Beautiful and Rare Bose Spatial Control Fm/Am Stereo analogue receiver, model 551. It has a beautiful real walnut veneer cabinet, powerful 100 WPC power with Bipolar Discrete output transistors and beefy power supply. It has the incomparable vintage Bose design, craftsmanship, attention to detail, parts quality, beauty, performance and musicality that only Bose can offer. It is also unique in that it has the Bose 901 Equalizer built into the receiver for using the the top of the line Bose 901 speakers. Bose 901s require their matching equalizer for optimum sound. The receiver is in very nice well cared for condition, beautiful back lit analogue tuning dial, back lit analogue signal strength and tuning meter, illuminates the stereo beacon and locks in stations. It has an excellent phono section, and many inputs and controls for connections of multiple components. See the specs below. It is very attactive and has the fold down control panel door on the front, unique. Everything works, sounds very nice and is quite powerful. The shipping cost includes safe packing, insurance, prompt shipping and tracking number. Buy with confidence, see my feedback. Good listening, SonnY :))Bose Spatial Control ReceiverWell, Bose may not be known for their receivers but this is one nice looking stereo! This is the Bose Spatial Control Receiver which doesn’t seem to have a model number on it but I believe it is considered model 551. It puts out 100 watts per channel and has a built in EQ for the Bose 901 series IV speakers. Bose also made a model 550 that had a built in EQ as well but only sported 40 watts per channel and had no spatial control.The front of the receiver has a flip down panel to access the controls.The power switch is on the back of the unit and when it is on you can still turn the unit on and off by touching the Bose logo on the front of the unit.Specifications:Tuning range: FM, MWPower output: 100 watts per channel into 8Ω (stereo)Frequency response: 20Hz to 20kHzTotal harmonic distortion: 0.09%Input sensitivity: 2mV (MM), 200mV (line)Signal to noise ratio: 83dB (MM), 97dB (line)Channel separation: 60dB (MM), 65dB (line)Dimensions: 20-1/2 x 6-5/8 x 16-3/8 inchesWeight: 36.5lbsYear: 1979Here you can see the slider knobs used to control the EQ for the speakers.These Bose receivers aren’t that common and it’s probably due to the fact that not that many were sold. The sales copy explanation behind how the “spatial” effect worked was somewhat complicated and, of course, they were really designed to work with the Bose 901 speakers (though they could work with any speakers).Many customers probably opted for a more simple solution to their audio needs. Nonetheless, these receivers do sell for decent amounts of money. In fact, if you’re a Bose fan then one of these units is probably a necessity.