LISTSERV mailing list manager LISTSERV 16.0

Help for ARSCLIST Archives


ARSCLIST Archives

ARSCLIST Archives


[email protected]


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Monospaced Font

LISTSERV Archives

LISTSERV Archives

ARSCLIST Home

ARSCLIST Home

ARSCLIST  August 2016

ARSCLIST August 2016

Subject:

Re: Fwd: [ARSCLIST] : Fancy speakers? Check. Sub-woofer? Check. Electric Utility Pole?

From:

"Richard L. Hess" <[log in to unmask]>

Reply-To:

Association for Recorded Sound Discussion List <[log in to unmask]>

Date:

Tue, 16 Aug 2016 09:32:23 -0400

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (109 lines)

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
factors.

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 run.

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.

Cheers,

Richard




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
http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

March 2024
February 2024
January 2024
December 2023
November 2023
October 2023
September 2023
August 2023
July 2023
June 2023
May 2023
April 2023
March 2023
February 2023
January 2023
December 2022
November 2022
October 2022
September 2022
August 2022
July 2022
June 2022
May 2022
April 2022
March 2022
February 2022
January 2022
December 2021
November 2021
October 2021
September 2021
August 2021
July 2021
June 2021
May 2021
April 2021
March 2021
February 2021
January 2021
December 2020
November 2020
October 2020
September 2020
August 2020
July 2020
June 2020
May 2020
April 2020
March 2020
February 2020
January 2020
December 2019
November 2019
October 2019
September 2019
August 2019
July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003
October 2003
September 2003
August 2003
July 2003
June 2003
May 2003
April 2003
March 2003
February 2003
January 2003

ATOM RSS1 RSS2



LISTSERV.LOC.GOV

CataList Email List Search Powered by the LISTSERV Email List Manager