My New 1U GSSL Design (AKA SB4000) RELEASED!!! - GOTO PAGE 9 FOR ORDERING INFO!

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snipsnip said:
what happened with the mini pushbuttons?  Did you decide to go with toggle switches instead?

My Proto will just be the standard kind.  For production you'll have to use either toggle switches, or illuminated (I hope).  There's a slight logistics problem with the illuminated.  I have to cram another relay in somehow, but I believe I can pull it off.  3 of those 4 pushbuttons already control relays, so I can just piggyback the 12V they're switching to light the switch up.  The 4th one was just toggling a single signal, didn't put in a relay for that one because it wasn't neccesary at the time and therefore just a waste of board space and money.  There will be a tiny little mounting board if you want to use the illuminated type (one board for each pair of pushbuttons).  It actually makes things even easier as it reduces the soldertail wiring (which I despise), and also eliminates 2 wires by having them mount on a mini board.

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ptown - You priced up your kits yet or is this too early? ;)
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It's a little early yet.  Both of us will have all the info for you guys as soon as I get this thing up and running.  Should be starting to power some of it up this evening.
 
It's aliiiiiiiiiiive........... It's aliiiiiiiiiiive........

Holy crap, I don't stinkin believe it.  It works.  First try.  Right out of the box.  No wrong values.  No screwed up nets.  No backwards parts.  No audible distortion.  No 60Hz hum.  No relays popping.  No fluctuatiing power rails.  Nothing.  Turned it on and went right to smashing a drum track.  Still quite can't believe it being there's over a 1000 things that could have gone wrong (literally).  I haven't tested the hpf or baragraph yet, those are next, but the heart of it is rock solid.  Don't really expect any issues with the hpf, it's pretty straight forward, at the moment I have it wired to bypass it.  The bargraph is the only thing that may need some slight value tweaking, but if that's the only thing I need to do I think that's a feat in itself.  I also haven't started to fine tune everything yet, and need to put it on the scope here yet to really see what's going on with thd and noise floor, etc.  But all and all things are looking very good.
 
mata_haze said:
AMAZING...simply great!

would it manage to drive an output trafo as well?

Best,
Mattia.

I don't see why not?  I mean I've never done it, so I can't say first hand what's involved - but correct me if I'm wrong with the GSSL it's as simple as changing the 4 100R output resistors to 22R (I think) and wiring the tranny between the output connectors and the XLR's, right?  Nothing more to it than that?  If so, then it's the same exact thing here.
 
ruckus328 said:
mata_haze said:
AMAZING...simply great!

would it manage to drive an output trafo as well?

Best,
Mattia.

I don't see why not?  I mean I've never done it, so I can't say first hand what's involved - but correct me if I'm wrong with the GSSL it's as simple as changing the 4 100R output resistors to 22R (I think) and wiring the tranny between the output connectors and the XLR's, right?  Nothing more to it than that?  If so, then it's the same exact thing here.

I was under the impression (perhaps wrongly?) that you were using THAT 124X line receivers and 164X line drivers in this design?  If that's the case then I can say from experience that the 164X drives a transformer very very well, I have them driving Cinemags and Lundahls in 2 compressors.

Well done on the design/proto, seems the many hours you put in were not in vain.

Cheerss,
Ruairi
 
Congrats! that's amazing considering the complexity of the design, at least from looking at it.  :)

When I finally get around to a SSL comp build, I will make sure to check out the kit!  8)

cheers

Mike
 
Thanks for all the comments guys!

Ruairi:

No, I stuck with 5532/34 (although personally I use OPA2604/604).  I decided to stay clear of the THAT chips as they're one source parts, I think there's some pin compatible TI & AD chips, but to just be honest I didn't look into it.


I wired up the hpf last night and ran some RMAA tests.  HPF circuits work fine.  No drop when switching between Oxford & Aarhus modes (I compensated for the gain difference when switching)  Those "Tilt" circuits really are nice, aren't they? - it was my first time hearing them.  Really glad I added them now, I can definitely see myself using them alot on the drum buss.  EXT Input seems to be working, I haven't actually hooked up an external signal to "duck", but unit stops compressing when I press the external in button just as it should.  I'll know for certain this function is in order this weekend, but see no reason why it wouldn't be.  RMAA test showed noise floor at -100dB.  My CRC fitted GSSL comes in a -101dB.  I was honestly hoping for -105 to -110.  Going to put it on the scope today and see if any of the rails are noisier than the others.  And want to play with some things on the power supply to see if I can get it down any further.  Stereo crosstalk is down at -100dB as well.

All that's left electrically is the bargraph circuit.  And I have a number of mechanical/silkscreen issues to address.  Waiting on some new switch samples before I can finalize the front panel scheme.  One thing I'm starting to debate if I should change - I have the compressor in Aarhus mode by default.  I'm wondering if I should have it in Oxford as default.  All of the silkscreen pushbutton text reads with the button IN, then OUT.  So it will read "Stereo/Mono" like in my pic if I leave it as is.  Think it looks a little nicer to read "Mono/Stereo".  Thoughts anyone?
 
How's it coming along? I'm Getting into DIY and looking for a first project. I wanted to do the GSSL, but it seems I'll be in for a Shadowbuss-board or two :D Not sure about the faceplates though, might prefer some custom made ones with my own design...
 
Things are going very good but alot of testing involved for a thing of this magnitude.  Are features are completely functional but I'm making some minor improvements/adjustments.  I believe I'm done tweaking the power supply at this point.  Noise levels from 5Hz to 50KHz are at -130db on an RMAA scale.  Not too shabby.  Too be honest the power supply is overkill at this point, but NOBODY will have noise/power issues.  The grounding scheme is very simple, just a simple wire from the power supply to the star ground, pin 1 of the inputs/output XLR's to star ground, and IEC ground to star ground as well of course.  Adding CRC to the Power Supply Inputs does absolutely nothing to decrease noise floor at this point, I think I've crossed the threshold of how quiet you can get this thing.  I've got THD readings of .002%.  Going to do some adjustments in the audio section and increase L/R isolation a bit.  I'm getting about 10db more R>L crosstalk than L>R at 20KHz.  Crosstalk levels below 10KHz are down around -90db or so.  That being said, highest R>L crosstalk point is -65db at 20KHZ (still acceptable), but I'm annoyed by this more than anything so going to try to get that down to at least the -80db area.  I have a good idea where the culprit is, so going to do some trace cutting and jumpering to confirm this.  Bargraph is working great and looks awesome.  It's definiately the icing on the cake and really glad I incorporated it.

If you want to do your own faceplate you're more than welcome to, but a word of caution, if you want to use all of the features, you're going to pretty much need stick to the layout I've got, there's not really any other way to cram everything in there otherwise.  Also, if you're planning to use the bargraph, have you panel professionally made.  It mounts to the rear of the front panel, and is visable through a rectangle cutout, but there's no front bezel, so if you try to hog out the bargraph cutout yourself, it will look like crap, trust me.  If you don't want to use the bargraph, like I had previously mentioned, just break it off - but to be honest I don't know why you wouldn't want it, it's an awesome feature.  That all being said, I'll be showing my final frontpanel design in about a week or so, I'm VERY happy with it.  It looks totally like anything else you'd go into the store and buy, which was what I was aiming for.  I also decided to not put the name Shadowbuss on the front but rather a model, was thinking something like SB4000 or something along those lines.  Ties it in with the original, and you'll all know what the SB stands for, but makes it sound a little more professional and will look good in the studio.

Because of the additional tweaking I'm doing, it's mandatory for me to do one more round of Prototyping before I pull the trigger on production boards.  Even though it's just minor tweaking, I don't want to roll the dice on something like this without having built the absolute final version myself first.  Will have my next prototype round in a couple weeks.  All in all thanks for all of the support and patience guys, I can honestly say the wait will be worth it, this was an incredibally easy & fun build.  I'll post some new pics of the finished unit later today.
 
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