6SN7 2 stages Amplification-2outputs Pre-Amplifier (External LC Channel Divider)

I introduce my own design Pre-Amplifier.
Show full-circuit drawing below

This Pre-Amplifier has following charactors and functions
1)　3 input circuit, 1 for RCA, 2 for Cannon 3P connectors
a) RCA high impedance input for Equalizer amp with Peerless 4651 transfomer (10k: 60k),
it has gain of 7.8dB
b) Cannon low impedance (600 ohm) input for CD player without Attenuation
c) Cannon low impedance (600 ohm) input for AUX with Attenuation (15.7dB)
2)　Low impedance input (600 ohm) 1)-b), 1)-c), connected to input transformer (Triad 66B-139).
66B-139 is (600: 50k) , has 19.2dB gain.
3) CD player is connected to Triad　A-11J transformer （60k:600) before Pre-amp input.Through this transformer, change impedance into 600 ohms, and attenuate 20dB.
4)　1st stage tube is parallel connected 6SN7. Output transformer of 1st stage is UTC A-25. A-25 can be used with 1st stage output DC(max 8mA), and change signal impedance to 600 ohm.
5)　After A-25, Signal line is changed into 600 ohm impedance, then insert Bridge-T 600 ohm Main Attenuator here.
6)　Main attenuator output is connected to UTC A-20 transformer, get 2 individual output for high and low frequency and change impedance into 150 ohm (6dB attenuation).
7)　Once lead high and low frequency signal to channel divider output connectors on back panel
8) External channel divider is LC circuit with 150 ohm input impedance. LC circuit divides signals at 500Hz with 12dB slope. Output Load impedance is 470k ohm. connect back to pre-amplifier.
9)　2nd stage amplification has Low/High individual circuits. Both has parallel connected 6SN7.Output transformer for high frequency is UTC A-25, for low frequency UTC S-11(Max DC=11mA). Both Transformer changes signal impedance into 600 ohm.
10) High frequency output has another Bridge-T attenuator to make balance with low frequency.
(Max attenuation is 16dB)
11) Power transformer is Hashimoto PT-180 fixed in external box.
12) Use 5AR4 rectifier tube and Hashimoto Choke C30-80 to get B+ DC high voltage. Hashimoto choke has 2 inductors inside, I connected 2 inductors in series and make double pai capacitor input filter.
13) Using total 6 pcs of 6SN7, supply heater power in DC. I used SBD bridge diode for rectifier.
14) BOX is TAKACHI SL series,
It’s very complecated pre-amplifier, but circuit itself is very old fashioned and simple. And purposely change signal impedance into 600 ohm, where I need to make signal line longer, insert attenuator, etc.