LISTSERV mailing list manager LISTSERV 16.0

Help for ARSCLIST Archives


ARSCLIST Archives

ARSCLIST Archives


ARSCLIST@LISTSERV.LOC.GOV


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

ARSCLIST Home

ARSCLIST Home

ARSCLIST  June 2014

ARSCLIST June 2014

Subject:

Re: Upgrading Audio Systems

From:

Robert Cham <[log in to unmask]>

Reply-To:

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

Date:

Sun, 22 Jun 2014 11:09:43 -0400

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (109 lines)

Random thoughts about ground, cables and RF.

Back in the early '70s Fred Schiller, the chief of maintenance at WHA 
told me, "Follow the rules about grounding, and when that doesn't 
work, start lifting and adding grounds till it does.  I think of Fred 
every time I go into a studio.

The biggest problem that I've found in radio stations is installers 
that thought punch blocks were "ends", and that therefore the drain 
wires didn't continue through.  Lots of lovely antennas to pick up RF.

In the '80s, I was trying to record in a church across the street 
from a 50KW FM on a short tower.  Tried everything.  What worked was 
star quad mic cable.  PROCO worked as well as Canare.  I recall also 
having to get creative with grounding as well, but what I did I don't 
remember.

When I worked for API, we frequently had problems with RF from the 
defense installation down the block.  It manifested itself as noise. 
Saul Walker told me, just increase the gauge of the ground bus.

In a house, I'd drive more ground rods.  We used to salt the earth 
around ground rods at transmitter sites.  On top of Mt. Mansfield, we 
kept losing the submersible pump, 300' down the well to lightning. 
It was the best ground on the mountain.  Granite is not the best 
conductor known to man.

Diodes make great RF detectors, but a diode isn't always an 
electronic devices.  On top of Mt Mansfield, we had problems with our 
107.9 mixing with FAA transmitters at the site, and interfering with 
the frequency that the bombers at Plattsburgh Air Force base used for 
landing directions.  It seems that they didn't like to listen to 
Robert J Lurtsema, while landing .  Harmonics were involved along 
with sum and difference mixing.  We searched for weeks, and finally 
found the "diode".  It was a rusty bolt on our tower.  I've also seen 
poor bonding between chassis panels in an audio mixer act as "diodes".

Bob Cham




>When I started to work in the music studio of the National Film Board of
>Canada in 1979, we had a mic cupboard full of good stuff. There were a
>number of brand new AKG-414s. But I was told that I couldn't use them
>because of RF problems, and the NFB was actually considering selling the
>mics since they were unusable. I got our maintenance department to make a
>"special" cable that tied pin 1 to the shell of the connector. Bingo, the
>mics were clean of RF and I scored big points with my new boss. In the 20
>years I was there, I never found the RF source even though the studio was
>surrounded with chicken wire supposedly well grounded.
>
>Louis
>
>
>2014-06-21 16:00 GMT-04:00 Richard L. Hess <[log in to unmask]>:
>
>>  On 2014-06-21 3:54 PM, Paul Stamler wrote:
>>
>>>  Remarkably, I heard similar stories from the engineers at the Ravinia
>>>  Festival about Neumann mics. They also went to C451s and some Shure
>>>  SM81s, and the problem was solved. The SM81s and C451s had far fewer
>>>  problems with humidity than the KM 84s.
>>>
>>  That is interesting as Neumann has published on the subject and also
>>  developed their double wound (in opposing directions) spiral-shielded mic
>>  cable (called double Reussen shielding, I believe). Here, the cable is
>>  called "Gotham" cable after Gotham Audio, for a long time the sole importer
>>  of Neumann mics into the USA. I had thought it was Neumann cable, but
>>  perhaps it was Gotham. It is still available. I still have a pair of 50'
>>  and some 10' cables that I bought in the 1970s and they are still
>>  performing well (though I don't use them that often).
>>
>>  http://roadworthycables.com/gotham-cable
>>
>>  Although this was not the article I recall, it seems interesting and talks
>>  about Pin 1 and Pin 0 (the shell) and I do recall some of that discussion
>>  from the earlier paper.
>>
>>  https://www.neumann.com/download.php?download=lect0047.PDF
>>
>>  Part of what they published (IIRC) was relating to the shield ground and
>>  pin one. I do not recall exactly what they recommended, but I do think that
>  > it was an early indicator of a pin one problem.
>>
>>  I have yet to have an RF problem with my KMS-105 or TLM-103, but neither
>>  of those were hung in the church, used on the floor.
>>
>>  In fact, the only mics that ever gave me a problem here in Aurora were the
>>  ATM10a's, which, also, coincidentally were the least expensive condenser
>>  mics I ever bought.
>>
>>  To fill out the list, although none hung in the church, all were used
>>  there without any RFI issues: Rode NT5, Rode S1, Sennheiser MKH416T with
>>  homemade P48-T12 adapters, and dynamic Shure PG58, SM58, and EV ND767.
>>
>>  Cheers,
>>
>>  Richard
>>
>>  --
>>  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.
>>
>
>!DSPAM:639,53a6d05b250421275014965!

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

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