LCR is not active at all; it is the very same passive EQ as your RC? I think you a bit confused with terminology. The main logical explanation (there are many of them) is that capacitive filtration is very bad one and need to be minimized or eliminated. Capacitance still might be conditionally used in the peripherals but when a dielectric deals get constantly recharges by AC in the middle of the band-pass then it is not a good idea and indictor behaves much better in those cases. If you look how the filters are made in the 6-chenal Melquiades the you will clearly see my vote – the RL filters sound way more superior then C-filters.
Yes, the MC-tyrannies certainly would add colors on palette. Be careful with trios miniature WE high gain triodes – they might be very “live”, much more live than you would like them to be. The WE high gain triodes were a bit not stable and you might get over a great number of them until you find a pair of the same gain and the same noise characteristics. Considering the price of WE437A it might be a pain in ass. I did not play with WE437A but I spent along time to play with 417A. The 417A and WE437A are the very same triode but 437A is taken a bit farther – it has twice more power (7W vs. 3W) and higher transconductance (beginning of 40.000s vs. high 20.000s). The 417A were very unstable, I had 30 or 40 of the original WE and I was able to have 4-5 of them suitable for the first stage. Evan if they were properly handled and used the still were a bit too prone foe some strange noises. They also tend to be oscillative what they get older, again, even if all anti-oscillative precautions are taken care. BTW, Stefano running the WE437A you might find the use of the Alnic shock-absorbing socket savers. I mentioned them
…and I think it might be beneficial for this type of tube.
So, you have 46-48 dB of gain by two stages juts because WE437 has higher transconductance. In my 2-stages I used the tube with transconductance of 55.000 and I have 68dB of gain. In my book it is a bit low and I like very high gain phonostages: 75-85dB – the higher is better. You claim that your phonostage has a low output impedance – how did you mange to do it? What is the impedance number you got? How do you couple the output? I also do not feel as an optional step-up at preamp level is a good idea architecturally. If you have capacitive output at your phonostage (that you mostly have) then it fine and it is OK to drive your preamp. Then you decided to have more gain and you switch to the preamp’s input that has step-up. You will have your gain but now you have a cap on the phonostage outs side and a transformer in the preamp input – 2 DC clocking devises that are not necessary together. One might argue that in this case you would use a transformer with no gap and an ability to care DC but I would argue that at line-level I would like to have only ether transformer or cap -we do not deal here with high currents and bit, killing-inductance gaps.
Thomas, about your phonostage: as I understand it has remote power supply… so, why it is so big? It must be virtually empty inside. I feel that the phonostage with no PS must be very small to sit right to TT with very short cartridge cable. If you have 48dB gain then Stefano might run let say Ortofone Mono that has 3mV directly to your phonocorrector and do not run the output signal across the whole unit back to the output jacks. Also, in the chasses type you used if it was my phonostage then I would use input and output on the different sides of the chasses. I would reverse the layout making the front tubes as input and putting a set of RCA jacks right there, as far as possible from the power enters. I also find that tonearm cable that runs in front a phonostage is kind of cool idea.
"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche