Amp Build: Brown Note 18Watt Lite IIB

[luvmyshiner]

Tung, I've been enjoying the hell out of this post. You're inspiring me to try something a little bigger than what I've done so far. Keep it up brother.

[tunghaichuan***]

Tung, I've been enjoying the hell out of this post. You're inspiring me to try something a little bigger than what I've done so far. Keep it up brother.

Cool, glad to hear that. PM me if I ever can help out.

tung

[luvmyshiner]

Thanks Tung! I don't know if you saw my "Firefly" build or not, but I really enjoyed it, and CB has fallen in love with tube amphs as a result. Since I built the Shiner Cab v. 1.0, that will accommodate something larger, I've been playing around with the idea of building another amph. I haven't decided what that will be yet, but you make the research much easier and very enjoyable.:

[tot_Ou_tard]

Very cool indeed. It's gonna take me several reads to undertand everything that you are saying.

Great photos too, Thanks!

[tunghaichuan***]

Very cool indeed. It's gonna take me several reads to undertand everything that you are saying.

Great photos too, Thanks!

To be truthful, when I was composing the text, it came out in one long stream-of-consciousness, so if anything is unclear, post in this thread and I'll try to make it clearer.

tung

[tunghaichuan***]

Thanks Tung! I don't know if you saw my "Firefly" build or not, but I really enjoyed it, and CB has fallen in love with tube amphs as a result. Since I built the Shiner Cab v. 1.0, that will accommodate something larger, I've been playing around with the idea of building another amph. I haven't decided what that will be yet, but you make the research much easier and very enjoyable.:

Since you've already built a Firefly, I'd recommend the Tweed Princeton 5F2-A circuit for your next build. I cut my teeth on this circuit and have probably built at least 10 variations on it. It sounds great clean or cranked and loves pedals, especially Boss OD pedals.

The 5F2-A is basically a Tweed Champ 5F1 circuit with a tone control. The tone control makes the amp more versatile.

Here are some of the amps I've built:

http://www.diycustomamps.com/princeton.htm

The last one on the page with the yellow face plate was built for a friend a couple of years ago who is still using it and loves it. That is probably my finest work to date. Since it was for someone else, it had to be bullet proof.

As luck would have it, I have a layout and schematic on my site:

http://www.diycustomamps.com/images/...eton_schem.pdf

http://www.diycustomamps.com/images/...ton_wiring.pdf

If you decide to build this, PM me. I have some supplementary materials you might find useful.

This is a great beginner's project. Maybe I should do a tutorial on this one next?

tung

[luvmyshiner]

This is a great beginner's project. Maybe I should do a tutorial on this one next?
tung

Definitely.:

[tunghaichuan***]

I'm going to skip ahead a little bit. I need to work out some issues with the face plate and the back plate and get them ordered when I do. This may take some time, so I thought I forge ahead with some information on the circuit board.

Pix here:

http://www.diycustomamps.com/images/18W_lite/board/

Once the location holes for the stand offs are marked and drilled in the chassis, the circuit board can be completed.

The first step is to stuff the board. I had all the parts gathered up in one place which makes it easier. Following the layout, I start at the left end of the board and work my way to the right. The top side of the board is the ground side, so it is important to orient the electrolytic caps with the negative end pointing towards the top of the board.

I try to center the component between the eyelets as best as I can. Once the leads are through the eyelets, I bend them towards each other so that they hold the component on the board. I tend to be anal retentive about parts positioning so I'll make sure that the color bands on the resistors all point the same way, and make sure that any writing on the components faces the same way.

Once all the components are on the board, I run the various wires connecting the components. I usually put them underneath the board, but I decided to put them on top this time to show where they go. Marshall put the wires on top of their eyelet boards back in the late 60s/early 70s. It shouldn't affect anything, but aesthetically, I like the wires under the board. OTOH, a beginner might want to put them on top to make the amp easier to trouble shoot.

Edit: as you can see from the photo, there are a few different spools of wire underneath my bench. I like to color code my builds to make trouble shooting easier should the amp need it after the initial construction is finished. Most of the wire in the amp is 20 gauge, solid conductor. I like the solid conductor wire better than the stranded because it retains its shape once bent. Stranded conductor wire is more flexible and I use it for wiring leads to the speaker.

I color code as follows: grounds, black 20 ga. 300v single conductor, cathodes, green 20 ga. 300v single conductor, high voltage leads, red 20 ga. 600v, single conductor, grid inputs, blue, 22 ga. 600v single conductor. Sometimes I use shielded wire for grid inputs: RG-174U has a 24 ga. central conductor surrounded by an outer shield. This is useful in high gain amps, but as this 18 Watt Lite IIB is relatively low gain, I'm not going to bother.
(end edit)

The next step is to attach the flying leads. These are wires from components on the board to components off the board such as tube sockets, volume and tone controls

Once all the flying leads are done, it is time to solder. I like to use eutectic solder as it has no plastic range. It solidifies very quickly so there is no plastic state. It is either molten or solid. The solder I use has lead in it, so it may be hard to get in Europe due the the RoHS regulations.

There are a few eyelets left unsoldered. When all the solder joints have been made, I use a pair of wire snips to cut off all the excess leads.

Edit: I keep a pair of prescription safety glasses on my bench and wear them every time I do anything amp building related. When I first started amp building, I didn't consistently wear safety glasses. Big mistake: one time I flipped solder up into my face and it missed landing in my eye by about a 1/4." It made me a believer and I wear my safety glasses every time I'm in the shop. I've gotten to the point where I feel kind of weird if I don't have them on.

Always wear safety glasses when doing these types of projects.

Now the board is finished and ready to be mounted in the chassis and wired into the circuit.

tung

[tunghaichuan***]

Chassis & face plate update:

I just ordered some necessary parts from Mouser and Hoffman amps so that I can finish up drilling the chassis. I needed some IEC inlets and Cliff-style jacks. Once I get these parts, I can contact BNP Lasers for a quote on a face plate.

For the face plate I'm leaning towards black plastic with white writing. I believe it will be less expensive than aluminum.

I'm not sure about the knobs yet. I have some that are same as the ones on Budda amps. They are kind of wedge/triangle shaped.

Stay tuned....

tung