Pass B1 preamplifier.

I’ve been working on a preamp based on the B1 buffer designed by Mr. Nelson Pass. It’s using two pcs 2SK170 per channel and from what I understand it operates in Class A.

The pcb is fully populated and I just recieved the 20K stepped attentuator.

I’ve used 10000uF/25V Dubilier caps, 1uF MKP’s (3pcs) and 12uF Jantzen cross-caps.

This is how it looks now.

I have a Regulated linear +18Vdc PS made, but I’m thinking of using a SMPS wallwart (18V/1A) to save space and be able to use a smaller chassi for the preamp.

Got the box for this preamp today, it’s a cute little box. 235x150x80mm, which is perfect.

2012-04-12

Drilled holes in the backplate and fitted all connectors, but as you can see I really shouldn’t measure by eye…not really symetrical.

2012-04-13

Mounted everything except the fuseholder in the box. Left to do now is internal wiring and mounting the fuseholder.

I’ve also soldered silverwire in PTFE tubing between RCA-inputs and the B1 PCB today.

2×0,6mm silverwire for signal and 2×0,6mm silverwire for ground.

2012-04-14 (my mothers birthday btw 🙂  )

Fitted a fuseholder to the backpanel, was alot more work then I expected since I didn’t own a big enough drill and had to widen the hole with my Dremel.

Got some more internal wiring done. Tried to keep it neat and away from the PCB.

I did the wiring for the input selector and volume attentuator too, but now I’m taking the rest of the day off.

2012-04-15

Internal wiring done. Just waiting for the PS to arrive and I’ll need to order some 200mA slowblow fuses.

2012-04-17

Today I got the external +18VDC/1A powersupply 🙂

Now I’m just waiting for some 200mA fast blow fuses that should arrive this week.

/mayday

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