The SB4001 pushes the limits and sets new standards for the 500 Series Format. Boasting Quad VCA’s, 6 ratio’s, 10 Attack Times, High Pass/Boost/Slope Sidechain Filters, Wet/Dry Blend Control, External (Key) Input, Classic Stepped Release Settings, Classic And Alternate Auto Release, Variable Release Control, as well as “Grind” Mode (a proprietary valve style harmonic drive adding vintage color), the SB4001 is capable of delivering whatever sound you need. Whether Clean, Dirty, Vintage, Subtle, or Crushed, the SB4001 is sure to be one of the most flexible compressors in your arsenal.

All units are made in the USA to an exceptional level of craft and workmanship.



  • Made in the City of Brotherly Love: Philadelphia, USA.
  • Quad VCA’s (For Superior Dynamic Range)
  • Electronically Balanced
  • True Bypass (Relay Controlled)
  • Protection From 48V Phantom Power
  • Powder Coated Front Panel For Extra Durability.
  • All Hand Made Thru Hole Main Audio Path
  • Ratios – 1.5,2,4,6,8,10
  • Attack Times (Stepped) – .1,.3,1,3,5,10,15,20,25,30,40,50
  • Release Times (Stepped) – .3,.6,1.2, Classic Auto release (A1), Alternate Auto Release (A2)
  • Release Times (Variable – Engaged By Last Position On Stepped Switch) – Any Time From .1 Sec to 1.2 Sec
  • Sidechain Filters – 60Hz, 90Hz, 120Hz, Boost Mode, Slope Mode
  • Wet/Dry Blend (For Parallel Processing)
  • “Grind” Mode – Special Valve Style Harmonic Drive Mode, adding vintage color
  • External/Key Input – Accepts Balanced or Unbalanced Inputs (inserted before sidechain filters)
  • Gain (-6 to +18)
  • Premium Grayhill Rotary Switches
  • Premium Sealed Pots
  • All Machined Aluminum Knobs

Review by Grammy Award Winning
Producer / Composer / Engineer William "Bill" Pearson

“I was excited to try the SB4001. The buzz on the street was that it was a fantastic buss compressor that went the extra mile – and beyond. I was expecting greatness and it did not disappoint. I had been on the hunt for a flexible 2 buss compressor for quite some time. Right from the outset, the build quality was impressive, but from the moment I inserted it into my analog 2 buss chain, I knew I’d be keeping it. The mix I was already working on instantly became much “larger” and the glue factor was off the hook. Actually, a touch TOO “off the hook” for my personal mixing esthetic, and that’s where the blend control came in. Backing off to around 40% wet made all the difference for me. This mix still needed to be dynamic and breath, and the 4001 did just what it took to make the mix simultaneously pop while still retaining dynamics. Awesome!! How did I live without this guy?? There is so much this thing can do, and it’s so versatile, I don’t expect to be removing it from my 2 buss chain anytime soon. Thanks Mike for making me look great with such an awesome box!!!”

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