X-Bosoz Finished

[AR2]

I am finished with my 6 channel balanced preamp. It's all started when I decided to do three way active speakers. Than I compiled various amps, that I changed in a meantime. Here is my original link for the speakers:
Finally, my new LAMBDA-PHL-Esg3 speakers are done. Check them out.
It turns to be very complicated project since all speakers are with different sensitivity, amps are different - vacuum tube and solid state. I also wanted to do mods on digital crossover. So one after another it lead to this latest combination:
DCX2496 was moded to exclude circuitry all together after DA converters. Wires are bypassing signal directly to XLR connectors.

[AR2]

And this is whole output board of DCX 2496

[AR2]

On the preamp side I decided to go with separate case for PS since there was no room for everything in one case. The big transformer is 2 x 55v 300VA and for the negative rail I have two smaller ones 18V each. Besides two power supply boards I have soft switch and start circuit board that I got from some earlier group buys designed by Maxhawk
Soft switch version 2 anyone?

[BobEllis]

Looking forward to more pictures, since I am startting the same sort of thing with an analog active XO.

What did you use for the power umbilical? (connectors, cable)

[AR2]

Based on my various gain needs, in my design X Bosoz is separated from DA converters by Lundahls 1674 transformers. They are ether 1+1 : 2+2 or 2+2 : 1+1
They are ballanced and they completely kill 2.5 V DC that is coming out of DA converter. I am using Lundahl in front of XBosoz for low and high channels. For mid I am having only Lundahls without XBosoz. XBosozs are used all in ballanced configuration. Before the output I am using 6 channel ballanced Apex relay volume control.
For both cases I milled appropriate aluminum plate to serve as double bottom where everything is attached as well as to serve as a shield against noise. Power supply lines are routed underneet the plate and holes are surounded with rubberized material in order to prevent wire cuts.

[AR2]

Lundahls at home nicle tucked in.

[AR2]

Just to make sure they do not leave their places... I clamped them.

[AR2]

Boards all together assembled - 4 XBosoz boards and 3 Apex Boards.

[AR2]

And one more view.

[AR2]

Rear panel with XLRs and single ended option with switch and RCA plugs. Black round connector is 9 pin connector that is used to connect power supplies and grounds. One wire is for chasis ground, directly connected to earth from power plug, and signal grounds are connected to power supply grounds that are further connected over thermistor CL-60 to the chasis ground.