B1 Rev. 2

Official Court Jester
Joined 2003
Paid Member
Has anyone made a board for B1 Rev.2 with a complete power supply?
Some pictures, please.

ask 6L6 :clown:

What's wrong with the kiss,boy ?

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Just come across this B1 Rev 2 preamp when search around for my still build in progress balanced ACA amp (I am a total newbie and this is my first DIY Hifi build, finger crossing). I mainly will using DAC or computer to steam the music to the ACA amp, and seems people are suggestion B1 Buffer as preamp.

The setup in my mind is as I will need to convert from unbalance (DAC/Computer) to balance (ACA monoblock) and looking at audio transformer path. Which is reason somewhere in the over 400+ pages forum and suggest need buffer amp, as ACA cannot just use audio transformer/passive amp.


I am thinking:

- DAC/Computer (unbalanced) --> Audio transformer (convert to balanced)--> 2x B1R2 (with 12 pin 50k pot for volume control to two board) --> ACA Monoblocks

Questions:

1. Am I on the right track?? Or it will not work?? Any other suggestion?
2. Do I need to swap the path of 2xB1R2 and Audio Transformer, so it is DAC to B1R2 first then Audio Transformer? (sorry I still not sure about input/output impedance matching, and what effect of audio transformer will do on impedance)
2. What ratio of Audio Transformer should i using?? 600:600, 10K:10K, or 600:2k4 (for V stage), 10K:40K??

Stan
 
The pcb I mentioned in post #146 is put to good use for my new b1 r2. I did the mods Zen mod suggested, put a couple of vishay mkp1839 from supply rails to ground center. With the new SH pass x150 and ancient dynaudio contours its working swimmingly.

Just in case I run it with a cap now, but I'll try small isolation transformer to have a taste of the "iron pre"