Should I add balanced power (buzz)

doctorcilantro
doctorcilantro Posts: 2,028
edited October 2013 in Electronics
I have found a nasty ground loop sounding buzz, but it is actually my dishwasher! On the fence about what to do. One thought is to add a cheaper isolation transformer, but I wouldn't mind my tube gear on regenerated AC

The noise floor of my tube amp with shorting plugs is quiet a bit quieter than running DAC in, and dishwasher off. I feel there is still improvement to be made, even after getting the dishwasher out of the picture.

I have a small 100w AC regenerator for my DAC(s)/Preamp.

Problem is I can not connect my tube amp to it.

Considering a larger regenerator or isolation transformer.

Question - does the AC>DC>AC process of the regenerators effectively isolate it from circuit?

thanks for your thoughts!
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  • thsmith
    thsmith Posts: 6,082
    edited October 2013
    I used to use an Enterprise server regenerator which addressed several problems but not ground hums. Maybe different regenerators will but not in my case.
    Speakers: SDA-1C (most all the goodies)
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  • doctorcilantro
    doctorcilantro Posts: 2,028
    edited October 2013
    This is a crazy buzz, not really a 60hz hum. It would suck to add a fancy PS Audio P3 and have this get through. I should email them.

    My buddy just told me about Signal transformers, and DIY in a small box. Signal DU-3, DU-5, or DU-7.
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  • drumminman
    drumminman Posts: 3,396
    edited October 2013
    I've been using a signal DU-3 on my power amp, and a DU-1/2 on my digital front end for several years. I bought both on ebay and wired them for balanced power according to Jon Risch's instructions on AA.

    I don't know that I can answer your question, but I can say that they vastly improve the sound of my rig. Because wiring for balanced power reduces the capacity by half, the DU-3, normally rated for 3000 watts, is now "only" 1500 watts. It may be slightly anemic for my situation, but I don't hear signs of it being starved for power. When I plug the PA directly into the wall it doesn't sound as good.

    I have my CDP and DAC on the DU-1/2, which is 250 watts. Prevents digital hash from being put back into the AC, cleans up the sound a bit as well.

    I have lamp with an add on dimmer switch plugged into the same circuit, and I've never heard a difference in noise with the light on or off. These are notorious for introducing buzz into an audio system. The balanced trannies must be doing their job.
    "Science is suppose to explain observations not dismiss them as impossible" - Norm on AA; 2.3TL's w/sonicaps/mills/jantzen inductors, Gimpod's boards, Lg Solen SDA inductors, RD-0198's, MW's dynamatted, Armaflex speaker gaskets, H-nuts, brass spikes, Cardas CCGR BP's, upgraded IC Cable, Black Hole Damping Sheet strips, interior of cabinets sealed with Loctite Power Grab, AI-1 interface with 1000VA A-L transformer
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  • Speedskater
    Speedskater Posts: 495
    edited October 2013
    Solving interference and noise problems is better done at the source.
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  • doctorcilantro
    doctorcilantro Posts: 2,028
    edited October 2013
    Speedskater wrote: »
    Solving interference and noise problems is better done at the source.

    Indeed, so I messed with the dishwasher and regrounded it seems have lessened the noise.

    AC outlet is correct polarity, with .5v between neutral and ground.
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    Zu Union Cubes
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  • Polkie2009
    Polkie2009 Posts: 3,834
    edited October 2013
    Wouldn't a dedicated circuit for your amp take care of the problem?
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  • doctorcilantro
    doctorcilantro Posts: 2,028
    edited October 2013
    Polkie2009 wrote: »
    Wouldn't a dedicated circuit for your amp take care of the problem?

    What is a dedicated circuit?

    The ground is being shared at the panel even though there is technically nothing but the amp in the 20a circuit (noise comes through when DAC is disconnected).

    From what I gather is you can't juts isolate the ground to Earth on this one circuit either, the whole point is to go back to breaker that will trip.
    For Sale 2019:
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    Decware EL34 amp
    Allnic H-1201 phono
    Zu Union Cubes
    iFi iDSD DAC, .5m UBS, iFI Gemini cable, Oyaide Tunami XLR 1.3M, Oyaide Tunami Speaker wire 1.5M, Beyerdynamic DT1990 headphones, PS Audio P3 power center

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  • SCompRacer
    SCompRacer Posts: 8,500
    edited October 2013
    doctorcilantro wrote: »

    From what I gather is you can't juts isolate the ground to Earth on this one circuit either, the whole point is to go back to breaker that will trip.

    That sounds like a GFCI circuit breaker. I use two for the whirlpool heater/pump circuit in the master bath. Like this?

    gfci-circuit-breaker-wiring.gif


    A dedicated circuit just serves a single appliance or your two channel rig without sharing its power connection with other outlets and lighting circuits. I have two 20 amp circuits for my audio system.
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  • doctorcilantro
    doctorcilantro Posts: 2,028
    edited October 2013
    Interesting!

    I checked my disposal and it runs into a GFCI.

    I need to verify where the wiring actually goes as I haven't been able to fully pull out the dishwasher; I'm guessing it runs direct back to the breaker and not a GFCI.

    thanks
    For Sale 2019:
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    Decware EL34 amp
    Allnic H-1201 phono
    Zu Union Cubes
    iFi iDSD DAC, .5m UBS, iFI Gemini cable, Oyaide Tunami XLR 1.3M, Oyaide Tunami Speaker wire 1.5M, Beyerdynamic DT1990 headphones, PS Audio P3 power center

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  • doctorcilantro
    doctorcilantro Posts: 2,028
    edited October 2013
    I had some guys make a 240v outlet for a microwave since our 110v micro broke. I wonder if this has something to do with my problems. Maybe the 2 phases can now interact more?

    Electricians coming tomorrow.
    For Sale 2019:
    Tortuga Audio LDR passive preamp
    Decware EL34 amp
    Allnic H-1201 phono
    Zu Union Cubes
    iFi iDSD DAC, .5m UBS, iFI Gemini cable, Oyaide Tunami XLR 1.3M, Oyaide Tunami Speaker wire 1.5M, Beyerdynamic DT1990 headphones, PS Audio P3 power center

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  • Speedskater
    Speedskater Posts: 495
    edited October 2013
    The two 120Vlegs come from the same power company 240V center-tapped power transformer so they are always linked together. More likely (as often happens) the Neutral and the Safety Ground are connected together at a 240V appliance.
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  • Glen B
    Glen B Posts: 269
    edited October 2013
    doctorcilantro wrote: »
    I have found a nasty ground loop sounding buzz, but it is actually my dishwasher! On the fence about what to do. One thought is to add a cheaper isolation transformer, but I wouldn't mind my tube gear on regenerated AC

    The noise floor of my tube amp with shorting plugs is quiet a bit quieter than running DAC in, and dishwasher off. I feel there is still improvement to be made, even after getting the dishwasher out of the picture.

    I have a small 100w AC regenerator for my DAC(s)/Preamp.

    Problem is I can not connect my tube amp to it.

    Considering a larger regenerator or isolation transformer.

    Question - does the AC>DC>AC process of the regenerators effectively isolate it from circuit?

    thanks for your thoughts!


    Try a plug-in noise filter before you do anything else. The filter goes between the dishwasher and outlet.

    http://www.smarthome.com/4845ACF/Advanced-Control-Technology-AF120-15-Amp-Plug-In-Noise-Filter/p.aspx
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  • Glen B
    Glen B Posts: 269
    edited October 2013
    Speedskater wrote: »
    The two 120Vlegs come from the same power company 240V center-tapped power transformer so they are always linked together. More likely (as often happens) the Neutral and the Safety Ground are connected together at a 240V appliance.
    The ground and neutral bus bars are bonded together at the service panel. A 240V appliance has no neutral, only hot/hot/ground, therefore no neutral/ground connection at the appliance. Neutral and ground are never supposed to be connected together anywhere but at the service panel.
    Main System: Denon DP-59L | Audio-Technica AT33EV | Marantz SA-11S2 | Classe DR-10 | Classe CA-300 | Classe RC-1 | PSB Stratus Gold i's | DIY Balanced AC Power Conditioner | Acoustic Zen and NeoTech cables | Oyaide and Furutech power connectors | Dedicated 20A isolated ground line.

    Home Theater: Toshiba D-VR5SU | Laptop #1 |Outlaw Audio OAW3 wireless audio system | Marantz SR-19 | Phase Linear 400 Series 2, modified | AudioSource 10.1 EQ (for subs) | Axiom M3 v3’s | Axiom VP150 | Optimus PRO-X55AVs | Dayton 12” powered subs (x2) | Belkin PureAV PF-60 line conditioner.

    Party System: Laptop #2 | Audioquest Dragonfly USB DAC | Technics SU-A6 | Acurus A-250 | Radio Shack 15-band EQ | Pioneer SR-9 reverb | Cerwin Vega DX9's | Dayton 100° x 60° horns with titanium HF/MF compression drivers.
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  • doctorcilantro
    doctorcilantro Posts: 2,028
    edited October 2013
    Glen B wrote: »
    The ground and neutral bus bars are bonded together at the service panel. A 240V appliance has no neutral, only hot/hot/ground, therefore no neutral/ground connection at the appliance. Neutral and ground are never supposed to be connected together anywhere but at the service panel.

    We opened the panel, electrician and I, and I took pictures.

    When I measured the wiring coming out of wall for dishwasher it found what seemed to be 2 hot wires and a ground. One of these hot wires goes to chassis. Dishwasher says 120V (of course I can find no info online about the model!):
    • MwqfoaLl.jpg

    Today, I put a cheater plug on the amp for testing only, hooked it up to an AC regenerator, and turned on the dishwasher.

    A loud buzz comes out of the speakers when dishwasher is running.

    At this time, I measured 20V AC across chassis of DAC to + Rachel binding post, 30V AC across AC Regenerator chassis to + Rachel binding post, and 3v from chassis of Rachel to + Rachel binding post. Trying to measure DC just kept rising.

    Also , the noise filter just mentioned appears to only filter noise above 80kHz, and this buzz is very audible.
    • rftE33Fl.jpg
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    • kVlytjdl.jpg
    For Sale 2019:
    Tortuga Audio LDR passive preamp
    Decware EL34 amp
    Allnic H-1201 phono
    Zu Union Cubes
    iFi iDSD DAC, .5m UBS, iFI Gemini cable, Oyaide Tunami XLR 1.3M, Oyaide Tunami Speaker wire 1.5M, Beyerdynamic DT1990 headphones, PS Audio P3 power center

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  • Speedskater
    Speedskater Posts: 495
    edited October 2013
    Glen B wrote: »
    The ground and neutral bus bars are bonded together at the service panel.
    Very true!
    Neutral and ground are never supposed to be connected together anywhere but at the service panel.
    Very true!
    A 240V appliance has no neutral, only hot/hot/ground, therefore no neutral/ground connection at the appliance.

    Now on this I disagree.

    I believe that some appliances also have 120V sub-circuits (like receptacles).

    In electrical forums, I often read about appliance outlet boxes being mis-wired. I also read about the challenges of choosing and wiring 240V receptacles.
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  • doctorcilantro
    doctorcilantro Posts: 2,028
    edited October 2013
    Someone told me the bonding screw should be removed! Doesn't make sense to me. how would neutral dump to ground?

    I need to get this evil dishwasher out of here. I will wash dishes by hand with audiophile rubber gloves.
    For Sale 2019:
    Tortuga Audio LDR passive preamp
    Decware EL34 amp
    Allnic H-1201 phono
    Zu Union Cubes
    iFi iDSD DAC, .5m UBS, iFI Gemini cable, Oyaide Tunami XLR 1.3M, Oyaide Tunami Speaker wire 1.5M, Beyerdynamic DT1990 headphones, PS Audio P3 power center

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  • Speedskater
    Speedskater Posts: 495
    edited October 2013
    The Neutral and the Safety Ground must only be connected together at one point and that point is the Service Entrance area. When current flows through the Neutral, there is a voltage difference from one end of the wire to the other end. No current ever flows through the Safety Ground wire so both ends remain at zero volts. When the Neutral and the Safety Ground are connected at a load, the Safety Ground voltage will vary with the Neutral current.
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