Mini SSL? Schematic included...

[jwhmca]

One of my Clients went "All Digital." (FOH application) Now they hate the sound and want me to build them an Analog mix bus... I said "Do you want it modeled after anything?" They said how "about an SSL 4K"

So, looking at the Schematic for the quad bus mix amp card in a 4K, it looks pretty simple.

The questions is:

How much "SSL" sound can we impart into a mix buss? What things should I be looking for to get it to sound like an SSL 4K?

 

[JAB]

Why a 4000?
I've worked on a 4k G, and its a good enough sounding board, with the exception of the VCAs, which I don't mind, but some folks loathe. However, as far as colour goes, I find the 4000 is tight and clean enough, but that the overall sonics aren't really the selling point of the board; the flexibility of the routing and the channel comps and eqs are what sell it for me. just my subjective impression though. I'm sure others have differing opinions.

But the bus amps / master summing? I remember it being all monolithic IC and passives. Nothing wrong with that, especially if clean and simple is the goal. Also pretty inexpensive to put together for a smaller summing mixer, which is nice.

Taking a few amp stages from the master section and using it for your friend's summing will likely give them a reliable analog summing solution that has a pretty small sonic signature (although, if you strap a mixbuzz or SB4000 across the output it will be closer to what people think an SSL sounds like). Driving some iron on the output of the summing amps, if possible, would add some colouration, but will of course be different from 'the ssl sound'.

Remember when asking about "the SSL sound" that a board has hundreds, even thousands of amp stages inside it, and it is the cumulative effects of these, along with the busing and panning implementation, and various other factors, that rolls together into the 'sound' of the board. Any single amp stage was designed to be as clean as possible, so isolating sections of the board means that you'll be isolating a small portion of the sonic signature. The long and short of it is that if they want "SSL sound" they need an SSL.

However, you may be able to get them a good sounding summing solution by using the SSL schems.

 

[jwhmca]

Why a 4K?

1. I have the schematics.
2. They like they "way it sounds"
3-28. I have the schematics.

 

[pucho812]

IMO opinion the 4k takes your audio and makes it all fit into what I would call a tight box...  They have their own sound and it's very surgical. that's cool.  If you really wanted to be cool, do a few different mix amps and make it switchable. That way they can pick and choose per song...

 

[jwhmca]

If I scanned or made the schematic, could we'all look and see if it has flavor to offer?

If so, would it just be the "Quad mix buss amp"?

 

[abechap024]

that would be cool to take a peek at those schemos.

 

[living sounds]

I think the EQs and compressors in the console are the reason to use it, not the degradation caused by the rest of the circuit.

 

[pucho812]

been a while since I looked, correct me if I am wrong but doesn't the ssl  sum 2X before it leaves the console?

 

[jwhmca]

Here is the schematic

 

[pucho812]

o.k. that's 1 channel of the quad card correct?

there should be a second card with Left, Right and Mono... which is why i am thinking it summed 2X before leaving the board. I know the 6000 are just that with the A, B, C stereo busses.

 

[jwhmca]

Yes, that is just one channel. There is another schematic that has the circuit I posted for an input then appears to go through a "DBX 202X" and a couple more 5534's, but doesn't really look like the compressor circuit

 

[Michael Tibes]

The 6k sums twice, the 4k just once. The vcas mentioned are most likely the vca part of the compressor, the original schemo has the mix bus amp and the vca in the signal path on one page, the sidechain on another page - if I remember right. I wonder how much the mix amp contributes to the ssl-sound. There was a project for a 5534-based active summer somewhere including a little nifty pcb, this might do the trick as well, if the bus doesn't become too long (in physical length) or the number of channels goes too high.

Michael

 

[pucho812]

The 6k sums twice, the 4k just once. The vcas mentioned are most likely the vca part of the compressor, the original schemo has the mix bus amp and the vca in the signal path on one page, the sidechain on another page - if I remember right. I wonder how much the mix amp contributes to the ssl-sound. There was a project for a 5534-based active summer somewhere including a little nifty pcb, this might do the trick as well, if the bus doesn't become too long (in physical length) or the number of channels goes too high.

Michael

o.k. then what is the let right and mono card then on a 4K ???

 

[jwhmca]

Any idea what TR1 and 2 are doing? Some kind of DC servo?

 

[SSLtech]

o.k. then what is the let right and mono card then on a 4K ???

I have absolutely no idea what you're talking about.

Mixes are summed just once, then fed to distribution.

So... no. 4000's sum just once.

Keuth

 

[thefastvinny]

o.k. then what is the let right and mono card then on a 4K ???

Pretty sure all of that is on the 25 Card. After the signal hits the 25 it goes to the 26 cards for the Quad Stereo Outputs.

Just another thought not really SSL related, I have heard of a few peeps out there that have played with using Output Tranny's in between the console main outputs and the speaker amps. Some Transformers can "tighten" or "color" your sound and make it a bit less digital and harsh. Just an idea

 

[jwhmca]

That is actually another job I need to do... adding transformers to the outputs. Has anyone done this? Any hints on where and how?

 

[helterbelter]

Okay, i have been following this thread the last couple of days. I'd like to add my 50cts, even though it might not be what you have in mind.

I have built a couple of (passive) SSL summingboxes for other people. The idea is very simple, and it's actually the same as what people do with the Neumann V475 2B summing amps, with the exception that I used 10k resistors instead of 5k1. The summingamps that I have used are SSL SL552 Indepent Main Output modules. They are from the 5000 series, but they are very decent built and excellent sounding summingamps, based on MAT02 opamps and 5534 opamps. They have balanced inserts pre-fader AND postfader. The fader is just a 10kLin pot on the front that controls 2x2 DBX 2151 VCA's that are on-board.

I've sold one of these thru ebay, about 2 years ago, the auction delivered me a very nice stash of cash, and the new owner is still very, very pleased with the summingbox.
And I must say, I think it sounds better than the Neumann. More modern, a bit fatter.
(oh, on a sidenote, the circuitry is somewhat identical to the 9000 pre amp, but it has fixed gain and it uses bipolar caps, and a bit  shorter signal path).

So, if the console has got balanced direct outputs, postfader, you can route these into the summingbox.

In case you can't find a 552 module, SL553, SL543, SL557, and SL594 share the same summingcircuit. The options for inserts, fader etc are different on each module, and some use LM394's instead of MAT02's.

Or you can build a couple of 9k pre's. As said, the circuitry is about the same.

 

[jwhmca]

Good to know,

The schematic shows the MAT02H's as transistors... and a little research says they are dual monolithic at that... I would still like to know there function in the circuit.

 

[abbey road d enfer]

These transistors are the real front-end of this circuit. Their noise factor is much better than that of the 5534.