Does anyone have a component map for the phono boards in a 1000A? I need something that has the circuit boards printed out with designators on it for the parts. Also the 7 or 8 IO tabs on the bottom of the boards. What each leg is and where it goes. I could map it out the hard way but was hoping someone may have already done the hard work already. Also I am looking for a small circuit I can replace the stock circuit with. Preferably with improved performance.
Thanks for the help. It would be nice if Sansui had maps of the boards like most of the other brands do.
Thanks for the help. It would be nice if Sansui had maps of the boards like most of the other brands do.
The phono boards are vertically placed in the rightmost rear side, the components are purely solid state germanium transistors . i had 2 pcs on my repair desk.
The phono section on the 1000A seems to be identical to the AU-70.
I traced the layout of the AU-70 phono board a while back - hope it's useful
I traced the layout of the AU-70 phono board a while back - hope it's useful
The same circuitry is used for all three, just the EQ parts are switched. This was very common at the time.
By tape they mean tape head, not line level tape.
By tape they mean tape head, not line level tape.
So the MIC uses it as a mic preamp. And the tape head uses it to boost signal before recording? What is the phono one for?
There is a separate in and out line in addition to these. I must be missing something.
There is a separate in and out line in addition to these. I must be missing something.
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For easy reference, here is a schematic snippet of the input section of the Sansui 1000A. The input
selector switch is S1 (multipole) and the legend below shows the Switch
position to input mapping. Inputs 1 to 4 go through the same 2 transistor circuit,
and the lower pole of S1 (bottom right in the pic) selects the appropriate equalization
network.
selector switch is S1 (multipole) and the legend below shows the Switch
position to input mapping. Inputs 1 to 4 go through the same 2 transistor circuit,
and the lower pole of S1 (bottom right in the pic) selects the appropriate equalization
network.
Tape has a couple of different EQ curves because different tape heads have different frequency characteristics, while today's phono has a completely different, single, well-defined RIAA curve. Mic has a flat frequency response. All three need quite a bit of amplification. The tape head preamp often has frequency response adjustments to account for the different responses that different heads could have. Your board has facilities to handle all three input sources, so it needs a switch to select the source in use.