General Answer: When an input is set to SSP mode the No.585 acts as a simple amplifier. In other words, the volume control in the No. 585 is disabled and the gain of its preamp is set to 1, so the No. 585 functions as if the signal source were connected directly to its power amplifier channels. However, under typical listening conditions, a preamp is almost always operated with a gain of significantly less than 1. In fact, for the preamp in the No. 585 to operate at a gain of 1 requires its volume to be set between 66 and 67, which is likely much higher than anyone sets their volume control for ordinary listening. This high effective volume setting in the No. 585 is necessary so that the volume control in the connected AVR/AVP can be used effectively. But if that AVR/AVP is noisy, or if the audio system is set up in an area susceptible to electromagnetic noise, the noise will be reproduced through the No.585. This will be most evident when there is no audio playing through the system but is usually imperceptible when audio is present. In the SSP mode the No.585 system does not introduce noise, but simply amplifies whatever is present on that input. For the best performance care must be taken with the volume level of the source, and it is recommended to always use the balanced inputs (XLR connectors - see owner’s manual for details) for any inputs you plan to set to SSP mode. Technical Explanation: In the past, the differing number of channels in each component made integration between two-channel and multichannel components difficult. Sending multichannel processor output signals to a stereo Preamplifier distorts calibrated processor output levels. Multichannel processor volume controls adjust the relative volume level of all channels in unison. However, stereo Preamplifier volume controls adjust the relative volume level of just the front left and right channels, leaving the center, surround, and subwoofer channels unaffected. To avoid these problems when the No.585 is connected with an associated surround-sound processor, the SSP mode allows selected input sources to pass through the No.585 without interference. When SSP mode is activated the No.585 volume control is deactivated to prevent the No.585 from distorting channel balance. As a result, the processor controls the relative volume level of all channels while maintaining its calibrated output levels. To connect the No.585 with a surround-sound processor (see illustration in owner’s manual): 1. Make sure the No.585 and all associated components are powered off and disconnected from electrical outlets. 2. Connect the output connectors on the surround-sound source component to the input connectors on the surround-sound processor. For example, if the source component is a Blu-ray disc player, connect it to the appropriate input connectors on the surround-sound processor. 3. Connect the front left and right output connectors on the processor to the desired input connectors on the No.585. For best performance, use balanced connections whenever possible. 4. Connect the center, surround, and subwoofer output connectors on the processor to the appropriate input connectors on the power amplifier(s). 5. Connect the No.585’s speaker outputs to the system’s front left and right (main) speakers. To activate the SSP mode for a selected input: CAUTION: Before activating the SSP mode for any input, set the associated surround sound processor volume control to a reasonable level to prevent sending dangerous signal levels to the associated loudspeakers. 1. Activate the Setup menu by pressing the Setup button. 2. Select Input Setup, and press Enter. 3. Select the input you wish to configure for SSP use, and press Enter. 4. Select SSP, and press Enter. 5. Set the SSP parameter to On. 6. Press the Setup button four times to step backward through the menu hierarchy and exit the Setup menu.