Author Topic: No ground and Balanced Combination  (Read 217 times)

Offline dflee

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No ground and Balanced Combination
« on: October 28, 2021, 08:31:30 AM »
I've got an older home that has solid copper wire (vs strand). This stuff is incredibly stiff with just hot and neutral.
Does this effect the audio system such that thinking about trying balanced is not worth it.The dac (MF M1), pre (Accuphase C11) and amp (MF M6sPRX) all seem to be truly balanced.

Thanks
Don
« Last Edit: October 28, 2021, 01:26:44 PM by dflee »
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Offline rollo

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Re: No ground and Balanced Combination
« Reply #1 on: October 28, 2021, 01:08:01 PM »
  Still grounded though Neutral.


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Offline Folsom

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Re: No ground and Balanced Combination
« Reply #2 on: October 28, 2021, 04:28:00 PM »
It has hardly any affect in a home stereo. Most of them might be positive.

Offline steve

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Re: No ground and Balanced Combination
« Reply #3 on: October 28, 2021, 07:05:51 PM »
Personally, I would not waste my time with balanced as I can completely dial out any 60hz hum, if any is present.

Second, any imbalance in a "balanced" tranny or circuitry causes its own problems 

Third, the balance created deteriorates with time, especially due to capacitors, transistors integrated chips, and other SS parts etc.

Fourth, I have already demonstrated a near perfect SE design amp, and perfect SE preamplifier design

Fifth, the cost of balanced designs

Of course there are other SE designs that might benefit from being balanced.

As far as grounds, pin 1s; If two components use a pin 1, there will be left and right channel musical signal return 
through the pin 1 wires from component to component. This will mix both left adn right channels together to some extent. Companies should design to minimize mixing under such conditions. Virtually none do.

With that said, using just one component with pin 1 ground wire will basically prevent L&R mixing from occurring. Just make sure when eliminating pin1 from a component that it is designed to be totally safe under that condition.

I would always connect the interconnects before plugging in the power cords, just to be safe.

cheers

steve
« Last Edit: October 28, 2021, 07:32:21 PM by steve »
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Offline Folsom

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Re: No ground and Balanced Combination
« Reply #4 on: October 28, 2021, 07:26:16 PM »
I agree that I think balanced is a waste. But as far as the ground it really doesn't matter for that factor in home audio.

Offline tmazz

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Re: No ground and Balanced Combination
« Reply #5 on: October 28, 2021, 08:52:46 PM »
Don, your wiring is 2 conductor, but what kind of cable is it? If it is BX or armor coated wired the metal armor around the conductors is very possibly being used as the path for the safety ground.

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Offline steve

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Re: No ground and Balanced Combination
« Reply #6 on: October 28, 2021, 10:34:51 PM »
I agree that I think balanced is a waste. But as far as the ground it really doesn't matter for that factor in home audio.

With most stereo systems and venues, I think you are correct Jeremy. But I know my system and other very high end systems would reveal such.

It all depends upon the quality of the overall system, layout of pc board or hardwiring, qualities of the
interconnects (ics), pin 1 wires. I find it interesting that one virtually never sees a channel separation spec
at, say 10khz and 20hz. I wish all manufacturers would.

For general consumption.

Any bleed through from one channel to another (say Right & Left) will cause a spacial deviation. Besides that, the other channel is amplifying the unwanted bleed through signal, thus adding to the power output. The actual frequency response in stereo mode is actually different from the single channel spec (usually right channel) one typically sees
in the specs. That is why channel separation specs are so important. It is a good reason why different manufacturer's models and products sound different.

(Usually, bleed through occurs in the highest frequency spectrum and lowest; so the highs will sound tinny, thin, maybe even harsh while the bass might be overdone, bloated, masking midrange inner detail.)

Another problem concerns two stereo components utilizing the AC line cord ground wires (pin 1 wires). The ground wires are another musical signal current return path along with both interconnect cable (ic) shields. So there are three paths total. Eliminating one pin 1 wire basically eliminates this third path.

(For two stereo components using a pin 1 connections.)

If the resistance and inductances for L, R ic shields, and pin 1 ground wire are equal at X frequency, 1/3 of R return musical signal current would flow through R shield, 1/3 would flow through L shield, and 1/3 through pin 1 path from component to component. Same if we looked at L signal return; 1/3 would flow through L shield, 1/3 would flow through R shield, and 1/3 would flow through pin 1 ground wire from component.

Channel mixing occurs in all three signal return paths. Yet virtually no one addresses this problem unless they are building monoblocks. I have seen, on numerous occasions in DACs, that the R and L output jacks use the same ground lead. Not good.

I performed an experiment 30-40 years ago using a single ground wire to connect two right channel input jacks and a single ground wire to connect two left channel jacks. The 18 gauge ground wires were only 6 inches long.

The selector switch was set to the CD position and was not playing, and a tuner was power on to a station. One could hear the tuner while seated 20 feet away. (I have performed other experiments over the years.)

When I switched to one ground wire to each jack, there was no hint of sound even with my ear "on" the speaker cone. Imagine a meter or two length shields/pin 1 wire instead of 6 inches. 

I think this is yet another example that a wire is not just a wire, even in an audio sense.

cheers

steve

« Last Edit: November 06, 2021, 10:23:32 PM by steve »
Steve Sammet (Owner/Designer, SAS Audio Labs, Ret)
"V" 40pf 1 meter 6N Pure Copper Wire ICs,
SAS Audio Labs Test Phono Stage
SAS 11A Perfect Tube Preamplifier
SAS 25 W Near Perfect Reference Triode/UL Monoblocks
2 way test Spkrs, 28hz -3db, to 20khz