Anyone With Info & Specs - Calbest Stereoplex

I picked up this unit - 18 tube Am-Fm-MX "Stereoplex" Model 6400 receiver made by Calbest Electronics - LA, Calif. at an Estate Sale and was looking for any specs, info and value.

It has a date of 1/29/64 stamped on the chassis. It has a very unique woodgrain face and seperate tuning knobs and indicators for AM & FM.

It appears all original except that some tubes may have been replaced.

Any help would be appreciated...thanks
Found this in a "for sale" listing from some time ago, for a different Calbest model:
Calbest Electronics (Calbest Engineering and Electronics) was not a small unheard of company. They were one of the 8 Companies who founded the standards and rules for FM stereo operation in the US. They also (Harold Parker) held a patent for Stereophonic Transmission systems using Narrow Band F.M. Multiplex subcarrier frequencies. They invented the Poll-O-Meter, which was used by cable companies across the nation to determine what signals a television set was tuned to by beaming a signal at the antenna on a home. It was used by radio stations across the nation by Billboard to figure out who was listening to what songs to determine what their top hits were.

They seem to have disappeared off the radar completely and out of the audio history books. But it sure wasn't for lack of a quality product. Not much is known about this company overall or it's products. They were a group of engineers who tried (unsucessfully) to enter the audio market in a time when kit built amps and super high end audio was saturating the market. They also manufactured Televisions from 1947-1968.
They were purchased by Monarch Corporation in 1968.

My guess, based on experience with comparable equipment from other manufacturers from that period, and factoring in its rarity, is that it may be worth a few hundred dollars if in excellent cosmetic and functional condition, and considerably less if not.

As with any tube equipment containing an amplifier that has an output transformer, it should not be powered up without having a speaker load (or equivalent resistive load) connected. And as with any vintage piece, if it is not known to have been powered up in many years, when it is powered up initially the AC voltage should be brought up slowly over a period of many hours, using a variac or equivalent.

-- Al
Thank you Al...appreciate your time and info