DIY Ground Box Thread

[Jake2]

I need to do a little more reading, as, no surprise whatsoever, it seems the RF shielding behaviour of conductors - the mix of absorption loss vs reflection loss - the portion of the source/incident wave that is absorbed vs the portion that is reflected - is... complicated. It varies rather a lot with frequency and material thickness (skin-depth once again the culprit) as you can see from the graph below, which is copper. I need to find an equivalent for graphite.

Reflection loss btw is not the same thing as the similar sounding return loss in an RF transmission line context, indeed it's pretty much the opposite (return loss being the ratio of the incident wave to the reflected wave in dB, higher the better for lower internal reflections).

Copper sheet

https://www.sciencedirect.com/topics/engineering/absorption-loss​

Absorption loss - Tim Williams, in EMC for Product Designers (Fifth Edition), 2017​

Absorption loss depends on the barrier thickness and its skin depth and is the same whether the field is electric, magnetic or plane wave: that is, it doesn’t depend on the wave impedance, in contrast to reflection loss. The skin depth in turn depends on the barrier material’s properties; steel, for instance, offers higher absorption than copper of the same thickness, at the lower frequencies where its relative permeability is high. At high frequencies, as Figure 15.2 shows, absorption becomes the dominant term, increasing exponentially with the square root of the frequency. Appendix D (section D.4) gives the formulae for the values of A, R and B for given material parameters.

Graphite foil vs Aluminium & Steel


Absorption-dominant radio-wave (0.2–2.0 GHz) attenuation loss is comparatively reported for materials of high electrical conductivity, namely metals (aluminum and steel) and graphite. These materials exhibit similarly high absorption loss (≤ 91.5%) and similarly low reflection loss (≥ 8.5%), both as fractions of the total loss in dB. The absorption loss is high (< 55 dB) and the reflection loss is low (< 10 dB) for both graphite and the metals. The absorption-dominant attenuation loss of these high-conductivity materials is in contrast to the notion that high conductivity (due to the high impedance mismatch with air) generally causes reflection-dominant attenuation loss. The metals and graphite are in foil form, with the graphite being thicker than the metals. The linear absorption coefficient (directly related to the absorption loss per unit thickness) is lower for graphite (≤ 93 mm⁻¹) than the metals (≤ 394 mm⁻¹), due to the greater thickness of the graphite. The absorption loss and fractional absorption loss contribution increase with increasing frequency, whereas the reflection loss decreases, as consistent with electromagnetic theory. On the other hand, from the viewpoint of the fractional loss in power, reflection dominates over absorption for all three materials in the entire frequency range. For shielding, the metals are more effective than graphite if the absorption loss per unit thickness (< 3400 dB/mm) is considered. For stealth, graphite is advantageous to the metals in the low reflection loss, though it is disadvantageous in the low absorption loss per unit thickness.

What is interesting is although reflection loss (the portion of the signal that is reflected) is low for both graphite and the metals there's a 2-3db difference, the metals being more reflective. Expect graphite felt is even less reflective due to multiple internal ' bounces' and associated absorption opportunities whilst copper would be more reflective than aluminium as it seems to be proportionate to electrical conductivity.

 

[cdacosta]

I need to do a little more reading, as, no surprise whatsoever, it seems the RF shielding behaviour of conductors - the mix of absorption loss vs reflection loss - the portion of the source/incident wave that is absorbed vs the portion that is reflected - is... complicated. It varies rather a lot with frequency and material thickness (skin-depth once again the culprit) as you can see from the graph below, which is copper. I need to find an equivalent for graphite.

Reflection loss btw is not the same thing as the similar sounding return loss in an RF transmission line context, indeed it's pretty much the opposite (return loss being the ratio of the incident wave to the reflected wave in dB, higher the better for lower internal reflections).

Copper sheet

https://www.sciencedirect.com/topics/engineering/absorption-loss​

Absorption loss - Tim Williams, in EMC for Product Designers (Fifth Edition), 2017​

Absorption loss depends on the barrier thickness and its skin depth and is the same whether the field is electric, magnetic or plane wave: that is, it doesn’t depend on the wave impedance, in contrast to reflection loss. The skin depth in turn depends on the barrier material’s properties; steel, for instance, offers higher absorption than copper of the same thickness, at the lower frequencies where its relative permeability is high. At high frequencies, as Figure 15.2 shows, absorption becomes the dominant term, increasing exponentially with the square root of the frequency. Appendix D (section D.4) gives the formulae for the values of A, R and B for given material parameters.

Graphite foil vs Aluminium & Steel


Absorption-dominant radio-wave (0.2–2.0 GHz) attenuation loss is comparatively reported for materials of high electrical conductivity, namely metals (aluminum and steel) and graphite. These materials exhibit similarly high absorption loss (≤ 91.5%) and similarly low reflection loss (≥ 8.5%), both as fractions of the total loss in dB. The absorption loss is high (< 55 dB) and the reflection loss is low (< 10 dB) for both graphite and the metals. The absorption-dominant attenuation loss of these high-conductivity materials is in contrast to the notion that high conductivity (due to the high impedance mismatch with air) generally causes reflection-dominant attenuation loss. The metals and graphite are in foil form, with the graphite being thicker than the metals. The linear absorption coefficient (directly related to the absorption loss per unit thickness) is lower for graphite (≤ 93 mm⁻¹) than the metals (≤ 394 mm⁻¹), due to the greater thickness of the graphite. The absorption loss and fractional absorption loss contribution increase with increasing frequency, whereas the reflection loss decreases, as consistent with electromagnetic theory. On the other hand, from the viewpoint of the fractional loss in power, reflection dominates over absorption for all three materials in the entire frequency range. For shielding, the metals are more effective than graphite if the absorption loss per unit thickness (< 3400 dB/mm) is considered. For stealth, graphite is advantageous to the metals in the low reflection loss, though it is disadvantageous in the low absorption loss per unit thickness.

What is interesting is although reflection loss (the portion of the signal that is reflected) is low for both graphite and the metals there's a 2-3db difference, the metals being more reflective. Expect graphite felt is even less reflective due to multiple internal ' bounces' and associated absorption opportunities whilst copper would be more reflective than aluminium as it seems to be proportionate to electrical conductivity.

In the past and recently, I read many scientific papers or studies. Most of the studies were in the field of defense, space or nuclear. Because the absorption frequencies are so high, with audio the different material used causes differing effects depending on the shielding or absorption material used. Also the distance between the material used and the conductors. No way to tell unless it is put into real world testing. Shielding can cause this odd HF distortion or peaky-ness within the listenable audio frequencies. I theorize the peaky-ness in the HF frequencies is because of reflection. Generally only happens with reflective material. This is not my area of expertise, nor do I have the equipment to test. I am going by years of off and on experimentation building and trying to tweak cables.

 

[EDhaenens]

I notice new people are getting lost in this thread. Therefore I made a summary of what is in this thread from building a ground box to treating AC line with rochelle salt. This file can be updated when new things get discovered. Hope this helps

 

[Stellabagpuss]

Great idea with the attachment, l am guilty of trying for "Peak Salt", at least that's what l am telling the police.

 

[cdacosta]

Great idea with the attachment, l am guilty of trying for "Peak Salt", at least that's what l am telling the police.

Have you installed the Rochelle salt along the AC wiring junction points? If yes, your experience or how is it effecting what you hear? And how much of the AC line have you treated?

 

[Stellabagpuss]

Have you installed the Rochelle salt along the AC wiring junction points? If yes, your experience or how is it effecting what you hear? And how much of the AC line have you treated?

Just making 0.5 and 1gram bags first. l have 15 mains outlets and 2 light switches, so that's a lot of bags, and that dosent even included the 9 psu ,so l thought it would make sense to have plenty to had, in regards too how much ,l am following your method, Hot Live side 1grams, Earth 0.5grams.
Hopefully this is tomorrow's task

 

[cdacosta]

Just making 0.5 and 1gram bags first. l have 15 mains outlets and 2 light switches, so that's a lot of bags, and that dosent even included the 9 psu ,so l thought it would make sense to have plenty to had, in regards too how much ,l am following your method, Hot Live side 1grams, Earth 0.5grams.
Hopefully this is tomorrow's task

I look forward to reading your reaction to after treating the junction points. Your whole home only has 15 outlets and 2 light switches? Can't be, must be that circuit only.

 

[Stellabagpuss]

I look forward to reading your reaction to after treating the junction points. Your whole home only has 15 outlets and 2 light switches? Can't be, must be that circuit only.

My house is on a different spur, My listening room has its own powerline, it about 120 foot away in a separate building.So listening room first.
My plan is to work backwards towards the house, but because l live in a rural area, it has it's issues, we all share the same powerline, so l guess the more sockets you can treat the better,especially in noisy areas of your home,like kitchens, heating pumps and TVs..
l am looking forward to testing

 

[cdacosta]

My house is on a different spur, My listening room has its own powerline, it about 120 foot away in a separate building.So listening room first.
My plan is to work backwards towards the house, but because l live in a rural area, it has it's issues, we all share the same powerline, so l guess the more sockets you can treat the better,especially in noisy areas of your home,like kitchens, heating pumps and TVs..
l am looking forward to testing

Sounds like a proper plan, makes sense. Treating just your listening room "should be" a eye opener. Treating the rest of the circuits will improve system performance further. Should be fun.

 

[kingoftown1]

Whipped up one of the dongle-style ground boxes for my SW-8 using leftovers as a low/no cost Sunday project.

Starting with wiring, this is a little lighter combined gauge than my normal, but it's also a very short cable.

• Unbranded "occ" iem cable from Audiophonics (probably not actually occ, but excellent way to get lots of finely-stranded copper)
• Neotech 26awg occ silver/ptfe
• Neotech 20awg occ copper/ptfe
• Duelund 26awg silver in cotton/oil
• unbleached cotton sleeve

The Duelund leaves residue on the silver, so it and everything else gets cleaned with alcohol, then treated with Furutech Nano-Liquid.

Inserted through the oak end cap. The fit was pretty tight, but added RTV gasket sealer to be sure.

The mineral mix wasn't scientific, just eyeballed:

• equal parts crushed black tourmaline and rock salt (ground fairly fine to maximize space)
• small parts graphite powder, silica gel, and a touch of rochelle salt
• occ copper/silver scraps from making the cable

The ends are just temporarily sealed with blu-tack to be able to experiment more with the mix in the future if needed. I can't fully speak to changes, since I have a couple other things burning in elsewhere, but there was a nice increase in image weight/tangibility and more 'snap' in percussion attacks once this got attached to a SW-8 chassis screw.

 

[cdacosta]

Whipped up one of the dongle-style ground boxes for my SW-8 using leftovers as a low/no cost Sunday project.


Starting with wiring, this is a little lighter combined gauge than my normal, but it's also a very short cable.

• Unbranded "occ" iem cable from Audiophonics (probably not actually occ, but excellent way to get lots of finely-stranded copper)
• Neotech 26awg occ silver/ptfe
• Neotech 20awg occ copper/ptfe
• Duelund 26awg silver in cotton/oil
• unbleached cotton sleeve

The Duelund leaves residue on the silver, so it and everything else gets cleaned with alcohol, then treated with Furutech Nano-Liquid.

Inserted through the oak end cap. The fit was pretty tight, but added RTV gasket sealer to be sure.

The mineral mix wasn't scientific, just eyeballed:

• equal parts crushed black tourmaline and rock salt (ground fairly fine to maximize space)
• small parts graphite powder, silica gel, and a touch of rochelle salt
• occ copper/silver scraps from making the cable

The ends are just temporarily sealed with blu-tack to be able to experiment more with the mix in the future if needed. I can't fully speak to changes, since I have a couple other things burning in elsewhere, but there was a nice increase in image weight/tangibility and more 'snap' in percussion attacks once this got attached to a SW-8 chassis screw.

Interesting. I would not install to a chassis screw or bolt, but that aside here is an idea just to try. Since you can just slip the cable and wire out of the tube, would be easy to experiment with. If you have a bag of Magnetite, just place the wiring and plug into the bag of Magnetite. Based on my experimenting, the Magnetite alone "should" perform better than the small tube of Tourmaline mix. You should hear the difference immediately.

 

[kingoftown1]

In this instance, I was looking to add some more of tourmaline's tonal balance to my system; but I do have magnetite and may try that later on once everything's settled.

 

[cdacosta]

Here is another Rochelle salt filtering across the AC line update...

I went around the apartment to check to see if there were any junctions (outlets or light switches) I did not treat. Apparently I missed two light switches, both on different circuits to my audio system. Both at the other end of the apartment. The only outlet in my apartment now that I have not treated is the fridge and washer and dryer, I did not want to bother moving them. When I move I plan to take the plates with me, the plates only cost 50 cents each at my local home depot.

For context, prior to the 2 junctions I just treated, I already treated IIRC 25 other junctions in the dwelling. The time of the day I did this is 11:40am on a Sunday, when most people are home, so close to peak power usage.

Out of curiosity after finding the first one, I wanted to know if treating this light switch made any audible difference. I was thinking probably not but had no idea. What I did was critically listen before and after application. Went back and forth several times, with and without. Very easy to test since the light switch plate does not have to be screwed in place to test. A little surprised there is a slight difference. Having the ground filtered or not made a bigger difference. How close the 0.5 gram of Rochelle salt was to the actual ground wire made a tonal change that was very noticeable. Sounded best closest, more analog presentation with no change to air, HF extension, or other downsides. The rolled up baggie further away or at the edge of the plate gave a slight nod toward neutral.

After finding the second switch and treating, made a bigger difference than the first switch noted above. After the two light switches were treated, presentation is a bit more relaxed, a bit more air and improved over all precision or PRaT. A bit more musical also. I love this tweak. No question, hands down best bang for the $$$ single tweak to improve audio system performance I have ever experienced, period. The key to best performance is to treat all of the AC wiring in the home.

The more I listen to my system it kind of blows my mind. In the world of high end audio, what does one get for $30? $30 USD is what it costs for enough Rochelle salt, roll of masking tape, small baggies and a precision scale. This tweak alone will leave someone feeling they upgraded and replaced their entire system. Bold claim, I know. Test what I am saying, I am not kidding.

 

[DecentLevi]

Progression notes with Rochelle salt hack recommended by @cdacosta

First few days I tried it behind AC wall faceplates. Initially I had mixed results, until shifting some things around. Trying it behind two auxiliary AC power cord faceplates on 2 other walls of the room (lamp, space heater and modem). I followed Chris (CDA)'s recipe down to the letter. Although being without a scale I got the same recommended salt and multi-pack of bags, used the same amounts, and eyeballed to compare to his photos in this post several times and I can say with certainty this is around 95% identical to his recommended amounts and precise placements he used behind the AC faceplates.

My system went from highly resolving and extended though somewhat bright - to even more resolving and with hyper extended highs that were just too fatiguing. After letting it settle for a day, still no change so I removed the larger bags from both of the "hot" line which is on the right when facing towards the faceplates, leaving only the bags installed in front of "ground" filtering behind the faceplates. One may surmise this hack with AC faceplates is like "HOT = TREBLE; GROUND = BASS", to some extent. At this point my system sounded better than the initial attempt, but something was off. It came down to my unique setup having multi-stage AC power filtering with a series of both Flux-50 knockoff from Aliexpress + iFi Audio Ground Defender before my multi-thousand $$ Furman central AC power conditioner PLUS the full recommended AC faceplate tweak from Chris was turning my system into a detail monster. So after removing both AC filters with just the very esteemed 15-core Valhalla AC cable into my power conditioner and already removing the taller hot side Rochelle filtering behind both AC faceplates leaving only the smaller Rochelle filtering the ground side on the left of the AC faceplate - this was the magic ticket. I also added Rochelle salt bags behind the main AC faceplate powering the main system (on both sides IIRC). Now sounding more neutral, analog and natural than before I started!
I would say this tweak is system-dependent - especially if you already have hefty / multi-stage AC power filtering, go easy on the larger bag on the "hot" / right side if any.

Today onto the ground box cable component side. Initially it was hard to notice a difference, but after installing at least 3, things started to sound even more lifelike and with more relaxed highs Most of my GB cables use 2 wire runs in parallel so each GB got 2 salt bags on the opposite end. Now with 10 medium-small bags wrapped like short cigarettes then wrapped parallel to the recommended copper ground box cables on various component sides - things are sounding quite stunning indeed! That along with a few small bags on top of various wall-warts in the system and one more and on the hot side of another ancillary AC faceplate (on the front only due to it being inaccessible for removal in tight quarters) - what I am hearing now friends, is making my (+/-) $7K sound system best most any other system I've heard under $20K at any CanJam I've been to! Quite unbeatable and enough to make your hair stand up! I'd describe it as that X-factor or 6th element. 4D sound, impressive detail, FR & resolution, uncanny realism and an unquantifiable factor. A lot of this amazing sound is also thanks to the Lhy OCK-2 external clock and my special mesh faraday fabric shielding I have on the walls around the desk of my system (mainly), and also iFi DC blocker & Flux-50 into the DI-20 DDC and various iFi DC blockers, not to mention the 4x custom +1 premade ground boxes I'm using so far. So good I'm overwhelmed and will let this sit before adding any more to the system.

 

[DecentLevi]

made a few updates to my above post ^