Here is your chance to own a piece of 1960's music history. The 50's and 60's were an extremely exciting time for sound engineering. Musicians and sound engineers were working together in the studio and on the road creating, then fine tuning new ways to manipulate sounds from guitars, vocals and other instruments. "Reverb" was one of the first effects and "echo" was also a big one. In the early days, devices were very large, quickly being replaced by a footswitch by the late 60's and early 70's.

This device is probably one-of-a-kind. It was made by the Altair Company. It is called the Model EG-600 Echo Amp. This prototype also appears to have been modified by someone adding both overdrive and Reverb. It has 2 channels in and one channel out.
It is missing the power cord and the screws to the front cover (8) and the screws for the amplifier (3) inside. I have temporarily replaced the 3 screws inside the cabinet that hold the amp, so it could be shipped safely. Besides that it appears to be complete and original.
I took a lot of pictures inside the unit, but if you need more, just ask. I think I captured the essence of the device. "It has a 4 tube amp that includes a 6x4, which is an indirectly heated full wave rectifier tube for small currents. It has a 12AX7, which is the workhorse of almost all vintage tube amps. The 12AX7 is a miniature high-mu twin triode. The 12AX7 is typically used as a class-A amplifier in the hi-fi, professional line and microphone preamps and is usually, always found in the preamp sections of most tube guitar amps. This tube is used a lot for that purpose and is an essential ingredient to the rock guitar sound, pretty much defining the sound of rock guitar from the 1950s to today. - courtesy of "effectrode.com"
The amp also has a 6BA6, which is a miniature remote-cutoff pentode primarily designed for use as a high-gain radio-frequency or intermediate-frequency amplifier. Features include small size, low grid-plate capacitance, and high transconductance.
This echo device is huge by today's standards. It measures 11" x 11" x 18", then add another 1"+ for the knobs in front. It is a behemoth and so rare, only a few of you out there are going to know what it is. It is still a viable working piece of equipment and a museum quality addition to any collection!