Well, the output amp (and an output Tx) will definitely add more gain but I can't see the reason of having such a small gain in the input amp. Unless it's not a mic preamp, I'm definitely missing something

From what I remember of the manual, the internal operating level is -10dBV (where 0dBV = 0.477V into 200 ohms). The smallest input level is -50dBv so the gain needs to be 40dB. The amp has 25dB and the transformer secondary taps give up to 15dB for a total of 40dB.

Cheers

Ian

That is a little weird use of dBV...

0dBm (1 mW) is indeed 0.477V @ 200 Ohms, a power level with 0dBm=1mW.

dBu was commonly voltage wrt 0.775V without specific impedance qualification. dBV was voltage wrt 1V again without impedance qualification... -10dBV was (is?) a very popular semi-pro recording equipment 0VU reference level (0.316V) again independent of termination.

I recall another dBV ( x) voltage reference with stated OdB voltage reference level included inside parenthesis. For this case that could be stated X dBV(.477V). dBV without stated reference implies a 1V voltage reference.

I've seen dBv used interchangeably with dBu (voltage ratio wrt 0.775v)

Of course there are any number of variants in popular dB usage.

JR