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SPL PASSEQ – No Longer Available

Passive EQ with 72 passive filters (36 boost/36 cut per channel) - 120V

Product Description

With 72 passive filters (36 x Boost, 36 x Cut per channel), the SPL PASSEQ surpasses all previous designs of this type by a wide margin. Each channel is divided into three Cut and three Boost bands, each offering 12 switchable frequency ranges. The Cut and Boost ranges are not identical; crossovers are designed to work with like a precise mechanic cogwheel so as to allow the engineer access to the largest possible number of optimal, wide-band S-curves with variable slopes.

A further noteworthy PASSEQ feature is its individual sonic adaptation of each inductive filter through separate coil/condenser/resistor combinations: In stark contrast to earlier filter design and construction, each PASSEQ filter is optimized for the frequency assigned. To ensure the best possible signal warmth, richness and musicality in processing, coils for critical voice frequencies are custom-made for the PASSEQ. This achieves the widest possible range and tonally appealing sound color palette from any passive EQ.


  • The most powerful passive EQ ever made — 144 passive filters (72 per channel) in one EQ
  • Individual coils per filter
  • Single core coils, which means that every one is wound individually on its own dedicated core, this excludes sonic degradation from mutual influences while at the same time improving THD values
  • 120 V makeup amplifiers based upon SPL unique SUPRA-OPs with 150 dB dynamic rage and 200 v/ms slew rate
  • Individual design and component specificity for each filter
  • Custom made coils for critical mid-frequency ranges
  • Boost and cut crossovers mesh perfectly so that with the high number of frequencies one can dependably command the most elaborate set of response curves that to date any passive EQ has offered
  • Transformers from Lundahl with perfectly matched sonic characteristics provide for balanced I/O stages
  • XLR contacts from Switchcraft
  • Switches and potentiometers from Elma and ALPS (including ALPS “Big Blue” with 41 steps)
  • Internal, linear power supply featuring a generously proportioned toroidal transformer and voltage selection (110-120 V, 60 Hz or 220-240 V, 50 Hz)

Product Specifications

Condition New
Tube or Solid State Solid State
Channels Dual-Channel
Chassis 19-inch Rack-mount
Rack Spaces 3u
Digital I/O No
EQ Type Parametric

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I would like to thank VK for the wonderful sales assistance, service and prices. This was my first purchase with you and it won't be my last. I only wish I'd discovered you years ago!
Matthew R.
I had two Grammy wins this year - Ray LaMontagne & Carolina Chocolate Drops. Both made with help from Vintage King!
Ryan F.
In almost 20 years in Pro audio buying, never did I receive a unit so well packed and exactly as described. Works flawlessly. The whole process has been so smooth. I will never hesitate to do business with you guys in the future and will recommend you to everyone I know.
Martin C.
This was my first experience buying something from Vintage King (although I surf the "used" categories on the website frequently!), and, despite being on the other side of the world, I had absolutely no trouble and everything went very smoothly.
Phil T.