Ground Loops and Proper Grounding by FM Acoustics

[Alrainbow]

I think low power isolation transformers are not good. For most solidstate audio systems it seems the Isolation transformer should be over 20KVA (150kg).
there are some UI isolation transformers from Dantrafo Group (Denmark) and it seems Wavac uses Denkenseiki (Japan) transformers.
I am thinking about using both of them and check the result.

It seems not all isolation transformers are good for sound but it seems the good isolation transformers have least negative effects on the sound.

Romy, David and some others do not like the sub-bass quality of isolation

the iso for signal is to me a well worth try
the power isolation is not always beneficial I feel.
but this alone is debatable.
I agree with you it’s not always better this is why signal iso should be first and will have simple A/B testing to be heard.

 

[DasguteOhr]

This is incorrect.

The device then has a drain path to the circuit breaker. Whether or not the ground is exposed with insufficient insulation to AC voltages depends on compliance of the connecting device (which may not have any AC voltages). You did not open a path to AC voltage. You didn't even open a path to ground if it's to enclosure. You don't invalidate insulation internally by touching the outside. If you did then touching something grounded then touching a TAD device would fucking floor you as electricity wrecked you going through arms and possibly across heart to dead you. We know that does not happen.

Very nicely explained, but with protection class II it is forbidden to connect the housing or interior to earth. otherwise the ground contact would not be missing from the mains IEC socket.
P.S
In addition, it is not a good idea to connect the earth contact (mains )to the signal ground because the power grid is not clean.

 

[Folsom]

Very nicely explained, but with protection class II it is forbidden to connect the housing or interior to earth. otherwise the ground contact would not be missing from the mains IEC socket.
P.S
In addition, it is not a good idea to connect the earth contact (mains )to the signal ground because the power grid is not clean.

"Forbidden" not really. No regulatory body or court is going to complain if you made a device double insulated and grounded the outer enclosure for extra safety. Connection of earth to certain areas of internals would declassify it as class II, but you can't expose connections on the external that could violate this by touching ground or it wouldn't be Class II.

It's actually pretty standard practice for a + and - rail device to have the ground (mid between + and -) connected to safety earth. How varies. Many like to use parallel resistor and capacitor. But tube guys often just star ground literally everything to one point. The problems you run into is mixing gear with different approaches and especially with poorly grounded turntables, as far as loops.

But I'd agree in general that anything that can be Class II should be... safety ground (earth after the panel) is a nuisance.

 

[wil]

In addition, it is not a good idea to connect the earth contact (mains )to the signal ground because the power grid is not clean.

I just read that most audio components are designed with chassis and signal ground connected.
Doesn’t the chassis ground (and connected signal) connect to earth ground (and the power grid)?

 

[DasguteOhr]

I just read that most audio components are designed with chassis and signal ground connected.
Doesn’t the chassis ground (and connected signal) connect to earth ground (and the power grid)?

Most of it have ground lift switch to break ground loops that mostly not perfect(resistor +cap).
Better way
For specified components with asymmetrical inputs and grounding regulations due to metal housings, there is often a solution that consists of placing two diodes connected in opposite directions between the ground connection (conductor to the Schuko plug) and the chassis. For safety reasons, they must be designed so that in the event of a fault they can trigger a standard 16A circuit breaker, ideally without causing any damage themselves. I usually use 25A diode bridges that can be screwed onto the chassis with a short circuit between plus and minus. Protective ground and chassis go to the two AC power connections. The meaning then is that induced ripple voltages in the protective conductors of up to around 1 V do not provoke any currents on the shields of the signal cables. Incidentally, this solution can also be seen in very high-quality HP measurement technology.

Then you just have to route the signal cables so that the areas of the ground loops that form between the shields remain small.

 

[Alrainbow]

I just read that most audio components are designed with chassis and signal ground connected.
Doesn’t the chassis ground (and connected signal) connect to earth ground (and the power grid)?

Exactly why most have noise
This is why I said try a iso isolator on input to a preamp
The preamp has the most gain next to a phono preamp
Any noise at source gets amplified on proceeding gain stages

 

[wil]

Exactly why most have noise
This is why I said try a iso isolator on input to a preamp
The preamp has the most gain next to a phono preamp
Any noise at source gets amplified on proceeding gain stages

I assume we’re talking about high frequency noise riding with the signal (not ground loop hum)?
What type of iso would you recommend for a pre amp? Have you experimented with any “ground box” implementations?

 

[Alrainbow]

Jensen Transformers - High performance audio transformers and ground isolators.

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www.jensen-transformers.com

What I meant is dc ripple and AC offset due to internal power supplies.
This is not really noise per se but does affect the sound in various ways.
Hum is common, but even if no hum is heard
Dynamics and top end sound is still effected.
There are many types shown in there catalog
I’ve used a combo se and bal iso so I can choose what type of cables.
it has dip switches on the bottom to configure the type of isolation you want to try.
They work every well , now they come in 3 different types
1- short cable on input side meaning must be close to device output
2- long cable on input meaning its output is close to input of next device
3- anywhere meaning both of above
They are not very expensive, there are companies who make more expensive ones.
This company makes many kinds of audio devices
I’ve used there SUT, s for phono carts too. the SUT, s are hit and miss for a few reasons.

 

[Alrainbow]

I don’t know why that link is in another language lol. Sorry

 

[Amir]

after room EMI/RFI shielding I will go for three separate Denkenseiki 10KVA isolation transformer :

https://www.denkenseiki.co.jp/products/nct-g_1kva/

 

[Folsom]

huh? What shielding? Why use an isolation transformer?

 

[matthias]

In my unbalanced set-up it is so easy to get the grounding right. I just apply some basic principles, no isolation transformers or grounding devices necessary for great sound.

Matt

 

[Solartiger]

I am running balanced interconnects and have a 3 phase main DB with solar inverters and battery backup.

All hifi plugs are on the same phase. Only consumers that are usually off in the evening share that phase.

I have a separate massive copper matt as the earth point for the hifi system. It provides the earth for the hifi power plugs and for the components that have a separate earth connection. From the main DB I only use neutral and phase and not earth. The hifi earth point has a separate massive copper connection to the main DBs earth point.

The power amps are connected directly to a separate hifi mini-DB board. The rest of the system is using a Gigawatt EVO4 power conditioner which is also connected to the hifi DB board, but with a separate power feed from the main DB.

Only one of the components (pre-amp) linked with XLR balanced interconnects is connected with the housing to earth. The system is very quiet without any hum, hiss or static, even in high volume. The system consumes 2.300W .

 

[Amir]

huh? What shielding? Why use an isolation transformer?

Room EMI/RFI shielding . There are so much RF pollution in my area.

my system has no hum no noise no extra harmonics in the loudspeaker .
I use isolation transformer before pure power 3000 AC regenerator.
My apartment is in a big complex (200 apartments shared) and the AC quality is awful.
I just test and I have no idea about the result.
The AC quality is very bad compared to a 20KVA UPS . The dc offset is also very high on my AC power.

 

[Amir]

I am running balanced interconnects and have a 3 phase main DB with solar inverters and battery backup.

All hifi plugs are on the same phase. Only consumers that are usually off in the evening share that phase.

I have a separate massive copper matt as the earth point for the hifi system. It provides the earth for the hifi power plugs and for the components that have a separate earth connection. From the main DB I only use neutral and phase and not earth. The hifi earth point has a separate massive copper connection to the main DBs earth point.

The power amps are connected directly to a separate hifi mini-DB board. The rest of the system is using a Gigawatt EVO4 power conditioner which is also connected to the hifi DB board, but with a separate power feed from the main DB.

Only one of the components (pre-amp) linked with XLR balanced interconnects is connected with the housing to earth. The system is very quiet without any hum, hiss or static, even in high volume. The system consumes 2.300W .

What is the size of Massive copper matt ?
Could you send me a picture?
What is the benefit of copper matt?

 

[Solartiger]

Copper earth mat

We put a pipe system above the mat to be able to water the earth in dry summers.

Joining the earth mat, the ground wires and the connection to the main DB earth. The screw has been replaced with a copper one.

Everything ready, joining box and pipe for watering!

This is probably not very precise at this scale but it shows, the earth resistance is very low.

Because earth mats have so much contact surface with the soil, you get get a very, very low earth resistance. I have another earth point at the other side of the house, which is the main earth for the DB board, against lightning etc. The main earth uses a combination of an earth mat plus deep rods. The two earth points are connected with a separate thick earth cable (the trunking coming down into the join box).

 

[Folsom]

Room EMI/RFI shielding . There are so much RF pollution in my area.

my system has no hum no noise no extra harmonics in the loudspeaker .
I use isolation transformer before pure power 3000 AC regenerator.
My apartment is in a big complex (200 apartments shared) and the AC quality is awful.
I just test and I have no idea about the result.
The AC quality is very bad compared to a 20KVA UPS . The dc offset is also very high on my AC power.

I don't think room shielding is realistic.

Haven't found regenrators to be useful except in extremes. Considering changing the power cord running into one drastically changes the sound...

 

[wil]

Copper earth mat

We put a pipe system above the mat to be able to water the earth in dry summers.

Joining the earth mat, the ground wires and the connection to the main DB earth. The screw has been replaced with a copper one.

Everything ready, joining box and pipe for watering!

This is probably not very precise at this scale but it shows, the earth resistance is very low.

Because earth mats have so much contact surface with the soil, you get get a very, very low earth resistance. I have another earth point at the other side of the house, which is the main earth for the DB board, against lightning etc. The main earth uses a combination of an earth mat plus deep rods. The two earth points are connected with a separate thick earth cable (the trunking coming down into the join box).

That’s very low resistance at your earth ground. The best I could get was 8.0 ohms reduced from 80).

However, despite all my labors with my earth ground, I found no difference to the sound coming out of my speakers. I have a good safety ground anyway…

It appears to be a given that a low resistance earth ground will have sonic benefits, but does it really?

 

[Amir]

Copper earth mat

We put a pipe system above the mat to be able to water the earth in dry summers.

Joining the earth mat, the ground wires and the connection to the main DB earth. The screw has been replaced with a copper one.

Everything ready, joining box and pipe for watering!

This is probably not very precise at this scale but it shows, the earth resistance is very low.

Because earth mats have so much contact surface with the soil, you get get a very, very low earth resistance. I have another earth point at the other side of the house, which is the main earth for the DB board, against lightning etc. The main earth uses a combination of an earth mat plus deep rods. The two earth points are connected with a separate thick earth cable (the trunking coming down into the join box).

Nice Pictures

Thank you very much ?

 

[Amir]

I don't think room shielding is realistic.

Haven't found regenrators to be useful except in extremes. Considering changing the power cord running into one drastically changes the sound...

I have better sound when my car is -4 floor in parking area.
Lower EMI/RFI can help but I am not sure about how effective is it.

I had many power cords even very expensive, non of them is OK. Skogrand ac cables are very good, open and dynamics, Skogrand does not kill music energy . Maybe top level of Purist Audio AC cables be ok just for transport/dac .

If Pure Power (Richard) send me two 10KVA then I can use it.
One 10KVA pure power for one M700 (350w/ch)
One 10KVA pure power for other M700
One 3KVA pure power for CD and DAC and digital equipments
One 3KVA pure power for pre/phono

before all pure powers I will use isolation transformer.

Wall AC -> 4 Isolation transformer -> 4 Pure Power -> TAD System