SSL Plasma meter noise in the mixbus

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in our old '4000 - one of the very-first with plasma meters - the whole plasma driver electronics was located in a separate iron box, a meter or so away from the console. That was the only way they could make the first series acceptably quiet.

How they fixed this later on, I don't know

Jakob E.
 
Couple questions:
What console you have, E/G/G+?
What kind of noise plasmas are producing?
Have you tried adjusting of R1 (E consoles) / RV2 (G/G+ consoles) at 25 card?

-Paavo

p.s. There's dedicated SSL forum at: forum.sslmixed.com
 
looks like they sell a new switcher for $250 or around there,

OT: holy crap look at this DIY SSL!>  :p

http://forum.sslmixed.com/index.php?topic=8.msg53#msg53
 
CJ said:
looks like they sell a new switcher for $250 or around there,

OT: holy crap look at this DIY SSL!>  :p

http://forum.sslmixed.com/index.php?topic=8.msg53#msg53

I thought Andy was hanging out here as well!
 
CJ said:
looks like they sell a new switcher for $250 or around there,

If you are refering Normann's new Switching PSU, 250$ is price for 250V module only which is inteded to use with PSU that has price range of 3k$
http://forum.sslmixed.com/index.php?topic=164.0

Cheers,
Paavo
 
In fact I calculated that Normann's PSU pays itself back in less than 4 years with our 4056G+
Makes it very tempting... But yeah, 3k is plenty of $$$.

-Paavo
 
Yo can always turn the meter system off when you print, just like w/ the green screen. In fact, many just leave the green screen off and only use an external monitor, there really is no way to completely get rid of the noises these leak into the mix buss.
Yet another reason why I prefer the all VU versions....
 
Thanks for the replies guys!

It's a G+ with Ultimation. The sound is like class B computer interference - like the audio is running right next to an Ethernet router with cheap cables. It's noticeable and it shows up on the 2-mix enough that I don't want to print through the console. Noise floor is around 50-60dB with this issue. Not quiet at all.

Switching the meter ballistics and changing the meter display from input to output changes the pitch and volume of the squeal/noise.

 
A console we have (4080G+, 1991) was having the same issues.  We re-capped the meters and the noise came way down.  Also, these meters looked like they came from the factory with 220uF caps across the +/- supply rails instead of the smaller value indicated on the schematic (don't remember off hand), so we used the same value on the re-cap.

We also have a mid-eighties SSL 6K with plasmas that had the smaller caps. We re-capped those with the 220uFs, but didn't notice any difference (though the noise wasn't bad to begin with on this console). 
 
loopzilla6 said:
kilmister said:
Have you tried adjusting of R1 (E consoles) / RV2 (G/G+ consoles) at 25 card?

Is that the distortion trim on the output card? Help me understand what that particular resistor/pot does... Thanks!

The trimmer is intended to take noise down from mix bus. Hook up a level meter in main out and adjust the trimmer for lowest noise.

Are you sure noise is coming from plasmas?
We had high freq noise all over the console and guilty was a dying PSU of cheapo lcd screen fitted in place of VDU. Old tube screens are also making nasty noise to mix bus around 15kHz.

-Paavo
 
Thanks Paavo -

Yes - when I turn the Plasma supply switches off the noise goes completely away. Quiet as a (quiet) mouse. Everything else is still on except for the meters at that point - computer screen included. Thanks forthe replies everyone! Keep them coming!
 
maybe this might help>

"The radiation of electromagnetic (EM) noise from a plasma display panel (PDP) is analyzed using a three dimensional finite element method (3D-FEM) and measurements. The EM noise is not only the harmonic noise from the digital circuits, but also the broad band noise from the panel itself. The EM noise amplitude depends on the displayed patterns of the panel. From the measurements of the noise from different displayed patterns and the timing of the noise emission, we found that one of the main reasons for the radiation from the panel is the displacement currents between the electrodes of the panel. This phenomenon was confirmed by the computation using a 3D-FEM. The EM noise from the panel can be decreased by optimizing waveforms of driving pulses and the grounding method of the panel electrodes"
 
on the 4032 i worked on, we did turn off the metering when printing mixes like nielsk mentioned before....

at some point a tech recapped many parts of the console, cleaned switches and did something to the whole grounding, after that it went almost completely away.
sorry, but i don´t have more infos what he exactly did.
 

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