BIII with Broskie Unbalancer vs. EE Minimax Plus - My experience

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Well, in addition to the neohm 50R resistors in the I/V positions, I upgraded about 12 other resistors with a nice quality resistor. I also replaced the coupling caps with Duelund Cu PIO 1 uF coupling caps, which on purchased on sale from Parts Connexion.

I am very pleased with the end result.
 

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Wow! Beautiful job! What are those tubes - RCA clear tops?

I was playing around with my tubes recently and found a nice combination: Toshiba Hi-S 5963 as input tubes, and Raytheon 12AT7 output tubes. Very clinical sound! 300R MK132 cathode resistors.
 
Hello everybody, i'm really excited reading this thread, i can't stand in my shoes waiting to build my B III + Unbalancer DAC!
But i'm 1/2 steps behind you and stuck deeply in finding out how to assemble an Unbalancer even starting from Glass-ware PCB... 😕
Could someone please suggest me all R and C values for an I/V stage Unbalancer for a B IIIse DAC?
I would use JJ ECC802 input and EH 6CG7 output tubes and 2.2/3uF C3 (too much?); a Janus Shunt Regulator to power B+ and Heaters, set to 250/260V and 12.6V.
Just to state one of my problems, i can't figure out R12 correct value to achieve this as i'm not able to quantify the current flow on it. How can i calulate current flow in the Unbalancer?
Thanks to anybody will be so kind to help me! :up:
 
Just another question: i see 6n2p tubes need a different circuit layout from 12ax7, as they have filaments on pin 4 and 5 (and 6,3V power).
Could i mount them on Unbalancer as it is or should i implement some kind of adapting mod?
 
Thank you, but i'm still a little bit confused about resistors value. I'll find out about R12 values, but i'm not sure about i/v, cathode, anode and CCS resistors for the following tubes i have, to make Unbalancer work well:
- 12BH7
- 6N23P
- 6N2P
I would like to try 30 ohm i/v resistors for the latter, but Broskie's schematic here The Unbalancer shows 34R CCS resistor using 60R i/v resistors: he fears that using 30R i/v resistors, cathode voltage would be too low for CCS to work OK (6N2P has a very low anode current of about 2mA), so what resistors should i use for CCS set and cathode resistors with 30R i/v resistors? 120K for anode is OK?
50 ohm i/v should be OK for 12BH7 and 6N23P, i guess i should use 6.8R CCS and 300R cathode resistors, am i wrong? Then for anode i should stay around 24K for both? Could i lower i/v resistors any more (mostly using 6N23P)?
I will use Unbalancer as a preamp in my system so i would need 2V output at least...
 
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