AA-11 Deluxe Stereo Preamplifier
- Separate basic and secondary controls
- Push button selected inputs—greatly simplified operation
- Self powered—DC filaments—silicon diode rectifiers
- Deluxe styling group
- Switch-selected loudness or volume control
- Cathode follower outputs for stereo tape recording
- "Derived" center-channel monophonic output
- Rumble and scratch filters for optimum record reproduction
- Channel and phase reversal switches for convenience
- Low distortion triode stage circuit design
- For use with any stereo or mono power amplifier
A Masterpiece in design and performance! ... This New Deluxe STEREO PREAMPLIFIER
Beautifully designed to match the acclaimed styling concept of the top of the Heathkit high-fidelity line, the new AA-11 Deluxe Stereo Preamplifier brings you every feature you've ever wanted in a "master-control" center. Both non-technical music lover and technically-inclined audio-phile alike will applaud its many refined features, professional quality performance and exceptional simplicity of operation. A real beauty designed for installation in the most elaborate of stereophonic systems.
To achieve both clean-lined design and simplicity of operation, all switches and controls are divided into two distinct groups; the first group is the basic, or primary, controls, which are located on the plastic front panel. The other group is composed of secondary controls which are located behind the hinged cover on the lower front panel. The primary controls consist of nine push-button switches for selection of five stereo inputs, three monophonic inputs and on/off switch; a dual-tandem VOLUME/LOUDNESS control (one knob) which varies volume level of both left and right channels simultaneously, and separate dual-concentric (friction clutched) Baxandall-type Bass and Treble controls for individual channel adjustment.
The primary switches allow fast, easy selection of (1) stereo phonograph (magnetic or ceramic); (2) stereo tape head; (3) stereo microphone; (4) stereo FM; (5) stereo auxiliary input; (6) monophonic AM tuner; (7) monophonic FM tuner; (8) monophonic auxiliary; and (9) OFF/ON switch. All equalization circuits are switched simultaneously by the program source selector buttons.
The secondary controls consist of (1) a BLEND control which varies from complete mixing of the left and right channel signals for monophonic output to complete separation for stereophonic listening, or any intermediate position to provide just the right amount of "center-fill" to eliminate the "hole-in-the-middle" effect; (2) a BALANCE control for adjusting channel outputs to equal amplitudes; (3) a SCRATCH FILTER switch to attenuate record surface noise; (4) a RUMBLE FILTER switch to attenuate turntable rumble; (5) a STEREO-MONO switch for monophonic record reproduction; (6) a CHANNEL REVERSAL switch to insure that each loudspeaker reproduces the correct stereo channel; (7) a PHASE REVERSAL switch to insure in-phase stereo speakers; and (8) a VOLUME-LOUDNESS switch which converts the volume control to a loudness control. The unique filter circuit employed for this purpose is so effective in maintaining proper tonal balance, even at exceptionally low background music levels, that correct and simultaneous adjustment of both volume and loudness may be achieved with a single control over its entire range . . . and it eliminates confusion when operated by a person unfamiliar with its function. Check the high performance specifications, convenience features and many extras you get at the amazingly low price of this quality preamplifier.
SPECIFICATIONS—Channels: Two. Inputs: 5 stereo each channel and 2 monophonic. Input Impedance: Tape head, 220 k ohms; Phono, 47 k ohms for magnetic, 75 k ohms when used with ceramic; Microphone, 500 k ohms; Multiplex 600 k ohms and Aux, 600 k ohms. All monophonic inputs 600 k ohms input impedance. Outputs: One low impedance to power amplifier and one low impedance to tape recorder in each channel plus a "derived center channel" monophonic output at 10 k ohms impedance. Frequency response: ± 1 db from 15-30000 cps. Harmonic distortion: Max. .15% @ 2.5 volts output. Intermodulation distortion: Max. .3% @ 2.5 volts output. Hum & noise All values relative to 2.5 V rms output; 2.5 mv input at Tape Head input, 50 db or better; 6 mv input at Mag. phono input, 60 db or better; 2.5 mv input at Microphone input, 60 db or better; .1 volt input at Aux. 75 db or better. Channel separation: 1 kc, 40 db or better. Rumble filter: 3 db down at 42 cycles. 12 db attenuation per octave. Scratch filter: 3 db down at 6 kc. 20 db attenuation per octave. Baxandall tone controls: 12 db boost, 16 db cut at 20 cps; 12 db boost, 20 db cut at 20,000 cps. Controls: Separate Bass & Treble, each channel; Volume-Loudness, Blend, Balance, Rumble Filter, Scratch Filter, Volume-Loudness switch, Stereo-Mono switch, 9 push button Source Selector switch, Phase Reversal switch, and Channel Reversal switch. Tube complement: (8) 12AX7, (2) 12AT7. Power requirements: 117 V AC 50-60 cycles. Dimensions: 5½" H x 11½" D x 15 5/8" W. Shipping Weight: 19 lbs.