[Derrick Fawsitt]

I have just acquired a pair of Quad 989 ESL speakers and am delighted
with them. I have however reported to Quad that there is a slight
"fizzing" noise emanating from one of them. You have to put your ear
close to it to actually hear it. It started to occur during the
extremely hot weather we had recently here in the UK and Quad said they
were inundated with calls about other users experiencing the same
problem and that it might be due to the high humidity. However, it has
persisted up to now despite the cooler weather and yet I am reluctant to
have to haul my spanking new speaker into my car to bring it to Quad
over what appears to be a minor problem, or is it? How should I regard
this, is it serious or potentially serious and what action should I take
in the matter. The speakers are not easy to transport and I am reluctant
to stand them up, (in case they fall), or lay them down on account of
the "stress" it might put on the panel in relation to its base.
What to do please, I would be so grateful for help and information.
--
Derrick Fawsitt

[mikewest]

If it is humidity, why not invest in a good dehumidifier for your hi-fi
room

mike
www.mikewestgatesound.co.nz

[Mr.T]

"mikewest" wrote in message
ps.com...
If it is humidity, why not invest in a good dehumidifier for your hi-fi
room

Or speakers that don't require a high voltage power supply :-)

MrT.

[Adrian Tuddenham]

mikewest wrote:

If it is humidity, why not invest in a good dehumidifier for your hi-fi
room

I understand that the membrane in the Quads needs a certain amount of
humidity to allow it to distribute the charge. Somewhere on the Web I
have seen an article which describes how to repair/rebuild them (sorry I
can't remember where).

They may just need some dust removing.


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

[Chris Malcolm]

Derrick Fawsitt wrote:

I have just acquired a pair of Quad 989 ESL speakers and am delighted
with them. I have however reported to Quad that there is a slight
"fizzing" noise emanating from one of them. You have to put your ear
close to it to actually hear it. It started to occur during the
extremely hot weather we had recently here in the UK and Quad said they
were inundated with calls about other users experiencing the same
problem and that it might be due to the high humidity. However, it has
persisted up to now despite the cooler weather and yet I am reluctant to
have to haul my spanking new speaker into my car to bring it to Quad
over what appears to be a minor problem, or is it? How should I regard
this, is it serious or potentially serious and what action should I take
in the matter. The speakers are not easy to transport and I am reluctant
to stand them up, (in case they fall), or lay them down on account of
the "stress" it might put on the panel in relation to its base.
What to do please, I would be so grateful for help and information.

A not uncommon ESL problem. Anything which reduces the resistance of
the gap between charged grid and membrane will cause it. High humidity
will do that. Note that getting cooler doesn't necessarily mean
lowered humdity. The most common cause if it persists is a tiny bit of
hair or fibre which the charge makes stand on end across part of the
gap, and it may be that high humidity is making it possible for a
little hair in one speaker to arc.

If you take the top off you should be able to remove the protective
cloth sock and see the naked membranes. You may be able to locate the
arcing by looking for it in a completely dark room, or by listening
and using a good torch. Once you've found it it will be obvious whether
it's easily accesible and can be easily removed, or will need the
speaker to be taken apart. Don't try that unless confident of your
skills.

It's not a good idea to leave it alone for a long time, as if it
persists it can end up causing local spark burn damage of various
kinds. ESLs don't mind tiny local damage, but it matters if it's
allowed to spread into larger damage.

--
Chris Malcolm DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

[Chris Malcolm]

Adrian Tuddenham wrote:
mikewest wrote:

If it is humidity, why not invest in a good dehumidifier for your hi-fi
room

I understand that the membrane in the Quads needs a certain amount of
humidity to allow it to distribute the charge.

No, they have a conductive coating.

They may just need some dust removing.

Which can be easy or hard depening on where it is.

--
Chris Malcolm DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

[Adrian Tuddenham]

Chris Malcolm wrote:

Adrian Tuddenham wrote:
mikewest wrote:

If it is humidity, why not invest in a good dehumidifier for your hi-fi
room

I understand that the membrane in the Quads needs a certain amount of
humidity to allow it to distribute the charge.

No, they have a conductive coating.


I seem to remember reading that the coating depends on humidity for its
conductivity.


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

[[email protected]]

Adrian Tuddenham wrote:
Chris Malcolm wrote:

Adrian Tuddenham wrote:
mikewest wrote:

If it is humidity, why not invest in a good dehumidifier for your hi-fi
room

I understand that the membrane in the Quads needs a certain amount of
humidity to allow it to distribute the charge.

No, they have a conductive coating.

I seem to remember reading that the coating depends on humidity for its
conductivity.

You read or remember incorrectly. If that was written
somewhere and you can find it, I'd recommend you
see if you can get your money back, given the unreliability
of that source.

Having such a dependency on humidity is a real bad
idea, engineering wise, because of any number of
reasons, like the high degree of variability of humidity,
the tendency of very fine airborne salt particle and the
like to become dissolved and deposited under high-
humidity conditions, the great difficulty in controlling
the process during manufacturing, and many others.

Also, having worked on Quads and other electrostatics,
owning service documentation and more, rest assured
that they DO NOT, and NEVER have depended on
humidity for conductivity. They rely on specific, carefully
applied high-resistance coatings such as graphite, vapor-
deposited metals and the like.

[Murray Peterson]

wrote in
oups.com:


Adrian Tuddenham wrote:
Chris Malcolm wrote:

I seem to remember reading that the coating depends on humidity for
its conductivity.

You read or remember incorrectly. If that was written
somewhere and you can find it, I'd recommend you
see if you can get your money back, given the unreliability
of that source.

Probably a mis-interpretation of the patent. G.B. Patent 815,978 reads:

"A suitable material for the diaphragm is nylon, the surface of which,
owing to its affinity for moisture, has the above stated resistance over
the relative humidity range 95% to 38%."

--
Murray Peterson

[Adrian Tuddenham]

Murray Peterson wrote:

wrote in
oups.com:


Adrian Tuddenham wrote:
Chris Malcolm wrote:

I seem to remember reading that the coating depends on humidity for
its conductivity.

You read or remember incorrectly. If that was written
somewhere and you can find it, I'd recommend you
see if you can get your money back, given the unreliability
of that source.

Probably a mis-interpretation of the patent. G.B. Patent 815,978 reads:

"A suitable material for the diaphragm is nylon, the surface of which,
owing to its affinity for moisture, has the above stated resistance over
the relative humidity range 95% to 38%."

It certainly was the resistance of nylon which I remember reading about.
If the diaphragm really is coated with nylon and the nylon depends on
moisture for its conductivity, wouldn't it cease to conduct if the air
were totally dehumidified as previously suggested - or is the water
content maintained independently of the air humidity?

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

[Adrian Tuddenham]

wrote:

Adrian Tuddenham wrote:
Chris Malcolm wrote:

Adrian Tuddenham wrote:
mikewest wrote:

If it is humidity, why not invest in a good dehumidifier for your hi-fi
room

I understand that the membrane in the Quads needs a certain amount of
humidity to allow it to distribute the charge.

No, they have a conductive coating.

I seem to remember reading that the coating depends on humidity for its
conductivity.

You read or remember incorrectly. If that was written
somewhere and you can find it, I'd recommend you
see if you can get your money back, given the unreliability
of that source.

See URL below and Murray Peterson's quote from G.B. Patent 815,978.


Having such a dependency on humidity is a real bad
idea, engineering wise, because of any number of
reasons, like the high degree of variability of humidity,
the tendency of very fine airborne salt particle and the
like to become dissolved and deposited under high-
humidity conditions, the great difficulty in controlling
the process during manufacturing, and many others.

Also, having worked on Quads and other electrostatics,
owning service documentation and more, rest assured
that they DO NOT, and NEVER have depended on
humidity for conductivity. They rely on specific, carefully
applied high-resistance coatings such as graphite, vapor-
deposited metals and the like.

I thought those were all far too conductive to be used because the
charge is supposed to be fairly stationary for low distortion. That was
why P.Walker used a very high resistance nylon coating which needed
moisture for conductivity.

http://www.quadesl.org/Hard_Core/Pan...ting/originalc
oating.html


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk