[schw06]

I'm suffering from Sunday night/Monday morning syndrome where everything sounds great in the late evenings but has an electronic hash and thinness to the sound during heavy A/C use times. Rather than taking the "let's demo products until I find what fixes it" approach, I'm wondering if there are ways to test for the issue I am having so that I may have a good chance of picking a conditioner on the first try. I own an Uberbuss currently and am happy with it but it apparently doesn't solve this issue.

[jtwrace]

First thing I'd do is check the voltage and monitor it during the time(s) that you would listen and see if it swings much.  There are other things but at the end of the day there is only so much you can do before the point of connection.

[HAL]

Yes, A Fluke 43B power line analyzer is a very good meter to use for AC issues.  I bought one a few years back when I was having AC problems.

It will let you monitor power line distortion levels which correlated well to AC issues here when I was investigating my issues.  When the distortion levels hit about 6%, I had power transformer hum in my toroids.  Tracked it down to dirty AC power meter contacts that the power company came and cleaned.

Normal levels of AC distortion in my place is around 2% after the correction.

The meter will also log AC line voltage for long term stability.

You do need to monitor the distortion levels over long time periods to see when it changes.   

[Speedskater]

Both Fluke and Dranetz  make very nice modern power line analyzer's. But the cost from about $1500 to $3500!  The good news is, they can be rented. While lots of vendors rent the units this is the only one I found that listed prices.

http://www.testequip.com/sale/details/HTE0733.html

It looks like the range is $150 per week to $350 per month.

[catastrofe]

I was having issues with my power quality last year, and monitored my voltage using this device, which is reasonably priced:
 
(http://www.idealindustries.com/products/test_measurement/power_quality_meters/voltage_performance_monitor.jsp)

It showed my voltage dropping down to 105V.  I convinced my power company to place a monitor on my meter, and they sheepishly admitted that they had a faulty capacitor bank at my substation, in addition to some blown fusing.

[rw@cn]

Yes, call your power company. They will put a monitor on your meter. You may have to complain, but they will do it and fix what is wrong (or at least put it in the queue).

[Speedskater]

The power company's monitor will only measure minimum and maximum voltages.  You need a meter like the ones above to measure quality (harmonic distortion).

[Big Red Machine]

I have the opposite problem where I have 123/124 volts all the time.  If you can find out if the voltage fluctuates then the power company may be the answer.  If the A/C is adding noise but the voltage is stable at the audio circuits then perhaps a balanced power unit after the Uber would do the trick.

[Speedskater]

A long time ago, the US standard voltage was 110V then 115V or 117V then 120V now it drifting to 125V.  I see products with 125V on the label.  Some legacy audio equipment may have problems with 125V.

Balanced power is expensive, has problems with the electric code and is overrated as a solution.

[TomS]

A long time ago, the US standard voltage was 110V then 115V or 117V then 120V now it drifting to 125V.  I see products with 125V on the label.  Some legacy audio equipment may have problems with 125V.

Balanced power is expensive, has problems with the electric code and is overrated as a solution.

I am looking at my Belkin PF60 in my HT right now and the meter on it says 126.4v. I have no idea how accurate the meter actually is but it varies 118 to 125 or so over time (days). I would think degraded sonics and transformer/choke noises would be caused by the distortion, as HAL notes above, possibly caused by bad connections along the wiring chain.

I didn't have a way to measure it before/after, but I had a master electrician come and touch up the whole wire path from breaker box to wall outlets a while back and it did improve things some. I still have some noisy toroid transformers, even a little faint buzz in my UberBuss and Felix's.

It's a nice safety check to have an expert look it over, even in a brand new home, as builders always push the trades to finish faster than they'd like and the inspectors don't always check everything either.

[Hugh]

+1.

After we moved into our home, we had an electrician installed dedicated 20A lines for our HT & music rooms.

It helps.

It's a nice safety check to have an expert look it over, even in a brand new home, as builders always push the trades to finish faster than they'd like and the inspectors don't always check everything either.

[Soundminded]

I'm suffering from Sunday night/Monday morning syndrome where everything sounds great in the late evenings but has an electronic hash and thinness to the sound during heavy A/C use times. Rather than taking the "let's demo products until I find what fixes it" approach, I'm wondering if there are ways to test for the issue I am having so that I may have a good chance of picking a conditioner on the first try. I own an Uberbuss currently and am happy with it but it apparently doesn't solve this issue.

A vacuum tube amplifier with a poorly regulated or unregulated power supply and no feedback is the worst of all possible worlds. Thermionic emission of the cathodes varies wildly with its temperature. That varies with the square of the current which in turn varies with the applied voltage. Lack of regulation also allows the quiescent operating points of the tubes to drift all over the place while lack of feedback means gain is also unstable.  If I were the owner of a store selling these I'd keep them all on a large UPS and the store temperature constant. When the unhappy customer came back with one I'd plug it in and show him that the amplifier is not the problem, it's the rest of his system. That would be the perfect lead on to sell him something else like expensive wires or some other gimmick I could make a huge profit on.

[Quiet Earth]

It does seem like the line voltage is slowly creeping up everwhere in the U.S. I wonder why? It has been a very steady 119 to 121 V over here for many years now. Pretty much day or night.

Balanced power is expensive, has problems with the electric code and is overrated as a solution.

What do you reccomend as an alternative?

[Quiet Earth]

A vacuum tube amplifier with a poorly regulated or unregulated power supply and no feedback is the worst of all possible worlds. Thermionic emission of the cathodes varies wildly with its temperature. That varies with the square of the current which in turn varies with the applied voltage. Lack of regulation also allows the quiescent operating points of the tubes to drift all over the place while lack of feedback means gain is also unstable.  If I were the owner of a store selling these I'd keep them all on a large UPS and the store temperature constant. When the unhappy customer came back with one I'd plug it in and show him that the amplifier is not the problem, it's the rest of his system. That would be the perfect lead on to sell him something else like expensive wires or some other gimmick I could make a huge profit on.

Gee, that was helpful.

[TomS]

Gee, that was helpful.

Yeah, I seem to have missed the improvement suggestion in that post too 

David has a good question and the right approach to going after it. I hadn't thought about renting a quality instrument like the 43B. My electrician didn't even have one. Great ideas already, so keep 'em coming 

[HAL]

One reason the distortion measurement is important as it is an indicator of how much DC is on the line.  The asymmetrical nature of the waveform that is the distortion is also to some extent a DC offset.
 
Toroidal transformer cores are very sensitive to DC offset saturating the core and that makes the mechanical hum/buzz.

At around 6% line distortion, my power amp toroids were making a good amount of mechanical hum/buzz.

[Soundminded]

Gee, that was helpful.

Do I really have to spell it out? If you don't want your amplifier drifting around all over the place always sounding different buy equipment that is solid state not tubes, has a well regulated power supply, and was designed by someone who knows how to apply the very difficult principles of negative feedback correctly, not by someone who doesn't and throws up his hands saying the idea is no good and therefore shouldn't be used. Or you could just go out and buy a double static conversion UPS for a few thousand like the Lieberts and Eatons i referenced on another thread. Or you could buy a variac and a meter and just keep adjusting the voltage by hand all day. Whatever floats your boat.

[Quiet Earth]

It's not the content, it's the intent. Yours is always derogatory.

[Æ]

It does seem like the line voltage is slowly creeping up everwhere in the U.S. I wonder why?

Utility companies are systematically (slowly) upgrading all their equipment.

[Æ]

It's not the content, it's the intent. Yours is always derogatory.

He is correct, but not all solid state equipment is well regulated either. Simple linear supplies are dependent on the line voltage too.

One can address some of the issues by making sure their house wiring is in good shape. Tighten down (re-torque) all the wires inside the breaker panel and make sure all the wire leading to the outlets are screwed down tight, not stab locked.
If you have any major appliances (washer, dryer, refrigerator) on the same side as your audio equipment, consider not using the appliances during listening sessions or switching around some of the house wiring. Of course always be safe, and if one cannot service their own house wiring, have a competent electrician do it.