Dynaco PAS-3X
Overview
It functions as a two-channel control center capable of both monophonic and stereophonic reproduction. Designed as an update to the PAS-3, the PAS-3X added a cathode-follower output stage and featured a more flexible input configuration, including dedicated circuits for phono, microphone, tape, and FM sources. It was built with a consistent design philosophy across the Dynaco line, emphasizing performance.
Specifications
| Frequency characteristic | 10 Hz ~ 40 kHz ± 0.5 dB (Aux) |
| Harmonic distortion factor | Below the measurement limit |
| Cross modulation distortion factor | 0.05% or Less (at 2 V, Rated Output) |
| Signal-to-noise ratio | Phono:74dB Aux:85dB |
| Input circuit | Phono, Tape head, Special (used as Phono2), Mic (can be used as Phono3), Tape head AM-FM, FM-multi, Tape, Spear |
| Input sensitivity | Phono:2.5mV; Tape head:188mV; Spear:100mV |
| Input impedance | Low level : 50k Ω; High level : 250k Ω |
| Output voltage | 10V/100k Ω |
| Phono allowable input voltage | 250mV |
| Tone control | Bass : ± 20 dB (20 Hz); Treble : ± 18 dB (20 kHz) * ±14 dB in 1973 catalog |
| Semiconductor used | 12AX7 : 4 Pieces; 12X4 : 1 Piece |
| External dimensions | Width 343x Height 108x Depth 230 mm |
Design
The PAS-3X is a tube-type preamplifier designed with negative feedback applied across the entire circuit to reduce distortion. A special tone control circuit disconnects when the knob is centered, allowing the unit to function as a flat amplifier. Both bass and treble controls adjust the left and right channels independently. The input circuit supports microphone or phono use through a special configuration.
Product Family
The PAS-3X was positioned as an update to the PAS-3 preamplifier. Optional wooden cases were sold separately, including the PAT-4/PAS-3X Common Wooden Case (¥3,900, circa 1970) and the DW-1 Wooden Case (¥6,500, around 1976).
Market
The PAS-3X was offered in Japan with a finished price of ¥42,000 (around 1970), ¥49,500 (around 1973), and ¥92,000 (around 1976), while the kit version was priced at ¥64,900 (around 1976).
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