Active analog crossover, designed by Nelson Pass specifically for PureAudioProject and our Open Baffle Speakers.

Based on the design of the legendary B5 crossover, the JFet based crossover circuits allow smooth and continuous -12db low and high pass filtering, between 100hz to 550hz.

Also, PAP-C1 features an adjustable low-bass boost and upper-mid notch options.

In addition, PAP-C1 offers a continuous ‘loudness’ right on it’s front panel. This unique option allows optimal low/high balance at any volume, even the lowest one…

All these plus the personal touch of Nelson Pass, allow audio fans to enjoy their open baffle speakers with their favourite amplifiers at best, in a pure-analog, smooth sounding bi-amping mode, and at any volume level !

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Nominal Input Impedance: 15 Kohms

Output Impedance: 500 Ohms

Measurments made into 10 Kohm loads

High frequency bandwidth: -0.5db @ 100KHz

Power consumption: 4 watts, max power output 20W

Power Supply: Input 110-240v AC, Output 24v DC

Dimensions (W,H,D): 8.5″ X 3.12″ X 13″; 21.5cm x 8cm x 33cm

Made by FirstWatt in the USA, for PureAudioProject

“A couple of months ago I bought a PAP-C1 from you and in the meantime it has found its place in my audioset. Included some pictures.

That PAP-C1 does EXACTLY what is promised: dividing the signal between 120 Hz – 550 Hz (and have the options for a bass boost and mid/high equalisation).

The turntable is a air-stabilised air-bearing 400 kgs affair. It’s my main source. The preamp is a PT8/4019a tube affair with stepped attenuators from measuring gear. The poweramp for the woofer are 2 monoblocks based on the Eimac 35TG triode (ultra-parafeed; 8 watt). The poweramp for the midrange is a stereoblock based on a single pushpull pair of 6C45’s (2,6 Watt). The poweramp for the tweeter is a stereoblock based on the E2c (1,1 Watt).

The PAP-C1 sends the low (below 500 Hz) directly to the 35TG amplifier which feeds the woofer and the mid/highs to both 6C45 + E2c amplifiers.

I’m impressed with the PAP-C1 as it adds nothing to the sound. It “simply” divides the signal as promised…

Positively surprised by the amount of ripple/noise rejection of the internal capacitors…

This is indeed a seriously well executed audio gear !  Don’t know of it’s the minimalistic and proper design or component-choice or the combination; it simply works perfectly. Thank you for making this available.”

Costomer, Netherland 


For Easy Wiring of Bi-Amped Speakers

Bi-amping requires thorough cabling solution, connecting the output of your power amps with binding posts to drivers with various industrial terminals…

We solve this complexity by supplying a simple Bi-amping Distribution Board with binding posts that receive your favorite Speakers Cables (Banana or Spades) and Gold Plated Screw Terminals to which you connect the inner cables that run to the specific drivers.

The Bi-amping Distribution Board is a one layer audiophile grade PCB, with outputs for main driver (full range, wide range, or tweeter) and two outputs for woofer. It features two output configurations for woofers, in series, when connecting to the center row of terminals, or in parallel, the upper row of terminals.

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