SB4000 Bus Compressor – Build – Finished

Well, we finally did it;  talsit and I finally finished building the SB4000 compressor.

Here are some images of our handiwork.  The meticulous wiring layout is mostly due to talsit.  Firstly you can see the heat-shrink applied to all bare terminals – here the compression engage and side-chain switches, and even heat-shrink also applied to cable bundles for support:

Next you can see some of the XLR wiring at the back, which uses a star-grounding scheme, that means each pair of XLR’s ( left and right ) is returned to ground separately ( which helps reduce noise and hiss ):

Next you can see the mains switch which has been hot glue-gunned for protection to remove any possibility of direct exposure to a bare live mains voltage ( should you feel the need to stick you face inside of the box whilst it’s on…. ) and the cable-ties for strain relief and rigidity to movement and bumps – it’s all about safety:

We also made sure that for future possible tweaks, things would be tied down, but not TOO much so – hence the plastic clip is used with a cable-tie, since the cable was too thick to fit through it directly and it means easy less fiddly access later on – you can also see the ribbon cable that feeds the display here too:

Red and Blue cabling was used for a consistent colour scheme throughout – to match the blue capacitors and the red circuit board – attention to detail was important to everyone involved:

For those who bought a kit of parts from diypartssupply, you would all have the same meter.  It is marked with + and – slightly indented into the white plastic, which took us a while to find…. Noting that throughout Red is + and Blue is – we hope that these images might help some other people figure out how to wire it.  We also checked this with a diode checker ( which can verify the LED on the meter – the small tabs ) and the diode check on your multimeter can move the meter also to verify it’s polarity and orientation – which we verified before soldering:

And here it is, in all it’s finished glory – waiting only for some better and sexier pot and switch knobs, and some testing and calibration – which I’ll write about next time.  It has been switched on and neither exploded nor got hot, and the switch lights and start-up procedure seemed perfectly fine.  The voltages also check out perfectly – so hopefully that means we have a fully functional compressor!:

2 thoughts on “SB4000 Bus Compressor – Build – Finished”

  1. Howdy! Congrats on the successful build. I’m in the process of building my own and documenting it on my blog. Seeing other thoroughly documented projects like yours has helped me immensely. Thanks for taking the time to show off your build!

  2. Nice clean build!
    Perfectly layouted and cabled….
    SB4000 layout seems to make things much easier as it was at times of the first GSSLs.
    Hope it sounds just as good as it looks!

    Best regards,

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.