Independent Dual Power Supplies for Both Channels and a Separate Preamplifier Power Supply
Obviously, no stereo imaging can be true unless there is complete channel separation. And one of the drawbacks of conventional amplifiers is that a single power supply creates Dynamic Crosstalk Distortion - a fact first discovered by our own engineers. This form of distortion had been overlooked in conventional measuring methods, which reveal static, rather than dynamic distortion. Following this important discovery, Kenwood's engineers re-designed the power supply into two totally independent supply systems, each with a large separate power transformer, and four large 12,000 µF electrolytic capacitors. A transistorized voltage regulator reduces interference between stages. But not content with this, they also designed a separate power supply for the preamplifier stage to suppress interference between the power amplifier and preamplifier in the same channel. You could, in fact, call this a "three-power supply system"/ the effect is that Dynamic Crosstalk Distortion has been virtually eliminated. Transient response is much improved. Excellent damping yields crisp and accurate sound. And so reproduced sound - particularly in the bass frequencies - is wonderfully rich and clear.
Direct-Coupled Equalizer Section Realizes very High Signal-to-Noise-Ratio:
An exceptionally high 83 dB Signal-to-Noise-Ratio (IHF-A curve) for Phono 1 & 2 is the result of a well designed, three-stage, direct-coupled ICL equalizer section, using FETs. Both phase and transient response are excellent, and distortion is low over a very wide range. Moreover, the use of the Gain selector at the +10 dB position allows a high 73 dB Signal-to-Noise-Ratio: for phono 0,8 mV sensitivity. The maximum phono input level for Phono 1 is a high 250 mV RMS, so there's no danger of overloading when you're playing musical passages of exceptional dynamic range.
Sophisticated Tone Control Give You Real Mastery Over Your Sound
Kenwood's concern for musical purity has given top priority to tone controls, so an elaborate system has been devised to suit all individual listening conditions and needs. BAXANDALL negative feedback low distortion tone controls give you the advantage of great precision and enormous flexibility for adjustment. The control range is 17,5 dB, in 1,5 dB click0stop steps. There are two selectable turnover points, 400 Hz for bass and 3 kHz for treble. These let you precisely compensate for your room characteristics. Moreover, the tone defeat is not simply a tone-out switch, but a true bypassing circuit, so that distortion and channel crosstalk are eliminated and tonal quality retains its excellence.
Two Steep Slope Filters
Here again, a bypassing defeat circuit is used to minimize distortion. These two filters have a characteristic steep slope of 12 dB/oct, allowing the music to pass freely while cutting out interference. There is a high filter with a cut-off point of 8 kHz, and a subsonic filter with a cut-off point of 18 Hz. High frequency noises such as record scratch, and low or subsonic influence generated by record warp or turntable rumble are effectively eliminated.
Unique tape-Through Circuitry
Kenwood's versatile tape circuitry permits simultaneous recording of two tape decks, and monitoring of both. There's also inter-tape dubbing both ways. And there's our now familiar tape-through facility that lets you listen to a different source while recording or dubbing takes place.
The Simpler The Circuitry The Better The Sound
Many circuitry design improvements have been made to enhance tonal quality. Some of them are major developments such as our DC power amplifier and dual power supplies, developed at our laboratories. With a full ICL (Input Capacitor-less) system, ICL circuitry is used in both the crucial equalizer and tone control sections. For all these circuits, inputs are directly connected to the unit without having to pass through input capacitors which produce distortion. Moreover, if you look inside the KA-9100 you'll probably be surprised at how "clean" it looks. This is not just cosmetic treatment, however. We know that there are clear-cut audio advantages in reducing wiring, and by making direct connections to the printed circuit boards. The more wiring there is, the more chance for hum and noise and various kinds of distortion that affect the sound. One example is the speaker selector. Instead of long wiring leading to the back panel and picking up noise on the way, there's a long shaft, and the actual selector is next to the speaker terminals. There are many other examples of this wire elimination to be seen, all contributing towards the refinement of that special Kenwood tonal quality.
Professional, Full-Scale Attenuator Type Volume Control With Gain Control
The dual combination of a tree-step (+10db, 0, -10 dB) Gain control and full-scale attenuator type 32-step volume control provides you with highly accurate volume attenuation. This means that the entire audible range is increased or reduced logarithmically. Your sound, even at low levels, remains naturally balanced. The Gain control also is highly useful when using tape decks and turntables which need some compensation for sensitivity low throughout the attenuation range. As you can see on the back page, other comparable models rarely maintain this low residual noise level over the whole volume range.
Two-Step Loudness Control
This loudness selector boosts the low range frequencies below two levels, giving you more control over which levels need more boosting. At -30 dB volume level, a 10 dB boost is made at 100 Hz or 30 Hz. You'll find this gives your ear the necessary compensation when listening at very low volume.
Pre-Out and Power-In Terminals
A thoughtful feature for the more professionally minded in the selector that allows the DC power amplifier and full ICL control amplifier to be used separately for multi-amp hi-fi systems.
Twin Power meters
These days, audiophiles are interested in every aspect of their components, and such features as accurate power monitors are essential. Kenwood's power meters are of a logarithmic compression type with two selectable ranges: 0,01W - 100 W and 0,01W -0,3W (for low level monitoring).
Specifications
Power Amplifier Section
Power Output: 90 watts per channel, minimum RMS, at 8 Ω. From 20 Hz to 20 kHz with no more than 0,03% Total harmonic Distortion:
Both Channel Driven :
95 + 95 watts (8 Ω) at 1,000 Hz
110 + 110 watts (4 Ω) at 1,000 Hz
Dynamic Power Output: 470 watts (4 Ω)
Total harmonic Distortion:
0,03% at rated power into 8 Ω
0,01% at 1 watt into 8 Ω
Intermodulation Distortion (60 Hz : 7 kHz = 4 : 1)
0,03% at rated power into 8 Ω
0,01% at 1 watt into 8 Ω
Power bandwidth: 5 Hz to 60,000 Hz
Frequency Response: DC to 100,000 Hz +0 dB. -1 dB
Signal-to-Noise-Ratio: 115 dB (short circuited)
Damping Factor: 50 at 8 Ω
Input Sensitivity/Impedance: 1,0 V/ 50 kΩ
Speaker Impedance: 4 Ω to 16 Ω
Pre-Amplifier Section
Input Sensitivity/Impedance
Phono 1 : 2,5 mV/50 kΩ
Phono 2 : 2,5 mV/50 k Ω
Tuner : 150 mV/50 kΩ
Aux : 150 mV/50 k Ω
Tape A, B : 150 mV/50 kΩ
Signal-to-Noise-Ratio:
Phono 1 : 83 dB
Phono 2 : 83 dB
Tuner : 100 db
Aux : 100 dB
Tape A, B : 100 dB
Maximum Input level Phono 1 : 250 mV 9rms) T.h.d 0,03% at 1,000 Hz
Output/ Level Impedance
Tape Rec (pin) : 150 mV/450 Ω
Tape Rec (DIN) : 30 mV/80 k Ω
Pre Out : 1 V/330 Ω
Frequency Response:
Phono : RIAA standard curve +0,2 dB, -0,2 dB
Aux. Tape : 7 Hz - 50 kHz +0 dB, -1 dB
Tone Control
Bass ; ±7,5 dB at 100 Hz (turnover at 400 Hz)
Treble : ±7,5 dB at 10 kHz (turnover at 3 kHz)
Loudness Control (-30 dB): +10 dB at 100 Hz; +10 dB at 30 Hz
Subsonic Filter: 18 Hz. 12 dB/oct.
High Filter ; 8 kHz, 12 dB/oct.
General
AC Outlets: 2 switched, 1 unswitched
Power Consumption: 660 watts at full power
Dimensions (W x H x D): 430 x 149 x 384 mm (16-15/16" x 5-7/8" x 15-1/8")
Weight (net): 16,7 kg (36,8 lbs)