Amp Build: Brown Note 18Watt Lite IIB

[tunghaichuan***]

Hello all,

I'm getting ready to start my next project, the 18Watt Lite IIB amp as found on the Brown-Note site:

http://www.brown-note.com/schematics/

I'm going to post pix in this thread to show the process I use for building an amp.

I've already drawn up the chassis and the eyelet board in CorelDraw so I know precisely where to drill all the holes.

I drew up the face plate this morning and I wonder if anyone would mind taking a look at it and giving me some suggestions.

Attached is a .pdf file with three different color schemes. What do you think of the colors, fonts, etc.?

I'm leaning towards the black at this point, although I could have it done in gold as well giving it more of a Marshall vibe.

Once I get the face plate file finalized, I'll send it to Jeannie of BNP Lasers to cut and etch a face plate for the amp.

More later...

tung

[Bloozcat]

I'd probably go with the blackface as well. I can appreciate the nod to Marshall, but why not make it your own?

What the deal with the Brown-Note transformer, as opposed to say, a Heyboer?

[duhvoodooman***]

I like the black, too. Maybe you could go with gold lettering? That would look classy.

I'm REALLY interested in this build, Tung--I've been kicking around the idea of making an 18W Marshall clone for quite a while and just haven't gotten down to it yet. Maybe this will light a fire under me!

I'm curious about how you're planning to go on the transformers, too.

BTW, we have a killer player who stops in here occasionally by the name of Chuck D'Aloia, and he's a featured artist for Brown Note. Hangs out/plays in their booth at NAMM shows, etc. Great jazz player and a confirmed Tele guy. Check out his intro HERE, and take a look at his website, which is linked there. He lives up in the Saratoga Springs area, about 30 miles north of here.

[tunghaichuan***]

I'd probably go with the blackface as well. I can appreciate the nod to Marshall, but why not make it your own?

Yeah, that's the way I'm leaning.

What the deal with the Brown-Note transformer, as opposed to say, a Heyboer?

It think that is Rocco's (owner of Brown Note) take on the 18W. It is probably a custom wound OT, maybe it's even made by Heyboer, I don't know.

I'm not actually using his transformer set, just the layout.

I have a NOS Custom Coil PT that I got for $10 at a local electronics store. The OT is a 15W PP 8K:8 ohm Edcor unit:

http://www.diycustomamps.com/images/...18w_parts3.jpg

tung

[luvmyshiner]

Very cool Tung! I looked at some of their kits, and frankly they seem a little pricey. I take it you're actually building the entire thing from scratch?

[tunghaichuan***]

More stuff:

I gathered all the parts today, chassis box, transformers, tube sockets, tubes, passive parts, and blank eyelet board:

http://www.diycustomamps.com/images/...18w_parts1.jpg

http://www.diycustomamps.com/images/...18w_parts2.jpg

I did intend to use some NOS bakelite sockets, but I stumbled upon a bunch of nice ceramic ones, so I think I'll use those instead.

I'm lucky in that Mrs. Tung (aka SWMBO) has allowed me to have an entire room in the basement to use as my shop. Since it gets very messy when I build a project she likes that I can just shut the door and she doesn't have to look at it.

The shop itself is a 10' x 12' room with two benches, a closet for storage, bookshelves for my tube amp/electronics books, and storage for my tubes, transformers and various other parts.

Here are a few pix of my shop:

http://www.diycustomamps.com/images/18W_lite/shop1.jpg

http://www.diycustomamps.com/images/18W_lite/shop2.jpg

http://www.diycustomamps.com/images/18W_lite/shop3.jpg

practice area:

http://www.diycustomamps.com/images/18W_lite/shop4.jpg

The next step is to make and stuff the eyelet board, then drill all the holes in the chassis and mount all the components to it.

tung

[Bloozcat]

I'm going to enjoy watching this project unfold...

BTW: Nice "man cave", there, tung...:

[tunghaichuan***]

Very cool Tung! I looked at some of their kits, and frankly they seem a little pricey. I take it you're actually building the entire thing from scratch?

Thanks.

Kits can seem pricey until you factor in the cost of having to source all the parts yourself, pay for shipping, order parts that you forgot the first time, pay additional shipping. With kits, you pay for the convenience of having everything shipped to you at once which helps a first time or novice builder avoid lots of brain damage.

I've been building amps for about 10 years now, so I usually have most of the parts I need on hand. I'm also a world-class scrounger. I bet that I have less than $50 in the amp. I have more time than money, so scratch building is the only way for me.

tung

[tunghaichuan***]

I'm going to enjoy watching this project unfold...

BTW: Nice "man cave", there, tung...:

You can almost smell the testosterone, can't you?

tung

[tunghaichuan***]

I like the black, too. Maybe you could go with gold lettering? That would look classy.

Thanks for the suggestion. BNP has aluminum stock that is black that engraves to gold lettering:

http://www.bnplasers.com/AMPBUILDERSMATERIALS.htm

I'm REALLY interested in this build, Tung--I've been kicking around the idea of making an 18W Marshall clone for quite a while and just haven't gotten down to it yet. Maybe this will light a fire under me!

I hope so, I think this will be a cool build. One of the features of this amp is the inputs: one input is a single triode of the 12AX7. The other input is both triodes in parallel which gives slightly more gain and a bit more complexity in the tone due to the differences in the triodes.

I'm curious about how you're planning to go on the transformers, too.

As detailed in an earlier post, I'm using a NOS Custom Coil Unit. It is rated for 70-90mA, 290-0-290. It also has 5V and 6.3V taps. Instead of a 6.3V rectifier, I'm going to use a 5Y3 or 5V4 on the 5V tap. I built another amp with a 6.3V 6CA4 rectifier on the same filament winding as the other tubes which is a bad idea. If the recto ever shorts out, it will take out the tubes the output transformer. Using a 5Y3 is much safer. I should get about 300v plate volts, which I've found sounds very good in a PP EL84 amp. Also I can run the amp in true Class A. The only limiting factor is whether the OT can take it. Class A is inherently hard on transformers, especially ones made for Class AB operation.

The one thing I don't like about the Edcor transformers is the exposed solder tabs. It is inherently dangerous to have exposed B+ outside the chassis.

BTW, we have a killer player who stops in here occasionally by the name of Chuck D'Aloia, and he's a featured artist for Brown Note. Hangs out/plays in their booth at NAMM shows, etc. Great jazz player and a confirmed Tele guy. Check out his intro HERE, and take a look at his website, which is linked there. He lives up in the Saratoga Springs area, about 30 miles north of here.

Cool, I'll check him out. :

One of my grad school professors lives in Saratoga Springs. He was my favorite, and one of the coolest people I've ever met.

tung

[tunghaichuan***]

The next step: making the eyelet board.

Full pictoral tutorial here:

http://www.diycustomamps.com/images/.../eyelet_board/

Main points:

I make templates from 3" wide, 1/16" thick Grade XX Garolite from McMaster-Carr. The Garolite comes in three inch wide by four feet long strips. Since I don't have a miter box or a power saw, I mark the garolite using a Sharpie and a square, rough saw it to length with a hack saw, and then trim off the end with a laminate trimmer with a flush cutting bit and a straight edge. Kind of a PITA, I know.

Next I take the 1:1 artwork I previously generated in CorelDraw, cut it out and tape it to the front of the blank template. I make a template so that I only have to do the aforementioned step once. Once I have a template it is just a matter of taping the template down to a new blank board and marking it. This is a lot less of a hassle than drilling through paper taped to a board.

Using a jig I made, I set a fence on the drill press to get nice consistent, even results. I then drill out all the eyelet holes and the four board mounting holes.

Next I take the template and trace the holes onto a piece of G10 glass epoxy board using a Sharpie. G10 is used as the substrate for high-quality PCBs. This is a better material for eyelet boards than Garolite, but it is very expensive. I bought a 3' by 4' sheet a few years ago and had it cut into three-inch wid lengths. I'm down to the last of it and unfortunately G10 prices have skyrocketed in the last few years

Then using the same method for the template, I drill out all the holes on the drill press using the attached fence and setup template.

The next step is setting the eyelets into the board. I put an eyelet into each hole (leaving them out of the mounting holes, natch) and tape them down with masking tape. This allows me to turn the board over without all the eyelets falling out.

I flare the eyelets using a small hammer and a 5/16" center punch. I then secure the eyelets by flattening down the flare witha 6" long, 1/4" diameter steel rod. Viola, the board is done.

The same method can be used with turrets as well. The only difference is the setting method. I personally don't like turrets, they do look cool, but are a PITA to modify once the components are soldered to them.

Since this is a scratch build, I have to do all the handwork myself. This is another advantage of kits: the eyelet board comes ready to stuff and install. Also, the chassis comes finished. Making eyelet boards and drilling out chassis can get very tedious.

Next up: drilling all the holes in the chassis.

tung

[Bloozcat]

I'm going for the popcorn, be right back.....

[tunghaichuan***]

Before I go on with any more of the tutorial, I think I may have gotten ahead of myself.

When I first started building amps about 10 years ago, I just winged it. I'd work up a hand drawn layout (maybe) or use Fender's. I mostly built Tweed Champs & Princetons in the beginning because they are easy to build and sound great.

Now I use CorelDraw to mock up the amp in 2D before I ever touch any tools. I have generated an entire amp using CorelDraw. This allows me to precisely position parts in the chassis and make 1:1 drilling diagrams for the board and the chassis. I even have the footprints of several transformers which I accurately measured and rendered in CorelDraw. This allows me to print these off onto clear overhead projector sheets. I use them to put right on the chassis to mark where the holes go without having to measure.

With some of the more involved/complex amps that I have built, I generated a a full-color wiring diagram. I have come up with my own color code for wiring amps so that I can troubleshoot easily.

Next up: drilling and punching the chassis.

tung

[tunghaichuan***]

Drilling the Chassis, Part I.

Pix here:

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

Let me start by saying that chassis work is my least favorite part. It can be a royal PITA to get all the holes in the right places and lined up correctly. It is also very easy to put holes in the wrong places and completely ruin a chassis. For this project, the chassis is one of the most expensive items.

This is why I recommend kits to beginning builders. The nice thing about kits is that a lot of the tedious work is already done. I'm no machinist, so it has taken me many years to get to the point where I can get consistent results when fabricating chassis.

I use the Bud Industries AC-409 for many of the amps I build. It measures 2" tall, 7" wide and 13" long. It is about .040" thick. It is made of aluminum and is easy to drill/punch. It can be used for just about any amp from 1-20 watts depending on the number of controls on the face. I can get about 8 controls on the front of one of these: on off switch, standby, pilot light (small), TMB tone controls (small knobs), volume control (small knob) and an input jack. For more than that I would move up to the next size chassis which measures 2" x 7" 17".

I like to make a 75% sized drawing of the chassis and the various holes that will be made with their measurments. I print this out on 8.5" x 11" paper as a reference.

Once I have made the board, I start by drilling and punching the chassis. "Punching" refers to using a chassis punch. This is a device that has a draw bolt, a die and a cutter. These are great for tube amp work because they make nice round holes.

The first step that I do is to mount the board. I used the unstuffed board itself to mark the locations for the standoffs. These keep the board components from touching the chassis. I trace inside the holes with a fine-point Sharpie then use a spring loaded center punch to mark the location of the hole. Then I drill out the hole using an appropriately sized bit. Then I mount the board to make sure that everything lines up correctly.

Next I drill/punch the holes for the tube sockets and in this case the chassis-mounted cap can. I use three methods here. I need a 1.375" hole for the cap can, but don't have that size chassis punch. So I use the biggest punch I have which is 1.25". To make a hole I measure and mark the location. Then I use center punch to put a small dimple where the hole goes. This dimple keeps the bit from wandering. Since this is a large hole I then use a stepped drill bit to make a hole that is just the diameter of the draw bolt on the chassis punch. Next I assemble the punch, and tighten it down on the chassis until it cuts out the hole. To enlarge the hole to accept the 1.375" diameter cap can, I take a template made of .75" MDF with a 1.375 hole bored in it and tape it down over the existing hole using double-sided carpet tape. I try to center the jig as best as I can. Then I use a laminate trimmer with a flush cutting bit to follow the template and cut the hole to its required size. This is okay to do with Aluminum, but don't try this on steel: you will damag the bit, the work, and/or yourself. Since most of the drilling punching operations leave a sharp edge, I then use a deburring tool (sometimes called a "chaser") to deburr the sharp edge.

Next I cut out the rest of the tube socket holes. The octal socket requires a 1.06" hole, the two power tube sockets require .75" holes and the two preamp tube sockets require .875" holes. I use my chassis punches to cut out the octal and power tube socket holes, but I don't have a .875" punch, so I go to the stepped drill bit. The last step on the bit is .875" so I just drill through. There is a sharp burr left that needs to be removed so I use the deburring tool to scrape it off.

A word on stepped drill bits: the best ones I've found are Irwin brand Unibits. They have a single flute and make nice round holes. Several of the cheaper bits make triangular shaped holes.

Next I flip the chassis over and proceed to fit the transformers. Starting with the power transformer I measure the location and cut the feed-through hole for the various wires. I then debure the hole using the deburring tool. Since I did not have a mounting pattern, I carfully positioned the transformer and marked the inside of the mounting brackets with a Sharpie. I then remove the PT and center punch the hole locations and then drill them to size with an appropriately sized bit.

Mounting the output transformer was a little easier as I had a footprint drawing on a clear sheet to overlay on top of the chassis. Once I had marked the center line of the mounting holes, I placed the sheet on top and then marked the hole locations with the center punch. I use sheet metal screws to attach the OT to the chassis as the board covers up one of the mounting locations on the inside. Getting a nut off the machine screw when covered by a board is very frustrating, and can't readily be put back on.

Finally, I locate and drill the location for the feed-through hole for the OT's wires. This hole needs to have a rubber grommet to protect the wires. (The PT doesn't need a rubber grommet; the wires do not come into contact with the chassis) The OT I'm using for this project has both the primary and secondary wires on one side. Generally, the primary wires are on one side and the secondary wires are on the other. Having both on one side does not seem to affect the sound.

That's it for part I.

All that needs to be done is to drill out the holes in the front and back of the chassis.

tung

[duhvoodooman***]

Tung, this thread is so PACKED with cool info and photo links that I'm gonna "sticky" it right away. : :

Hope you don't mind, but I added "Amp Build:" to the beginning of the title to clarify the content.

[tunghaichuan***]

Tung, this thread is so PACKED with cool info and photo links that I'm gonna "sticky" it right away. : :

Hope you don't mind, but I added "Amp Build:" to the beginning of the title to clarify the content.

Awesome, thanks for making it a sticky. No worries about adding the the clarity of the title, I'm all for anything that makes the thread easier to use/understand/find.

The next step is to order the face plate. I'm divided between glossy black engraving to gold or glossy black engraving to silver. Duhvoodooman has voted for black engraving to gold. Any other recommendations?

Another issue is that I want to use an IEC connector onthe back instead of my usual ghetto rubber grommet & knotted power cord. I've never done this before, so I'd like to do this with this project as that's going to become standard on all my future builds. Now just to figure out how to do it.

tung

[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.: