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...fabled...
Kenwood
KT-917

fm broadcast monitor







- Review by Mitch Margolis -

" The Kenwood KT-917 is a remarkable tour-de-force example of a meticulously engineered FM tuner. It sounds good; quality differences between stations and assorted recordings are quite plainly audible. It's big: About 18.5 x 6.4 x 18.3. It's heavy: About 33 lbs. And it's loaded with real radio type stuff, which is aimed at boosting RF and audio performance. Stuff you'll likely never see again in modern FM tuners due to component and set-up expense. What kind of stuff you ask?

9-gang(!) variable tuning capacitor for real front end selectivity, in addition to the filters in the Intermediate Frequency section. This keeps strong local stations from overloading the front end, allowing reception of unmolested distant signals.

Extremely quiet (low phase-noise) local oscillator circuit permits signal-to-noise ratio to reach 90 dB. No phase-locked-loop noise here.

Double-balanced mixer for I.F. conversion, usually seen in expensive commercial/industrial/military receivers. Best way to do the job though due to lowest harmonic and spurious output content.

Robust power supply has no slowly charring parts.

Dedicated multipath meter shows delayed-signal interference level. Great for pointing antennas either at the strongest signal, or more better, in the direction with the least multipath interference.

Low distortion, pulse-count, FM detector is free of the artifacts associated with conventional tuned-circuit demods, and does not drift or age.

Clever Distortion Detected Loop circuit monitors distortion caused by slight mistuning or multipath and slowly corrects errors until minimum possible distortion is reached.

Three I.F. filter bandwidths using Surface Acoustic Wave filters(!) rather than conventional tuned circuits. Tuned circuits can actually be pretty good, if there's enough of them, but they tend to need alignment periodically. SAW filters have better group delay and don't need occasional attention. This means the tuner will never start to sound fuzzy or congested over time due to IF component drift.

Sample-and-Hold 19kHz pilot and 38kHz subcarrier detection effectively ignores disturbances to sync pilot. This means that channel separation remains stable even when the signal strength is low.

Regenerated pilot from the S-and-H system is used to cancel the 19kHz pilot carrier rather than using clunky and treble-damaging tuned circuits to filter the pilot out. Muy Bueno!

Multiple antenna connections. Multiple audio output connections, all low impedance. Multipath oscilloscope output permits visual inspection of the amount and severity of multipath content via 'scope screen. Basically shows AM multipath content versus FM signal spread. Handy for choosing optimum antenna direction.

There's more but you get the idea. What about the sound? All of these features do their part to bring in more and better quality signals then would otherwise be available. The result is that the differences in sound quality and character between various stations seem almost artificially exaggerated. Stations running modest amounts of limiting clearly stand out as capable of providing exceptionally satisfying audio quality. Good live broadcasts have an especially compelling sonic personality. And dog-squeeze broadcasts still sounds like dog-squeeze broadcasts; not much to be done about that except tune away! The tuner doesn't impose any coloration of its own, but is instead quite neutral. Sound and music come through without that annoying tuner-homogenization effect one hears in the cheap stuff. If you live, as I do, between two FM radio markets then the combination of features and sound quality makes this tuner the one to have!

Other audio system elements: B&W 801 Mk-III speakers, VTL Deluxe-300 monoblock amps (O.P.T. by Mercury Magnetics).

Strengths: Very rigorous no-compromise design of RF, IF and audio stage design, handsome cosmetics.

Similar Products Used: Scott LT-110 and 310 FM tuners, Sony ST-S555ES. "




Usable sensitivity
1.9 mv

Signal-to-Noise Ratio
Mono  90 db
Stereo 84 db

THD at 1kHz Stereo
Wide    0.04%
Normal 0.09%
Narrow 0.12%

Capture Ratio
Wide    0.8db
Normal 1.4db
Narrow 1.7db

Alternate Channel Selectivity
Wide    35db
Normal 60db
Narrow 60db

Stereo Separation at 1kHz
Wide    60db
Normal 55db
Narrow 50db

Frequency Response
10~16kHz +0.2/-0.5db

Rejection
Spurious -125db
Image      -125db
IF             -125db

Dimentions
6.4"H - 18"W - 18"D

Weight
33 lbs net






AllegroSound
−  Established 1973  −
"love what you listen with"
Los Angeles, California USA
Rick@AllegroSound.com
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design & orig content ©AllegroSound, Los Angeles USA. All rights reserved.

AllegroSound
−  Established 1973  −
"love what you listen with"
Los Angeles, California USA
Rick@AllegroSound.com
telephone 323.960.5014

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