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 (http://www.thefret.net/showthread.php?t=6816), 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_lite/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_lite/18w_parts1.jpg

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

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...:AOK:

[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...:AOK:

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

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 (http://www.thefret.net/showthread.php?t=6816), 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. :AOK:

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/18W_lite/eyelet_board/

Main points:

I make templates from 3" wide, 1/16" thick Grade XX Garolite from McMaster-Carr (http://www.mcmaster.com/). 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 :mad:

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.....:munch:

[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. :AOK: :dude: :bravo:

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. :AOK: :dude: :bravo:

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.:bravo: 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.:AOK:

[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.:bravo: 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.:AOK:

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/princeton/tweed_princeton_schem.pdf

http://www.diycustomamps.com/images/princeton/tweed_princeton_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.:AOK:

[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

[M29]

This is awesome tung I am waiting on every thread. I can smell the solder way over here:rockon:

M29

[tunghaichuan]

Which knobs should I use?:

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

Top are the ugly-a$$ Rat Shack cheapies. On the bottom left are chicken head knobs. Bottom right are Budda-type triangle knobs.

I may use the chicken head knobs with the black face plate and white writing for a Hiwatt vibe:

http://images.miretail.com/products/optionlarge/Hiwatt/483132jpg.jpg

tung

[M29]

If you are going to go pointy I would go Chicken. IMHO of course:D I do like the triangles though.

M29

[just strum]

Chicken heads.

[luvmyshiner]

Chicken heads.

+1:AOK:

[tunghaichuan]

The Budda knobs look cooler, IMHO, but they don't turn as easily as the chicken head knobs.

Chicken head knobs it is. :AOK:

tung

[tot_Ou_tard]

The Budda knobs look cooler, IMHO, but they don't turn as easily as the chicken head knobs.

Chicken head knobs it is. :AOK:

tung
I agree the Budda's look cooler, but they might be more difficult to turn.

Then again, it's not like you have to turn them in the middle of a song.

[duhvoodooman]

Late to the party, but I like either the chickenheads or the triangles. Save the Rat Shack knobs for a pedal!

[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/18W_lite/chassis/chassis_31.jpg
http://www.diycustomamps.com/images/18W_lite/chassis/chassis_32.jpg
http://www.diycustomamps.com/images/18W_lite/chassis/chassis_33.jpg
http://www.diycustomamps.com/images/18W_lite/chassis/chassis_34.jpg
http://www.diycustomamps.com/images/18W_lite/chassis/chassis_35.jpg
http://www.diycustomamps.com/images/18W_lite/chassis/chassis_36.jpg
http://www.diycustomamps.com/images/18W_lite/chassis/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.:AOK:

[tunghaichuan]

Lookin' sweet Tung.:AOK:

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

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 (http://www.bnplasers.com/) 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/18W_lite/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 (http://www.bnplasers.com/) 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

[duhvoodooman]

Coming along nicely, Tung! Looks like you should be ready to apply the electrons shortly. Wait a minute, I shouldn't use a word with "short" in it.... :eek: ;)

[tunghaichuan]

Coming along nicely, Tung! Looks like you should be ready to apply the electrons shortly. Wait a minute, I shouldn't use a word with "short" in it.... :eek: ;)

So far this has been a fun project. The only downside is that I haven't had a chance to work on the Triboost pedal. :(

Duhvoodooman finished the enclosure for my Triboost pedal and it looks fantastic :AOK:

tung

[tunghaichuan]

Wiring, Part 1: Preliminary Stuff

Pix here:

http://www.diycustomamps.com/images/18W_lite/wiring_pt1/

This morning I did some preliminary work on the chassis to get it ready so that I can wire the circuit.

The Edcor output transformer (http://www.edcorusa.com/products/transformers/xpp/xpp15-8-8k.html) has quick-disconnect tabs rather than flying leads so the first order of business was to make and attach flying leads to the OT. I found some quick disconnect connectors at McMaster-Carr (http://www.mcmaster.com/) when I was investigating using Edcor's transformers. I also bought some 600v, 20 ga. stranded wire in three colors: blue, brown and red. These are "standard" colors for plate and center tap leads on push pull transformers. The black and yellow wire is 300v, 18 ga. for the speaker leads. The quick disconnects use a dual crimping connection to hold the wire onto the lead.

The Edcor OT is slightly underrated for this application at 15w. The circuit puts out 18 watts, as indicated by the name of the circuit. Another thing I don't like about the Edcor OT is the lack of insulated flying leads. Using quick disconnects is inherently unsafe as there at least 300v on the plate and center tap leads. In one of the photos you'll notice that there is some red heat shrink covering two of the unused tabs. These tabs are ultralinear connections which are usually used in hifi amps. However, a few guitar amps have used UL taps most notably some Fender amps from the early 70s and some modern Dr. Z amps. There is also high voltage on these leads as well hence the heat shrink.

Once the leads are connected to the OT, it is a matter of twisting the black and yellow speaker jack leads and threading them through the grommet in the chassis. Then braiding the blue and brown plate and red center tap leads and threading them through the chassis. The wires are put into their proper places on the inside of the chassis as they they will be covered by the eyelet board and will be hard to get to.

The next step is to install the eyelet board. First I put the threaded hex standoffs in the chassis with lock washers to keep the board from vibrating loose. Next the board is put onto the standoffs and bolted down with machine screws and lock washers. I keep most of the machine screws loose until I line up the board to make sure it is positioned correctly.

Now that the board is installed, I can proceed to soldering all the flying leads into the circuit to finish up the amp. At this point I would estimate that the amp is about 50% done.

Stay tuned for more wiring.

tung

[duhvoodooman]

Tung, any further progress on this amp build?? Dying to hear a clip from the finished product. C'mon, man--your adoring public awaits!! :poke: ;)

[tunghaichuan]

Tung, any further progress on this amp build?? Dying to hear a clip from the finished product. C'mon, man--your adoring public awaits!! :poke: ;)

I really need to start the wiring. I was going to start last week, but I wanted to build the Tribooster (http://www.thefret.net/showthread.php?t=8927). Which reminds me, I need to post a pic of the guts. :)

Tomorrow is my day off, so I'm going to try to get some work done then. :AOK:

tung

[Ch0jin]

Well, I started out with the best intentions... Just have a quick scan over the new threads over a coffee... Then I start reading this thread. Close the office door and don't move till I got to here haha.

Love the amp/fx build threads!!!!

Cant wait to see and hear more about this one as I've been psyched to build my own lower power tube amp for ages now. I'm even considering an 18W from ceriatone.

[tunghaichuan]

Had a chance to start on the wiring this afternoon.

Some pix here:

http://www.diycustomamps.com/images/18W_lite/wiring_pt2/

I started with wiring the power supply. First I wired the rectifier tube socket. I decided to use a 5V rectifier to take advantage of the 5V winding on the power transformer. Normally, an English circuit like the 18W would use a 6V rectifier such as the EZ81/EZ80/6CA4.

Next was the standby switch. This is merely a switch to interrupt the B+ from the rectifier to the first filter cap in the power supply.

After I got the can capacitor wired. This is kind of a PITA, as the solder lugs had several leads stuffed in them. This layout is a bit different that what I'm used to. Normally, all the filter caps are on the eyelet board. In this case, two of them are mounted on the chassi in the capacitor can. The other two are on the board. A nice feature of this design is the 200K ohm resistor to ground, which bleeds off the B+ when the amp is turned off. Caps can and do store a charge, so this makes working on the amp safer.

Finally, I got the IEC inlet, on/off switch and screen resistor wired into the circuit.

It looks very messy now inside as I have not cut any of the power transformer's wires to length. I like to leave them their original length until I finish and test the amp and get it working right. Then I will clean up the wiring and try to resolve noise issues, if any.

Wiring can be very tedious so I like to do it in small chunks. I got through today's wiring with a minimum of cursing and swearing :rotflmao:

The next stage of the wiring will be wiring the filaments. I hate wiring the filaments :D It is my least favorite part of amp building, although this probably won't be too bad.

After that, the power amp, preamp input and output jacks, volume an tone controls, and then the gounds. Once I finish the grounds, the amp will essentially be done. The only thing left to do is fire it up and make sure it works right.

Stay tuned...

tung

[duhvoodooman]

Looking good, Tung! :AOK: Getting close now....

[M29]

Sweet Tung, well underway! I notice you have the rectum fryer upside down.:D Just kidding, awesome work indeed:D

[luvmyshiner]

It's been awhile since I caught up on this thread. WOW! I can't believe how great it's looking Tung. Can't wait to see the finished product.

[tunghaichuan]

Guys,

Did some more minor wiring this morning. Got a few things corrected that needed to be and started the filament wiring. Filament wiring is my least favorite part of amp building.

Thanks for the kind words, but it is starting to look like a rat's nest in there. It's not the cleanest build I've ever done.

This one is:

http://www.diycustomamps.com/images/princeton/prin7_guts.jpg

That was built for a friend of mine and had to be absolutely perfect.

I hope to get some more wiring done this evening.

tung

[M29]

Tung,

Just curious on your friends build. Did you need to put shielded wire on the inputs or just did it in case of squeal? I had to use them on one amp but later on I took them off and it worked fine, can't figure that one out. This has been a touchy area on some of my builds.

Beautiful job:AOK:

M

[tunghaichuan]

Tung,

Just curious on your friends build. Did you need to put shielded wire on the inputs or just did it in case of squeal? I had to use them on one amp but later on I took them off and it worked fine, can't figure that one out. This has been a touchy area on some of my builds.

Beautiful job:AOK:

M

Again, thanks for the kind words.

I built the amp with shielded wire just to make sure that it was dead silent. I wasn't taking any chances with that one. I also used a 330uF/450V cap in parallel with the first 47uF cap on the board. It is the blue chassis mounted cap in this photo:

http://www.diycustomamps.com/images/princeton/prin7_front.jpg

I was afraid that it would make the amp to stiff sounding, but my friend loves the amp. And the amp is dead quiet which surprised me as most SE amp usually have some hum in them.

tung

[F_BSurfer]

Real nice tung been away for awhile trying to get caught up here have been working on a 18w trem trying to find time to get it done........Not doing scratch build bought chassis, board,& parts from ceriatone pick a some gds transformer up off ebay....I'm just a rookie at this might have some ?'s if you don't mind....

[tunghaichuan]

Real nice tung been away for awhile trying to get caught up here have been working on a 18w tmb trying to find time to get it done........Not doing scratch build bought chassis, board,& parts from ceriatone pick a some gds transformer up off ebay....I'm just a rookie at this might have some ?'s if you don't mind....

Sure, I'd be happy to help (if I can). You can PM here, or send an email to steve[at]diycustomamps.com

tung

[tunghaichuan]

Okay, I spent about two hours today finishing up the wiring. I'd been kinda stalled as I was facing wiring the filaments, and I hate wiring filaments. But a little poke from Duhvoodooman got me going again :AOK:

Pix here. (http://www.diycustomamps.com/images/18W_lite/wiring_pt3/)

I started off by finishing up the filament wiring. It went okay, but it takes a while and is painstaking work. Did I mention I hate wiring filaments? :D

Next I finished up the power tube socket and preamp tube socket connections. I like these new ceramic sockets, they take solder very well. I got good consistent, clean joints using them. We'll see how well they hold up, I think they are Chinese-made.

Next I wired the input sockets. This amp has the feature of having a single triode input and two triodes in parallel. Kind of like jumpering an old plexi, but the amp is pre-jumpered. One input is the single triode, the other is both in parallel. Two triodes in parallel give a slightly more complex tone due to the differences in the triodes and a little bit more gain.

Then I wired the volume and tone control. The tone control is a lot like the Tweed Princeton control, it is a low loss type that subtracts treble so you get a brighter sound and a less bright sound as you turn the control down. It uses different values for the pot and cap as the 18W is a brighter amp.

Finally, I wired the grounds. I used star grounding in this amp; every grounding node has its own return to the star ground. This is done to prevent ground loops, which introduce noise into the amp. This amp had the most individual grounds I've done: seven total.

This last pic (http://www.diycustomamps.com/images/18W_lite/wiring_pt3/wiring_20.jpg) shows the finished wiring.

I'm going to let this sit over night before I give it one finally inspection to make sure all the wiring is correct. Then I'll install the tubes and fire it up. With any luck, it will work the first time and then I can check the bias and basic tone.

Stay tuned.

tung

[duhvoodooman]

:AOK: :bravo: :AOK: OK, now we're talkin'! Looking forward to the report after you flip the switch!

[M29]

Beautiful work man:AOK: Any start up rituals? Gas masks, respirators, wet suits...:D

[Ch0jin]

Beautiful work man:AOK: Any start up rituals? Gas masks, respirators, wet suits...:D

Haha, yeah I'd like to know the answer to that also :)

Do you use a variac to run them up and monitor you rails as you wind it up?

When I fired up my home brew the first time thats what I did. I also thought it'd be a cool idea to run a separate heater supply for startup so all the tubes had the correct heater voltage even though the rail voltages were lower. (I just borrowed an old transformer someone had for this)

Anyway, we're all hanging out to see what happens :)

[M29]

:munch:

[Kazz]

Looking good there Tung.....looking good

[tunghaichuan]

IT LIVES!

Pix of the finished amp (http://www.diycustomamps.com/images/18W_lite/final/).

To tell the truth, I don't really have a start up ritual. I just check the wiring and hope for the best. I do make sure I have my safety glasses on and look away when I flip the on/off switch :D I really need to build a lightbulb current limiter to start up amps. I've been lucky so far, but eventually my luck will run out.

I spent about 15 minutes checking over the wiring this afternoon to make sure I didn't pull some boneheaded move and mis-wire something. Everything looked good so I plugged in a "hole filler" 5Y3 to check the voltages. Since there were no other tubes installed (and no current draw) the voltages were high, but about what I expected.

I have to tell you all, I was really sweating this build, my hands were shaking so bad I could barely plug the rest of the tubes in. I used a couple of Sovtek EL84s that I pulled from Valve Juniors. The two preamp tubes are low end Sovtek 12AX7WA tubes, nothing special. I call them hole fillers because if they short out or die in the circuit, then it is no big loss.

After I got the tubes installed and the amp warmed up, I checked the voltages. They looked a little low, but nothing outside of spec.

So I plugged my guitar in and turned it up a bit and got clean, glorious EL84 chime. The amp is very bright, especially with my single-coil equiped guitar. The tone knob doesn't have as much range as a Tweed Princeton's but it does make the amp slightly brighter or slightly darker.

Then I cranked it up all the way. Wow, tons of power tube grind. This circuit sounds very good, and I haven't even tweaked it yet. #I input is the single triode and it sounds good, the #II input is both triodes in parallel and is even better, more grind, more complexity.

The output transformer is only rated for 15 watts, so I was kind of concerned, but it didn't even get warm when playing the amp cranked up. I think it is up to the task. :AOK: The amp might benefit from a better OT, Heyboer, GDS, or Trinity. The Edcor sounds very good clean, very chimey so it might be a great choice for a Vox AC15 circuit.

Even though the voltages are low, the amp biased the power tubes to about 68% which is about where I want them for Class AB operation. I plan on using some different rectifiers: a 5V4, 5AR4, and a Groove Tubes SS plug in rectifier to see how different plate voltages change the tone of the amp.

Oh yeah, I did do one boneheaded thing: the on/off and standby switches are upside down so that the amp is on when they are in their off positions Doh! :thwap: Easy enough to fix, and it does't really affect anything.

Coming up next, some sound clips. Although it may take me a few days. This was my last day off for a few days, but hopefully I can get something recorded and posted to my web site.

This was a fun build, and now for some tweaking.

Thanks to DVM for a kick in the pants to get the project finished. :dude:

tung

[M29]

Awesome Tung congrats:rockon: I know the feeling!
If you look at different transformers I highly suggest the GDS (Vintage). I put the standard GDS in at first but upgraded to the vintage and what a difference!!! I love it. Much more intricate, musical and defined.

Again congrats on an enjoyable build for you and us too. I love this stuff and I really enjoy your way of presenting it to us:AOK:

M

[F_BSurfer]

looks good tung bet it sounds great to

[warren0728]

man that looks great! :master:

[Ch0jin]

Grats!! Good to read it fired up first go too :)

I'm not much of a fan of those spade connectors on the tranny though. They scream "accidental shock" to me. I guess once it's all inside an enclosure though it'll be fine.

Really nice looking build though. Very neat and tidy. Good job :bravo:

[duhvoodooman]

Excellent news! :AOK: :bravo: :beer: Congrats & looking forward to those clips BIG TIME!

[tunghaichuan]

Grats!! Good to read it fired up first go too :)

I'm not much of a fan of those spade connectors on the tranny though. They scream "accidental shock" to me. I guess once it's all inside an enclosure though it'll be fine.

Really nice looking build though. Very neat and tidy. Good job :bravo:

Yeah, I'm not real keen on those quick disconnect spade connectors. I flipped the chassis over and almost made contact with one of the connectors. I think Edcor is really short sighted for not putting insulated flying leads on their transformers, but what do I know? The Edcor was only $20 so it nice to experiment with and easy on the wallet.

The power supply is still a rat's nest and needs to be cleaned up.

Also, it really needs a head cab.

tung

[tunghaichuan]

Excellent news! :AOK: :bravo: :beer: Congrats & looking forward to those clips BIG TIME!

I'm going to use the Triboost for one clip, I think it will sound good. I have high hopes for the new Green Screamer as well. It sounded pretty good into the EF86 amp I did.

The amp could benefit from some different tubes. The ones in it are marginal at best. I need to buy a couple more sets of JJs. I will definitely put in a couple of the used Mullard and/or Telefunkens I have. That should wake up the amp nicely.

tung

[Ch0jin]

... but what do I know?

tung

Haha true. I've shocked myself so many times on consumer electronics that had just plain dangerous component layouts, I guess I'm a little paranoid, but like u said, what would I know :)

Now go back and rock that thing!

[warren0728]

clips....clips....clips....clips....!

just sayin'....

[luvmyshiner]

Very nice Tung!!!:bravo: Now, if you're finished trying to electrocute yourself, go grab an ice cold Shiner and celebrate.:beer:

Um, not this Shiner, one you buy from the store.:messedup:

[Kazz]

Very nice Tung!!!:bravo: Now, if you're finished trying to electrocute yourself, go grab an ice cold Shiner and celebrate.:beer:

Um, not this Shiner, one you buy from the store.:messedup:


Ha.....You are Ice Cold......lmao......CB would say you are luke warm at best LMAO.

[tunghaichuan]

I had the day off today, so I recorded some sound samples:

http://www.diycustomamps.com/mp3/BN_18W/

I finally got a chance to sort out some of the problems with the 18W. Namely, I fixed the wiring on the on/off and standby switches. I had them reversed so that the amp was on when the switches were in the off position and vice versa.

I also experimented with different rectifier tubes. The first one I tried was a 5Y3. I used a 150 ohm resistor on the EL84s to get the bias to about 70% plate dissipation. The plate voltage was fairly low at about 270, so I tried a Groove Tubes Solid State plug in. This is a tube base that has SS diodes in it to plug in in place of a tube rectifier. I had to use a 270 ohm cathode bias resistor to bias the amp to 70% again. The amp was louder and brighter, but more sterile sounding. I didn't like it either so I put in a 5V4GA tube rectifier and a 200 ohm cathode bias resistor. The plate dissipation was 72%, which is close enough for rock 'n roll. Now the amp was sounding pretty good, even with the Sovtek "hole filler" EL84 tubes.

Finally, I swapped out the Sovteks for a matched pair of JJ EL84 tubes. These made the amp considerably brighter, but not harsh or shrill. Since the amp is bright to begin with, I'm still kind of on the fence as to whether I like the JJs or the Sovteks better.

I recorded the sound samples with a different setup this time. I used a Sure PE52 Vagabond mike that I got from a friend over 20 years ago. I think it sounds better than the SM58 I was using. I recorded this into the mixer and panned it to the right. I then plugged a Behringer GI100 cabinet simulator into the mixer and panned it left. I recorded three samples using the BYOC Triboost on the germanium boost setting. I recorded three samples of the new Green Screamer I got from GC a few weeks ago. I then recorded the amp cranked all the way up with nothing pushing it. I recorded a clean sample to illustrate what the amp sounds like at low volumes. Finally I recorded some samples with a MI Audio Tube Zone that a friend sent to me. It was kind of a shock, this is a spendy boutique pedal that is basically a Marshall/Dual Rectifier in a pedal box. Very high gain, lots of tonal variation with a switch and a well voiced tone control.

Again, sorry for the bad playing, but I wanted to demonstrate how the amp sounded.

tung

[duhvoodooman]

Very impressive sounding amp, Tung! The dimed crunch is very nice, and it obviously takes pedals well! I really like the sounds using that Triboost! They all sounded good, though.

Which guitar was it, BTW?

And no apologizing for one's playing allowed around here! :nono: ;) :rockon:

[sumitomo]

Very Very cool,I like the tones that amp puts out the tri boost sounds great,but that green screamer is no sloutch either and playing sounded good also.Sumi:D

[tunghaichuan]

Very impressive sounding amp, Tung! The dimed crunch is very nice, and it obviously takes pedals well! I really like the sounds using that Triboost! They all sounded good, though.

Which guitar was it, BTW?

And no apologizing for one's playing allowed around here! :nono: ;) :rockon:

The amp still needs to have the bugs worked out of it, it is kind of noisy at high volumes, but nothing that I can't live with. The tone control seems to work better with the JJ tubes than the Sovteks, which I find kind of weird.

The Linear and Clean boost settings on the Triboost don't sound nearly as good as the Germanium settings. I'm thinking I'm going to have to buld a Dallas Range Master clone here in the near future.

The guitar I used is the Hohner Revelation RTS (http://www.diycustomamps.com/images/Rev_RTS_1.JPG). It has become my main guitar.

tung

[tunghaichuan]

Very Very cool,I like the tones that amp puts out the tri boost sounds great,but that green screamer is no sloutch either and playing sounded good also.Sumi:D

Thanks for the kind words. I love that Green Screamer pedal, it's like an ideal tube screamer: warm and fat, but without the nasty, nasally mid hump of the originals. It sounds much smoother than the Boss SD-1 Super OD that I have.

tung

[warren0728]

man that amp sounds great! :bravo: :beer: :pancake:

i loved the clean and cranked samples and i liked how handled the pedals....

hhmmmm....that triboost sounded great.... :thwap:

[tunghaichuan]

Thanks for the reply.


man that amp sounds great! :bravo: :beer: :pancake:
i loved the clean and cranked samples and i liked how handled the pedals....


It is a great sounding circuit and sounds good even with marginal tubes. I left the crappy Sovtek 12AX7WA tubes in it. I bet it would sound better with good tubes in it.



hhmmmm....that triboost sounded great.... :thwap:


Get DVM to build and paint you one, it is a very useful pedal. :poke: :D

I should record some clips with my modded Valve Junior. The Triboost sounds pretty good through the VJ.

tung

[warren0728]

hhmmmm....that triboost sounded great.... :thwap:



Get DVM to build and paint you one, it is a very useful pedal.

it's tempting....i'm sure once my dvm phazer pedal shows up it will be even more tempting....i need to get through christmas first though.... :thwap:

[Algonquin]

There has to be a great sense of accomplishment when a project like this is completed!

Very nice work :AOK:
David

[tunghaichuan]

There has to be a great sense of accomplishment when a project like this is completed!

Very nice work :AOK:
David

Thanks for the kind words.

Actually, it is always a huge relief to me when the amp fires right up and operates the way it is supposed to. :D

The amp is *almost* done. It remains incomplete in that it needs a head cab. The amp isn't all that safe to operate without one. Building cabs in on my short list of skills to acquire.

tung