SSL 6k External to Mon Bleeds a little A buss.

[Jermbob]

My SSL 6k External to Mon bleeds from the a little A buss, and makes a crazy pop, with loud transients. Something on the 154 or 195 card? What should I do?

[Artur D'Assumpção]

Hi,

Can you please elaborate, your description was a bit confusing. Please detail exactly what's happening.

Cheers,

Artur

[Jermbob]

When I'm mixing at a loud level, and I press the external to monitor button, I get a noisy crackly bleed of sound from the "a" buss. It makes a click or pop sound at the loudest parts, like kick drums or snares. It didn't use to do it, now it does. It happens on both channels.

[radardoug]

Are you pinning the stereo bus meters? Are you mixing with the master fader partway down?

[Artur D'Assumpção]

Hi,

You should first check if the problem is after the Programme or before (either on bus A,B or C). You can patch out the A,B,C and Programme at the patchbay and check when you push Ext.Mon if you can hear that click/pop. This will allow you to check if: 1 - the problem is in the audio or monitor path. 2 - if it's in the audio path, 3 - if it's in one specific bus, in the programme summing, or after.

There's also the possibility if it's only in the monitor path, that the problem is being triggered when you switch the monitor using the Ext.Mon. You'll have to figure that out with this type of divide-and-conquer approach to isolate the fault.

Having this information in hand it will help you isolate on the big diagram block schematic (that A2 diagram that's on the service manual) on which card the problem might be.

Then what I would do, is put the candidate card on the extender and probe the audio until I find the culprit. Typically the cards have an audio and logic section. The problem can also be on the logic side of things (or mechanical if the problem is in the switch).

Anyways, my suggestion is to start with the top approach and see where it leads you.

Cheers,

Artur

[xmax]

What version 6K? the early ones had 4 026 cards with gold can DBX VCA's,
the later version used hybrid amps and had many more broadcast features,
I'm not sure how SSL identified the 2, but I would like to!. Also If I recall that's
all fet switching, it seems the fets are leaking some audio, meaning they are
seeing a voltage they shouldn't biasing them into passing audio. Or the shunts
fets in that circuit are not seeing the voltage they should. It could be as simple
as the power rails have drifted enough to make them unhappy, get a reading
at the center section of audio and logic voltages. N

[waltzingbear]

I believe Norman (Xmax) is thinking in the right direction. One of the FET switches in the controller is not turning off correctly. It can be a variety of causes, you'll need to track the offending source down and fix it. Too many potential sources to shot gun.

Alan

[Matt Sartori]

Would be interesting to know if you got it fixed?

Matt Sartori.