SSL 9k - background

...so of course I've picked up one of those traditional colds myself... It's playing havoc with me beer-guzzlin' I can tell ya! :wink:

Keef

Hey Andy,
Hope you get well soon from the flu.

:sam: Have some ginger soup with sugar bring out the fire in you, works well curing the flu!! :thumb:

thats right! I swear, I've never gotten over a cold quicker than taking ABSURD amounts of vitamin C and drinking ginger tea......

slice the root ultra thin, place in pot of water, start flame, boil until you can just smell the ginger aromatics, add suger, white, brown, honey, whatever your taste....

it brings that fever to climax and lets you finish it out in peace

billy

Hi - many thanks for all the messages!

Back to the mixer:

For the inputs and outputs, ideal would be the 9k balanced input and output as used on the insert sends and returns. The neat thing is that these can be used in a totally balanced circuit: the + and - sides of the input come from pins 1 and 7 of IC44, the + side of the output feeds into R355 and R345, - into R344 and R356.

Otherwise the 4k G series line input and the traditional 4k balanced output, again these can both be run completely balanced in a similar way, the only downside compared to the 9k stages is that the 9k has a slightly better bottom end.

Or use the SSM2141 / 2142 pair. These are actually very good chips, and save the hassle of finding 0.1% resistors (assuming you can find the chips!). An invertor can be added between pins 6 and 1 of the 2141 to effectively create a G series line input.

But for the mixer - the 9k multitrack bus mixer appears to use an AD829 ("What do you mean appears to use? I thought you designed this? :roll: " "Yes but it was a long time ago, and I'm now trying to work out from the circuit what I did and why! :? ") which I would only recommend using if you are going to make it balanced. It is very quiet and very fast - essential for a mix bus with potentially 128 inputs, but I don't know whether there would be distortion problems if it was used unbalanced? Maybe fine, but in any case for only 16 or 24 inputs the good old 4k single 5534 (see the '11 or '294 card) should be perfectly adequate. Or two if it's balanced.

Solos - ah well, now we're back in the FETS/relays argument again! If I was building a box for a studio and had a reasonable amount of money available I would use SSM2402 switches, particularly since the box would be balanced so there would be no distortion problems.

Hmm...seems like we have the basis for an interesting group designed project here! Shame I haven't got time to draw stuff up, but I haven't finished designing/building my bass guitar amp yet, and I 'm getting very frustrated at having a beautiful new speaker with an empty 2U space in the top. And I don't know when I'll get round to building my own summing mixer, knowing me it'll probably wait until the dreadful old 6:4:2 that I'm using now actually falls apart.

On the other hand, I suppose if someone offered to layout the PCBs and supply me with a few blank boards it might be worth it :?: Anyone out there use Proteus?

I hope Fabio is reading this...

whoa! I would lay this out in a heartbeat. I would FIND time for this..

Anybody have any of the S S L schematics? My friend just bought an E series console - I would like to check out the mix amp and Line input schematics of that and the G series.

Thanks, JEff

[quote author="Andy Millar"]
I 'm getting very frustrated at having a beautiful new speaker with an empty 2U space in the top.

[/quote]

Hi Andy,
That sounds like an interesting project, are you thinking of building a tube amp, IC or hybrid? I guess you are looking to build the power amp as well?

I am very interested in building a bass preamp/processor also may be include a evelope follower or something..... Haven't really got a clear idea on what would be an interesting feature to look into, except combining an envelope follower with some notch filters to shape the note or may be adding a ADR circuit in parallel with the envelope follower for selection before the notch filters....

Andy... you rock!

so what do you want us to do to help?

Fabio is currently looking for some new circuits to layout and if he can't i'm sure somebody will. i've never used PCB software but if it comes to the crunch i'll learn if it gets this project moving foreward.

i'm not familiar with the differences between the circuits that you've talked about but i like the idea of using the 9k circuitry.

I am reading now guys! :green:

B-man!

What do you think Fabio, you like what your seeing?

Cheers mate,
Tony

still interested Andy!

I haven't really run away to hide! Give me a couple of weeks, I've got a few other little projects to get out of the way first (like the bass amp).

Or if someone wants to kludge the circuits together as I described above I'm more than happy to (very nicely) have a look over them.

It would be fun to get this one off the ground...re the concern about getting everyone here to agree a spec, given fexible enough 'input' cards and a 'summer' card, it should then be possible to add solos, pans, whatever as required.

I'm all for it. maybe you have some schemos laying around?

[quote author="Svart"]I'm all for it. maybe you have some schemos laying around?[/quote]
Will be great, but for start will be nice to clear out 4k summing amp "ssl_82e26" . Lot of values are blurred...

kind bump,
no pressure meant at all

bump again.. :thumb:

It would be great to see what Andy can sketch up. I would happily work on it from there.

Bump?

bumpidity!

wow... just stumbled over this very interesting thread... what happend to this project? seems like this got somehow lost in the www-grave-yard?

regards
loca
(another silent diy-dude ...or lurker...)

bump.

Wonder what happened to Andy?

For the life of me I can't seem to find the links to the 9k schemos that were on the forum..