed to something else. DAC?
The ncore supplies are smps so what I was hearing would have to be attributed to something else. DAC?
- Status
- Not open for further replies.