VBITNGC building & comment

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step by step assembly with photos.
the vbitngc has 3 units.the first assembly is tube buffer unit.

Part list below:
Tube PCB *1
E88CC*1
10K 2W*2
3.3K 0.4W*2
1uf 200V mkp *2 *
the sch of tube buffer and amp

**
the tube that I used is 6922.the coupling caps is 2 ero 0.47uf160v connected in parallel per channel.

the source of suitable tube sockets:
http://www.diyaudio.com/forums/showthread.php?postid=758149#post758149
http://www.diyaudio.com/forums/showthread.php?postid=758154#post758154
thanks dave
 

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the second assembly is amp unit.
The parts for the amps board were printed by their value on the boards.
Part list below:
AMP PCB *1
LM3875TF *2
50K log Poti stereo *1
330uF / 35V low ESR *4
180R 0.4W 1% *2
18K 0.4W 1% *6
47K 0.4W 1% *2

**
the bypass caps that I used is Fc 100uf/35V.
 

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I had the same problems, fitting the tubesocket on the PCB.

Hanzwillem, strange there is no comment on your post about the wrong PS PCB layout. I posted some other questions, but received also no answers.

Are Franz and Zang together on a lazy hollyday;)
 
Sorry, I spend my weekend with my little daughter. Just in a hurry:

It seems in fact to be a mistake in the silk screen of the psu board. So, think about a correct bridge topology, before you solder the diodes!

I think, "my" schematic and the schematic from Zang are adequate. Two corrections: the filament voltage is +6.3VDC and ground (not -6.3VDC) and the 85VAC are too high to use with 63V electrolytics.

http://www.diyaudio.com/forums/showthread.php?postid=753303#post753303

About the tranny:

You could use one, two or three trannies. Important is to have:

- 2 x 20VAC about 165VA (you are free to do your own gain calculation, depending on the available tranny as mentionned in the LM3875 datasheet)
- 6 to 8VAC 10VA (filament 6.3VDC and NE555/relay circuit)
- 35 to 45VAC 5VA min (anode voltage)

Franz

BTW:
Nice PSU simulation, to simulate the available trannies: Search for Duncans Amp Tools, PSU simulator. It is free.
 
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