SSlmixed.com Forum
Tech discussion => 4K,6K,8K Series => Topic started by: silvershark on December 09, 2013, 06:29:12 PM
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Hi there
I'm new to the world of SSL desks and have just bought a cut down 24 channel 4000 Series desk. The desk is lovely and I am slowly learning all about it however
I am having some problems with the Phantom Power. The lights are on for all 4 voltages on the desk (i.e. 48v/+18V/+11v/-18v) but there is nothing getting to the mics - or at least I am not getting any signal through the desk.
I have checked using dynamics and powered condensers and they are fine but nothing with a standard phantom power condenser
Am I missing something - or is there a problem with the desk?
Thanks in advance for any assistance it's greatly appreciated
Cheers
Grant
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On a standard E series, the Gain pot has a 48V switch combined, think it's down for 48V and Pull up for off (can't quite remember)
'Radio DK' E series, has no activation on the channel, but a global 48v switch on the Centre.
The G series the 48v button is where the 'Pad' is on the E series.
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Hi Sintech
Thanks for reply
It's a G-Series so has the 48V button
We've just done some more testing and it looks like although the 48v light is on there is no voltage coming through. Although there is a really nasty buzz when you plug a condenser in and bring up the fader
I am thinking that it may be a good idea to get a tech in for the day to check it over and also make sure everything else is ok. I've had a hell of a job with the DL wiring as well..
Thanks
Grant
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Hi, if you have VU's you can borrow the 250v regulator card and pop it into the 48v position. If the LED is on, some kind of voltage must be present, you can measure this at the patch bay.
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Grant, out of interest who supplied your cut down G?
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Hi
I'll try that.
On the power supply there are five LEDs one for each of the following voltages;
+20/-20/+13/+48 and +250
All are lit except the 250 one. Does anyone know if this should be lit? I'm guessing it should and perhaps this may have something to do with he problems I'm having?
I bought the desk from another engineer in the same studio complex as I'm in but he got it from AES
Thanks
G
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The 250v is just for consoles fitted with Plasma meters.
You should have a 250v on/off switch by that LED for a UK supply, apart from the Jap version (661J) it's hidden behind the removable front panel.
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Ok
I have VUs not plasmas but there is no switch beside this but I think the desk might have originated from Japan actually. Do you mean the power supply front panel?
Can anyone recommend any techs that are based in London area, I'm in SE London
Thanks
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Yeah, the power supply front panel.
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Ok I'll check that out? Do you think the out be messing with the Phantom Power and causing the problems I'm experiencing
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The 250v should be off for your console with VU meters.
If it’s 661J you won’t be able to “borrow” the 250v regulator as it’s a different arrangement to the standard supply.
The 48V regulator circuit is independent from all the other rails, so whatever that’s pumping out is fed via the 48v switch to the mic lines… so very passive in terms of the console end.
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Jap 661 looks like this:
(http://i44.photobucket.com/albums/f23/sin-tech/photo_zps383f8adc.jpg) (http://s44.photobucket.com/user/sin-tech/media/photo_zps383f8adc.jpg.html)
Standard version has this arrangement:
(http://i44.photobucket.com/albums/f23/sin-tech/ssl-661e-power-supply-638299_zps1fbfb9d6.jpg) (http://s44.photobucket.com/user/sin-tech/media/ssl-661e-power-supply-638299_zps1fbfb9d6.jpg.html)
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That looks like it but I've left studio know so ill need to check if it is a 661
Thanks very much
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Check that you have ground connected to your mic panels. Phantom needs the ground.
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HI
Another question on this
I have checked everything and digging around the patchbay I have discovered that there is what appears to be an earth wire connected to input one on the Mic Lines on the patchbay. This is not connected to anything at the other end. Could this be causing the problem I am having? What should this be connected to?
Many thanks
G
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Yes, it should be connected to pin 1 at the XLR/mic end, as Pelle pointed out, the microphone has no reference to ground, hence the problem.
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Ok
Once again excuse my lack of knowledge but if I understand correctly I need to connect the end of this to the XLR wall box where my mic signal is coming from?
Many thanks
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Ok
Once again excuse my lack of knowledge but if I understand correctly I need to connect the end of this to the XLR wall box where my mic signal is coming from?
Many thanks
yes but highly recommended to get a tech in to have a look at the whole thing as it sounds as if there might be other things worth looking at in that instance.
my 2 cents.
Mattia.
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I agree, I think I will get someone to just give it a look over
Can anyone recommend a tech in the London area?
Grant
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myself! ;)
Mattia.
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myself! ;)
Mattia.
+1
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PM'd you
Thanks
G
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Hi dude. Quote: 'I've had a hell of a job with the DL wiring as well..'
Why is the DL wiring a problem? The SSL mic DL wiring (DL's 01 and 02) are wired balanced into the SSL and to the patchbay with all three wires (hot, cold and screen) connected to the patch (Row A) from the DL. They then get fully normalled down to row B and the wires from there into the channels have no screens connected at the patch but the twin screen balanced cable goes to Bicc B on the upper buscard and the screens are connected on that at the 6 way Bicc.
From there, the upper buscard is screened to one of the copper earth bars running throughout the console and has the signal ground terminated at the end near the console connector panel.
I would suggest looking at one of the following locations (all of these have the screen wire connected):
1 The installation wiring at DL's 1 and 2 on the SSL 96 way DL sockets should be fully wired (hot, cold AND screen).
2 Also, any studio mic panel wiring should be wired the same with screens connected to make it a balanced connection from the studio panel to the SSL connector panel.
3 All studio loose mic cables should be wired with screens 1 to 1 (especially to avoid AC earth leakage and possible death).
Remember screens should not be dropped for mic cabling between the mic and the SSL especially as a singer may have their lips against a mic and could get killed if an AC earthing failure happened further down the signal chain. The SSL is AC earthed depending on the links in your power supply and studio technical grounding scheme but if the patchbay is remote and in the same metal rack as other, maybe unbalanced gear, I can really see an accident about to happen if an unbalanced bit of gear has a fault, the whole rack goes AC live, along with the remote patchbay, and the singer gets electrocuted ... maybe not such a bad thing if he/she can't sing in tune!!!
If these rules are followed, you should be okay but, if the installation wiring is different to this, you may may problems.
My post doesn't really address the 48v phantom mic problem but could be relevant.
Hope this helps and regards from Jim Lassen (www.profcon.co.uk). Also on FACEBOOK
(http://www.facebook.com/pages/ProfCon-wwwprofconcouk-Professional-Connections-Jim-Lassen/371183312969924?ref=hl/)
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Silver Shark (Grant?)
Me again, I've just seen an earlier post from you about an earth wire connected to input 1 on the patchbay. Along with some of the other patchbays with SSL (but not user option wiring), this wire is probably a green 7, 16 or 32/0.2 tech grounding wire and should go to the end of the two copper bars in the block by the tech ground point hanging out at the console connector panel. It is an SSL internal signal ground wire and not directly related to the studio installation.
There you will (or should) also see a bunch of other green wires from the other patchbays all screwed into the copper block. The patchbays, having metal front panels, are screwed to the frame which, in itself, is technical ground but the green wire soldered to one of the patchbay jack screen positions (any one of the 48 or 56, it doesn't matter which) is actually a hardwired ground to the copper block, even though the patchbay is screwed into the frame as well. The patchbay screens are shorted to the frame and the green wire, via the copper block, also ends up shorted to the frame and goes to the 0BA (M6) technical grounding point.
The mic panels are a separate issue as I tried to explain in my last post but I'll clarify the whole signal path again.
1 All studio mic leads have their grounds connected both ends.
2 All studio wallbox wiring also has screens connected at the wallbox AND at the DL end.
3 From the DL, the balanced twin screen cables go to the patchbays and the individual screens are connected to the bantam jacks.
4 In this case, the mic lines (they should really be called mic sources in my view as they are not a line signal!) are fully normalled down from row A to B (just the hot and cold, not the screen on any patchbay).
5 Row B (which is NOT individually screened at the patchbay end) takes the signal to the upper buscard Bicc B (which is screened).
6 So, from the mic right through (via wallboxes and DL's) to the patchbay row A (mic lines!), the screen is fully connected.
7 The individual mic screens go to the patchbay on row A. This is screwed into the console frame (which becomes part of the technical ground). Also, the green wire, as an extra measure, ensures the patchbay screens get taken to the copper block which ends up being screwed to the frame as well, creating one big happy tech earth ideally!
8 The SSL internal wires from row B (mic inputs) are unscreened at the patch end but ARE screened at the 6 way Bicc end.
9 From the Bicc end, they hit the upper buscard and that has a 50/0.25 white wire (SSL couldn't get the same size wire in green at the time and stuck to white!!!) linked to one of the copper bars (one was for mix earths and the other for power earths) for each section of 8 channels.
10 The two copper bars come together at the end and are screwed to the frame (see point 7).
11 The idea was that the SSL console would be the hub of ALL of the studio technical screens before going off to a studio technical earth position, ideally just before the main earthing stake or point.
So, let the console grounding design do it's job and connect ALL the screens right through from the mic to the console patchbay. Effects and multitrack stuff could be different as they are bi-directional and there is a risk of ground loops but the one way mic circuit (with associated phantom powering) especially needs the signal ground connected to work properly and not cause injury or death!
To address your point, connect the loose green wire to the copper block with the others which may be there (it should be a similar length).
I think your 48v problem lies with screens being dropped at the wallbox or DL's, hence no phantom power as it needs the screen connected throughout, as detailed above, to make it work (and be safe). If someone has dropped a mic screen between the mic and patchbay, they should be ... (I can't say as it's too rude!).
Hope this helps and sorry for all the detail. I have prepared a comprehensive schematic of the SSL power and ground wiring with help from Sintech and others on this forum and will send it to Mattia for inclusion soon.
Also, Sintech (Andy H) visited me today and suggested I PM you regarding other wiring issues you may have so I will do that now.
Finally, why I am doing this shxt on a Friday night when I should be out begging as usual?
That's it, I'll shut up now people. This should hopefully earn me another 63 positive Karma points (I'm trying to catch up with Andy ... no chance really!).
Regards from Jim Lassen (www.profcon.co.uk). Also on FACEBOOK (http://www.facebook.com/pages/ProfCon-wwwprofconcouk-Professional-Connections-Jim-Lassen/371183312969924?ref=hl/)
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Haha, bring on the Karma for Jim - cabling advice can save lives!
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That's it, I'll shut up now people. This should hopefully earn me another 63 positive Karma points (I'm trying to catch up with Andy ... no chance really!).
Regards from Jim Lassen (www.profcon.co.uk). Also on FACEBOOK (http://www.facebook.com/pages/ProfCon-wwwprofconcouk-Professional-Connections-Jim-Lassen/371183312969924?ref=hl/)
Just gave you mine!
;)
Mattia.
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Ta for the Karma points Marc and Mattia. I was on 18 and Andy on 28 but I notice we have both moved up 2 so, no difference! I'm only kidding on this of course as Andy deserves his massive lead with all the effort he puts in to solving problems on this forum. Also, on that note, I reckon Mattia, who started this whole forum off in July 2012, needs more than just 5 ... come on people ... vote for him!
Anyway, I'm about to send Mattia and Andy (Sintech) my final version of the SSL power/tech ground wiring tonight so it can be posted in some form here. Apart from what I have already written, this should clarify most of the SSL actual console internal power and tech grounding issues (ignoring the power supplies themselves).
Regardos all from Jim Lassen
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Jim, you just got a Karma point from me too!
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Lets hope nobody would lift the "screen" on the mic lines!
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Xmax. That SSL power/grounding schematic is old school as they say and I remember it from when I used to work at SSL. I've just sent Mattia and Andy our finished (it never is really!) version so it can be posted on this forum. It contains loads more details of both the console power and tech grounding. I guess Mattia will show this in the Technical Manuals and documentation menu soon.
Thanks for the Karma point Andy, I'm only a mere 9 behind you now! Regards all from Jim Lassen.
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A masterpiece is never finished! But I see it as this: SSL wanted to maintain a "star ground" referring to the audio "0V" since it is floating in the supplies
it is usually "anchored" to the studio's technical ground i.e. a huge wire going from the copper bar in the desk to the earth spikes, then
branched out to the patch bay and computer, the third pin on the a.c. line of the power supplies only goes to the chassis of the power supplies.
Sometimes "ground" can confusing at times so I try look at is as such: The desk is the ground "star" (via huge cable) If ground loops are created
in the outboard gear due to poor "technical ground" then said inputs (or outputs of gear) "screen" should be lifted, at step further is to add a .1uf cap
but that is a talk for another time! but since mics have no ac ground the screen should should never be lifted (as you know)! sometimes tube mics
can create a ground loop then you can either lift the screen or ac connection to the screen in the mics p.s. my 2 cents on SSL ground. Did you check for
48v at the top and bottom row of mic bay? I saw no mention, but I did not read the whole thread. cheers. N
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Thanks everyone for help with this
Got the earth hooked up this evening and it seems to have fixed the problem
Not quite tested everything yet but so far so good
Many thanks
Grant