hi u all the good helpers...
i bought the console in august this year ,through internet from a shop
called primal gear(they said there are a few cracking switches -
nothing special...)
when console arrived(september- to holland amsterdam) i immediately
checked, patched -sprayed (F5 Caig) and starting mixing an album...
i could hear the hum right away ...asked help from mike ...and found
you guys...
next thing i'll try is to take the audio +/- 18v from a different psu
and see what does that do.
Barak -open for all the ideas you have
On Jan 31, 2010, at 8:13 PM, Ike Zimbel wrote:
Hi Brian and Matt,
Brian, for the record, I believe that console you are talking
about was an Elan. Matt, the "Neotek Sound" that I am familiar with
definitely does NOT include power and ground hum. As I mentioned
earlier, I have heard about Neotek consoles having noise problems
but none of the consoles that I have been involved with over the
past 20+ years (close to 350 channels of Elite, ELite II, Elan and
Series II) have exhibited the problem that Barak is talking about,
nor the problem and fix that Brian has described here. Most of the
consoles that I have dealt with have an un-weighted noise floor
below -82.00dbu, with one Elite II that I have done a lot of
upgrades on hovering around -90.00dbu. Having said that, when I look
at an FFT of the noise spectrum on those consoles, the dominant
frequencies are 60, 120 and 180hz. So, the consoles are definitely _/
susceptible/_ to power and grounding noise issues.
But, my point here is that in spite of "doing everything wrong",
the consoles are usually quiet, and therefore what Barak is dealing
with, and what Brian described should be treated as anomalies, that
should be solvable. In the case of the Elan that Brian mentions, it
is clearly something that went wrong in the manufacturing process.
Like what? We may never know, but maybe a bonehead mistake like
getting the shield and Tip or Ring mixed up in some signal runs to
and from the patch bay...like the 2-mix insert. Sometimes these
things are very hard to find. 30 years ago I was the production
manager for a company that made lighting consoles here in Toronto.
There was ONE factory defective desk that we built, out of about
100+ units, (which, ironically ended up being purchased by my very
own brother...) The console worked perfectly and passed all of its
pre-delivery tests. Once out the shop door, however, it started
having problems with "ghosting" in the dimmers it was connected to.
I looked the thing over on site and never could find the problem.
Eventually the desk was traded in, and, sometime after I had left
the company, underwent some sort of re-build (I think a "stretch" to
add more channels). During the course of this work, an un-used
centre-tap wire on the power transformer was found crushed between
the base of the transformer and the chassis. This was leaking half
of the secondary voltage onto the chassis, upsetting the DC ground
that the dimming circuits referenced, causing the dimmers to
"ghost". So parts get put in wrong, connections are mis-wired, wires
get pinched etc.
In the case of Barak's console, there are still some questions
that need to be answered. In particular, Barak, did you ever own
this console when it wasn't exhibiting this problem?
I have a few more thoughts on this but, I will save them for another
post...or two.
best,
Ike
On 1/29/2010 6:02 AM, Matt Syson wrote:
Hi
I have to say that my experience of Neotek's is limited to a series
1 (in the flesh) but the wiring and particularly grounding,
appalled me, having spent 30 or more years un humming desks for
several manufacturers.
There may be a 'following' for the 'Neotek sound' but there are so
many fundamental 'wrongs' going on.
Metalwork, DC power ground and 'mix bus reference ground should all
be separate until intentionally joined at one defined point, not
scattered randomly around the chassis.
Having to fiddle inside the supply to 'null' the hum from there
suggests very poor layout and wiring practice.
The 'sound' may be great but you have to work for it and try to
preserve it against interference from multiple sources.
Matt S
Brian Roth wrote:
Hello Ike, et al:
I recall a new Neotek desk that was delivered here in OKC... 20+
years ago. I cannot recall if it was an Elan or Elite.
From DAY ONE it had "hum issues" on every bus. As I worked with
it, I was shocked to discover the grounding system, which was
"every ground was connected to every ground", including random
connections to the metal work on the front panels.
This was a NEW desk from Chicago.
Audio ground returns were randomly connected to the front panel
metal.
I quickly tested the desk with a battery=powered power amp/speaker
combo in order to eliminate any wiring probs, with no I/O besides
my battery-powered system, and at other times my iso'ed scope.
It still hummed/buzzed. Many other tests done..including one
oddity...as I "unscrewed" modules from the frame, the noise changed.
Desk's owner yelled and cried at "Chicago", with no replies for
months. Desk owner SCREAMED, and finally had a reply apparently
from the "unknown mystery circuit designer"...
Solution? Install six or eight feet of 18 or 16 GA wiring INSIDE
of the PS-3 (??) PSU box in series with the "ground return"
wiring, and then fuck with the positioning of that series "wads of
wire" inside of the PSU to "null" the noise.
That came directly from "Chicago".
Egads.....
Best,
Bri
Ike wrote:
Hi Jim, Matt, Barak,
The Elite is different from the Series boards in that the
motherboard is only the width of the master section - 4 modules.
The channel modules buss thru 4 x 16 way .100 ribbon cables and 8
x 3 way .156 Molex headers to the patchbay, fader and meter. So
pulling modules is a bit more complicated. However it is not hard
to disconnect one or both sides of the desk in one go by pulling
the .100 headers from the bottom of the motherboard.
Fitting the master modules in the motherboard is a pain and
has been the topic of another recent thread.
Barak, have you done anything with the master
modules? Another thing you could try is to remove the FX return
and Aux master modules (desk will run without them) so you can
see how the stereo master module is fitting in the motherboard.
There may be some Molex pins bent, missing or not making proper
contact. Try pushing up on the motherboard and see if the hum
changes or goes away. Also check to see if the ground strap is
bolted to the bottom of the mother board.
Best
Ike
--
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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