Amp Build: Brown Note 18Watt Lite IIB

[Bloozcat]

I like the way you detailed the parts layout on the board, tung. It's really helpful to see just how the board is populated before any soldering begins.

Great tutorial, keep it coming...!

[tunghaichuan***]

I like the way you detailed the parts layout on the board, tung. It's really helpful to see just how the board is populated before any soldering begins.

One thing about the layout, it doesn't match Brown Note's exactly. I've taken the liberty of adding another power supply node. The Brown Note schematic/layout have the preamp tube and phase inverter both connected to the same node on the power supply. In that circuit the anode and screen each have their own node on the power supply. I decided to decouple the phase inverter from the preamp. No reason, really. Just wanted to do it. I can reconfigure the circuit and make it exactly like the layout/schematic if I want to.

I got confirmation from both Mouser and Hoffman amps that the parts have shipped. Once I get the parts in hand, I'm going to have the face plate made. I'm also going to have BNP Lasers make me a template so I can route out the hole for the IEC inlet. It will be a square of plastic with a laser cut hole in it to the dimensions of the IEC connector.

tung

[tunghaichuan***]

Next step: getting the chassis ready for the face plates.

I received all the parts I needed to finish the project yesterday. The next step is to generate the face plate and back plate files. With the 13" long by 2" wide chassis, it is possible to print out 1:1 face plates to make sure the controls are in the right place and are labeled correctly.

http://www.diycustomamps.com/images/...chassis_31.jpg
http://www.diycustomamps.com/images/...chassis_32.jpg
http://www.diycustomamps.com/images/...chassis_33.jpg
http://www.diycustomamps.com/images/...chassis_34.jpg
http://www.diycustomamps.com/images/...chassis_35.jpg
http://www.diycustomamps.com/images/...chassis_36.jpg
http://www.diycustomamps.com/images/...chassis_37.jpg

After some minor editing, I believe the face & back plates are ready to send off to BNP Lasers. I'm going to go with black plastic with white writing for a Hiwatt vibe. I won't drill any holes for the controls until both plates arrive at my house.

Stay tuned...

tung

[luvmyshiner]

Lookin' sweet Tung.:

[tunghaichuan***]

Lookin' sweet Tung.:

Thanks, Shiner. It'll look pretty good once I get it all done, unless I do something stupid to screw it up. Wouldn't be the first time :

tung

[tunghaichuan***]

Update:

Got the face plates ordered yesterday. I made a few changes to them to make the labels easier to align. Both plates cost me $33.75 shipped. Jeanne at BNP Lasers said that they'd be on their way by next week.

When I get the plates I can finish the chassis and then move on to the wiring.

EDIT: Got an email yesterday (9/27/08) from Jeanne at BNP Lasers, the face plates have been shipped out USPS Priority Mail. I'm hoping to get them by Weds. maybe sooner.

tung

[tunghaichuan***]

Finishing the Chassis, Part 2

Pix here:

http://www.diycustomamps.com/images/...e/chassis_pt2/

The face plates arrived Monday night, a couple of days before they were expected. My first thought was that they looked great. BNP Lasers does a good job. My second thought was: damnit! I made the holes for the volume and tone pots a little too big. The Alpha pots I'm using are 5/16" diameter and I specified 3/8". Slightly too big. One function of the face plate is to center the components. The holes in the chassis can be a little bit bigger than the component and having a face plate fixes this. So I had to measure very carefully to get the holes for the two pots in the chassis concentric with the holes in the face plate.

Tuesday morning I spent about two hours finishing the chassis. First, I fitted the front face plate. It was just a matter of taping the face plate onto the front of the chassis, tracing the holes with a fine-point Sharpie, running a center line down the front of the chassis, measuring and marking the locations of the holes with a tape measure and locating the center with a square. One I got the hole locations marked I used a center punch to mark the hole and drilled a pilot hole with a 1/16" bit. Then I drilled out the hole to the correct diameter with a stepped bit. The volume and tone pot holes came out great. The pilot light hole had to be drilled out a bit bigger to get the pilot lamp assembly to sit in the face plate hole correctly.

Once I got the front face plate done, I moved onto the back face plate. The back face plate has a rectangular hole for the IEC inlet. This is the first time I've used one and it looks much neater than drilling a hole, using a grommet and knotting the cord inside the chassis. I made a template out of 3/4" MDF using the hole in the back face plate as a guide. I roughed out the hole using the template taped to the chassis with double-sided carpet tape. I removed most of the material in the hole with a drill bit and further cleaned it up with a jig saw. I then used my laminate trimmer with a top mounted bearing on a flush cutting bit to cut the hole to size. Finally I used a file to clean up the corners. The hole in the chassis is kind of rough, but that is okay as the IEC inlet and back face plate cover it up. It came out great for a first effort: centered and aligned.

The other two holes were drilled out in the sam manner as the front plate: marked, located with a center punch, and drilled out.

Next I finished drilling the holes in the chassis to mount the chassis mount capacitor can and the tube sockets. With these it is a matter of using the socket it self to locate the holes, marking them with a Sharpie, locating the center with a center punch, drilling a pilot hole, and drilling them to size with the correct size drill bit.

The last step was attaching all the components to the chassis: the transformers, the front and back components, the tube sockets and the cap can.

The next step will be to start wiring. First I will need to attach the leads to the output transformer as it has quick disconnect terminals instead of flying leads. Once this is done, I can install the eyelet board and begin wiring the circuit.

Stay tuned.

tung