Scott Stereomaster Type 350B FM Multiplex Stereo Tube Tuner
Scott Stereomaster Type 350B FM 멀티플렉스 스테레오 진공관 튜너
| 상품번호 | 227290926514 |
| 상태 | Used |
| 거래유형 | 즉시구매 |
| 출고국 | 미국 (US) |
이베이 판매가
$219
약 322,806원
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상품 설명
The tuner works great, pulls in stations nicely. All tubes are USA made and work fine. It is is very good cosmetic condition, the faceplate is in excellent shape, with a couple of minor scuffs on the outside border of the faceplate (see photos).
More information:
The 350B replaced the original 350. The 350B eliminated the 6BN6 Gated Beam limiter used in the 350, and went back to the 3 tube IF using 6AU6's. The 6X4 vacuum rectifier used in the 350 was also replaced by a selenium rectifier in the 350B. The multiplex circuit remained essentially the same, the major change being the addition of the "Sonic Monitor" feature. The level control was eliminated from the front panel of the 350B, to make room for a switch to control the "Sonic Monitor". The "Sonic Monitor" switch basically detuned the 38 kHZ oscillator, so a beat note with the 19 kHz pilot signal would be heard, if the station was broadcasting in stereo. A mechanical change was made, which moved the 12AT7 audio stage from the multiplex decoder sub chassis, to the main chassis, yielding what some call the 3 tube multiplex circuit, although there was now change in the circuit topology. The gain of the 6BL8 composite amplifier was increased by a change in the value of the cathode resistor, and the Q of the 38 kHz oscillator tank was reduced, both of these changes were to improve the stereo performance. At least 4 different variations of the 3 tube IF were used in the 350B. There was the traditional circuit using 3 6AU6's. Another variation had a 6U8 limiter, like the 314. I am not sure what the triode section was used for, but I suspect it was used to operate the "stereo guide" light that was offered for a while. Most of the "stereo guides" used a 6AV6 tube on a small add on chassis, to control the "stereo guide" light. Most of the Scott "stereo guides" were add on kits that could be added to any early Scott multiplex tuner or receiver, but some 350B's may have had an integrated "stereo guide" circuit. The Sonic Monitor" circuit that was introduced on the 350B eventually replaced the optional "Stereo Guide" light. Another 350B variation used a 6EJ7 as the first IF amplifier, and the 4th variation I know of, used a 6HS6 as the limiter. Both the 6EJ7 and the 6HS6 had more transconductance than the 6AU6's that they replaced, although Scott seemed to always come back to the all 6AU6 lineup.