bernhard@decum.dec.com (Bernhard Carli) (08/17/88)
[This is for the line eaters ................................................] >Well here it is, the hardware fixup for the A1000 from Amazing Computing V3N4. >PAULA >----- |------| >| | | | >| | __________________________ |TL084 | >| | TL084 / \ |-|\ | >|AUD|-----|\ | | 2| >--@-------->>--- L >| A | 13| >-@-X--R90--R98--R97--R96--R89-@--|/ 1 | >| | |--|/ 14 | | | | | 3 | >| | | 12 C110 C106 C109 C105 C104 | >| | | | | | | | | >| | | GND | GND | GND | >| | | | | | >| | | |---------@-------------| >| | | >| | | >| | | |------| >| | | | | >| | | __________________________ |TL084 | >| | | TL084 / \ |-|\ | >|AUD|-----|\ | | 6| >--@-------->>--- R >| B | | 9| >-@-X--R87--R91--R92--R93--R88-@--|/ 7 | >| | |--|/ 8 | | | | | 5 | >| | | 10 C107 C101 C108 C102 C103 | >| | | | | | | | | >| | | GND | GND | GND | >| | | | | | >| | | |---------@-------------| >| | V Ref >| | >| | >| | A1000 Audio Schematic Modification 1 >----- > < - phono plug (must mount a new set for Mod 2) X - Test Point @ - connection >Modification 1 : Simply locate chip UG5, and solder an insulated wire (22 - 24 Gauge) to connect pins 14 & 3 and 8 & 5. >Mike So they do only a bypass of the RC-filter? But what did CA= that on newer 500 and 2000 you can switch the filter off by software? Did they supply some kind of analog switch that would allow to bypass the filter??? If the filter is turned off - how disturbing is the sampling-frequency noise? Bernhard