Dynaco FM-1 Tuner
The Dynatuner is a fresh engineering concept, not an adaptation of an existing production design. To produce a tuner having optimum performance, every portion of the circuit has been carefully investigated in terms both of performance maxima and of the overall stability of operation and simplicity of adjustment required of a kit design.
The result of this effort is a tuner which provides the same top performance in your home as it does in the laboratory. Without any test equipment -- just following the simple adjustment procedures in this manual -- the kit builder will achieve the high performance normally obtainable only with laboratory test and alignment equipment.
There is no longer any question whether adjustments have shifted during shipping and handling as frequently happens with FM tuners. In the Dynatuner all adjustments can be easily checked; and of course, the periodic maintenance required of all tuners is simply and easily made without a trip to the serviceman. This adjusting technique has been obtained without any sacrifice in tuner performance. In fact, the reverse is true. The care and control necessary to make these adjustments absolutely reproducible has resulted in a significantly higher level of performance combined with the required stability.
In addition to the adjustment requirements, the basic engineering objective was to produce a tuner design of adequate sensitivity for fringe area reception, with distortion levels of the recovered audio signal comparable to that measured on the best of audio amplifiers.
The significant advantages of etched circuit construction in terms of reliability, reproducibility and durability are amply demonstrated in the Dynatuner. Their use has further accomplished the ultimate goal of improved performance. In no other tuner -- kit or factory wired -- has exact component placement and lead layout been so accurately defined. 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 circuit configuration.
There has been no intent to enter the sensitivity specification race (claims often engineered by the advertising department). However, using the sensitivity standards proposed by the Institute of High Fidelity Manufacturers this tuner belongs in the highly sensitive class and, in fact, will provide listenable reception of more stations than tuners of ostensibly higher sensitivity rating.
The concentration of effort to reduce distortion has also produced a tuner which is unquestionably the lowest distortion receiver on the market today.
There are many parameters in addition to sensitivity and distortion which are part of a completely satisfactory tuner design. Some are measurable; some are intangible. Extensive field testing under adverse and marginal conditions has proven the Dynatuner to be as fine a tuner as can be obtained today regardless of price or specification claims.
BASED ON IHFM STANDARD T-100
Outputs: Tape output. Audio output.
Usable Sensitivity: 4 microvolts for total noise and distortion 30 dB below 100% modulation.
Signal-to-Noise Ratio: 70 dB below 100% modulation level.
Harmonic Distortion: Less than 0.25% @ 100% modulation.
Drift: Less than 0.03%.
±0.25 dB 20 cps to 20 kc.
±0.5 dB 10 cps to 40 kc.
Capture Ratio: 5 dB.
Selectivity: 54 dB.
Audio Hum: 73 dB below 1 volt output.
AM Suppression: Greater than 63 dB.
IM Distortion: Less than 0.5% from 10 microvolts to 100,000 microvolts @ 100% modulation.
Audio Output: 2 volts @ 100% modulation.
Output Impedance: less than 5000 ohms.
Discriminator Peak to Peak Separation: Greater than 900 kc.
Antenna Input: 300 ohms balanced. 75 ohms unbalanced.
Dial Calibration Accuracy: 0.2%.
Power Consumption: 50 watts.
Tubes: 2 6AQ8 (ECC85); 1 6AT8A; 2 6BA6; 2 6AU6 (EF94); 1 12AX7 (ECC-83); 1 6FG6 (EM84); 1 6V4 (EZ80).
Accessories: FMX-3 Stereomatic Multiplex Integrator with 1 6BL8 (ECF80) and 1 12AX7 (ECC83); >30 dB separation.
Stewart Hegeman, Ed Laurent (MPX circuitry by Sid Lidz)
Dynaco's first FM tuner, which was offered with the FMX-3 stereo adapter available separately, in kit or pre-assembled form.
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Copyright © 2000,2001 Greg Dunn