In a system separate from the one in which I use the BCD-1 I'm using a transport with a Benchmark DAC-1 (at least until I save up for a BDA-1!). I want to match the output level of the DAC-1 with the 4.6 Volt output of the BCD-1's balanced analogue outputs.
The DAC-1 manual specifies maximum output levels, "at 0 dBFS," of the balanced analogue outputs not in volts, but in dBu, as follows:
+29 dBu with internal attentuator off
+19 dBu with attentuator set at -10 dB
+9 dBu with attentuator set at -20 dBu
-1 dBu with attentuator set at -30 dBu
The factory setting is -20 dBu and can be changed by moving four internal jumpers. To my ears, this setting is much the same as the fixed setting of the unbalanced analogue outputs, which Benchmark does specify as 2 volts.
So, how do I translate dBu into volts so I can level-match the outputs of the DAC-1 with those of the BCD-1? (The DAC-1 also has external miniature trimpots that can lower the output within each of the above settings.) I'd prefer to have the internal attentuator in the "off" position, because it offers by far the lowest output impedance of the four balanced settings (60 ohms). But I don't want to overload the balanced input of the BP-25 preamp I'm using with the DAC.
Assistance from the technically literate much appreciated.
TIA,
Joel