Audio quality after power cut

[ifor]

Yesterday evening we had three or four power cuts over the course of about 30 minutes. When we were fairly sure the power was back on to stay on we decided to play some vinyl. My wife chose Elbow's Build A Rocket Boys. Being a 45 RPM LP I put it on the Technics SL-7 to avoid the hassle of moving the drive belt on the Manticore Mantra. It sounded dreadful (not initially my observation, but I had to agree). Believing the Mantra to be a better sounding TT than the SL-7 I decided to switch TT. It still sounded dreadful, but by the time we were listening to side three it was sounding pretty good again.

Can anyone explain this? Was the power cut to blame?

 

[Covenanter]

Please don't be offended if I say I suspect it's more likely to be a psychological effect than anything else.

Chris

 

[ifor]

Please don't be offended if I say I suspect it's more likely to be a psychological effect than anything else.

Chris

I'm not offended, but am 100% certain it was real, though I've no idea why it should be so.

 

[Electro]

After a power cut the mains voltage can fluctuate quite a lot as the engineers work around the original problem by switching power in from other circuits .

A 10 % change in line voltage can give around a 20 % change in amplifier output power.

This might explain part of what you heard .

 

[chebby]

Some people think their electronics need to be kept powered on 24x7 for optimal performance.

If that includes you then - of course - your enjoyment will be affected by the time switched off.

My local dealer once told me to expect my old Nait 5i/CD5i/NAT05 system to take up to 6 weeks to 'recover' completely from a long power-off (like going on holiday).

I didn't believe it and thought a few minutes play (from 'cold') was plenty.

 

[ifor]

It certainly wasn't a long power cut. Adding them together it wouldn't have been more than 15 minutes. I do leave my stuff on 24 x 7, but have no opinion as to whether or not it makes any difference. The power cuts affected the whole town and nearby villages; apparently a pylon had burst in to flames somewhere not far away. I didn't know they did that.

 

[bigfish786]

Coal used at the local power station?

 

[ifor]

Coal used at the local power station?

They turned off coal at Didcot quite a while ago. Apparently it was a pole not a pylon that went up in flames.

 

[ifor]

After a power cut the mains voltage can fluctuate quite a lot as the engineers work around the original problem by switching power in from other circuits .

A 10 % change in line voltage can give around a 20 % change in amplifier output power.

This might explain part of what you heard .

Would that account for the music having no depth? It was just dull

 

[Vladimir]

If the record gradually improved in SQ, it's psychological. If the sound reproduction suddenly got better, it's the power coming back in full potential like Electro explained. That would be my logic of it.

 

[ifor]

Maybe I should have asked the question differently. It's been assumed that I'm attributing it to the power cut. I'm not; I'm asking whether there is a possibility that it might be responsible for what we heard. We put on a record we know well and it sounded poor, thin and lifeless; not what we are used to. Over time it got better. I don't know why it sounded so bad, but we had just had a power cut. It w my wife, sitting in the listening position, who first noticed it and she would have no opinion at all on mains quality, power on 24 x 7 etc.

 

[The_Lhc]

Maybe I should have asked the question differently. It's been assumed that I'm attributing it to the power cut.

Well, when you title the thread "Audio quality after power cut" that's not an unreasonable assumption to make.

I'm not; I'm asking whether there is a possibility that it might be responsible for what we heard.

That's exactly the same question, I don't know what point you're making there?

We put on a record we know well and it sounded poor, thin and lifeless; not what we are used to. Over time it got better. I don't know why it sounded so bad, but we had just had a power cut. It w my wife, sitting in the listening position, who first noticed it and she would have no opinion at all on mains quality, power on 24 x 7 etc.

As said, if the mains being supplied was below standard voltage then yes it could well affect the sound quality.

 

[andyjm]

Mains has a wide range. In the UK, 253v to 216v is the acceptable voltage tolerance. Electronic equipment sold in the UK has to operate correctly within this range, and the supply authority has to maintain supplies to this tolerance.

it is extremely unlikely that even if mains voltages were reduced below this range that it would impact an audio amplifier. For those who have posted above that it could, I would be interested to hear how this effect might occur.

The most likely cause of the OP's perceived loss of quality is suggestion bias.

 

[ifor]

The most likely cause of the OP's perceived loss of quality is suggestion bias.

Please explain.

 

[Jota180]

Possibly after a few power cuts in succession you're sitting there half expecting at the back of your mind there could be another or that there's something fundamentally wrong with the power supply itself. Could put you on a mini downer and only after the electricity supply stayed on for a while did you start to relax and have confidence in it again.

It takes time to trust something after it fails and that's basic human nature, probably much wider than human nature.

 

[ifor]

I don't buy that all. It would never have crossed my wife's mind that a powercut might cause problems of that sort. She thought it was down to what she regards as being the poorer of the two turntables being used, but this proved not to be case when transferred to the other TT.

 

[chebby]

I don't buy that all. It would never have crossed my wife's mind that a powercut might cause problems of that sort. She thought it was down to what she regards as being the poorer of the two turntables being used, but this proved not to be case when transferred to the other TT.

Do you have any ideas about the cause of the impaired performance?

 

[ifor]

I don't buy that all. It would never have crossed my wife's mind that a powercut might cause problems of that sort. She thought it was down to what she regards as being the poorer of the two turntables being used, but this proved not to be case when transferred to the other TT.

Do you have any ideas about the cause of the impaired performance?

None, at all, but having had the powercuts I wondered whether that might have been the cause. If it wasn't that I've no idea what it might have been.