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Need Help: What In My Home Electric System Killed the Sound?

Could really use some troubleshooting from you electric experts out there, of which I certainly am not one.  House is in rural western Maine.  My electrician (licensed and very experienced, but not in audiophile context) is running a dedicated line to the 2-channel rig.  He installed the new line up to the outlet, but didn't complete yet (we're waiting for delivery on the outlet), so the new line is temporarily capped off at the wall.  In the meantime, elsewhere in the house, he changed a broken recessed light socket and changed the related wiring to that light.  Those are the only two changes to the electric I am aware of.   The 2-channel system remains plugged into the same outlet we've been using for years (until the dedicated line is in).  This weekend, the life is gone fro the system.  For example, volume at "25" on the pre-amp would normally be quite loud, but now it needs to be turned up to 40 to get the same loudness.  Regardless, dynamics are gone, tempo is a tiny bit slow and has lost toe tapping, and vocals moved from near field to way back in the mix.   Nothing was changed in the system (Rega Saturn CDP; McIntosh C52; McIntosh 452; and Polk SDA 1.2 TL (heavily modded)).   Any thoughts on what might have cause these symptoms?  Electrician can't pinpoint anything.  Any input appreciated.  
whitecap
chlv0ter's avatar
chlv0ter
31 posts
 
Something clearly changed, it's sometimes a painful process of elimination to isolate the issue.  Good feedback above.  Did anything else in the house change other than the minor electrical work?  What else is on that circuit you use for audio?  I've seen a loose ground or neutral in the elect panel cause issues.  Hope you find the culprit...

auxinput
2,920 posts
 

"For example, volume at "25" on the pre-amp would normally be quite loud, but now it needs to be turned up to 40 to get the same loudness".  Also, the description of the vocal midrange disappearing into a recess.

This is exactly what I have experienced with equipment where the internal power supply is vastly under-powered (i.e. not enough capacitance after the power supply regulators).  What happens here is that it starves the audio circuit and you feel like you have to keep turning up the volume to hear stuff (but you never quite get to the point where it is satisfyingly loud enough).

Obviously, something happened to your electrical circuit when the guy fixed the light.  Electricians do have a tendancy to want to chain outlet after outlet.  It could be that he tapped into your audio circuit somehow and it is now being chained after several outlets/light fixtures.  The idea of a dimmer knob on a light fixture is an excellent idea.  Dimmer switches do not turn down the actual use of electricity.  They just shunt it through a variable resistor so that it limits the amount of electricity/voltage going to the actual light bulb.  This could be playing havoc with the voltage supplying your audio equipment.  I would take a voltmeter and measure the voltage of your audio power outlet to make sure you're getting at least 115V.  More does not hurt and 125/130V is fine for audio equipment (though some preamps can sound harsher with higher voltage if the internal power supply is not filtered as well).  A higher voltage can have small benefit as the audio power supply as it allows a higher level of voltage capacitance in the main power supply before the voltage regulators step down to what's required in the audio circuit.

I believe your audio equipment is being starved by either voltage or current. 

auxinput
2,920 posts
 
Oh, if you're chaining 5-6 outlets/lights in a row and your audio is last in line, the resistance and connections between each outlet could cause enough of a limit to sage the voltage/current. Even though you may measure good voltage at your audio outlet, it can still starve when the audio equipment attempts to pull more current from the line.
jfritz
1 posts
 
Old homes typically are prone to all kinds of electrical noise.  I feel the some of the best advise is already given above.  My preference is to use multiple power filtering and protection mechanisms and devices.  Typical surge suppressors provide protection, but many times that protection is a fantom or occurs too late.  Isolation transformers or other good power conditioning devices provide a continuous baseline for power.   It is important to note that older electrical codes allow the use of the neutral as ground rather than a dedicated ground.  With that said everything in you house is somehow interconnected.  A simple enhancement for this is to make sure that your panels have a dedicated ground to a ground field.  Sometimes you have to install multiple rods in multiple locations to obtain a good ground field.  See IEEE guidelines or other resources for grounding advise.  Your dedicated homerun for your audio system is great idea.  If you feel power shy you could always run better gauge wire.  Use 12 gauge (20 amp) rather than 14 gauge (15 amp).  One step up is 10 gauge (30 amp).  Depending on your electrical codes you can run a heavier gauge wire on a smaller breaker in the fuse box.   
cousinbillyl
190 posts
 
Watts (and therefore KiloWatts) are amps x's voltage. Since motors (fridge compressor and furnace fan motors as examples) work on current, this current draw remains constant, but the voltage is higher, so you use more 'watts'. Hydro company makes more money, blah blah blah.

If memory serves me correctly, over at diyaudio, Nelson Pass conducted a small experiment. Using a Variac, he adjusted voltage on numerous systems. EVERYONE in the room preferred 'lower' voltage settings. 115v was one of the preferred settings. 120v was bad, and anything above this was horrid in comparison to 115v. YMMV
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