Dynaco Dynatuner FM-3

The Dynatuner is the culmination of more than threee years intensive research on a new concept of FM tuner design. Both the tuner and the stereomatic multiplex integrator represent a totally new design so inherently non-critical, so completely stable, so accurately reproducible, and so easily aligned that the average kit builder will have no difficulty in meeting its specifications in full, without the use of any test instruments whatsoever. The Dynatuner will be most recognized for its low distortion, but it has achieved the most successful blend of sensitivity, stability and linearity yet realized.

The Dynatuner is a kit in every sense; no sections are pre-built or pre-aligned - but Dyna's proven engineering has made it the easiest of all FM tuner kits to build,, and simpler than most competitive amplifiers. The use of heavy duty XXXP and fiberglas pre-punched circuit boards assures exact placement of all components - an essential factor in critical tuner circuits. The excellent specifications of the Dynatuner are possible, and guaranteeable, unit to unit, lab model to production kit, because of the extraordinary uniformity which etched circuits provide, and the inherent stability of the Dynatuner circuit configuration.

 

The design of the Dynatuner evidences several engineering innovations. A cathode coupled RF stage, rather than a cascode input, has been refined to provide equivalent sensitivity without the disadvantages of cross-modulation (images) generally associated with the cascode design. Outstanding AM supression has been achieved,, with noticeable improvement in difficult urban reception areas, and reduced interference from multipath dispersion. Four stages of IF amplification, furnishing four stages of progressive limiting, plus careful attention to limiter design, result in superior suppression of impulse noise such as auto interference, and yield more usable low level signals than other tuners of equivalent sensitivity. We have expended some gain (sensitivity) to achieve better low level limiting, where it counts the most. The Dynatuner limits on noise alone - contributing to its low interstation noise level.

 

The Dynatuner's combination of performance 9high sensitivity, lack of drift, low noise, high selectivity, and lowest distortion) reliability (top-grade etched circuit construction, highest quality parts, conservative operation of components, ease of alignment) and simplicity of construction and operation, plus unsurpassed flexibility (with the FMA-2 and the FMX-3) make it an outstanding example of the Dynakit reputation for obsolescence-proof design.

 

Specifications

Based on IHF standard T-100

Useable Sensitivity:  4 mV for total noise and distortion 30 dB below 100% modulation

Signal-to-Noise Ratio:  70 dB at 100% modulation

Total Harmonic Distortion:  less than 0,25% at 100 % modulation

IM Distortion:  less than 0,5% from 10 mV - 100,000 mV at 100% modulation

Drift:  less than 0,03%

Frequency Response:  10 Hz - 15 kHz ±0,5 dB

Audio Output:  2 volts at 100% modulation

Output Impedance:  less than 5000 ohms

Discriminator peak to peak Separation:  greater than 900 kHz

Antenna Input:  300 Ω (balanced), 75 Ω (unbalanced)

Dial calibration Accuracy:  0,2%

Useable Sensitivity Stereo:  3 dB less than mono mode

IM or T.H.D. :  less than 1% ( including 19 kHz and 38 kHz residual)

Stereo Separation :  30 dB

Capture ratio:  5 dB

Selectivity:  54 dB

Audio Hum:  73 dB below 1 V output

AM Suppression:  greater than 63 dB

Power Consumption:  55 watts