AudioNervosa
Electro Stimulation Ward => Power Conditioning => Topic started by: mdconnelly on August 09, 2016, 11:10:38 AM
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Well, I can always tell it's summer because my UberBUSS starts humming. I live in an old section of town where all the power cables are up on poles. Invariably, as neighborhood power demand goes up, my Uber starts humming.
I have been in touch with Dave E and have tried it in numerous outlets, and have tried turning off all breakers except to my audio system. The Uber just keeps on humming. It's typically worse in the evening. Some days I can barely notice it. Other days I can hear it from the other room.
I've found two products that currently claim to deal with this:
Emotiva CMX-2 ($99)
AVA HumDinger ($140)
The price for either is quite reasonable. I know Van Alstine offers a 30 day money-back. The CMX-2 is actually available via Amazon so I suspect I could return it as well.
Anyone have any experience with either of these or know if a better solution at a reasonable price?
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maybe eliminate the uberbuss
I can't tell you how many times power conditioning was removed to the betterment of a system.
I know we get used to the sound, but many times the removal is an improvement. I know sacrilege!
give it an unbiased try, you may like it as the air and dynamics come back
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A couple summers ago I did exactly that... Removed the Uber and indeed, it did quiet the room by removing the humming. But what I remember was that it seemed to recess the soundstage, like I went from 5th row orchestra seat to further back. For me, the Uber has always benefitted SQ, far more than other conditioners I've tried over the years (including Shunyata Hydra & Running Springs Jaco)
But you're absolutely right... it always good to question assumptions so I will absolutely give it another shot. Still, would love to hear anyone else's experience with taming DC on the AC.
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Seems to me killing annoying hum is worth losing a little transient response, as long as it is subtle, not a smothering effect. Then in October you can remove it and "lift the veil." But it will probably still have some DC and you'll prefer having no hum after you get spoiled with silence. If the hum is caused by lam rattle then it will get worse with time.
Regen is an ($) option. But doesn't a regen amp have a power transformer also? :?
More info on mains DC:
http://sound.westhost.com/articles/xfmr-dc.htm
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Thanks Rich. You may remember that I tried a PS Audio regen years back (wow, I'm getting old) and was less than impressed. And, as you indicated, that's a pricey solution.
Anyone know if calling the power company (Duke Power here), would actually result it getting them to deal with it? My experience with them on a different problem during a remodeling effort a few years back was somewhat less that useful, but I haven't a clue if there's actually anything they could or would do.
Thanks for the link!
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I had a power problem after a lightning strike in the neighborhood and then had transformer hum problems. I got a Fluke 43B power line analyzer and the distortion level had risen from 2% to 6% THD compared to a friends house. Had the local power company come in and they checked. Sure enough they pulled the meter from the base and cleaned the contacts. Reassembled it and then checked and back to 2% THD like everyone else. No more hum.
Does not take much residue build up on AC contacts to cause problems. Might be something to check.
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See what other equipment is connected to the same buss your music room is on in your breaker panel. Your AC unit will share the same buss, but if you have some other heavy 120 volt hitters (refer, freezer etc) on the same buss, it might cause enough draw to cause the buzzing. You may have to move some of the load around in your breaker panel to even out the load.
Also, check the connections in your breaker panel in regards to the main lugs feeding the panel and the breaker that feeds your music room. Loose screws connections can cause problems, especially under heavy amp loads.
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Great suggestion.
That was the first step in checking the hum problem here. That was good, so that showed it was something on the service side of the power system.
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See what other equipment is connected to the same buss your music room is on in your breaker panel. Your AC unit will share the same buss, but if you have some other heavy 120 volt hitters (refer, freezer etc) on the same buss, it might cause enough draw to cause the buzzing. You may have to move some of the load around in your breaker panel to even out the load.
Also, check the connections in your breaker panel in regards to the main lugs feeding the panel and the breaker that feeds your music room. Loose screws connections can cause problems, especially under heavy amp loads.
Yep, checked that. I cut all circuits except my dedicated audio 20a circuit, but the hum is still there, so I have to assume it's definitely coming in from outsite... not all that surprising, I guess, given the age of the power on polls in my neighborhood.
I will take a hard look at all the connections but I had a new panel installed during a remodel 2 years back and it looks to be in good shape. This summer Uber-hum predates the new panel anyway.
I have been in touch with Emil (also here on AN) and am buying his Emotiva CMX-2. Hopefully that will take care of it. Stay tuned...
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I'm not a fan of Duke Power service, but you are paying for quality of service, not just kWh. If the DC blocker fixes the symptom of hum then you have DC and they should come fix it, if possible. It could be other houses on your transformer causing the problem that they can't do anything about.
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Welcome to the wonderful sound of summer. DC on the lines is a fact of life in many areas.
Hate it and it is a PITA to get rid of without compromising SQ. I know: I've been working on the problem off and on for a couple of years. Getting rid of it isn't that difficult. Finding good sounding parts is.
Topround_ there are no inductors or transformers in the Uber. What is being energized by DC are the capacitor plates in the Power Factor Correction circuit in the BUSS. Plate swing in asymmetrical: ergo hum.
Mike and I talked about the Emotiva. Looks pretty good except for a fairly small gauge (for AC) common mode choke. He's is getting one, so am I. I'm not above tweaking other well designed gear. That is a large portion of what I do.
The other thing is that you can smother the Uber with pillows, blankets, cats, concrete. It doesn't generate heat
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Got the Emotiva CMX-2 yesterday (thank you, Emil!).
Upon initial install early yesterday afternoon, no buzzing from the Uber to be heard. Of course, the worst buzzing always happened in the evening so last night, maybe around 11pm, I cut the music off and got down within a foot of the UberBuss. Yes, could faintly hear a slight buzzing, but nothing like it had been. So, whatever the CMX-2 is doing, it seems to be working to large extent and definitely worth the price of admission.
I will say that I was a bit concerned that the addition of the Emotiva would somehow affect sound quality (although it claims no current limiting). Well, after maybe 3 hours listening last night and another couple this morning, I couldn't discern any negative effect from it. I'll give it a few more days to acclimate (it and me), but for now I'm calling it a qualified success.
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PS Audio used sell a product called the Humbuster that I remember getting some good write-ups. It was discontinued a while back, but perhaps you can fund one on the used market.
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Yep, I started looking for a Humbuster first. Even used, they are over $250. The Van Alstine HumDinger is also an option with some good feedback, but still $140 versus the Emotiva CMX-2 at $99 (and a good bit less used ;-).
So a number of products that adddress DC on the AC, but the Emotiva seems like best bang-for-the-buck.
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Yep, I started looking for a Humbuster first. Even used, they are over $250. The Van Alstine HumDinger is also an option with some good feedback, but still $140 versus the Emotiva CMX-2 at $99 (and a good bit less used ;-).
So a number of products that adddress DC on the AC, but the Emotiva seems like best bang-for-the-buck.
In our discussions I'm thinking that the Emotiva is the solution. The Humdinger is only a 10A solution (AFAIK - so I have been told) and the PSA unit is long gone.
I have one coming and I will be doing a tweaker's gaze on it. The only thing that jumps out at me is the wire gauge in the common mode filter choke.
Time will tell.
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I picked up my Emotiva today at the PO. Over the next couple of days I'll be taking it apart, analyzing it looking for tweaks, take some pictures and then report back. I'll need to unbalance a line to test it. Some fun, eh!?
It'll be great if it works as well as I hope
:thumb:
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Dave, looking forward to your insight regarding the Emotiva. While it definitely has cut down on my Uber-buzz, it is still there at times... just to a far lesser extent.
EXCEPT... I did find a set of outside flood lights that, when on, definitely makes the Uber buzz a good bit more. The circuit controls two pair of outside CFL floods. Interestingly, whatever this circuit is doing is not at all mitigated by the Emotiva nor the DigiBuss. No idea why it is making the Uber buzz more than usual, but it's easy enough to turn off (these lights are actually rarely used). I have a feeling it is related to the CFL bulbs so I hope to swap them soon to see if that makes a difference.
Strange thing this electricity stuff...
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I would almost bet your hum is transformer related. My guess it would be on the transformer(s) on the utilities power pole. With the increased demand for power in summer, the increased load on the supply transformer could cause an internal imbalance and resulting harmonics. I have heard transformers up on poles humming away under heavy load. If the transformers are compromised, you can bet they are passing the harmonics down the line. :(
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I would almost bet your hum is transformer related. My guess it would be on the transformer(s) on the utilities power pole. With the increased demand for power in summer, the increased load on the supply transformer could cause an internal imbalance and resulting harmonics. I have heard transformers up on poles humming away under heavy load. If the transformers are compromised, you can bet they are passing the harmonics down the line. :(
+1