SSlmixed.com Forum
Tech discussion => 4K,6K,8K Series => Topic started by: christiancarvin on October 07, 2013, 08:52:17 PM
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Hi everyone! (Excuse my poor English writing!)
I own an ssl 4040E build in 1979.
I'm trying to align each module of the desk.
I've downloaded the 611 I/O module calibration.
The problem is that it concerns 82E291 input cards and 82E13 cards.
My desk is fitted with 82E01 (no VR)
and 82E14 (2 VR)
http://cjoint.com/13oc/CJfjiLiU8Yl.htm (http://cjoint.com/13oc/CJfjiLiU8Yl.htm)
As you can see on the picture there are 2 VR on VCA card. One is a 60k trim pot (fix the reference value) and 500k trim pot (adj offset: what is that for?)
the main problem is that 2 faders give different levels with the same level input....I don't how to fix that.
If you have any suggestion....Thanks!
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Hi Christian,
welcome at the forum! Your E-Series must be a very early one. Would be great to see more posts from you and perhaps some pictures of the console!
I have a G so can't really help. My guess is that the second Trim is to the trim the VCA for minimum distortion. I would just turn it and see what happens. You can mark the setting with a pen so that you can return to it.
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Thanks for reply!
So here is the console:
http://cjoint.com/?CJiiAF8XpGJ (http://cjoint.com/?CJiiAF8XpGJ)
My guess is that the second Trim is to the trim the VCA for minimum distortion
I have already tried that but nothing changed...Maybe I didn't turn the VR enough...
I'm going to make a topic on the desk repairs...I'm learning it on my own so I will need help!
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Hi Christian, the line up for the 14 card is going to be pretty much the same for the 13 card, really only the VCA type differed.
As a ballpark, you can flip your VU's into 'VCA to Meters' with all your faders sat on 0dB, and get an idea if anythings wildly off.
VCA Card 82E13 (Non-Ultimation only)
Set the console to Record status and press the channel FLIP and DIRECT buttons. With +14dB applied to the Line Input, measure at the Group Output and adjust VR3 for +14dB output with the large (VCA) fader set at 0dB. Measure this output again for fader settings of +10, -10, and -20dB. Adjust VR2 (dB/V adjustment) to correct or evenly distribute any measured error.
Set the fader to 0dB and, using a distortion meter, adjust the Symmetry present VR1 for minimum distortion.
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Best to leave the Distortion trim alone, you really need a Distortion meter for it to make any sense.
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Thanks for replies guys!
As a ballpark, you can flip your VU's into 'VCA to Meters' with all your faders sat on 0dB, and get an idea if anythings wildly off.
It's a real mess here! even with fader down there are some VUs up...I think that is the trouble...How can I fix that?
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Hi, if the meters all the way over and don't indicate any fader movement, it could be the lack of VCA voltage +5v rail from the VCA card. This can be checked with a multimeter.
0v = fader fully up
Also:
Bad connections: at the fader/fader bus card (unplug the small ribbon/ swap the fader from a working channel)
Reseating the module in the bucket.
Bad fader, dirty faders.
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They move with faders moving.
But the values are all different....
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Thats good.
With the channel on an extender, you should be able to trim the 14 card so 0 on the fader = 0VU
You can also monitor a tone going through the module, set at unity, and meter that on the LF and RF VU's
You should get things pretty good with this method.
All the faders have a tolerance, and normally numbered so they stay in the same position.. maybe things got moved around in a move.
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With the channel on an extender, you should be able to trim the 14 card so 0 on the fader = 0VU
I've done it for two modules.
The problem is: If I have 0dB on two faders and 0dBVU on LF et RF and I put faders at - 10dB I'm going to have -10dBVU for one and -14dBVU for the other.
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Yeah, better to get the audio right.. and not the VCA to meters. Is there enough adjustment to get the two channels equal? To match in pairs 1-2, 3-4 and so on.
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If there were I didn't find them...just this 60k trimpot on the vca card
make it good just for one value...
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Hi, on the schematic here, the 500k is marked Adj. offset, and the other is unmarked. Don't have any other info regarding the 14 card.
(http://i44.photobucket.com/albums/f23/sin-tech/14card_zps4057a74f.jpg) (http://s44.photobucket.com/user/sin-tech/media/14card_zps4057a74f.jpg.html)
If you put the channel on the extender, switch to VCA to Meter, one trimmer (most likely the 60K) will move the meter up and down, increasing/decreasing the output of the VCA by the same amount.
I've lined channels up like this with good results in the past.
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This is what I've done on two modules with the 60k trimpot...it makes a good pair for one value but when you decrease the two faders exactly the same way values are not the same anymore....
(Sorry for my English and thanks for your replies!...)
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Hi ok, so what your saying is it also effects the Fader Law. Could it be the two trim pots are interactive?
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At first I thought that the 500k trim pot would have made the law level...but unfortunately no....
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Just a quick experiment here, even though LR aren't calibrated for the faders, you have relative inconsistencies up to 5 dB at different levels, when viewed VCA to meters.
(http://i44.photobucket.com/albums/f23/sin-tech/2_zps858fa4dd.jpg) (http://s44.photobucket.com/user/sin-tech/media/2_zps858fa4dd.jpg.html)
(http://i44.photobucket.com/albums/f23/sin-tech/0_zps797672f3.jpg) (http://s44.photobucket.com/user/sin-tech/media/0_zps797672f3.jpg.html)
(http://i44.photobucket.com/albums/f23/sin-tech/-7_zpsa0b587e8.jpg) (http://s44.photobucket.com/user/sin-tech/media/-7_zpsa0b587e8.jpg.html)
(http://i44.photobucket.com/albums/f23/sin-tech/-20_zps9a8ff34a.jpg) (http://s44.photobucket.com/user/sin-tech/media/-20_zps9a8ff34a.jpg.html)
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I have to study this new post carefully and I'll make a report! Thanks for your time!
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I still don't have the answer to my problem....I can't make proper stereo with two mono modules.
to get the same level: one fader is high and the other is low...as you described on your experiment.
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With a test tone, was able to adjust the gain of the VCA.
The two channels are spares, and were never setup for the faders in the Test console.
I think it's a little hit and miss! the small fader paths are perfect to the meters (when in Stereo Bus Mode)
Be interested how well other peoples consoles are set up.
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When mixing.. currently match L/R on a pair of channels with an NTP plasma meter on the 2bus, just like this one:
http://www.youtube.com/watch?v=6JulvE7lpIk
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I've downloaded the 611 I/O module calibration.
Do you have a link available for this calibration?
thanks!
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It's in the section:
SSlmixed.com Forum » Tech discussion » Technical Manuals & Documentation
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THANKS!
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Hi Christian, the line up for the 14 card is going to be pretty much the same for the 13 card, really only the VCA type differed.
As a ballpark, you can flip your VU's into 'VCA to Meters' with all your faders sat on 0dB, and get an idea if anythings wildly off.
VCA Card 82E13 (Non-Ultimation only)
Set the console to Record status and press the channel FLIP and DIRECT buttons. With +14dB applied to the Line Input, measure at the Group Output and adjust VR3 for +14dB output with the large (VCA) fader set at 0dB. Measure this output again for fader settings of +10, -10, and -20dB. Adjust VR2 (dB/V adjustment) to correct or evenly distribute any measured error.
Set the fader to 0dB and, using a distortion meter, adjust the Symmetry present VR1 for minimum distortion.
Hi all-
I've got a similar console to OP, a 6040e from about 1984?? Came from NBC...
I'm beginning to get to the calibration of channels and can't find much literature on what I've got. The manuals online are as new as 1993, and the manual that came with my desk has lots of info from various consoles including 4k and other G and G+ desks, which doesn't help me that much.
Most of my channels have the 82E01 or 82E241 Input card (mic transformer) and 82E13 output cards. Probably half of the output cards have a gold DBX vca.
From what I read in this post, my output card is similar to OP's output card, but only some of my e13's have a VR3, some do not. One has had a trim pot added to it near T1 on the output card from Channel 11 (pic attached). There is also a small "L. Trim" pot next to the dynamics card, below my stereo bus routing buttons...
Any help would be greatly appreciated! I will try and get some more pics and posts up. New to the forum as I am just getting this monster up and running.
Thanks in advance!
Spencer
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The problem with the original poster's VCA card might be down to the card's design not having as many adjustments as the later '13 card. The 500k pot adds a DC bias to one of the differential analog inputs; this leads me to believe it's an adjustment to the symmetry and therefore distortion. The retrofitted 60k Bourns trimpot, I'm guessing, fulfills the same function as the the '13 card's VR3 pot, Offset, so that it's possible to align all the VCAs to match at one point of the faders' position. There doesn't seem to be an adjustment equivalent to the '13's VR2, Fader Law, which is why the faders only match at one point. Are all three leads from the trimpot all used, or only two?
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The problem with the original poster's VCA card might be down to the card's design not having as many adjustments as the later '13 card. The 500k pot adds a DC bias to one of the differential analog inputs; this leads me to believe it's an adjustment to the symmetry and therefore distortion. The retrofitted 60k Bourns trimpot, I'm guessing, fulfills the same function as the the '13 card's VR3 pot, Offset, so that it's possible to align all the VCAs to match at one point of the faders' position. There doesn't seem to be an adjustment equivalent to the '13's VR2, Fader Law, which is why the faders only match at one point. Are all three leads from the trimpot all used, or only two?
Hey thanks for reply-
I was hoping that the retro-fitted pot would be to act as a type of V3 trim since there's already two other trims on this particular 82e13 card (vr1 & vr2). From this post it sounds like my added trim does NOT function as VR3, as it is a 500k pot. It's only attached at two legs in series with R13, and there isn't really anywhere for the far leg to attach to and it looks cut (very tight space here). This measures close to 58k ohms.
This is treated as something different than VR3? Where would the 60k trim be located if retrofitted? I'll re-read this post in case that's covered and I've missed it. Also please let me know if I've confused the 500k DC bias pot you've mentioned with another pot/if I'm misunderstanding your post. My VR1, VR2 and retrofitted pots all appear to be 50k, 500, and 500k ohms, respectively.
Another thing that the modified 82e13 card has is another resistor in series at r27 (at the top of the card between the VCA and T3 amp). It gives me a reading of about 4.9k, where the original DBX card with NO MODS reads 14k in across R27.
Has anyone else installed consoles with 82e13 VCA output cards with only VR1/VR2, with or without the added 500k pot across R13??
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Hey again-
Did some more digging in the slew of paperwork I have for this desk. I found the schematic for the 82E13 card with a few revisions made already. I have some cards like this, others without VR3. Looks like the VR trim that's in series with R13 DOES act as variable trim VR3. I've highlighted these sections on the schematic, which has been super helpful.
I'll try calibrating one of these as though the channel is a late model 82e13 with vr3 and post results. Looks like I will have to do some modifications to the cards with only vr1/vr2 in order to be able to calibrate them the same way.
Be back soon...
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Hi Spanzor,
My observations were mostly directed towards the original poster with the 82E12 card. The '13 cards I've dealt with have been retrofitted with the 500K pot acting as VR3; so it's certainly possible to add them to any '13 card without VR3 already.
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Hi Spanzor,
My observations were mostly directed towards the original poster with the 82E12 card. The '13 cards I've dealt with have been retrofitted with the 500K pot acting as VR3; so it's certainly possible to add them to any '13 card without VR3 already.
cool! got some soldering to do then...
thanks man!!
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Hi,
I am interested on installing the VR3 trimmer to the Gold can 82E13 cards. Could you explain your experience? How did you do it finally?
On the other hand, I have some 82E13 cards just recapped and they do not work well. The signal goes very low, distorted and not responding to the fader.
I only replaced the electrolytic capacitors. Should the 2,2uF rectangle (C8) capacitor be replaced? (I have attached a detailed photo)
Does someone have the schematics of the 83E13 "Gold can" version?
Thanks to all in advance.
Regards.
Oihan
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I have this......
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Many many Thanks!!
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I am checking the schematics... so, the card could be updated to the newer version, changing C8, R61, R13 and adding VR3 500K, D30, D31...
Does someone did this? What do you think about it? It is better to mantain as it is?
Oihan
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I'd say it's better to get the VCA card working in it's present configuration before you worry about updating. First things to check are all the supply voltages: are the +/- 15, +/- 18, and 5 volt voltages present? One of those would be missing if one of the replaced bypass caps is shorted.
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Hi Chris,
Sorry for my late reply.
I have measured these values: 17.4/17.8v (pins 29, 30, 32) and 5v (33 and 35). I did not measure +/- 15v, because I am not sure how to do that. Soldering a wire to the output leg of the TR3 regulator and pmeasuring between pin 32 and the wire, would be fine?
Thanks again in advance.
Oihan
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It'd be better to measure between pins 30 and 32 for +15V, and 29 and 32 for -15V. Assuming they're good, check pin 3 and pin 6 of T1 with a scope. That's your pre-fader out. Also check T3 pin 6 with a scope; that's post-fader.
Chris
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Hi Chris,
Thanks for your help. I do not have any oscilloscope. I will try checking the op amps again and check all the diodes. I also will recap it again.
I will write back soon.
Regards
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Hi all,
I have been checking the VCA 82E13 card and I found 2 resistors with wrong values (R43 and R44). I measured 10ohm on each resistor and I have replaced them by 22ohm resistors. The problem is solved now.
Thanks to all, thanks Chris... for helping.
Best regards.
Oihan
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You're very welcome.