Cary Audio Design SLP-88 Preamplifier Operations Manual
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SELECTOR SWITCH
The 4-position rotary switch connects a choice of input program source, both channels simultaneously. All program line sources are selected from this front panel 4 position switch. As you switch from source to source inputs, you will hear a soft mechanical clicking sound. This is normal and proper. The clicking sound is the double pole, double throw (DPDT) relays switching positions.
WARNING!!!
MAKE NO ATTEMPT TO PUT THE SLP-88 INTO SERVICE WITH THE TOP OFF OR THE CABINET OPEN. NEVER OPERATE THE SLP-88 WITH THE TOP COVER REMOVED. CONTACT WITH OPERATING VOLTAGES PRESENT INSIDE THE SLP-88 CAN BE FATAL!
HEADPHONE SWITCH AND JACK
Switching to the on position will engage two output transformers for the headphones. The primary of each transformer is connected via gold plated relays to the output section of the SLP-88. Please be aware, engaging this switch still allows signal to flow to the Rocket 88 or your basic power amp in your system. Turn off your amplifier to listen to headphones. With this design there are no interruptions in the output signal path. You will note that a blue LED will light above the headphone switch when it is turned to the on position. Make sure that you turn off the headphone switch before listening with your amplifier. It won’t harm anything but the low frequencies may be rolled off a bit to the amplifier if the headphone switch is left in the on position.
SPECIAL NOTE: Polarity Inverting Design
Your new SLP-88 is a polarity inverting gain stage preamplifier design. This means that a positive direction signal coming into the SLP-88 will be polarity inverted as it is amplified and sent to the power amplifier as a negative direction signal. The SLP-88 has one gain stage and one buffer stage in each channel. This polarity inversion is common on many high-end preamplifiers. If you are concerned about ‘Absolute Phase’ in your system, reverse the positive and negative leads either on the back of both loudspeakers or at the output terminals of the power amplifier. Remember to do this for both channels. Please remember, only switch the speaker cable polarity at the power amplifier or at the loudspeaker, not at both. Once again, operating in the polarity inverted phase mode will not harm or hurt anything.
