Building my Pultec EQP-1A

Making Stuff, Studio Comments (0)

My little holiday project this summer was to build a pair of Pultec EQs, one for me and one for my partner in crime at HopeStreet, Bob.  I chose to source everything from RecProAudio to save finding suitable parts from separate vendors, but also because Ron has commissioned hand made capacitors for the filter stage, and chosen high quality Sowter and Hammond transformers and the Cinemag Pultec replacement inductor.  It’s a full point-to-point job with a silk-screened chassis and the original tube make-up gain stage.

I had kind of underestimated how fiddly a point-to-point build would be.  Most of the things I’ve built I’ve sourced or etched a PCB for – with this build, there is a lot of interconnecting wire to assemble, and it can get messy!  Lucky Ron has some photos that show you a good order to assemble in, which prevented me creating a birds nest of hook-up! It gave me a new-found appreciation for the artisan-like skills that designers needed to build electronic devices before the days of the PCB.  There’s a real elegance to a good design/layout.

Pretty happy with how they turned out! They sound very transparent when the filters aren’t engaged, but then oh so sweet when you give it a twirl.

 

  • You need to assemble/prepare all the switches first
  • Front panels with switches installed
  • Don't drop this bit (took me 10 minutes to find it in the carpet!)
  • Rear panel houses the amp section and output transformer
  • Assembling the amp
  • Ampy and power supply fully assembled
  • Filter board and front panel
  • Attaching the rear panel/amp to the filter section
  • Completed unit
  • Did I mention I made 2?
  • Completed units
  • Smoke test!
  • Wiring can get messy
  • Close up of the power supply and inductor
  • Output transformer and the big caps
  • Another close up
  • Finished units on their maiden voyage at The Aviary

» Making Stuff, Studio » Building my Pultec EQP-1A
On February 5, 2013
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