tube summing amp?

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I have converters RME fireface 800. I like to mix in analog way (8 buss). and wanted to study some circuit Summing tube amp.  http://www.thermionicculture.com/products/fatbustard.html eg.
to see if it is myth or reality which is better final mix analog.
I also have several "gear" to mix in analog.

http://magooamps.googlepages.com/studio
 
Supermagoo,

You can do same simple circuit as you do with a single NPN transistor that have a inverted input, but maybee 10 times up or more, with the input serial mix resistors and the feedback resistor.
(use the second 12AX7 tube half as a dc-coupled cathode follower after the first inverted gain amp, and you get a better output drive)

Can maybee work with decent result up to 8 mixed input resistors, each with same value as the feedback resistor.
(because the low open loop gain in the bus/mix amp, less than 30 dB for a single 12AX7 tube half)

If you want a better sum/mix amp for more inputs, you can build a differential amp (op-amp) with two dual triodes, (four tube half) so you get more open loop gain.

Sorry, I can not write a on-line schematic just now, but maybee some one have a application scanned, for this I have talk about here above ??

--Bo
 
thanks for the info. It would be great if you could post a schem.
I just want to build a small summing to see who is better. mix within Nuendo or the Summing (myth-buster).
I would also like to try some compressors and EQ's by groups  busses and make a final mix in real time.
 
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