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You can't stand in the same river twice

T

timH

pfm Member
I should probably post this in the audio forum but I'm hoping you guys might have some less adversarial responses :)

Anyway there's a saying that you can't stand in the same river twice. There's two reasons for this. One you're different because it's a different time and two the river's different because its a different time.

What's this got to do with anything?

Well last night my system was really singing. I noticed it, my girlfriend noticed it. Today its just not there. I'm less involved, my girlfriend says it's 'more foggy'

So is it us - we've had a different day - we're different. Or is it the system - I had to switch it off for a while so it's only had 3 or 4 hours to warm up.


Tim

ps no smart Alec's telling me about one hand clapping please
 
Tim, I think the answer is night and day. I'll bet your night time mains voltage is higher than during the day. Along with lower daytime voltages, there's also a lot of grunge on the lines – from air conditioners and the like.

I solved the problem by:
1) moving – there are now only 3 other houses on the same transformer with us, and one is on solar
2) running dedicated mains lines from the junction box (one 10ga & one 12ga)
3) filtering with a PSAudio Quintessence Power Center (which shows the mains voltage lower & THD higher during the day than at night)

Now the 'fi sounds great day and night. :D
 
I have to ask: was point 1 deliberate or was it just a coincidence? I can just see the look on my wife's face if I were to say something like: "I know you like the house, but do you see how many other houses share our transformer? We need to keep looking!"

In a related note, when I lived in Boston I had horrible problems with RF interference (it effected both Naim amps and Naim phono stages). When I called NANA to ask them what could be done about it the first thing they said was "you should move."
 
Flashgo, stackowax -

I have always wondered about the unintentional effects of the different way UK vs North american domestic mains are supplied. NA norm I beleive is to use small (5-10KVA), local 'pole pig' transfromers , shared by very small numbers of properties, and delivering a nominal 110VAc. UK norm is for large local substations (150-250KVA) serving maybe 50-100homes, reflecting much higher urban densities, at 240V.

Through transformers (in equipment PSUs) impedance is transformed as turns.ratio^2, so all else being equal - which it isnt - the 240v service has 1/4 the supply impedance reflected in the PSUs performance. Then the internal wirng here uses 'rings' which effectively allow 32A capacity at each socket, vs. 16A in the 110 radial service norm. Perhaps together these could be significant in some aspects.

(just an early morning muse while waiting for the first coffee!)
 
stackowax said:
I have to ask: was point 1 deliberate or was it just a coincidence?
Click to expand...

It sure sold me on this fixer-upper! "Aw shucks, honey, we'll have to re-wire the whole house...." I got to repurpose the 10ga wire to the original electric stove over to the 'fi.

stackowax said:
In a related note, when I lived in Boston I had horrible problems with RF interference (it effected both Naim amps and Naim phono stages).
Click to expand...

Likewise when I lived in SF. Those transformers up the utility poles radiated RFI like crazy.

Martin, I was just going to ask how many houses are on your transformer when your post appeared. ;) Interesting, I wonder if Naim suffers more RFI in NA than in the UK. Even dealers here will warn potential buyers of the potential for RFI with Naim gear. Off to bed here....
 
It does sound like mains quality. Some amps are prone to it and I think we do better in the UK than most. I know someone who lives at the end of a cable run serving a village, he's a DIYer and all his neighbours know when he's welding beacause the TV plays up.

Think yourself lucky there isn't a fabricator-welder at the end of your street!
 
timH said:
Well last night my system was really singing. I noticed it, my girlfriend noticed it. Today its just not there. I'm less involved, my girlfriend says it's 'more foggy'
Tim
Click to expand...

Some good references here to mains supplies and the drift in voltages during differing times of the day, but my philosophy is simply this:

My system always sounds better at night after around 9pm, why?? in my opinion it has something to do with the demand and droop on the power lines during peak times, but I think the main culprit is the ambient noise floor, after 9pm it drops considerably and after midnight it appears even lower, play some fave tunes after 2am and it sounds like someone has changed your entire system during the night.

;)

Paul
 
Agreed on the late night ambiance factor (combined with the benefits of choice beverages), but what I used to suffer and attribute to bad mains power was a broad spectrum grunge. It doesn't just raise the noise floor, it replaces the music and robs it of dynamics and integrity.
 
Definetly the leccy, as soon as the loonies have finished watching Corrie etc demand starts to drop. Come 11pm its bliss, and the lack of outside noise helps too. Share a bottle of wine after 9 while the system warms up then have a listen.

However, might I suggest that next time you and your ladys senses are on exactly same frequency you turn the hifi off instead

;)
 
I find humidity really affects the sound. When the humidity is very high the system sounds completely stunning. When the humidity drops so does the sound quality.

How humid was it?
 
Mark Packer said:
I find humidity really affects the sound. When the humidity is very high the system sounds completely stunning. When the humidity drops so does the sound quality.

How humid was it?
Click to expand...

Finally, a benefit to living in Pittsburgh (humidity)! Eat your heart out Phoenix, Tuscon, San Francisco, etc.
 
It seems logical moist air will be more dense than dry air. Does this:
a) improve sound transmission, particularly of low-level sounds?
b) improve dynamics / transients?
c) even Improve driver damping slightly as there is slightly more mass to move?
Must admit I can't listen late-night, I like it fairly loud!
AP
 
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