OK, that is a reasonable specification. You do not say if the inputs and output are balanced so I will assume they are. You don't want pan pots so I will assume this is an 8 into 1 mixer. Here is one way to do it.
1. Unbalance the inputs with a transformer. In a Neve mixer this would have been done with a 31267 transformer wired 10K:600. You could use the equivalent Carnhill transformer wired the same way. The signal is now 12dB lower than the input level.
2. Use a 1K log pot for the volume control .This will be reflected via the transformer to the input as an impedance greater than 10K
3. Feed the pot wiper via a bus resistor to the bus. As this is a mono bus we do not have to worry about crosstalk. But we do want to minimise interaction between channel so we choose a bus resistor at least 10 times larger than the pot value. A typical Neve value would be 15K.
4. The bus loss is equal to the number of inputs i.e. 8 times or 18dB. This is the amount of gain we need to make up.
5. With only 8 inputs there is no need to use the Neve standard method of a transformer input to the bus amplifier. We can just wire the bus straight to the BA283 first stage and set its gain for 18dB.
6. The output of this stage can feed a 10K pot as the master volume. The pot wiper feeds the output stage of the BA283.
7. We still need to make up the 12dB loss from the input transformer which we do in the output stage.
Cheers
Ian
