HNB 10.0 The final product

Finally, I am about 99% done with this build. I still need to protect the corners will metal covers. They will be black. This was a lot of fun to put together because I sourced none of the work out. In contrast, on my first amp the chassis was punched and drilled and the turret board was drilled and loaded with eyelets. Bought as a "kit" meant that all of the components were purchased together. Here, I had to use 3 different online sources.

This works well as an open back cabinet. The speaker is an Eminence Copperhead which has a very clear sound and is very efficient (99db sensitivity, I think). For one speaker, this little 10" really cranks. Considering the amp is only 5 watts, it amazes me how loud this thing gets. It is too loud for home use if you crank it up all the way. If I lived in an apartment, the neighbors would be complaining.

The light on my first amp is a bluish purple. I got to choose this one, so I came up with a goldish yellowy brown color. The first time that little lamp glows is a major victory. It glows when you turn on the power switch. The next switch is standby, which heats the tubes but gives no power (B+) to the rest of the circuit. The last switch is called "MUTE" but it really just makes the high gain setting work at lower volumes. Maybe I should have labeled that something different. At least it wasn't a mispelling!

The heavy inked area for the name of this amp looks cracked from a certain angle. Straight on it seems fine, though. There are minor imperfections all over this build - in the wood work, the lettering, and of course the finish (I am heavy handed at spray paint and lacquer). However, it is 100% my own work, and sounds absolutely amazing. Family members have sent checks to offset my costs, do this will be a family gift to my father-in-law.

The tone controls are actually very responsive. The thing really sings if you leave them full on, but turning down the treble, mids, and bass help balance the sound for the different guitar setup. My favorite clean sound is with the GAIN setting on 3, and the master VOLUME on 6-7. With my Les Paul, I can get some nice jazz like sounds. I would love to hear a real archtop through it, though. Because it is a low-power amp, you can get some great distortion at a sound pressure that doesn't split your ears. I don't think I ever need to go above 20-30 watts in this lifetime. (In case this stuff is new to you, a 50watt amp would be twice as loud as a 5watt amp.)

I may post one or more times about this build, maybe showing the corners and stuff. But for now, we can pretty much consider it done. Aww, look at it.



--gh

HNB 9.0 Final soldering

Here is the amp nearly done, from the front. As mentioned earlier, this would be the time that I would debug the amp for possible problems. Well, on this build I had no appreciable B+ voltage, even though the rectifier was working fine. Those silly electrolytic capacitors were all in there backward. Usually the marking is very clear as to which side is negative. The black stripe with no arrow wasn't helpful for me. I wrongfully guessed that the black stripe corresponded with the black end cap, marking that as negative. Duh, that black cover was on the crimped side, and usually it is there to insulate it from the casing. The casing is usually grounded, and the negative side is silvery. Well, it could have been worse for debugging, and luckily I did not destroy these four capacitors ($2.50 each!).

Here you can see that I sketched a part of the schematic on the back of the amp. It is the preamp stage. I wrote that this was "BlackLine Amp Serial Number: 00002," except that I mispelled it "BlachLine." Oh well. Look in the back of the workbench, I installed a permanent 1/4" audio jack for my amp building projects. It is connected to a speaker only for this purpose.

...and that speaker is mounted to the ceiling of my workshop! This is a nice 12" speaker from an old Dean Markley amp from the 1980s. I can sort of use it for some hi-fi stuff as well for basic debugging. The sound is weird coming from the ceiling! Behind that you can see the workshop clock mounted on my little data closet. Inside that small room is the nerve center for all the phone, cable, satellite, and ethernet connections.

--gh

HNB 8.0 Loading the turret board

I love absolutely every stage of building this amp. I began a few months back by drilling holes and mounting turrets in this fiberglass board (called garolite). Now I finally get to load some of the electrical components like these electrolytic capacitors. If there was a stage of building that I was apprehensive about, it would probably be the debugging stage. (That's when I found out that I mounted all of these power filtering capacitors reversed!) The little red handled doohickey is used as a heat sink. When soldering capacitors and diodes, you clamp this on the leads to absorb the heat. Resistors can handle a lot of thermal abuse, so I might skip using the heat sink on that. Sometimes I use a hemastat that I have laying around, but that sort of makes me feel like a stoner.

Here is the turret board fully loaded. I could only solder about half of the turrets because some of the wires from the tone and volume controls or the tube sockets will also connect to this board. In this picture you can see my Weller soldering station. It is not the fanciest, but it is a big improvement over soldering with one of those cheap irons. In the back you can see the wire that I used for 80% of this build. It is 22 gauge solid core. It is fairly skinny stuff, and very easy to work with. The last time I used 18 gauge stranded and it got sort of messy.

Actually, it was messy because I used eyelets, and not turrets. Also, I made the mistake of soldering everything 100% on. After putting it in the chassis, I had to desolder about 20 connections to hook up the wire. Being thicker and stranded it got messy fast. Solid core wire stays, which makes debugging hums and squeals nice. If you move it too much, it could break on the inside (almost impossible to find at first) which is why stranded has its advantages. I still used the 18-gauge stranded wire for the primary electrical connection to the power transformer, and for the heater circuit (higher current that actually makes the tubes glow). But the 22 gauge stuff was really a pleasure to work with.

--gh

HNB 7.0 - Mounting stuff on

I couldn't wait to mount those components. Most of these things will stay on the chassis, and I will solder and wire them up in place. The only thing I think I will remove to wire up is the input jack - but I couldn't get a feel for how this thing will look without that in there! In this image you can see the thread lock fluid that I use for all of the bolts. It tastes sweet, really sweet - like in a saccharine sort of way. When I monitored weather stations on the side of mountains in Montana, I used to taste the propylene glycol when I was bored. (We used that as an environmentally friendly antifreeze.) I eventually know what most hobbies that I work on taste like.

From the outside, the thing really looks done. It is all an illusion, though. I hope to be hearing something out of this within the week, though. The transformers will hang down from the chassis, so that is why everything looks upside down when I turn the chassis like this. For a second, after I lettered up the whole face of this thing, I thought that I had forgotten this detail and did everything upside down. I was just messing with myself - it was fine. I really wish that output transformer had some bells on it, it's a little on the ugly side.

I'll try to refrain taking whole image shots until I am really done with it. However, you can see what one little corner might look like. I knew that this would be a tight fit, but it was a little too tight. Before I painted it, I mounted threadserts so that I can screw the chassis to the cabinet. It bumps out about a quarter of a millimeter, but this was within the tolerance of my fit. Also, before painting I put some Bondo on the corners and on some rough spots. So, the chassis was tight enough that it didn't fit! I had to file out a place for the threadserts to glide on the little shelf, and use some candle wax to make it slide in and out better. I won't refinish that part, because it is never meant to be seen with the chassis properly mounted.

Here's a little view from the back. I am using Amy's new digital camera, and I don't know how to put the flash on! I know that those tubes look close to that shelf in the front, but it is over an inch away. I am not worried about heat, in case you are curious. The preamp tube (12AX7) never gets too warm, but that power tube (EL84) can cook flesh. So, I guess I am glad it is way up in there.

The next thing I will do is to solder some components to the turret board. That should be fun because I did not use turrets last time.

--gh

HNB 6.0 - Lettering the Chassis

Putting the markings on the chassis happens to be one of my favorite parts of building an amp. Of course, the H.N.B. amp is serial number 00002 (heh), so what do I know. To bring everyone up to speed, I am using rapidograph technical drawing pens, Leroy lettering sets, and good old-fashioned India ink. The chassis has been primed and then painted with a flat white canvas for me to work on.

The flat paint is key, if it was too slick (satin, medium glossy), then the pens wouldn't work right on the surface. It feels like a decent polyester film sheet (what you might call Mylar if you worked for DuPont, and you might call it "polyethylene terephthalate polyester film" if you were in my Introduction to Geography class). Here you can see that I am using a stool as a work surface, and a blank of 2" oak to clamp the chassis to. This gives me a little table to work on, so that the lettering system has a stable place to move across.

I will let you in on a little secret, for the whole words and sentences, I am using a CADLiner 950 autoscriber. This makes things move much faster. However, with 20 years of manual cartographic and cadastral mapping experience, I can do it all with a Leroy set if that was all I had available. Having said this, I do have to use the manual Leroy set for the numbers on the dial. Basically, the first thing I do is cut a template out of a piece of card-stock. The general shape is a dodecagon, or 12-sided polygon. A potentiometer usually sweeps 300 degrees, so I only use 10 vertices. You can barely make out the pencil line on the face of the front here. I need to see the thing, but I also have to erase it later.

What? Did I really just write erase? Yes, believe it or not, this is the magic of 100% India ink. India ink is a very old technology, but basically it draws on the surface rather than dyeing or coloring the surface. The black carbon sort of sits on top of the surface, and all you need is a nylon eraser and some spit to remove it. If you have ink laid out, and need to erase pencil marks around it, just go lightly and use no moisture at all. This is a very flexible process, even though drawing ink on top of paint sounds more permanent. (This is why I use lacquer at the end, it has to be sealed in.) In this photo, you can see I am laying out the "fives." From this angle, it just looks like I have mad skills for laying things out. Just remember that there is a polygon drawn lightly in pencil, and I am laying the numbers out on 10 little vertex locations based on a template that I created in Adobe Illustrator. You can probably see that template in the lower left of this photo. Note that I have used this before, you can see how I drew Mr. French on my last build (in 3-4 stages).

In this photo you can see the eraser under my right wrist, and a mechnical pencil under my left. Also, note the card stock template. The template shows me where to put the intersection of the "four" as it lines up with the vertex of the polygon. They all may be off up to a millimeter or so, but it still comes off as passable. Here I have drawn out almost all of the numbers. It might seem frightening, but I have to go in and erase the little pencil marks around the numbers before I am done. You can never tell that some of these numbers were erased and re-drawn. In fact, with 5 controls, I have 50 numbers to place on those dials - and I probably messed up about 5 of them. As long as I am careful about erasing it, you won't see it was ever "moved."

I am almost done with the lettering here. The last thing I did was draw out my father-in-law's initials, just like he signs them. There is a lot of "writing" on this amp, and I even included a hand-drawn partial schematic on the back (just filling in space). You will probably see that later, I hope that was a good idea. Next comes the scary part. To lock everything in, I have to put a clear-coat of lacquer on the surface. But, I also know that moisture is used to erase the ink off of the surface. The first time I did this, I imagined spending a half-hour drawing ink on the chassis, and then watching it melt right off when I spray-painted the wet lacquer over it.

Luckily, the lacquer seems to have the opposite effect. Instead of messing up the lettering, it actually darkens it slightly! If I like the way it looks after applying the ink, then it will look twice as good with the finish coat. I think the lacquer is slightly mixing with the shellac that is found in India ink, and it really brings out the contrast between the white background and black letters.

This leaves me with a final product that looks completely original, completely customized, and somewhat professional-ish. The standard "Arial" font that is used in cadastral mapping comes out well for these projects. When I look at it, it just screams to have dimensions, parcel numbers, and acreage calculations on it. One of these days I will create a "Cadastral Mapping" themed amp with north arrows, roads, blocks, lots, etc. That may be a little project that will sit in my office because the next amp I need to build is one that I will play weekly at church. It will not be based on the same schematic as these two, either. I want something like a Fender reverb sound for that.

However, I need to finish my father-in-law's Christmas present. The next step is to wire up the turret board. After that, I will mount the components (transformers, tube sockets, input jacks, potentiometers) on the chassis. Then, all that is needed is the final wiring. All will end with testing, trouble-shooting, and sound checks.

--gh

Astronomy Schashtronomy

I think I figured out why I don't really care about astronomy. In my family you cannot suggest an axiom or a rule without three reasons, so I guess I will present three reasons why I don't like astronomy. By the way, I will not split hairs with the field of astronomy. Since I know so little, I claim the author's prerogative to lump into astronomy everything from astrophysics, cosmology, quantum physics, etc.

First, astronomers just don't know squat about our universe. I am officially assigning the technical definition of "squat" as 10^-9. Astronomy is arguably the oldest accept discipline, and yet they only know one billionth about what goes on outside our world. Oh, and I don't want to hear anything about early astronomy being astrology either. It was an accepted lifestyle for a chosen few to sit out all night somewhere in the Arabian desert and try to understand the movement of those points of light. They may have assigned mystical principles guiding them, but they were still trying to figure out the cycles and patterns of the sun, moon, planets, stars, and occasional comet.

Some try to dismiss early "astronomy" because of it's superstitious roots. In the same breath they may mention how well the ancients could accurately predict solar and lunar eclipses and comets that skip a few generations. Well, you can't have that both ways - it was all a form of astronomy, regardless of the motivation. It took about 2,000 years to predict the patterns of the planets accurately, and then another 1,500 to explain why and how it works. So, astronomy will interest me more when the knowledge rate gets up to a respectable percentage, like 10%. (I think Physics and Chemistry are there. Biology is probably at 5%, and Geology may have reached 20-30%.)

The second reason for disassociating myself from an interest in astronomy is equally unfair. Basically, because astronomers know so little about the universe, theories just seem to come and go like fashion styles. It does not matter how silly it sounds (the universe is made up of little strings right now) - astronomers will defend the currently accepted and applied theories as if they had a total lock on the knowledge. If you don't like String Theory, just wait a few decades and the astronomers will catch up with you. In fact, we really don't even know why gravity works. We know how it works, thanks to a few principles outlined by Newton, Kepler, and others, most of the universe seems to follow along nicely (unless a black hole is involved, which somehow bends or writes its own rules). I do respect that astronomers usually admit when they are wrong (S. Hawking's losing a famous bet recently comes to mind), but their dignity and respect are preserved because the general public does not know the difference between the dismissed theory and its successor.

So, with a few of those bricks soundly planted in the cathedral of knowledge regarding gravity, astronomers are at a loss to explain what keeps the galaxy together. The galaxy should be denser or something, so someone invents dark matter that must be out there throwing the scales off, but keeping things together. I cry foul, but this is a seemingly accepted practice in astronomy. Imagine a molecular biologist trying to explain genetic mutation thus: 'Genes in a cell mutate on a slow but almost predictable rate. Nearly 99.99999% of the time, the Doosies and the Launchies say "NO" to mutation. However, once every 100,000 cell divisions, the Doosies and the Launchies say "YES" and the genes mutate.'

Third, and finally, I dislike the field because of our fixed perspective. Now, I admit that this is totally unfair, but astronomy will be more interesting when we can see the universe, or even our galaxy, from a different location. Imagine that we are in a cell of a human body, somewhere around the elbow. It takes a while to recognize that there are other cells, and then a theory comes along to suggest that we are on the wing of a collective "body" of cells. Later, someone notices that if we look outside of our "body," we can even see other human bodies walking around. Every picture of the human body is seen through a perspective of looking along the arm and around organs in the chest cavity, etc. You can see how difficult it is for astronomers, and they have done a phenomenal job with what they have. But, give them a spaceship that travels at hyper-light speeds and give us a picture of our galaxy from another angle! We think we know what parts of our galaxy look like, but they are ALL from a tiny point.

As you can see, my objections are really not fair. I don't begrudge astronomers and their currently published theories mostly because they know they have very little of the knowledge down. An astronomer who claims to know how the universe works is probably a shaman, and not an astronomer at all.

My last observation did not need to make my "three reasons" clause, but may be worth noting. Something that really tickles me about this field is the divergent mix of both left- and right-brained people. Maybe the right-brainers are held captive by the limited knowledge and react by calling items "red giants" and "white dwarfs." The left-brain inventory of astronomical designations like M275 and NGC2863 causes the right-brain brethren in the field to suggest names like "horse-head nebula" and "running man nebula." Oh, and then we had that whole "eye of god" image that went around the web a few years back - but I will not blame this on astronomy.

--gh

HNB 5.0 Chassis Painting

Well, over a month ago, I said that I would attend to painting and designing the chassis. I changed gears and designed/built the cabinet first. I only needed to add a few more holes before I put a coat or two of primer on.

I counted 46 holes that I drilled in this chassis! Every control, switch, wire, or bolt that mounts to and through this thing has it's own hole. This amp is about as simple as it gets, so you can see how complicated the whole process gets. After primer, I applied white paint. I am using non-fancy spray paint from the hardware store, or maybe even Wal-Mart. The white layer is actually a flat finish, not satin or glossy. I think I will put another coat of flat white on just to make sure I have good coverage.

The next stage will be to mount the white chassis onto a huge plank of oak to create a drawing surface. I will use some of my old-school cartography skills (and tools) to layout the faceplate design on the chassis. This will use technical drawing pens and regular old-fashioned India ink. Then, I will put a clear coat of lacquer to lock in that design and make it shiny. It should work out well, but - I am getting nervous again. Well, it worked out okay last time.

--gh

Name 25 Cities of the USA

Heh, when I first saw the 25 Cities of the USA, I misread the directions. I didn't push the start button, I just went and mentally named all of the cities. So, I guess I cheated a little - but I knew where each city was.

Got it in less than a minute, luckily.

--gh

Stuff that we learn

Okay, I have experienced theThe Baader-Meinhof Phenomenon personally, and am waiting to have it occur regarding my knowledge of that occurrence. (I guess Baader-Meinhof is usually recursive in nature.) Basically, when you learn a word, phrase, or piece of knowledge for the first time - you are destined to have it come up again within a day or so. That is the essence of Baader-Meinhof.

So, you will probably experience the word "Baader-Meinhoff" in the next week. If this is happening more often - perhaps the Internet is really to blame. I mean, I read about this from a link from Digg. Within a day or so, it will be copy-catted on Fark. Eventually, SomethingCool (does that even exist?) will link it - and eventually someone else will bring it up.

Not that it is bad - I think it is an interesting phenomenon - and will try to remember it. File that next to Godwin's Law...

--gh

N.B. I found out how hard it was to type an apostrophe in HTML. Basically, you have to type "'" to get it to look right. Of course, can you imagine what I had to type to make the code in the last sentence work? This N.B. is to state that apostrophes should be avoided in web addresses...

HNB 4.4 Assemble, Glue, Sand, Stain...

With all of the cabinetry cut and assembled, it is now time to apply the glue. You may see a little blue painting tape hanging off the edge - I put that on to collect the excess glue, because removing it after it dries can be difficult in inside corners. I use a bunch of clamps while the Elmer's glue (carpentry glue) is drying. Elmer's works just fine, no need for weird and fancy polyurethane foamy glues (very messy). I have to trust that the joints (dovetail, dado, and mortise&tenon) will hold with the glue only.

With the dovetail joint making router template that I have, a little bit of sanding is needed to knock down the edge. This is fine, because the end result looks very tight. If there is a gap, I will fill it with some wood filler - but very little of this is needed. The Keller dovetail system is a good solution. Also, I will round over the edges fully, making it look pretty amazing, actually.

I cannot remember the name of the stain, but my son picked it out. My first amp was light in color, and he wanted to see something darker. I think it is called "early american" from MinWax, possibly. I only applied one coat of stain, because the poplar was sucking it up pretty well. Oh, I also use some wood conditioner (MinWax) as well, because it makes it more even reception of this stain. This is important for the end of the grain which is seen in the dovetails. A little light-dark-light is okay, but I don't want too much contrast.

Okay, see how the speaker grille cloth really tightens up the look! This is the first time I have dealt with this material. It is acoustic grille cloth, and is meant to protect the speaker, hide the front, and permit sound to pass through. Looks dang tight is what I say.

I put a board across the bottom of the back to keep a foot from kicking out the back of the speaker. You may be tempted to say I am breaking my rule about not using fasteners, because there are two obvious screws holding this in. However, this needs to be removable, in case the speaker needs replacing or something. Yes, it probably makes the cabinet a little stronger, but it would have been fine without it. Technically, if you remove it to take out the speaker, then I am confident that the amp won't fall apart.

The speakers are mounted from the back. The baffle has t-nuts on the front, and the screws go right through and mount this. This means that you don't have to take the grille off the front to mess with the speaker. Of course, we hope that this never needs to be messed with anyhow - but I want this to be as close to a professional job as possible.

Here you can see how the dovetail joint looks rounded over. This is with two coats of clear polyurethane finish, so it is nice and shiny. I must have pushed that chassis in and out of the cabinet one hundred times during this build, because it was going to be a nice and tight fit. Here I can see that it will all pay off. I put rubber feet on the bottom, mounted the speaker, and put a handle on the top. I am very tempted to put metal corner protectors on this. I have some, but they will need modification. Of course, it looks awesome without it. But, the corners are the most vulnerable with this cabinet, and it is meant to be portable. Because I rounded the edges, there are some parts of the dovetail that are a 1/4" which might just pop right off (?) if it is struck to hard against a door, or car, or whatever.

So, now I need to get back to the electronics of this thing. There are a few more holes to drill in the chassis, and then it needs to be painted (and designed!). Then, there is the soldering, then testing.

--gh

HNB 4.3 Chassis shelf

With the dovetails routed out, now I need to build a shelf to hold the amp chassis. Here you can see my thumb holding the chassis inside the empty shell that will become the combo amp. My desire is to build a cabinet that is structurally solid without fasteners. Building a shelf right in will make it very solid.

In furniture-land, I think this would be called a mortise and tenon joint. I do not think I have an interest in building furniture - but I can really get into the allure that it holds. Of course, I would be the type of hobbyist that uses a router to do such things, since my real hero is Norm Abrams (and not Roy Underhill). Now you can see how integrating dovetails, mortise/tenon, and dado joints makes a strong structure for such a small little box.

I like this picture, it really shows how rough my carpentry skills are. Note that the front of the cabinet does not really line up on the corners. The funny thing is that some 60-grit sandpaper will clean that right up. I have been told by more hardcore enthusiasts that sandpaper should never really touch fine furniture. Well, luckily a guitar amp could not be considered "fine." Anyhow, here you can see how the shelf will hold the chassis.

Okay, maybe building some furniture would be fun. Here is my combo amp serving as an end table with a drawer! I will actually need to cut a bit of the shelf out, though, because some components of the amp (important stuff like transformers and tubes!) will hang down. That is what the picture below shows.

Luckily, I remembered to cut a dado joint near the front of the shelf to receive the speaker baffle. It would have been harder because the cut on the dado into such a delicate piece later. Here you can see the backside of the cabinet starting to look like my "plans." The speaker baffle is sitting within a groove (dado) cut into three of the cabinet sides, and the bottom of the shelf. The speaker baffle is just 1/2" pine plywood. This would be a no-no if I were building a larger (louder) amp because regular pine plywood has thick veneers, and possible voids within it. The real amp-makers try to use birch plywood that cabinet makers use. If I build anything louder than 5-6 watts, then I will keep that in mind.

--gh