Well I've finally found time to try the Croft EQ network, with some very interesting results.

If you recall the Stereophile plot of RIAA error for the Croft Phono integrated:



I have used the EQ network found in the 25R but installed in my Firebottle phono circuit, using different and higher gm valves to those that Glenn uses.
I have adjusted the series resistor to allow for the differences in the first stage source impedance to level the playing field.

I get the bass lift under 100Hz, but do NOT get the treble drop off as shown above, in fact the hf performance is excellent.
Whether the difference is down to the use of ECC83s in the Croft integrated I don't know but I have a certain regard for Glenn's EQ network as it makes use of readily available capacitor values, namely 10 nF and 1 nF.

The loss through the network is a little higher than the traditional all in one passive network, but when using high gain valves that is of little consequence.

All good stuff,
Alan