Ssu

I’ve been pretty busy for the last month. But things are starting to move forward again. I’m still working on the project page for the Source Selector Unit and something new as well.

It really is amazing how much I can accomplish when suddenly I can’t work on all the projects which have been keeping me busy for the last month. The SSU assembly is complete and I’ve done some testing.

As it turns out, there is a crew working on painting the exterior of my house today. Since I can’t work on many of my outdoor projects around the house, I thought I’d take the opportunity to get a little done on the source selector unit.

No, I haven’t fallen off the face of the Earth. And I realize that people are waiting for the completion of the Source Selector Unit. I just got unexpectedly busy.

It took a while but the DC checkout is complete and I’m finally ready to finish assembly on the Source Selector Unit.

The resistors for which I’ve been waiting showed up this afternoon. Time to get back to work on the Source Selector Unit.

As I said before, I decided perform the DC testing of the tube assembly for the source Selector Unit in the clamping fixture. But just as I started testing, I ran into a little problem.

I got some time today to finish out the vacuum tube assembly of the source selector unit.

So last night I posted about a mistake I made in wiring the latest project. And because of when and where I made that mistake, it took all afternoon to correct it.

I can’t believe I did that! How could I have been so thick headed to make this kind of mistake?

Yesterday I was bottling mead but today I got a chance to wire up the buffers and tie in the coupling capacitors. This completes installation of all the signal chain components. All that’s left on the assembly is the final power supply wiring.

Between regular chores, gardening, and yard work today I managed to steal a little time to make some progress on the latest project. The gain stages for the source selector unit are essentially complete and I’ll begin working on the buffers as soon as I can.

While I was preparing to begin assembly of the vacuum tube circuits for the Source Selector Unit, I was quickly going over the design and pulling components. And this is when I became aware of a little problem with the buffer circuit.

I had the opportunity today to sit down and finish up the wiring on the source selector unit chassis. It has been a productive week for this project. Now that the chassis is in good shape, I’m free to move on to the assembly and wiring of the vacuum tube circuits.

I made some progress today on the Source Selector Unit. The twelve twisted pairs are all soldered to the selector switch and I managed some chassis wiring as well.

This morning after installing the selector switch and all its pigtails in the chassis, I decided to install the base plate. The chassis in now all in a single assembly.

So what does one do when needing to keep twelve signal paths clearly separated and easily identified in a chassis? Actually the answer is remarkably simple.

I’ve been waiting for some wire I needed for twisted pairs and a Fender style fuse holder. I really like these fuse holders. I find them sturdy, good looking, and reliable. I have some cheaper ones but I reserve those for brassboards, quick projects, test equipment, and the like. While I’ve been waiting for my deliveries, I’ve been populating the chassis.

Today I got the shop cleaned up and applied the first coat of oil to the bubinga chassis for the Source Selector Unit. (Still looking for naming suggestions, by the way.) The oil really brings out the grain. I think it will look even better than I thought it would.

William Shakespeare famously wrote in the play Romeo and Juliet,

What’s in a name? That which we call a rose
By any other name would smell as sweet.

So this is my quandary today. What should I “officially” name my latest project?

I took some time this afternoon to get the metal work completed (mostly) for the Source Selector Unit/Preamp. All the drilling is complete and everything is properly fit to the chassis. The only metal work left to do is four holes in the mounting brackets which need to be drilled and tapped. These four screws will hold the top plate in place and make swapping tubes easier.

Well, eleven days since my last post and the cedar fence is done, the garden is in, a toilet has been replaced, and a new batch of black cherry cider is in the fermenter. So I decided it was time to get back to the metal for the source selector unit.

I’ve been working on a whole bunch of different projects this last week. But I managed to carve out a little time to get all the chassis metal for the source selector unit cut to size, fit to the chassis, and marked for drilling.

I’ve been catching up on all my spring chores and managed to steal a couple of hours in the shop this morning. The Source Selector Unit chassis is now all sanded. I also took the time to cut and fit the aluminum for the top and bottom plates. Now my attention will turn to getting all the holes laid out and drilled on the aluminum.

I actually spent a fair amount of time thinking about how to dress the chassis edges for the Source Selector Unit. But after much deliberation, a couple of scrap tests, and some evolution in thought as it progressed, I believe I’ve found a solution I really like.

A good friend of mine, who’s opinion I value, has made a suggestion concerning the Source Selection Unit chassis. And I’m looking for some input.

The chassis for the Source Selector Unit / Preamp is out of the clamps. I removed the clamps, cleaned up the little bit of glue squeeze out at the joints, and gave it a light sanding. It looks fantastic.

Today, I did a little drilling and then got the chassis into glue up.

Before I perform the chassis glue up, I decided I wanted to get the two pieces of metal for the back drilled. This means I can make the pilot holes for the mounting screws in the inside of the back without having to work with a drill inside the glued up chassis. It’s a little thing but it makes the first assembly go that much smoother.

So I had another productive day working on the Source Selector Unit / Preamp chassis. The chassis has all the major woodworking complete and is ready for glue up.

I got some time today to make grain decisions and cut some basic joinery. It finally feels like I’m making progress.