SB4000 Support Thread

[wave]

It's Alive! I went through everything we've covered one more time (replaced the fuse, re-soldered the transformer leads). I turned it on and measured the 20VAC at the transformer connections. Then I connected the main board and got the following voltages:

-15.02
-12.02
0.0
12.0
15.22

That's what I'm talkin' about!

I think it was the fuse after all. Boy is this thing brighter in person!

I can't thank you guys enough for all the help!

Congrats!!!
Now get that calibration done and start squashin some stuff. I'm still enamored with how good the unit sounds! So sparkly and nice

 

[drjoe]

Well my power is sorted out but I'm not compressing. VU is dark and slammed at 20, Bargraph is not lighting up.

In my DAW, I get no change in level when bypassing the compressor.

No AC voltage on TP8, TP10, TP11, or TP12

I'm happy with my clean power supply. Tomorrow I'll start trying to diagnose the remaining problems.

 

[sr1200]

OK you might have the wires in the wrong spot if your meter is pinned (would mean theres a constant voltage going to it) swap out the wires you got going to the light and the input of the meter and see what happens. 

Also, remember, that the INPUTs of the unit are on the LEFT of the thing if youre looking at the back panel and the outputs are on the right.  If you plug the thing in backwards it will still pass signal in bypass but you get NOTHING when you enable the comp.  (i did 1/4" TRS on my second unit and plugged it in backwards more than once when re-doing my rack)

Also, trace out the rail leads to the main board.  meaning make sure the -12 on the PS board is going to the -12 on the main board the -15 to -15 +12 to +12.... you get the idea.

 

[wave]

Well my power is sorted out but I'm not compressing. VU is dark and slammed at 20, Bargraph is not lighting up.

In my DAW, I get no change in level when bypassing the compressor.

No AC voltage on TP8, TP10, TP11, or TP12

I'm happy with my clean power supply. Tomorrow I'll start trying to diagnose the remaining problems.

Maybe this will help with your meter

 

[sdrjones]

Hi All,

After about a year of spending an hour here and an hour there I've finally finished my SB4000.

Here are a few photos...

https://picasaweb.google.com/sdrjones/2012_01_07_ssl_finished?authuser=0&authkey=Gv1sRgCJLA7YjGpK6D4wE&feat=directlink

What a great fun build - thanks to ruckus for the boards and ptownkid for the top quality kit - and everyone here for asking so many questions so I didn't have to. This was bigger and more complex than anything I've built before and I couldn't have finished it without all the top info on here. 

 

[drjoe]

OK you might have the wires in the wrong spot if your meter is pinned (would mean theres a constant voltage going to it) swap out the wires you got going to the light and the input of the meter and see what happens. 

Also, remember, that the INPUTs of the unit are on the LEFT of the thing if youre looking at the back panel and the outputs are on the right.  If you plug the thing in backwards it will still pass signal in bypass but you get NOTHING when you enable the comp.  (i did 1/4" TRS on my second unit and plugged it in backwards more than once when re-doing my rack)

Also, trace out the rail leads to the main board.  meaning make sure the -12 on the PS board is going to the -12 on the main board the -15 to -15 +12 to +12.... you get the idea.

Yep, my +/- were switched with the A/K. Now it's illuminated and sitting at 0.

My Ins/Outs are correct.

Proper voltage getting to main board. TP1-TP7 all match corresponding screws at J14.

Maybe this will help with your meter

Thanks! This did the trick.


I'm still not measuring voltage anywhere past the J4/J5 (main board connection to power supply).

No AC voltage between GND and  TP8 - TP12.

My bargraph is not lighting up so I tried re-connecting the wires to J17 (on control board) When screwing the terminal down the meter jumps to full-on then slowly fades to black. I'm sure the wires are terminated properly but the meter doesn't stay lit. I'm getting proper +12VDC at the meter input.

Anything else I should try before unwiring the main board and checking for bad solder joints?

 

[drjoe]

I'm reading +15.22 VDC at the wiper of VR3 and VR4 (L + R DIST TRIM), but no voltage on any of the other Trimpots.

 

[wave]

I'm reading +15.22 VDC at the wiper of VR3 and VR4 (L + R DIST TRIM), but no voltage on any of the other Trimpots.

Are you feeding the unit a 1K test tone while you are measuring?

 

[drjoe]

I'm reading +15.22 VDC at the wiper of VR3 and VR4 (L + R DIST TRIM), but no voltage on any of the other Trimpots.

Are you feeding the unit a 1K test tone while you are measuring?

Yes, indeed.

 

[drjoe]

Getting +/-15VDC between GND and two of the large unlabeled holes where a dbx VCA would mount.

 

[wave]

Getting +/-15VDC between GND and two of the large unlabeled holes where a dbx VCA would mount.

Can you post a hi-res photo of your mainboard?

 

[drjoe]

This is the best I can do for close up right now.

 

[sr1200]

check your diodes

 

[wave]

This is the best I can do for close up right now.

It's hard to see. If you can get any higher res and maybe post to flikr or something so I can get a better look

 

[sr1200]

actually, check that your caps are not backwards also...

 

[drjoe]

check your diodes

actually, check that your caps are not backwards also...

All of my caps are are in proper polarity. Diodes all check out the same (Using diode function mode testing .600 - .699 in one direction and 1. in the other direction) without de-soldering one leg. Is removing one leg necessary to test my diodes if they all test similarly?

I'm getting either +/-12VDC or +/-15VDC or both on all of my op amps. I also get one leg of each op amp with a small voltage that corresponds to a control on the front panel. I'm pretty sure my power is getting everywhere nice and clean.

My bargraph is not lighting up with the -20db signal being fed, but lights up during power-up/down. No change in the signal to my DAW no matter what I change on the front panel.

Any other tests I can do to rule out issues?

 

[ruckus328]

check your diodes

actually, check that your caps are not backwards also...

All of my caps are are in proper polarity. Diodes all check out the same (Using diode function mode testing .600 - .699 in one direction and 1. in the other direction) without de-soldering one leg. Is removing one leg necessary to test my diodes if they all test similarly?

I'm getting either +/-12VDC or +/-15VDC or both on all of my op amps. I also get one leg of each op amp with a small voltage that corresponds to a control on the front panel. I'm pretty sure my power is getting everywhere nice and clean.

My bargraph is not lighting up with the -20db signal being fed, but lights up during power-up/down. No change in the signal to my DAW no matter what I change on the front panel.

Any other tests I can do to rule out issues?

Drjoe -

1) Is the unit passing audio in both bypass and engaged modes?

2) Is makeup gain working?

3) Did you jumper the resistor by the threshold pot that says "47K or jump"?

If your makeup gain is working, this might be a case of you're not feeding it a loud enough signal and/or you didn't jumper the resistor mentioned.  You say -20db but you don't say dbwhat.  If you're talking -20dbu, that's way too low of a signal, and the bargraph wouldn't light up, and you probably wouldn't be able to get her to compress either (even if you did jumper the resistor)

 

[drjoe]

check your diodes

actually, check that your caps are not backwards also...

All of my caps are are in proper polarity. Diodes all check out the same (Using diode function mode testing .600 - .699 in one direction and 1. in the other direction) without de-soldering one leg. Is removing one leg necessary to test my diodes if they all test similarly?

I'm getting either +/-12VDC or +/-15VDC or both on all of my op amps. I also get one leg of each op amp with a small voltage that corresponds to a control on the front panel. I'm pretty sure my power is getting everywhere nice and clean.

My bargraph is not lighting up with the -20db signal being fed, but lights up during power-up/down. No change in the signal to my DAW no matter what I change on the front panel.

Any other tests I can do to rule out issues?

Drjoe -

1) Is the unit passing audio in both bypass and engaged modes?

2) Is makeup gain working?

3) Did you jumper the resistor by the threshold pot that says "47K or jump"?

If your makeup gain is working, this might be a case of you're not feeding it a loud enough signal and/or you didn't jumper the resistor mentioned.  You say -20db but you don't say dbwhat.  If you're talking -20dbu, that's way too low of a signal, and the bargraph wouldn't light up, and you probably wouldn't be able to get her to compress either (even if you did jumper the resistor)

Thanks for the response, Ruckus.

Yes, the unit passes audio in all modes and whether it's on or off. I get the same steady signal back into my DAW no matter what I adjust on the front panel.

Makeup gain is not working. Nothing on the front panel is affecting the signal, though I detect voltage changes on the op amps when turning knobs.

I have a 47K resistor in the "47 or jump". Should I pull that out and replace it with a jumper?

Sending -20db from the signal generator plugin in protools set to peak. -20dbfs? The same signal sent through a dbx576 registers as -22 on the VU meter. Even when I boost the signal to where it clips the 576, I get no meter activity on the SB4000.

I flipped it over and hit a few suspect joints with a re-solder, but no change.

 

[sr1200]

is the external key input switched on? and is the compressor engaged?  (i dont mean to be married) ;-P

 

[drjoe]

is the external key input switched on? and is the compressor engaged?  (i dont mean to be married) ;-P

I disconnected the key input switch to rule that out and I've tried all other combinations of buttons to be sure they weren't wired backwards.

I'm still not getting any AC voltage on TP8 - TP12.