AEMC SR759 AC Current Clamp Teardown and Q's

[noidea]

Hi All

I purchased an AEMC SR759 AC current clamp recently after finding one for a good price on fleebay and realising that it was the same as the Chauvin Arnoux C-173 that is a jack of all trades for AC current measurement from 1-10-100-1000A and with a 1V/ Amp output on the 1A scale useful for doing earth leakage current measurements. Anyway I have used it so far with my Keysight U1252b and Fluke 196C and its worked well except that I've only been able to use the multimeter inputs on the scope as the output lead is banana plugs not a BNC.

Now that my leakage current issues have been sorted I want to try to see if it's useful for doing some standby power measurements with the Fluke 196C but for that I need to use it on one of the scope inputs so I can use the math functions. The easy way I guess is to just buy a dual banana socket to BNC plug adapter but the isolated plastic Multicontact / Fluke ones are not cheap and it will also make things a bit unwieldy and more likely to get damaged as I take the meter out on site with me regularly.

So I am thinking of buying a pre made Multicontact coax test lead with the insulated BNC plug on it, cutting the end off and swapping the output lead over as most of the time I will be using it with the scope rather than the meter so would prefer this anyway. I know that other versions of what appears to be the same basic clamp design are available with a BNC lead attached but with different current range switch options. The AEMC SR661, Chauvin Arnoux C160 and Tektronix A621 all appear to be identical and use the same clamp casing / materials but I don't know if the little board inside with the range switching is the same.

I took it apart today and took some photos which are below, I knew that the outputs for each range had adjustment pots but I was surprised to see in what I thought was a passive device (beginner electronic understanding) that the two current transformer coils are feeding into BC547 transistors. The board also looks slightly generic as it has the tabs for mounting banana sockets to it that is another option.

Am I overthinking this, should I just leave it as is and use an adapter to change it to a BNC output?

Or if anyone has one of the clamps above do you mind opening it up and sharing some pictures of its insides?