Carl and Richard,
What both of you write reveals the extent of problems that others may find
subtle or even non-existent. I just want to add that these things are all
likely audible over a wide-range high-resolution system, and making fun of
anyone who wants a pole of one's own -- although it does seem extreme --
betrays an ignorance even of the perhaps greater sonic effects that you two
Thanks for the interesting short essays.
On Tue, Aug 16, 2016 at 9:32 AM, Richard L. Hess <[log in to unmask]>
> Hello, All,
> Better late than never to this discussion...
> This is an area I have suffered through on many broadcast facilities. I
> felt like "who died and left me as the grounding guru!" It happens if you
> know a bit more than others about something, you get involved with it. So I
> decided I needed to learn a lot more. Fortunately, I had access to Ralph
> Morrison and attended Neil Muncy's "Pin One Problem" seminar in the LA
> area. Neil didn't live long enough for us to have a very long talk about
> isolated grounds and wiring practices.
> Suffice it to say, that power systems need to be designed based on many
> I was able to stop one potentially hazardous situation. There was a
> facility with a microwave tower at one end of the building and the power
> entrance was several hundred feet away and they wanted to run an isolated
> ground for the equipment room those several hundred feet and use that as
> the ground entrance for that room that included the microwave gear feeding
> the tower. I don't care what you run several hundred feet, it has
> significant inductance when thinking about lighting discharges (which are
> very fast).
> Ralph taught be about ohms-per-square ... for any material, it doesn't
> matter what, if you have a square piece, the impedance (or at least the
> resistance) will be constant if it's a square foot or a square mile, though
> I wonder what happens when we have multiple wavelengths. I never discussed
> that with Ralph. This brings up the niceties of a traditional
> computer-floor-type signal reference grid. It's just a square piece of
> material that has been "swiss cheesed," So its impedance is higher than if
> it were a solid piece of coppoer, but no where near that of a single cable
> One last story from the field: A facility in Burbank had lots of video hum
> and we had isolated grounds with single ground conductors running in the
> conduit (as required by code). The racks were bonded together and there was
> a separate rack ground system as well.
> What apparently was happening was that the ground wire was acting as the
> secondary of a single-turn transformer (remember how well the Wen and
> Weller soldering guns worked with a single turn secondary). This injected
> hum into the receptacle grounds that was carried to the rack ground. We
> could see 50 mV of hum between adjacent racks (which did wonders to the
> unbalanced baseband video typically run between two adjacent racks without
> differential inputs (at least back in those days).
> The solution was bonding the isolated ground wires to the rack and the
> conduit where it entered the rack. In that way, the generated voltage was
> only induced in the conduit and didn't get into the rack. We couldn't
> easily pull the green wires as that might have been a code violation, but
> it wasn't a code violation to bond them at the far end.
> Briefly, when I built my home studio here in Aurora, Ontario, in 2004, I
> was concerned about the potential for lightning strikes. Our local street
> light had apparently been struck in the past and the house nearer the
> street light than mine suffered minimal damage, my house had some stuff
> fried, and the neighbour on the other side (farthest of the three of us
> from the transformer) had lots of stuff fried.
> So my studio and workbench ended up being powered through a 240:120 V 10
> kVA step down transformer, isolating the power from the incoming hots and
> neutral. The secondary of my separately derived system was grounded to the
> same cold water pipe incoming ground as the power system.
> I ran Romex from the transformer to a panel in the studio. I wired the
> panel single phase. There are nine branch circuits. Three of these feed
> individual plug-mold strips on the rear of my equipment shelves. Three feed
> wall receptacles around the room (including tape machines and powered
> speakers). Two feed the console. One is on 24/7 as is one of the plugmolds
> and one of the wall receptacles because I've added UPS's for many of the
> pieces of equipment. The other console one is switched.
> The ninth circuit feeds the workbench which has a GFCI receptacle wired at
> the workbench.
> This has worked very well. I used BX (AC) cable and although the inspector
> would not let me run an auxiliary ground ring, I arranged the BX so the
> console and wall receptacle feeds came down both sides of the room (one BX
> per circuit) and then they crossed in the console. All BX was anchored with
> metal clamps that effectively bonded two BX cables together. This formed a
> ring around the rear of the studio with two "horns" extending to the
> monitor wall.
> On 8/16/2016 7:47 AM, Carl Pultz wrote:
>> Interesting views, all. Thank you. And great to have input from Gary
>> Galo, whose credibility for me is very high, as we both work in similar
>> facets of audio. I haven't had a chance to try regeneration, but hope to
>> eventually. For small monitoring systems, it is practical. Unfortunately
>> not for larger facilities, as Corey points out.
>> Some years ago I was surprised by a utility crew, which came by to
>> install a transformer right at my drop. I think there was only one or two
>> serving my city block, and one of the guys said the new unit should help
>> stabilize the line. Of course I played some music as soon as they were
>> done. Sadly, I couldn't convince myself there was a difference. It is
>> shared with three other houses. Maybe if my gear was more sensitive to the
>> AC, it would have benefited more from the transformer, or from the newly
>> bonded ground and power connections. I may also have less interference than
>> a resident of Tokyo suffers.
>> We old-timers may be fully aware of this, but I always encourage
>> audiophiles to have a dedicated circuit or two installed for their hifi.
>> When I moved about 15 years ago, it was one of the first things I did, as
>> my stereo was sounding like crap compared to what was going on in the old
>> place. Living there in an older neighborhood, I was aware of the variation
>> of sound quality day vs. night. That house was near by an antenna farm, so
>> I had wired up shielded Romex with isolated grounds. Didn't go that far in
>> the new place, but non-spliced runs on new breakers brought the magic back,
>> with less variability than before. The service was 30 years old, so I
>> tested and reinforced the ground straps. I couldn't measure voltage drop on
>> the panel, but I wanted to be sure it wasn't contributing noise.
>> Some systems prefer to have all components on the same AC circuit. I've
>> found that's often the case with tube gear, or products such as Naim
>> systems, which are very concerned with common grounds. Remember turning the
>> plugs each way to find the best orientation? Can't really do that now, and
>> it probably isn't necessary with modern designs. When I was using a
>> power-hungry Bryston amp, it definitely liked its own AC line. My current
>> Benchmark components seem happier sharing. They use switching power
>> supplies. I wonder if Gary looked into the effect of the regenerators while
>> auditioning the DAC2/AHB2 system.
>> Anyway, I'm reminded of what I was told years ago when first getting
>> serious about hifi: everything matters. If it matters to you. It can lead
>> to madness. Or to joy.
>> We all can either lament or fear hearing loss. But, reading about the
>> research behind the MQA coding system has turned me on (within my limited
>> understanding) to the idea that high frequency perception isn't the only
>> thing our sense depends on. Fortunately, other factors that are not so
>> subject to aging are maybe more important. Note that our Japanese colleague
>> spoke of dynamics, imaging, and clarity, which are not primarily dependent
>> on bandwidth. My older brother, a professional brass player, has
>> significant loss of sensitivity, an occupational hazard. We were together
>> just last week and I made many adjustments to his hifi. He heard pretty
>> much all of it, just at a volume level that I could hardly stand. But
>> concert-like levels are non-negotiable for macho trombone players!
> Richard L. Hess email: [log in to unmask]
> Aurora, Ontario, Canada 647 479 2800
> Quality tape transfers -- even from hard-to-play tapes.