[Top] [All Lists]

Re: noisy 8020 mics

Subject: Re: noisy 8020 mics
From: "vickipowys" vpowys
Date: Sat Sep 24, 2011 6:44 pm ((PDT))
That is really interesting Bruce and many thanks for going public.

Yes I too thought I was going insane and that aliens had invaded my
recording space :-)

It is actually a relief to know that the mic series 80XX are at
fault, or at least some of them.  Pity Sennheiser won't 'fess up and
tell us exactly where the problem lies.

To recap, the problem for me is a periodic, randomly-occurring loud
fizzing noise in both 8020s mics, and I live in a relatively remote
location with dry and mild climate.

FWIW I tried a number of experiments to try and pin down the source
of the noise in (both sets of) 8020s.

Leads - tried 3 completely different sets, still got noise

Recorder - measured phantom power with multimeter at a steady 48.3
volts so OK for that

Batteries - tried both no-name and Sony batteries in SD recorder,
still got noise in 8020s

Other Mics - tried MKH20s with same recorder and leads and absolutely
no problems despite accidentally leaving the MKH20s outdoors on a
dewy night.

Warm-ups - tried turning on SD recorder and leaving 8020s powered on
for 3 hours before recording in early morning, still got noise

Fridge test - tested mics for one hour indoors in dry and warm
conditions (no noise).  Put mics in fridge for half hour down to 11
degrees C, got noise for about a minute or so.

Warm afternoon test - despite perfect conditions, low humidity, I got
noise, so might not be temperature/humidity after all?

Windy or Loud conditions - neither of these seemed to directly affect
the noise problem.

Experiences of others - two friends have had occasional problems with
8020s which they had put down to humidity or bad leads, and the
problem for them is infrequent so therefore almost impossible to
analyze the cause.  8020s have successfully been used by them in
conditions below freezing point, and in one case were accidentally
left out in the rain, but still worked just fine!

Repairs under warranty - when I returned my mics to Syntec in Sydney
(authorized Sennheiser folk for Australia), they had no knowledge of
any problems with the 8020 mics.  For the first repair job they
'cleaned the ground terminals which were dirty' but I still got
noise.  So I am keen to get more information  from other users around
the world,  before I return my second set of mics to them for repair.

Vicki Powys

On 24/09/2011, at 8:30 AM, bruce seifried wrote:

> Oh, man. I know this issue well. Unfortunately.
> Rather than trust my sometimes quirky memory, I will copy/paste part
> of one of my emails to my dealer:
> *********
> "Here's a recap of my MKH8020/8040 adventure:
> =95 Original order was for one pair each of MKH8020 stereo set, and
> MKH8040 stereo set. Order date 5/8/08.
> =95 One of the 8020 omnis went bad on my first remote job. Intermittent
> full output noise spikes ruined recording.
> This pair was replaced by Sennheiser on approximately 7/1/08.
> =95 New pair of 8020's both went bad before my first job with them. Both
> initially had low-level crackly noise problems. One of them
> subsequently improved, but both were returned to Sennheiser for a
> refund.
> =95 The 8040 pair were initially fine, and worked in my studio. They
> were set up here prior to a remote job in October, and one developed
> the same low-level crackles that the second 8020 pair had. This noise
> took about a minute to get going before manifesting itself, and was
> then continuous. These were returned to Sennheiser for a refund.
> I returned the 8020/8040 pairs for a refund reluctantly, since I did
> very much like their sound, especially the 8020s, but I no longer
> trust that these microphones are reliable enough for me to use in a
> professional situation.
> As a circuit designer myself, I will hazard a guess as to what might
> be the cause of these problems.
> If it were not for the intermittent full-level noise problem with the
> first 8020 pair, I would guess that there was some form of
> contamination to the high impedance section of the pc boards happening
> during manufacture, perhaps due to incomplete removal of flux during
> soldering. Another possibility is a bad batch of FETs or transistors
> sneaking into production. Less likely but still possible would be bad
> capacitors. Obviously, I did not open these to determine for certain
> what the problem(s) was/were.
> However, I did notice that the small circular pc board located between
> the two halves of the microphones was not firmly attached in place,
> and was not always accurately centered. In fact, in one of the mics as
> initially received it was so far out of alignment that there were
> positions of rotation of the XLR assembly where the pin was barely, if
> at all, making contact with the circular pc board trace. This might be
> a design decision that should be rethought, at least to improve on the
> dimensional tolerances  involved."
> *********
> My dealer, Steve Remote at Aura Sonic, was a complete saint during
> this nightmare, and managed to get Sennheiser to completely refund the
> cost of these microphones. I have refrained from going public about
> all this, since I had not seen any other mention anywhere of anyone
> else having these sorts of problems, and I was beginning to doubt my
> own sanity. I tried these mics with different mic cables, two
> different Sound Devices 702 recorders, the KORG DSD recorder, and the
> outcome was always the same. Sennheiser denied that anyone else was
> having these problems. Apparently, I'm not insane, as is now apparent.
> Yay!
> I feel your pain!
> bruce seifried
> eclair engineering
> On Sep 22, 2011, at 4:21 AM, vickipowys wrote:
>> All,
>> Does anyone else have problems with periodic loud fizzing noise from
>> Sennheiser 8020 mics?
>> Sennheiser replaced one set of mics ('faulty capsule' they said) but
>> the noise persists in the replacement mics despite me checking
>> absolutely everything by way of leads and phantom power voltage and
>> connectors etc. etc.
>> Help please!
>> Vicki Powys
>> Australia

<Prev in Thread] Current Thread [Next in Thread>

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the naturerecordists mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU