SB4000 Support Thread

[romplex]

Make sure you have the comp in the right mode, if you're seeing really low voltage, its probably not set right.  (had the same issue with all 4 that ive built!)

yeah i saw this problem in other posts, but i've tried it in every possible switch combination and i still get the same small readings

 

[sr1200]

ext in should be OFF. That essentially bypasses the unit if theres nothing plugged in (kinda). Comp should be IN (the big red button on the end... provided you wired the switches correctly... ive messed that up more than twice )
I dont remember if SSL mode has to be on or off, but its in Ruck's PDF guide toward the end.

 

[romplex]

I tried this settings too, still no change, getting voltages below 1 volt at the test points

 

[romplex]

Thanks for the advice. I applied a balanced signal and re-calibrated up to CV levels (I can't calibrate further, as i can't get enough GR to so so) Still having the same problem tho. I have a better set of measurements now.

Applying a balanced signal to both inputs at once and measuring the input and output with my fluke (and later scope just to confirm my fluke readings) across pins 2 and 3 of the ins and outs I got the following results.

With the input signal reading 1.23 Vacrms I couldn't get gain reduction.
With the input at 18.9dBu (6.778vacrms) here are my GR readings
Ratio 2:1
Thresh -20  | 14.9dBu (4dB of GR)
Thresh +20 | 17.8 dBu (1.1dB of GR)

Ratio 4:1
Thresh -20  | 16.71dBu (2.19dB of GR)
Thresh +20 | 18.7 dBu ( 0.2dB of GR)

Ratio 10:1
No GR in any Thresh setting.

I adjusted the threshold trimmer on the board and these readings were the most GR I could get with it set anywhere (it is set fully CC for these readings)

it should be noted that I have variable resistors in every slot that the board would take them.

So, either there is a calibration trimmer that I'm totally missing, or I'm guessing it's something in the control board. Any leads in the right direction would be great.

Adam, it sounds like your problem lies somewhere in your sidechain signal.  You're passing audio so we can check off faulty VCA's. 

Does your makeup gain work? 

Which VCA's are you using? 

You don't by chance have JMP3/JMP6 (by the audio VCA's) installed do you?

You're getting correct +/-12V rails?

Otherwise you need to just trace the signal and find out where it craps out.  Look on the schematic, start at the beginning of the sidechain.  Put the unit in Stereo Sidechain (aka Turbo Mode) and feed it a signal, just set it to 1V RMS for sanity purposes. 

Check Left sidechain - TP8 - Got 1V?

OK, move on - TP11 Still have 1V?

Next check U16 Pin 7.  Continue on down the path, let me know your findings.  You'll start to have DC voltage at U16 Pin1 and U16 Pin14 as it's a rectifier circuit.

Hey, you know what, it just dawned on me, did you install a 47K at R169 right by the threshold pot????  If so jumper him instead (you can just solder a piece of wire across the resistor to short it out, no sense in trying to remove the resistor.  Try that first before you do anything else.

i just saw this post gonna try this and see if it makes a difference.

 

[sr1200]

Oh yeah... thats what i kept doing... make sure your meter is set to AC.

 

[romplex]

ok i think ive done it, i wasnt giving enought of a signal to the comp when testing for the voltages, while i was doing this tho i noticed i had the THAT 2181C's and the 2181A's in the wrong places so i swapped them about, but i think i may have damaged one as i put it in the wrong way round when i moved them and proceeded to turn the unit on without noticing my mistake, im gonna purchase  a new one.

so i've done most of the calibration the only thing i cant get right is the HPF T2 setting, i only get enough adjustment on VR to take it down to about 16 dB where it should be 10 dB

also when i switch the top switch next to the bargraph it jumps straight into the red is this normal?

 

[sr1200]

Keep in mind the bar graph is displaying in dBVU NOT FS. so if you're feeding it signal at like -12 dbfs (around... 3 of my meters say different things) its gonna pin.  Analog is a different animal than digital esp. when it comes to metering.

 

[ONE TOO]

Hi everybody ! Just ordered the stuff from Ruckus(my Xmas gift ;D), so happy to 2 join this awesome forum about this Great project ! Guess i'll have questions soon... Already went thru the 55 pages congrats to all of you,i've seen Great pictures of this project and learned a lot from your posts.
Special x-tra x-mas Thanx to Mike (bring the m*********in' Ruckus !) and of course Jakob@gyraf for sharing their knowledge and make all that possible!!!! Peace.

 

[EmptyMusicBox1]

Hi everyboby i'm EMPTYMUSICBOX ans i have just finish a SB4000 with QUAD VCA option :



i have just a problem for the ratio calibration i don't understand how have the +10db for out DAW to the compressor ... and when i turn VR16 it's verry verry slow an i finish max to -10db  on smaart or blue cat ....

And i search a PCB and BOM kit for an aditional Crush'n Blend Kit ( Wet/Dry) for the SB4000 where i can find that ?

How to wire a XLR combo jack for the sidechain  ?

thx you

 

[eeags]

Hi,

I'm working on a build right now and I would like to use eao switches that I have lying around like the original ssl.  My question is how to wire them (I have three so I'd also like to use one for the on/off switch, overkill I know) so that the 12V lamps get proper power.  I know the circuit is designed for much lower powered leds.

Thanks for your help,
Eric

 

[sage]

Finally me and Marson put up in the studio the gear built in the past few months and here is a FB page with pictures, thanks to all on this Forum that have helped with these great projects:

http://www.facebook.com/marsonaudio

sage

 

[RichardM]

Hi Guys,

Just a little confused by the R77 R83 R121 R125 markings on the back of the rev4 sb4000 pcb. I put the resistors on the front. Should they have gone on the back or should additional resistors go on the back?Also am I correct to not jump 8 and 9 if I am not using the quad VCA add on? Thanks in advance!


Rich

 

[ONE TOO]

Hi everybody! Was wondering about r76 and r 96? Pcb says 680 k and bom says 680 k and 220k i think... Which ones should i use? I build the quad vca version. Any advice? Thanx guys!

 

[ONE TOO]

Hi everybody! Was wondering about r76 and r 96? Pcb says 680 k and bom says 680 k and 220k i think... Which ones should i use? I build the quad vca version. Any advice? Thanx guys!

Ok sorry guys, got My answer, was listed on the quand vca bom...

 

[Neufneuf]

Hi I'm a newbie here!!! Bought the sb4000 kit and build it up and sounds great!!!
Right now we are at the point of getting all the values set up straight!!!-->>Fine Tuning ;-)

My Problem is that my LED baragraph  Shows me all the Time the same Level regardless if i Switch Input or Output ;-(. Checked all the cables and values but didn't find the Problem.
Can somebody help me Out.
Thanx!!! ;D

 

[sr1200]

This has been brought up a bunch of times in this thread. The meter is VU scale not fullscale.

 

[Moby]

This has been brought up a bunch of times in this thread. The meter is VU scale not fullscale.

This project was "on ice" for me for a long time and I finally decided to finish it. Regarding Led vu I would really like to hear comments from people using SB4000. Did you find it useful or it's just "some light on front panel" ? If so I would skip that part and design the front panel without it  8) I'ts already overstuffed and I don't have a place to include wet/dry pot  :-\

 

[darnell]

Hey all,

Got my SB4000 all up and running.  Sounds great.  But......

I def get some weird readings while going through the calibration steps when I get to the CV level section. 

"With the unit in SSL Mode (aka stereo Sidechain, aka Turbo), export a 1Khz test tone. Measure the AC voltage between TP8 and ground and TP10 and ground (TP8 & TP10 are located near J3 & K5). Write these voltages down. Note* - If you don’t get any voltage at TP10 it means you are not in SSL mode."

I get 6.98ac at TP8 and 6.99ac at TP10. 

"Adjust VR8 until the AC voltage at TP11 measures the same as TP8."

TP11 adjusted to 7.02ac

"Adjust VR7 until the AC voltage at TP12 measures the same as TP10."

Here's where things get tricky.  I can only get a voltage of more than .003ac on TP12 if the unit is in T1 or i flip the ext in detector (i have the i/o bridged for now).  T2, does not compress at all, and I get no voltage on Tp11 or TP12 when T2 is engaged, so I am assuming it's a problem within the sidechain.  I get no voltage off of U1b pin 7 unless I'm in T1 or external in.  At this point, I'm not sure where to look specifically for the issue. 

It does seem that the HPF switch is selecting freqs, just not the T2 setting.  I have checked continuity on the ribbon cable.  I have hit all solder joints in the u1 area.  No luck.

Anyone have an idea of how I could troubleshoot this further?

I'll post a pic so you can see what I am working with.

Thanks,
Daryl

 

[sr1200]

Moby, if you're using the unit with digital equipment running in FS, you're gonna see that meter pinned almost constantly unless you're using it on something very low level.  I have 2 of the units, first one sits on my drum bus, and the second is used on my mix bus.  Drum bus is ALWAYS fully lit. Mix bus, not always, but again, not very useful, since I can see the level coming in on my DAW.  IMO, probably could have done without the output meter altogether since a lot of users are no longer fully analog. 

 

[Moby]

Moby, if you're using the unit with digital equipment running in FS, you're gonna see that meter pinned almost constantly unless you're using it on something very low level.  I have 2 of the units, first one sits on my drum bus, and the second is used on my mix bus.  Drum bus is ALWAYS fully lit. Mix bus, not always, but again, not very useful, since I can see the level coming in on my DAW.  IMO, probably could have done without the output meter altogether since a lot of users are no longer fully analog.

I thought so. I don't need it  8) Thanks