Troubleshooting an SSL Console

[Pigbenis27]

Hey there everybody!

So I own a 1987 SSL 4056 E Series Console which i've been running pretty seemlessly for several months now and of course it's about that time for parts to start giving out and little quirks to start popping up. Below I have a list of issues that I am currently troubleshooting and I thought it might be productive to throw this list up on groupDIY and see if there is any tech heads out there that can impart a little wisdom that might help me work through these problems quicker and save me the hours of research ad tinkering that I have before me. So thank you in advance to anybody out there that can lend a hand!!

1. Rythmic "Tapping" noise in quad buss:

so this is my biggest problem and the one that has stumped me the most. After several hours of use a popping, thumping or tapping sound starts appearing on all four outputs of the console's quad buss going to the monitors. This thumping noise is low frequency (The pitch never changes either) and happens at regularly spaced intervals. Upon shutting the console down; allowing it an hour to cool and then turning it back on the thumping actually goes away until several more hours later when it appears again leading me to believe it has something to do with a component overheating. The thumping is not happening in any of the individual channels in either the Channel or Monitor path and i have confirmed this by floating each channel one at a time which disconnects the channel from the quad buss. Not a single channel seems to be contributing to the sound and with all channels floated the sound continues. We can also visually note the thumping/tapping happening in the quad buss meters so we know it is in the console not the monitors and it is also apparant in the quad compressor meter. When the Control Room Level Pot is down the thumping is not audible but it can still be seen in both the quad meters and quad compressor meter. Alternatively; when the Master VCA fader is down the tapping can no longer be seen in ANY of the meters. It does not seem to matter which output of the console I am using (FR,FL,BR,BL, and Mini) as all of them are connected to the quad buss. I cleaned the Master VCA but this did not seem to help. I have been informed that this could be an issue with a bad IC Chip/Off Amp somewhere in the center section of the console. My only plan of attack at the moment is to identify which logic cards in the center section are feeding the quad compressor after the channels and then locate the IC Chips on those cards and start testing them to find a bad one. The problem also does not seem to be connected to the Echo sends, Cue Sends, External source selector, AFL or SLS systems as i have eliminated all of these systems with zero change in my problem. If anyone out there has any further info or a bright idea that may help me further identify the possible cause of this problem that would be very much appreciated as i currently have a crap ton of IC chips i need to test and i'm not even sure if that is where my effort needs to be directed.

2. I also seem to have a pretty nasty noise floor happening in my console again on the monitor path. The noise floor is inaudible when proper gain staging is used but with the control room level pot and master VCA both cranked it is extremely audible. The sound is a good old fashioned fizziness with random crackles and pops and at times even seems to fluctuate similiar to the sound of tuning a radio. I'm not hearing any actual talking or picking up any obvious signals like an actual radio frequency; the sound just seems to fluctuate randomly as if you were skipping through radio channels. I thought this may be some kind of grounding issue so i went through and checked all ground connections to the copper bar running through my console and then attached this ground bar to an 8ft. copper rod that i hammered into the ground beneath the console. The setup seems to meet grounding specs outlined in the manual but did little next to nothing to help the noise floor leading me to believe it must be a whole lotta noisy components contributing to the problem. I feel like i may have confirmed this as i noticed the noise floor drops when all of the console's echo send volume pots, and all the channel's line level input pots are turned all the way down. My question is how do i remove the noise from these pots? is going through the console and cleaning each pot my only solution to dropping the noise floor? And is there any other factor that may be contributing to the noise floor other than noisy components and improper grounding? Any ideas are welcome!

3. So there are 4 warning light on the top of the center section of the Console. These LEDs are there to indicate that power is indeed getting to the very end of all 4 power rails running through the console. The indicators are marked: +20v and -20v for the 20 volt power rails; +48 for the phantom power rail and +11 for the logic rail. Last week the LED for the +11 rail did not turn on which is VERY bad! however; upon pulling the center section and testing the actual +11 power rail at literally every point provided from the output of the PSU (an Atomic) to the end of the power cables to the input of the +11v circuit running through the center section to the very end of the +11v circuit which connects to the LED, I found that the console is getting damn near perfect voltage to the rail itself. Okay; so i figured the LED just went out. So i replaced it and it did not work. So again i replaced it but this time tested the LED first to insure it was a good bulb. it was so i replaced it and again it did not light up. So right now my power indicator is telling me that there is something wrong with my +11v rail yet from the very start to the very end of the power rail i am getting perfect readings and at this point i have used numerous LEDs not a single one of which is turning on. All i can think is maybe the wire leads from the end of the +11 rail that go to the LED somehow got disconnected from the rail or the wires got smashed or cut. I'm going to trace these wires but in the meantime i just though i'd ask if anybody out there has experienced similar problems are may have run into this oddity with their own console before?

4. And Lastly I am currently on the market for the following parts which all seem to be very hard to find so if anybody out there knows where i could source these components that would be extremely helpful!! The components i need to replace are:

1x SSL E series Conrol Room Level Knob (Not the actual potentiometer just the plastic gray knob itself. It looks as though someone in the studio turned the knob to hard and now the thing turns past it's orginial stopping points)

any replacement button tops for the Channel strip's VCA Faders' CUT and SOLO buttons. I have about a dozen of these plastic tops that ran away and would like to know where i can buy some replacement peices.

and I also have about 8 channels that came without any EQ cards in them. The card in question is a 82E242 parametric Equalizer card for SSL E116 channel strips.

Anyways like i said thank you for any help you guys can give me on any of these matters! Have a great rest of your day guys!

Tony

 

[Michael Tibes]

These questions are very specific SSL questions, you know that there is at least one forum which is for SSLs (and maybe other big consoles)? You might get help here as well, but maybe the chances are even better there. Unfortunately I don't remember the URL, but it should be possible to google it.

I haven't digested all your questions, but aren't the knobs from Sifam? Afaik they still exist, you might get lucky there. It might also be possible to glue the metal part to the plastic of the knob, in case nothing else comes up. SSL also sells spare parts, but I'm not sure if there is any 4k material left.

Michael

 

[Pigbenis27]

Thank you MIcheal i appreciate the info on the knob; in the event nothing else does come up then that's probably the best idea i got! And also thank you for recommending the SSL forum too i think i was able to find it i'm just waiting for the site admin to ok my profile and then i should be able to start posting on that guy! Thanks again for taking the time to help out and let me know if you think of anything else!

 

[pucho812]

when was it last recapped?

 

[Matt Syson]

The SSL4K is quite unusual that the logic supply 'hangs down' from the plus 20 Volt rail so the '11 volt' rail when measured against analogue common is whateve the plus rail is MINUS whatever the logic supply gives (nominally set for 6 Volts), meaning that when looking for logic faults you have to refer to the plus 20 Volt rail and hang down from that. Without seeing an Atomic supply in the 'flesh' some of your noise issues may be down to that. At least the original SSL linear supplies were 'quiet' electrically, even though very noisy physically with their 3 large fans.
Matt S

 

[Whoops]

These questions are very specific SSL questions, you know that there is at least one forum which is for SSLs (and maybe other big consoles)? You might get help here as well, but maybe the chances are even better there. Unfortunately I don't remember the URL, but it should be possible to google it.

I was also going to recommend that forum,
it's great, there's schematics and service manuals and you will find there a lot of SSL owners that share info on how to service them and keep them going:

http://forum.sslmixed.com/index.php

 

[pvision]

Re-reading this thread a thought occurred to me: if the thumping is on all four bus outputs, but isn't present with the fader down, it could be related to the bus compressor. The compressor uses the same VCAs as the master fader

One thing that links all four buses is the compressor sidechain. Maybe putting a scope on the sidechain might reveal if there's noise on the control line that is being reflected in the audio path

 

[pucho812]

Rereading this, if thump happens after it warms up but goes away after shutdown and restart, could be heat related, possible bad/faulty solder joint or component that is triggered when heated….

 

[sodderboy]

Great desk!
I think sslmixed.com has been a bit lonely lately.

Knob: if it turns down clicking, and turns CCW past 7 o'clock then the stop inside, inside, the ALPS quad pot is displaced. The knob is able to be opened carefully, but it is an arduous path there, un-powering, sliding the centre section up, removing cards, removing loom, work over a towel to prevent microbits from bouncing away to oblivion. The "stop" would be in the top deck, and I never had to go in there.

Quad thumps: patch around the VCA IN/OUT at the bay to hard bypass the COMP and MASTER fader, see if the noise goes away. Caps were questioned previously. At the very least, all bypass caps everywhere in the desk, especially the centre section, should be less than 12 ish years old. If I saw Panasonis HF or HFS caps there, I would keep them up to 20 ish years. Usually the non-polarized caps go first, with L-R imbalance symptoms, and that replacement need drives a complete re-cap of the centre. Dead patch the VCA IN and listen if the thump goes away.
With those tests you can determine the search direction. If it is backwards, then FLOAT channels till it goes away. If it doesn't then it points to the mix amps in the Centre.

Noise floor: "good old fashioned fizziness". I listened to a glass of tonic, and with my perception, "fizz" is somewhere between "hiss" (my "good old fashioned" Johnson noise) and "zizz" (a harmonic of 60 or 50 Hz). Fizzy tonic is a bit saw-toothy to my ear.
Is your fizz like white noise, or is it a bit saw-toothy with a possible pitch?
Mix bus noise has to be sussed in a properly designed system. Any "zizz" as I call it on a mix bus indicates problems outside the desk.
Mike