SB4000 Support Thread

[ruckus328]

Well I just finished calibrating and doing a shoot out against the real deal, and I must say its pretty close to the real thing. a little darker, but very well done.

Haha, thanks!

I only found one issue, The Gain reduction meter doesn't react as is should, I'll have to look into that or maybe thats the way it is.

Depends on the meter - $30 meter isn't going to react as your $100 sifam.  And even those aren't completely linear at higher throws.

One thought- do you think the power supply would be able to handle adding 3 more bar graphs, I'm thinking like the UA 2192

Definately no.  The 12V regulator is running hot as it is, each of those bargraphs pull about 100mA, I wouldn't feel safe adding 1 more, let alone 3 with the existing supply.  3 would fry the regulator without the addition of a massive heatsink - you'd be burning like 7Watts.

 

[dtrax]

Started working on this puppy yesterday. So far, I've put in about 12 hours of work (yea, I have no life lol). While it's been relatively easy, stuffing that PCB isn't for the faint of heart. I think it took me about 8 hours alone. Now I understand why SSL sells 'em for $3500...  :

Here's a pic of my progress:

I'm using those plastic standoffs with the sticky pads on the bottom. I love 'em, and requires a bit less work than drilling the chassis and using M4 nuts/screws. The chassis is from DIY Parts Supply, so I have to figure out a way to notch out the bottom lip. I don't have a dremel so I'll probably just order one, but I may get crafty with my drill press.

Thanks Mike for a great project. The assembly guide is very nice with this build. I'll report back when completed... I don't anticipate any issues (knock on wood)!

 

[Neily]

That looks great dude!

I think my board and front panel arrived today! Got a card for a parcel to pick up tomorrow! I can get started now! Got the same kit/case from ptown. So stoked! Wooo!!!!

Started working on this puppy yesterday. So far, I've put in about 12 hours of work (yea, I have no life lol). While it's been relatively easy, stuffing that PCB isn't for the faint of heart. I think it took me about 8 hours alone. Now I understand why SSL sells 'em for $3500...  :

Here's a pic of my progress:

I'm using those plastic standoffs with the sticky pads on the bottom. I love 'em, and requires a bit less work than drilling the chassis and using M4 nuts/screws. The chassis is from DIY Parts Supply, so I have to figure out a way to notch out the bottom lip. I don't have a dremel so I'll probably just order one, but I may get crafty with my drill press. :'(

Thanks Mike for a great project. The assembly guide is very nice with this build. I'll report back when completed... I don't anticipate any issues (knock on wood)!

 

[dtrax]

Well, naturally I spoke too soon. I finished up assembly and fired her up as the guide suggested; e.g., test pwr supply pcb with main pcb and control pcb disconnected. I'm getting some decent voltage on the rails. ~15.2VDC +/- and 11.77VDC +/- for the 15 and 12 volt rails respectively. That's an acceptable range, no?

My first issue was that when the compressor was engaged, it wasn't passing audio on the right side (it passed audio in bypass, as it should since it's hardwire. That at least ruled out bad wiring to the jacks). What happened was I installed one of the 2181A's backwards in U17.  I flipped it around to the correct orientation and the level on the right channel is SUPER loud. Suffice it to say, it's cooked. The VR trimmer pot can't adjust it for anything useful. I'm going to order a new one (a few, just to be safe...). For the hell of it, I pull one of the VCA's from the sidechain pcb and replaced the blown one, and it passes level just fine - both channels are trimmed to exactly the same level when engaged and when bypassed. FWIW, The output gain pot works as advertised. I also put the 2181 back into the sidechain pcb once I confirmed both channels at least pass audio.

My second problem, while it may be related to my first problem, is that I'm getting no compression at all. Even when I pulled the bad 2181A, I figured the left side should still function. Alas, no go. I've triple checked my wiring, diodes, caps, IC's and whatnot; I'm not seeing where I'm going wrong. Any insight? How should I go about testing the circuit to narrow down the problem? Eyeballing the pcb has only gotten me so far...

My ribbon cable crimping is a bit suspect, but I checked continuity of the cable and it's fine. I'm going to order new assemblies/headers and ribbon cables and make a new one now that I've figured out the best way to go about it. Just being thorough here.

 

[sr1200]

Did you you put the resistor next to the threshold pot? (if so, jump it, i was getting the same thing, i ran a lead between the two on the back of the board to bypass it... works fine now)


Neily, i can see you added that resistor in your pics... might wanna get a jumper ready as well.

 

[funkmuffin]

Just finished mine last night, and got it calibrated before I went to bed.  Haven't had a chance to actually hear it yet, since my monitors were off so I didn't need to listen to 1k for an hour.

What's all this about a resistor next tot he thresh pot?

 

[dtrax]

Did you you put the resistor next to the threshold pot? (if so, jump it, i was getting the same thing, i ran a lead between the two on the back of the board to bypass it... works fine now)


Neily, i can see you added that resistor in your pics... might wanna get a jumper ready as well.

Do you mean R169; the one where the PCB says "47k or jump"? I just tried pulling it out and jumping with some extra lead wire. Still, no go. ???

 

[Winetree]

Where do you get the plastic standoffs with the sticky pads on the bottom?

 

[Davo]

Where do you get the plastic standoffs with the sticky pads on the bottom?

you can get em at mouser or smallbear etc... just search for "adhesive standoffs"

cheers

 

[sr1200]

The only other thing that was wrong with mine was the actual meter wiring was backwards. (oh... I also had the EXT in engaged which basically bypasses the unit if nothing is plugged into it)

 

[ruckus328]

Did you you put the resistor next to the threshold pot? (if so, jump it, i was getting the same thing, i ran a lead between the two on the back of the board to bypass it... works fine now)


Neily, i can see you added that resistor in your pics... might wanna get a jumper ready as well.

Do you mean R169; the one where the PCB says "47k or jump"? I just tried pulling it out and jumping with some extra lead wire. Still, no go. ???

Is makeup gain working?

First things I would do is make sure the ribbon cable isn't in backwards, VCA jumpers are installed correctly, and ensure the "external in" is not accidentally engaged (which would severe the sidechain and make compression impossible without an external signal) - just temporarily disconnect one of the wires from J8, doesn't matter which one, this will make sure the relay isn't switched on.

If the unit is passing audio when engaged then we can rule out the audio path and the problem lies in the sidechain - you need to crack open the schematic and start tracing the sidechain signal until it stops.  Sidechain section starts at K5 and runs along the bottom of the schematic.  

Put it in turbo (aka stereo sidechain, aka oxford) mode.  Make sure your hpf is off.  With the unit in bypass feed it a 1V RMS 1khz signal.  

Disengage the bypass, Check the left sidechain (we can ignore the right sidechain for the moment - if either sidechain is working correctly it will compress)- measure AC voltage between Tp8 & ground - you should have 1V RMS still.

Measure Voltage between Tp11 & ground - you should have AC voltage here (though it may not be 1V if you haven't done the calibration procedure).  If you do have some AC voltage, adjust VR8 until you have 1V RMS here as well (in other words so you have the same 1V RMS at TP11 as you do at Tp8 to ensure unit gain.)  If you don't have any AC volts then your problem lies somewhere between these 2 points (and I would suspect the ribbon cable).  

If you do have AC voltage then continue down the schematic path.  You'll start to see DC voltage on the signal pins around U16 (Gates A & D).

Bottom line is at some point, the signal will disappear, once you figure out where that point is, it will be easy to narrow down the problem.

 

[ruckus328]

(oh... I also had the EXT in engaged which basically bypasses the unit if nothing is plugged into it)

Yes, this is special hidden bonus  ;D - External In switch also acts as a soft bypass if you're not feeding any external signal.

 

[sr1200]

Just  a quick note, I had a chance to A/B/C the unit against an SSL Gcomp Rack unit (one of the white new ones) and the Universal Audio SSL Buscomp (ok and D... the "OTHER" universal audio 4K bus comp)

Results: In "standard" mode the SB4000 was DAMN close to the SSL unit. (theres a release time that is different between the units so i omit that setting)  IMO i actually liked the way the SB4000 handled itself better sounded a bit smoother to me.  When compared to the plugins, they were.... how to put this nicely... "similar" in the way they handled the audio, but there was definitely a sonic coloration difference.  Not saying the plugs were bad, but there was some definite mojo happening somewhere along the analog signal path.

I gotta say though the real WIN here is the oxford mode with the HPF... neither the plugin or the SSl unit have these stock, and I would trade the "fade" feature for these mods any day!

Absolutely incredible job man, I really appreciate the work you and ptown did to make this thing happen!

 

[Winetree]

Great to hear about the comparison.
I'm thinking about using a pair of DBX 202c Gold cans.
What would be the sound difference?

 

[Andreas Pfeiffer]

Started working on this puppy yesterday. So far, I've put in about 12 hours of work (yea, I have no life lol). While it's been relatively easy, stuffing that PCB isn't for the faint of heart. I think it took me about 8 hours alone. Now I understand why SSL sells 'em for   :

Here's a pic of my progress:

I'm using those plastic standoffs with the sticky pads on the bottom. I love 'em, and requires a bit less work than drilling the chassis and using M4 nuts/screws. The chassis is from DIY Parts Supply, so I have to figure out a way to notch out the bottom lip. I don't have a dremel so I'll probably just order one, but I may get crafty with my drill press.

Thanks Mike for a great project. The assembly guide is very nice with this build. I'll report back when completed... I don't anticipate any issues (knock on wood)!

great idea: plastic standoffs
do you think the glue last some years?

 

[dtrax]

Andreas: I suppose they will, but for a commercial unit I'd certainly use something more secure. I prefer the way the metal rail standoffs like the ones on the mnats/hairball 1176. But time will tell.

Mike: muchas gracias for the tips. I'm at work now but when I get home I'll get crackin. Fwiw makeup gain does work and the ribbon cable has good continuity. I'll report back what I find.

 

[sr1200]

Ribbon connectivity can be good, but if its backwards you'll get some issues.make sure the dots are on the same side of the cable.

 

[Neily]

Hey guys. Could someone tell me what jumpers i should be jumping and which ones i should not be jumping. (I'm only looking for standard operation)


From what I can gather i jump the following:

R169 instead of a 47k resistor.
JMP1, JMP4

Is this correct?

Leave everything else alone?

 

[Neily]

Hey guys. Could someone tell me what jumpers i should be jumping and which ones i should not be jumping. (I'm only looking for standard operation)


From what I can gather i jump the following:

R169 instead of a 47k resistor.
JMP1, JMP4

Is this correct?

Leave everything else alone?

Sorry guys, ignore this I'm an idiot. I found my answer in the schematic file.

 

[Neily]

WOOO! Up and running! Calibration time!