Offered is an excellent example of the extremely rare Pierson KP-81 receiver.  Designed by Karl Pierson, the architect of the famous Patterson receivers, this impressive 20-tub

The KP-81 was Pierson’s vision for the ultimate communications receiver.  It is a very innovative design, having the following features:

·    A moving cast aluminum catacomb style band change mechanism to minimize stray capacitance and noise generated by typical band switch arrangements.   James Millen of National used the same approach in his better receivers for the same reasons.

·    An noise silencer with settings for voice and CW having remarkable effectiveness.  This is not typical simple clipper type noise limiter!

·    A very useful Independent, 5-step, high and low tone controls adaptable to listening conditions.  Combined with a switch to select between audio modes of  “communications” or “normal”, provide superior audio filtering

·    An effective crystal filter that can be operated in either series or parallel mode.

·    A crystal calibrator which is integrated into the bandspread tuning capacitor.  When the bandspread is turned all the way to the left  the, 100 kHz calibrator automatically comes on.  After setting the main tuning so that the calibrator signal peaks, the operator can  tune the bandspread with confidence that its scale is reading correctly.

·    Elegantly designed tuning indicators consisting of a vertical glass rod behind each tuning dial and light projectors farther back in the chassis.  The lights project onto the glass rods and the curvature of the rods produces a thin bright line surrounded by a dark band on each side.  It is a superior design with no dial cords or pointers to fool with.  

·    Band in use masking.

·    Very rugged heavy gauge brass tuning capacitors.

·    A modular design allowing removal of the two main modules allows easy access for repairs.  Simply unplug the connector cable and remove four screws and it is out in your hand to work on.  

·    An effective squelch control.

·    An all in one BFO control that both turns on and tunes the BFO, using an elegantly simple design.

·    Fold down front props, as used on modern test equipment, to tilt the front of the receiver up for ease of viewing.

·    A separate power supply with a heavy connecting cable to keep noise away from the receiver.  The power supply is housed inside a matching speaker housing with a large high quality Jensen speaker.

The condition of this receiver is excellent. There is minor paint loss in a few small spots along the edges, as shown in the photos.  All resistors and capacitors have been replaced in the center module on top of the chassis.  All out of tolerance resistors and capacitors have been replaced throughout the rest of the receiver, including the IF cans. However, because of the age of the equipment, there is no warrantee of any kind implied. 

Professionally aligned K4ICL, the receiver works well on all bands and the R-meter (not S-meter) is sensitive and effective.

Twenty tube receivers with this level of sophistication and quality are quite rare.  Our research reveals as few as 300 of these were manufactured, though the serial number of this one is 2002.
    

Because this is a heavy radio it will take a lot of layers of dense foam to protect it for shipping.  It will be relatively expensive to pack and ship to ensure its safe arrival.  The power supply will be shipped separately. The buyer is encouraged to pick it up to save on shipping.  If so, we will hold for future pick up for up to three months.