Bottlehead Forum
Bottlehead Kits => BeePre => Topic started by: Andrew Lee Rubinger on January 06, 2015, 07:55:18 PM
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Hi all:
Noticed something the other day, now that it's ultra cold here in Boston.
I have an electric space heater; when it's on and plugged into the wall sharing the same circuit in the fusebox as the BeePre, I get a very loud hum/buzz that does not change with the volume or balance controls.
Turning off the heater removes the buzz/hum.
So: I have my BeePre plugged into a Furman M-8 Power Conditioner, which I thought was responsible for providing clean power to whatever's plugged into it. The M-8 claims to filter RF and EMI.
So how is the operation of the heater affecting my BeePre behind the power conditioner? Is my conditioning solution insufficient?
Thanks in advance!
S,
ALR
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I have experienced this last year but as a intermittent and very annoying background buzz and it was electric space heater as it was tripping on and off on its thermostat in a different room. I normally use a gas boiler for central heating and hot water but do have a electric immersion heater that is used on occasion this also has the effect.
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I know the obvious answer is to turn off the heater while listening. I have a heater in my listening room and I do that, and turn off the humidifier too.
But the problem is the heater. It is putting noise onto the power line.
You can run a circuit from the other half of the incoming (alternate breakers are on opposite phases) to your system.
You could get a Corcom noise filter, try Digi-Key and Mouser for small ones. Try it on the heater, it might prevent the noise going back into your circuit.
You might want to contact Furman about the lack of performance in the M-8. The buzz might be from the motor on the fan. And there is a wide world of other noise filters and power conditioners out there.
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Thanks, all!
And I've just found another source of noise: the outside lights. So the solution I'm looking for is to isolate my system from bad power.
The bottom line I'm looking for: is it true that I'm running into EMF or RF? Or is there some other issue with my power that I need a conditioning solution to address?
S,
ALR
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It sounds like an isolation transformer might be in your future.
I found that outdoor quartz lights are really horrible for power line cleanliness.
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Ban all CFL and LED light bulbs, light dimmers, and no name cell phone chargers from the house. Prevention is better than a cure :)
I also use a mains filter box which was rather effective at removing the high frequency noise and the cracks and pops i used to hear switching lights on/off around the house. Only issue i have now is the large toroid in my main speaker amp growls angrily around midnight, whatever is upsetting it isn't in my house.
I picked up a large toroid isolation transformer on eBay recently which is on my to do list, will be interesting to see if it changes any of the above..
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My house is now fully CFL and LED lighting with PWM dimming. I don't have any noticeable noise issues, but I have all of the components plugged into isolation transformers. I use PowerVar. It is pretty much the standard for server rooms and medical equipment here in the SF Bay area. They are usually replaced every 3-5 years by the industry users, so I get them at fairly cheap prices. They are quite heavy, so shipping gets to be $$$$$. I started using them to keep the digital and analog equipment isolated from each other. (Really more to keep the digi-crap out of my TT systems) Now all of my components are on PowerVars.
Cheers,
Geary
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I really appreciate everyone's input. I'll be following up here once this is solved to help others looking forward.
Some follow-up questions, if I may:
* Is this ground loop hum I'm seeing? Using a multimeter I see that the difference between my (-) and ground is ~.6V with the patio lights off, and ~1.4V with them on. I should be seeing a number close to 0V, correct? Will an isolation transformer also be isolating the ground? It appears some models do not.
* What model PowerVac would be appropriate; there are many.
Again, thank you!
S,
ALR
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RE LED lamps, we have all sorts of them here at Bottleheadquarters including about a dozen dimmables in the lobby, and they are not a problem.
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...
* Is this ground loop hum I'm seeing? Using a multimeter I see that the difference between my (-) and ground is ~.6V with the patio lights off, and ~1.4V with them on. I should be seeing a number close to 0V, correct? Will an isolation transformer also be isolating the ground? It appears some models do not....
It's always difficult to tell what the source is.
What - exactly - are "(-)" and "ground"? If you are comparing signal ground vs power line safety ground, then you have missed the connection between them; fixing that (bad solder joint?) should be a pretty dramatic improvement. But maybe you meant something else?
Ground loop hum can be identified by testing in isolation - no inputs, no outputs. Turn the level all the way down, use headphones or a sensitive voltmeter on the outputs. Then add one by one the inputs and see if any of them generate the noise. If you must use a power amp and speakers to detect the noise, try using cheap crap interconnects and compare with heavy-duty ones (that have a lower resistance shield). Make sure both power and pre amps are connected to the same outlet.
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What - exactly - are "(-)" and "ground"? If you are comparing signal ground vs power line safety ground, then you have missed the connection between them; fixing that (bad solder joint?) should be a pretty dramatic improvement. But maybe you meant something else?"
This is measured by putting multimeter leads directly into the power cable that would ordinarily be plugged into the BeePre. Ground is the power ground, (-) is one of the AC leads that isn't the one which gives me a reading of ~114V. So that measurement is power coming out of the wall, without the BeePre in the picture at all.
The hum is audible when I have no inputs connected, and exists regardless of input switch, balance pot, or volume pot setting. Removing the output from the BeePre (and disconnecting it from the amp) makes the sound go away, so I can ensure it's not the amp having the issue. Usually the BeePre sounds just fine; the buzz/hum is occasional and is affected by other things plugged into the same circuit/fuse, so I've deduced that the power is an issue.
S,
ALR
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It sounds like you are chasing this down. Just to be sure, try a different pair of interconnects between the Bee Pre and the amp.
It is quick and easy. It might work, probably not. But it needs to be eliminated.
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I've always had good luck with the lower cost PSAudio power conditioners (e.g. the Duet). I'm getting ready to put together a power line filter from Classic Valve, which may look diminutive from the number of parts, however you'd very be surprised how little is in some commercially available audiophile "power conditioners", so once it's done I can report back. Might not be for a month or so...
http://www.classicvalve.ca/tubepcb-1.html#POWER (http://www.classicvalve.ca/tubepcb-1.html#POWER)
From the documentation: "designed to take care of common and differential mode noise and surges with a grounded supply, can to some extent reduce RFI that is picked up by the power lines"
(I have no commercial affiliation to Classic Valve FYI... although if I did, I could be making hella money on every $9 board sold! -j/k-).
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This is measured by putting multimeter leads directly into the power cable that would ordinarily be plugged into the BeePre. Ground is the power ground, (-) is one of the AC leads that isn't the one which gives me a reading of ~114V. So that measurement is power coming out of the wall, without the BeePre in the picture at all....
This is measured by putting multimeter leads directly into the power cable that would ordinarily be plugged into the BeePre. Ground is the power ground, (-) is one of the AC leads that isn't the one which gives me a reading of ~114V. So that measurement is power coming out of the wall, without the BeePre in the picture at all....
Thanks - that helps narrow it down a lot.
You are measuring what is called by electricians the voltage between neutral and ground. That is a lot of noise for that measurement, though sadly not at all uncommon :^( The usual solution is to have a separate circuit for the technical gear - not always practical though. An alternative is an isolation transformer, preferably with a noise filter as well.
114v is unusually low; we have seen some hum problems with low line voltage into BeePre. That issue is normally not sensitive to other noise sources on the same power system, so I can't say that's what is going on, but if you should get an isolation transformer, look for one that can step up the voltage a bit.
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a reading of ~114V. So that measurement is power coming out of the wall
Call your power utility and complain, they may be able to bump you up to 120V.
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Very helpful, folks. I'll try some things this week and report back here.
A little irritating: the power issues coming out of the wall disappeared yesterday, which makes diagnostics a bit tricky. :)
S,
ALR
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Suggests it migh be industrial - closed on the weekend. Or a neighbor on vacation?
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Thought this may be helpful in describing my power issues. :)
https://www.youtube.com/watch?v=WRm5s846-vI
Similar to anyone? Note that in this video I've attempted to introduce a TrippLite Isolating Transformer, which has not helped (in some ways makes it worse, as evidenced by the now-pulsating sound as shown in the video).
Do we know what is causing this, and how I might rectify (excuse the pun) it?
S,
ALR
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What kind of lights are the outdoor lights?
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Incandescent, old-school "Edison" ones. Is that relevant? I thought the deal was in trying to isolate the power to be "clean"? Which I thought the isolating transformer was supposed to do, no? Or does that not buffer against a ground loop?
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Andrew,
So, no noise till you turn on the outside lights. Then pulsing and it continues even after the lights are turned off. Sounds like some oscillation is set up. But usually oscillation is high frequencies.
I think the type of lights you DO have will deepen the mystery. Dan (Doc) expected something that normally generates noise like Quartz or LED.
Is there anything else on the outside light circuit other than the incandescent lights?
Do you have the BeePre input selected shorted?
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You might try measuring the wall outlet voltage while you turn the lights on to see if there is a significant change. Are the lights just connected to a regular switch, or is there maybe a motion detector circuit or a timer or something else incorporated with the lights?
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So, no noise till you turn on the outside lights. Then pulsing and it continues even after the lights are turned off. Sounds like some oscillation is set up. But usually oscillation is high frequencies.
Actually, there is a hum there without the lights that this particular recording didn't pick up so well; sometimes it's much louder.
I think the type of lights you DO have will deepen the mystery. Dan (Doc) expected something that normally generates noise like Quartz or LED.
Just incandescent.
Is there anything else on the outside light circuit other than the incandescent lights?
Yep: the LED television (which when on can also increase the humming volume) and other misc A/V things.
Do you have the BeePre input selected shorted?
I'm not sure what this means? The buzzing is not affected by the BeePre input selector, balance, or volume pots.
S,
ALR
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You might try measuring the wall outlet voltage while you turn the lights on to see if there is a significant change. Are the lights just connected to a regular switch, or is there maybe a motion detector circuit or a timer or something else incorporated with the lights?
Yeah, turning on anything else on that circuit will drop the voltage a bit. At rest, 118V. With outdoor lights on, 115V. With outdoor lights, amp and preamp all on, 114V. Measurements taken from the leads on the power input of the BeePre.
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Are those voltages measured with the Tripplite in the circuit?
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Are those voltages measured with the Tripplite in the circuit?
Yup.
Worth noting; the TrippLite apparently doesn't isolate the neutral output, only the hot:
Amazon review: "Unfortunately this product has the output neutral line tied to ground"
S,
ALR
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Andrew,
You had said that there was hum but the laptop speakers didn't produce it.
Many digital devices put noise onto the ac line. The isolation transformer will give you isolation but not eliminate it.
A selected open input can pick up noise. So for testing you take jumpers and jump the right hot to the right ground, the left hot to the left ground at the RCA jacks. This eliminates a source of noise.
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Are you getting the same voltage at the outlet with or without the Tripplite in there? I'm thinking you are, but thought I'd better make sure. I'm kinda with PJ that this could be an issue of low voltage at the outlet creating a regulator issue in the BeePre. Can you get the voltage to come up at all if you turn off everything except the amp and preamp? That drop from 118 to 115 or 114 seems pretty big for just a couple pieces of audio gear. I wonder if there is a connection in the house wiring that is less than perfect and creating some resistance. The fact that the outside lights are on the same circuit as wall outlets is, well, it's as bad as my house! We have a furnace, washing machine, microwave and some lights on one circuit. Completely stupid, and you would think I would do something about it besides go downstairs, turn off the washer and reset the breaker every time somebody turns on the microwave the when the washer and the furnace are running.
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If you have less than positive contact in your light and outlet circuit you should get an electrician (licensed and insured) to come in and make all the terminations over. The terminations at the outlets should be on the screws not the pins inserted from the rear of the outlets.
Dan, any molded case breaker that has tripped 6 times is no longer tripping at the name plate value. It should be replaced. They work on a bi-metalic strip that anneals and changes its value after a half dozen trips.
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Thanks Grainger, I should indeed replace it and reroute some of the cap appliances on the circuit.
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I concur that some inspection is in order.
I thought I was being all Mr. Handyman when I put a new microwave/range hood in, but the circuit feeding it also does my bathroom lights.
On the plus side, I know when my coffee is finished being reheated while I'm in the shower.
-PB
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I'd never give you advice on house wiring but the circuit breaker advice came from my buddy Ron. He has worked for Square D, Cutler-Hammer and ITE/Siemens in the molded case breaker divisions. I've replaced several since receiving that advice.
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Eight years ago, I bought my house that was constructed in 1930. To cut to the chase, EVERYTHING from the power transformer to the circuit box, and even a dedicated line was replaced, not to mention every outlet in the house. Even after all that, I found the best relief from first buying a large isolation transformer with 8 separate secondary windings and using a PS Audio P500 on one of those windings to do the rest. Almost everywhere I have lived has had to one degree or another, voltage/noise problems. You have to start somewhere, and more often than not, I find loose connections and more in one or more electrical outlets. You might start with this thinking and work your way back.
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A similar experience. I'm active duty Navy and move every three or so years. The best piece of gear I own is a PS Audio Premier Power Plant. Constant dependable 120v output no matter where I've lived including Japan! Having clean power makes a large sonic improvement.
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I'm running all my analog pieces on an old, first product, PS Audio P300. It is fed from my wall outlet.
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I had serious noise issues with my BeePre. After sleuthing, I realized that my AC voltage at that plug got down to 116V at times. At the breaker box, 120V, but lots of loss through all the wire nut connections and distance with a large current draw device (plasma TV) on the circuit. I did buy some silver conduction 'grease' but never got around to putting it on all the connections on that circuit.
In the end, I threw $$ at the problem and bought a PS Audio regenerator to get Ultra clear 120V and my BeePre has been very happy ever since.
Its a bit scary that houses can have so much resistive loss in the wiring.
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I also had noise problems related to my plasma tv. I couldn't find the cause until I noticed that the noise went away when switching channels. The noise did not start until the tv is on for some time so there must be some kind of noise buildup going on. I switched the wall connections around which seems to have solved the problem.
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My voltage is low (as low as 112V) in my listening room also as its on the same circuit as the family room plasma tv and has the longest wire runs in the house. The Bee Pre does not like lower voltage I have found. Re-wiring house circuits is expensive, so my about-as-expensive-but -better option was to buy a PSAudio power regenerator. Now I have ultra-clean, fairly low impedance 120V and very happy audio gear.
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I'm living in the Netherlands, and my Beepre struggles with the power (230v), the wallsockets deliver, to. When the voltage drops i'm getting some terible hum in my left channel. I already tried a small powerconditioner from furman. This device only filterd incoming power from hf noise. This didn't helped that much, so i send it back. I'm reading on this topic about the AC regenerators doing a marvelous job. Unfortunately such a device is way out of my reach pricewise. Nearly €5000,- is a really big investment.
Maybe i found a budget solution. What if one uses a DC-AC converter, the devices uses in caravans and motorhomes to connect home equipment to a 12v or 24v DC source. There are ones availble producing pure sine wave output at 230V. Connect one to a 12v DC supply so no batteries are needed.
I already orderd one of these devices and going to try this out soon. What are your thoughts on this. Is it actually a good idea or can i harm my equipment?
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If your line voltage varys that much. How about using a Varic to supply it? They are not that expensive and you can dial in the voltage of the day...John
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It looks as if the voltage standard for supply in the Netherlands is 230v +6%/-10% so in theory any equipment sold there should perform to spec within these limits. Perhaps the BH stuff can be considered a special case but I would have though it would be well within those parameters and therefore work without problems. Perhaps a comment from Doc would enlighten.
We are supposed to get a nominal 230v in the UK +10%/-6%, % the other way round, and I believe it is generally close to 240v.
I think the same power transformer is supplied to UK and the rest of Europe?
If you are suffering due to low volts I don't think a variac will help as the max it can supply is the voltage it's being fed.
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Most variacs will go up to a bit over the input, maybe 10% or so(?)
Those asymmetrical voltages disguise the reality, which is that originally the UK was on 240v, the Netherlands was on 220v. In order to have a single EU standard , the Eurocrats split the difference (230v) with a tolerance allowing each country to keep their original power generators. If you live in or near the EU, you are well aware of the bureaucratic difficulties involved!
In the early days of Bottlehead, our European customers were almost entirely from the UK, so we just made 240v transformers. We are gradually switching to transformers with semi-universal windings. By "semi-universal" I mean to include the varieties of "230-v" but not include Japan which is on 100v.
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good news for the new builders !! any chance we first comers from the continent could get a couple new transformers ? about one day in three, i get closer to 215/220 out of the french network, and some buzzing... what do you think ?
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Goodevening fellow Bees,
Trying DC-AC converter didn't help. It made the hum always present. Obvious because it converted exactly 230V, which is lower than power from my wallsocket most of the time.
I just found a nice deal on a variac (0-260v). Hope to receive the transformer soon so i can transform my own 240V :D I'll let you know if this is a solution to my humming problem.
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Finally found a solution for my hum problem. A variac which cranks up the voltage a bit is doing the magic. Very glad this solves the insufficient power condition in my case. Since the variac is providing the power there is a small hiss only the left Channel. At reasanoble listing volumes this is neglectable.
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If anyone else is following this, I can recommend the following part:
http://www.mouser.com/ProductDetail/Bel-Signal-Transformer/DU-1-2/?qs=sGAEpiMZZMsF1ODjcwEocH9a7K7rGcVvS%252b%252bhynsdO1Q%3d (http://www.mouser.com/ProductDetail/Bel-Signal-Transformer/DU-1-2/?qs=sGAEpiMZZMsF1ODjcwEocH9a7K7rGcVvS%252b%252bhynsdO1Q%3d)
It would work for both older homes in the US sitting closer to 110 or 115V, as well as sub 230V outlets abroad.