Nelson Pass B1 preamp build

[Bigman80]

From the back panel each input pair (L & R channel) go directly to the switch, lets say input 1 left channel to the first outer tag pin after the mounting bolt and right channel to the opposite tag, input 2 to the next pair of opposite tags and work you way round with all you inputs.
The R & L switch outputs are the 2 inner tags, run wires from these to the R&L Inputs of the stepped attenuator .
Join all of your input grounds together for each channel with a tinned wire, run a wire to your start earth point and back to the Stepped attenuator grounds

The L&R outputs from the attenuator go to the Pre amp input L&R

I use a start earth point at the output Grd of the power supply caps so you would need 2 grounds from there to the ground on the amp board input

The output from the amp board go to you RCA outs on the back pannel

Note make sure that bolt on the transformer does not touch the top pannel or ou will get a short on your transformer

Hope this helps

IMG_0089 by Alan Towell, on Flickr

Hi Alan

Thanks for the information. I understand most of that better than expected lol.

One question,

How do I know what channel is what on the attenuator there are no markings at all!!!

[Bigman80]

Oh!! It doesn't matter does it lol, as long as it's R in and R out to the R RCA it'll be right lol.

Can you tell I haven't done it before 🤣

[337alant]

Oh!! It doesn't matter does it lol, as long as it's R in and R out to the R RCA it'll be right lol.

Can you tell I haven't done it before ��

Oliver Yes you got it just keep you lefts and rights in phase all the way through the amp from input to output

Alan

[Bigman80]

Thanks Alan,

I really appreciate your help.

Oliver Yes you got it just keep you lefts and rights in phase all the way through the amp from input to output

Alan

[Bigman80]

Spent a couple of hours on the DCB1 today,

I now have power to the board and switches nicely fitted.

The Khozmo is in place and just need to cut the extender bars to fit. Just measuring up for the Elma selector switch.

I need to buy and fit two more RCA sockets too.

[ijrussell]

This is my DCB1 built by a friend for me. I went a bit foo with Khozmo attenuator, Audio Note Tantalum resistors and Mundorf caps but it's defintely worth it!

[The Black Adder]

There is nothing foo in regards to the Khozmo. Had one for years and have always been very nice.

Sent from my 9001X using Tapatalk

[Stryder5]

Won't the knobs stick out a bit.....lol.....sorry

Spent a couple of hours on the DCB1 today,

I now have power to the board and switches nicely fitted.

The Khozmo is in place and just need to cut the extender bars to fit. Just measuring up for the Elma selector switch.

I need to buy and fit two more RCA sockets too.

[Bigman80]

Looks very well made.

Somehow, on mine, the predrilled hole isn't central so the volume knob is off centre!!!!

Pants.

[Bigman80]

Won't the knobs stick out a bit.....lol.....sorry

Lol