> a value of say 14 for a transistor."14" ? ? ?
"140" is more likely for ANY modern small transistor. Are you sure you are reading it right?
> the math to convert this value, to the value it would be at the input stage of the B183av.
There is no way to know. It may be a bit higher at higher voltage; but I doubt that stage runs 24V on the transistor. On small transistors, 10uA is "large" base current, and I bet your preamp runs much lower current. Hfe fall-off at low current is very process dependent.
Measure it in-circuit. Put a transistor socket in a preamp and try transistors.
Is this snippet like your plan?
If I found the right plan, Q1 runs near 250uA collector current. If Hfe were 500, then base current would be 0.5uA. Base current flows in a 68K resistor. 0.5uA in 68K is about 0.1V.
So measure the DC Volts across the 68K base resistor. If it is 0.1V or less, Hfe is 500 or more. If you really believe that maximum Hfe is somehow vital, go with the transistors which give the lowest voltage across the 68K.
Oh, and have a mike and speaker. A dead transistor may have very-very-low base current, but it's still dead.