Hi Doug,
I think it's time to re-cap this thread. If I have read this correctly:
-the noise is confined to the Aux buses, doesn't show up on the 2-mix or
the channels, correct?
-Frank M. had an LED meter that was causing noise once (not a mechanical
VU, right Frank)?
-the problem shows up big time when switching meter select switches.
-the oscillator was suggested (by me) as a potential culprit, but seems
to be working. Matt Syson, this oscillator uses the Exar 2604 function
generator chip. I have seen, I think, one go bad in 24 years or so.
-Jim M. suggests that it could still be a power supply problem,
So,
To address the last point first, it could be a PS issue, but I
think you would be seeing that across all the channels. Nonetheless, I
did get burned by a couple of caps on the +/-18v rail outputs going bad
in a PS-3 once. These are C-132 and C-140, 100uf/50v. They are located
on the back edge of the board, on either side. At least one of them is a
pain to remove because there's a big 1N5404 diode tack-soldered over one
of its pads on the underside of the board. The symptoms of these being
bad is a lot of random sporadic noise on the outputs.
-Next, the meter boards don't just run off the +36 volt rail, they also
run on the the +/-18v rails. So un-hooking the 36v lead would do you no
good at all. The only way to completely disable them would be to pull
the Molex connectors. I can't remember how this works on an Elan, but on
the Elite there are a couple of 6-8 pin .156 Molex headers on the back
of the motherboard that feed the meters. If you can't find main
connections like that, you would have to pull every Molex (the larger
one) off of every meter to take them out of the equation.
-BUT-
-There is some circuitry on one of the master boards that, sets the
reference level, the response curve (Peak/VU) and the brightness of the
LED meters, and I have seen some of this stuff go bad over the years.
As I mentioned in an earlier post, I am on vacation and foolishly didn't
bring my Elan manual with me, so I can't give you part numbers, but it's
usually marked on the board, and this circuitry is always up around the
upper ends of the circuit boards in question.
Good luck...I am starting to get some wry looks from the family!
Best,
Ike
On 11-07-19 10:09 PM, Doug Easley wrote:
Continuing the chase of aux noises, I noticed today that when I press the
monitor on in the meter select I get a funky ripple buzzy crud added to a hummy
sound. This is the first thing I've found that has affected my noise. By
pressing the peak/rms switches I can make the optional phase meter go back and
forth sometimes and hear a click noise for every LED movement. So maybe I'm on
to something. Then I thought well disconnect the meter power and it will go
away but no such luck. With meter power disconnected the same sound would
happen. There are some meters that only have a few sections working which
hasn't been too much of a problem so far. I can meter in pro tools and I have
analog VUs on the master. Is there some way to bypass the bargraph meter
circuit to see if that's my problem. Are there caps in there that are supposed
to keep it quiet?
thanks for the responses, doug
On Jul 18, 2011, at 4:09 PM, Ike Zimbel<[email protected]> wrote:
Hi Doug,
Following on Matt's suggestions, I would agree that the oscillator section
could be suspect. I would also check that all of the logic chips are well
seated and that their leads and sockets look good. Replace them if they don't.
Also make sure that all of the ground connections, including mechanical
connections to the front panel (pots, switches etc.) are clean and tight. It is
unlikely that the Aux sends are creating this noise, but more likely they are
amplifying noise that's coming from something common to them, again as Matt
said. I am away from the shop for a couple of weeks so I don't have access to
my Elan drawings to give you specific chip names, locations etc.
Best,
Ike
On 11-07-18 8:54 AM, Matt Syson wrote:
Hi
You are looking for something 'common' as it adds up when listening to more
stuff on Solo.
It could be supply noise (check with an oscilloscope) or a module which is
seriously noisy or even talkback or slate tone circuitry that has access to aux
busses although may be nominally 'switched off'.
Double check all possible outputs and look for any 'common' circuitry (the
'block diagram' should get you close). Ultimately, pull modules or 'break up'
the mix bussing if it is available on plugs.
Matt S
On 18/07/2011 13:35, [email protected]<mailto:[email protected]>
wrote:
Hello, I think this is the way to post here.
I have a 15 year old 40 channel Elan I bought new. It's been very reliable. It
was in a fire 7 years ago. I got it back in commission after a couple of idle
years of storage and cleaning/repairing. It was recommissioned and has done
pretty well, everything works except some partially working l.e.d. meters.
Lately the master section has a small ripply sound when cranked all the way up
without channels turned on. Small annoyance, but irritating. However when you
solo the auxes you get a really intense version of hiss noise ripply trash,
sounds like a combination of computer interference meets bad caps/junk. As I
said it's appeared of the last few months. Soloing A,B,1,2,3,4, just adds to
the crap incrementally. When using the track busses to pro tools, it's fine ,
goes to pro tools good and quietly.
I recently tested and or replaced all the resistors in the power supply and
recapped the power supply. I also disconnected the Elcos for everthing except
the monitor one to the amps to make sure it wasn't from another piece of gear.
I still have the trashy sound in auxes. Any suggestions? Any logical procedure
to locate the source of my noise?
thanks , doug
--
Ike Zimbel,
Zimbel Audio Productions Ltd.
Toronto
416-720-0887
"Studio House Calls". Authorized Warranty service for Allen& Heath,
Clear-Com, Drawmer, Soundcraft, SPL and Yamaha. Repairs and upgrades to analog audio
equipment including: AMEK, dbx, Neve, Neotek, MCI, Soundcraft and more. Ask about our RF
frequency co-ordination services!
www.zimbelaudio.com
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--
Ike Zimbel,
Zimbel Audio Productions Ltd.
Toronto
416-720-0887
"Studio House Calls". Authorized Warranty service for Allen& Heath, Clear-Com,
Drawmer, Soundcraft, SPL and Yamaha. Repairs and upgrades to analog audio equipment
including: AMEK, dbx, Neve, Neotek, MCI, Soundcraft and more. Ask about our RF frequency
co-ordination services!
www.zimbelaudio.com
------
View the list online at: http://www.mail-archive.com/[email protected]
You can unsubscribe at anytime by sending an email to mailto:[email protected] with
"unsubscribe neotek" in the message body. If you have any difficulties, or
questions --please send an email to mailto:[email protected].
The Neotek list is lovingly hosted by Catapult Web. Remember that any message
or reply sent to the list will be automatically forwarded to all subscribers.
Vive Le Neotek!
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