The Powerman -- Revised Edition
Here is a zipped file containing the work-up and final Microsoft Visio files for the project below. Download it here.
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August
I downloaded the schematics from Mark Lavelle, as well as got several questions answered about his build of the Powerman. I downloaded every picture I could find of this amp (Yeah, I know, they were all off of Mark's website, but hey...)
I began working with Bobby on the redesign of the amp schematic to suit my needs... actually, my wants! The original amp has only one control knob. My design has knobs for Master Volume, Master Gain, Treble, Mid, and Bass, a larger power transformer, and an additional 6021W tube. I also had to completely redo the layout of the amp to accommodate the additional parts needed for the tone stack.
With the schematic finished, I found a friend with a copy of Microsoft Visio to use to put the schematic in to an easily printable format. I also plan on putting the layout, wiring diagram, and drilling template into Visio. This way, I can package it up for anyone with Visio that wants it.
I talked to a local computer repair shop and they gave me a couple of blown power supplies to do this project... they were just going to throw them away anyhow, why not put them to good use! Good rule of project design - "Look high and low for cheaper or free parts!"
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September
I ordered all my parts, minus the power and output transformers... I have to wait until I get my allowance from my wife before I can order these. These can be the most expensive parts you put in your amplifier. Well, these and your tubes, but I will get into this a little later. Most of the parts came from Doug Hoffman (www.hoffmanamps.com), and Mouser Electronics (www.mouser.com). Mouser's website is a little difficult at first, but if you are ever thinking about building a second amp, you can add it to your project repertoire for one click ordering. I found 7 6021W tubes on EBay for cheap. I also found on EBay, a sale of 600 volt, Teflon coated wire. This was 200' in 4 different colors... so I can somewhat color code the wiring inside my amp... for $10. I found a cheap source for Garolite (G-10) for the circuit board. At $8 per 12x12 sheet, this was the cheapest I could find it. In fact, the place I found it, Interstate Plastics of Sacramento, CA, (www.interstateplastics.com) has a bin of scraps if you are ever in that area. The only problem I have found with the Garolite was the cutting. After cutting the board for my amp, my carbide, laminate cutting jigsaw blade looks like this now...
Jigsaw Blade
I finished several layouts for the amp, using graph paper. I outlined all of the parts onto a sheet of graph paper, as well as outlining the actual board that I removed from the power supply. Then, I cut out all of the little pieces and covered them with tape. Going inch by inch on the schematic and referencing the pictures from Mark's site, I laid out the design, just like Mark's Powerman. You can download a copy of my graph paper sheet with the outlines of the parts from the "FILES" section, at the bottom of this page, if you want to play around with the idea of building this amp.
12th -- I received all of the parts orders. I am ordered a 5 watt, 350 Ohm power resistor, the cement type, and a thin, cylindrical, axial lead, 5 watt, 350 Ohm resistor. I am hoping this will work for my amp. I am looking at trying to get all of the parts as small as possible inside the box. Unfortunately, I ordered 715P Orange Drop Caps by Sprague... the size of the capacitor is probably close to the size of their egos! These things are space hogs.
15th -- I taped the drilling diagram to the Garolite board I cut out. I am waiting to drill the holes. They are 3/32" holes that will house the turrets and 1/8" hole for the eyelets. Due to the space constraints, I have decided to use both eyelets and turrets. I think it will also add a pretty cool effect to the look of the amp when it is open to see parts peaking down to the board from a turret to an eyelet.
26th -- Yesterday, I went to Home Depot and found a universal drill press stand... it turns your ordinary corded (or cordless I guess) drill into a drill press. I guess it's okay... the drill bit, as it goes into the Garolite, seemed to bow a bit, but not too much. Close enough for government work anyways. If you need one, they are made by Wolfcraft and it was around $20 in Northern California... don't go to Lowes, they don't have them, but they will waste an hour and a half of your life trying to figure out what you want, plus you do get shown every drill press known to man! Anyhow, I got my board drilled. There were only two minor flaws in my layout. Where the power transformer connects to the board by way of the red and green leads, I put them too close together, resulting in me having to free hand 2 holes there, and off of pin 7 of the output tube, I forgot to place a eyelet for the other end of the 22n capacitor. This wouldn't be necessary, but I am using turretts with the tubes. This way, I have extra lead from the tube down in the turret if I ever want to take the tube out and use it in another project. My next step is to populate the board with the eyelets and turrets. One thing I may try next time, is to clamp the Garolite between 2 pieces of thin wood. I had to sand the Garolite, leaving minor scratches in the face of the board. If I wouldn't have sanded, I wouldn't have been able to flare the eyelets and turrets due to the clumping of the Garolite material that melted while drilling.
27th -- I got all of the turrets and eyelets installed. It took me a little longer than normal. I used the tool from Doug Hoffman's site (www.hoffmanamps.com) combined with the universal drill press stand to flare the backs of the turrets and eyelets. Well, low and behold, the press arm of the drill press broke off... it's only plastic... but the thing is, I wasn't putting a whole lot of pressure on it. Well, needless to say, that went back to Home Depot. I did get another in exchange because it is handy to have around. Maybe one day I can afford the real thing! I swung by Pacific Hardware in Vacaville, CA, and grabbed a couple washers. They are 2" across, and the barrel of the flaring tool fits through the center hole just right. So, I mounted the tool to my workbench and flared them like I was thinking about doing in the first place. I mounted the holder part to the workbench, and hit the backside of the flaring part with a small detailing hammer. Worked just fine!
28th -- I was able to scavenge 2 old 8 ohm 15's from a console radio, along with a tube that I can't read the writing on due to dirt and dust. I am thinking of using these 2 speakers to test my amp when it is complete. Maybe buy a generic speaker box that will hold a 15 from Wal*Mart. They have them that are already carpeted in grey... what can I say, I'm lazy and don't have a whole bunch of tools! Here is a picture of the scavenged speakers.
30th -- I started populating the board with components today. It's going pretty smoothly. The biggest lesson learned so far... if using turrets, ensure you trim the lead of the component PRIOR to securing it with the solder. The back side of the turrets are so small, that if you just solder the leads, then trim them, there is no room to insert wire for jumpers on the back side of the board. The way I laid out this project, it uses some jumpers under the board to make a clean look on the face of the board. Sorry, I have no pictures of the plugging yet, but hopefully soon I will be able to add a couple more photos.
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October
2nd -- I have placed about 30% of the components and jumpers into the board. Things are coming along well. Since my mess up that was talked about in reference to the soldering of components prior to trimming the leads, I had to figure out how to get the wire to connect to the turrets. To accomplish this, I used pieces of the leads that I had trimmed off. I placed them into the turret and soldered a good "volcano"... in fact, this is the first time I have ever gotten a good "volcano" solder... I'm still relatively new at this whole electronics thing. The result was a good strong "pole" type connection point to attach the jumpers and off board wires. As I progressed through the connection of wires to these poles, I tested with my meter (A UEI DM383B) for continuity. The meter I have uses a sound to show continuity between 2 points. I got good strong sound between all of the points. Hopefully this will suffice for this project... maybe next time I won't be so ignorant when it comes to the construction and planning of my projects.
Another thing I realized was that I didn't place a couple of connection points and jumpers on the Layout and wiring diagram located in the "Files" section at the bottom of this page. Bear with me, I will get these changed out as soon as I can. I am planning on placing the bill of materials in that section too as soon as the project is completed and tested for proper function of all aspects. I also plan on adding the actual Microsoft Visio file that I built so you can just download one package and printout everything you need to complete the project. I will also place it in normal .jpeg or .gif files and Zip it up for ease of downloading too.
I also heard from Mark Lavelle via the AX84 message boards. He said he had no problem with me renaming the amp, as long as I put a link to the original on my site somewhere...
WWW.HARMONICAPPLIANCES.COM <-------- Here's Your Plug Mark!!!! Thanks!
Mark has been an ENORMOUS help thoughout the planning of this. He is a knowledgeable guy that is very down to earth and willing to help out his fellow man! He is a gentleman and a professional! Thanks Mark!
6th -- Well, I bit the bullet today. I found a Sony Mavica on sale and I broke under the pressure! Well, at least now I can give all you 1 reader out there a group of pictures of the build. Hope you enjoy the work in progress!
Capacitor Detail Capacitor Row More Capacitor Detail Diode Area
Tube with "Peaks"
15th -- I recieved my knobs in the mail today. I decided to go with a non-standard knob design. Actually, I couldn't find a knob that I liked, so I hit the web. After a few nights of searching for unique knobs, I was at a loss. I was surfing around Musician's Friend and saw dice knobs for guitars in a couple of different colors. That got the old gears a spinin'. I remembered that D&D had some funky dice that were used to play, so I hit Ebay. I wanted a design with some hard angles, and decided a 4-sided die would work great. I found a great deal on 9, 4-sided dice, for right around $2.00, that would give me 4 extra to play around with in case I mess something up. So, they came in today, and tonight I am going to drill them. I need to hit Pacific Hardware in Vacaville and find something to use as set screws... yeah, I could probably just force them on, but I like to do things the hard way! The dice are a funky grey with black numbers, and purple specks in them... not very appealing to the eye, so I will probably buy some of that new Fusion Paint by Krylon, that adheres to plastics and coat them in black, then tip them in chrome spray paint.
25th -- Well, I finally got to work on my amp some today. I got the dice drilled, and also tried the set screw idea... cracked the poor dice into three pieces! Oh well, guess I'll go with the friction method! I coated the dice in Elmer's Pro-Bond Glue. A lady at the Wal*Mart said it was the best for something like that... so, I am waiting for the cure phase, then it's time to sand and paint. Now for the bad news. I went to drill the holes for the pots and phono jacks. I was going to put them along the vented side of the power supply. Well, the bit took advantage of those vents and ripped a few of the vents to shreds. So, my amp is now going to be housed in a large metal project enclosure from Radio Shaq! Bummer!
27th -- Well, after sanding, which took off almost all of the glue, I decided that next time I'm gonna slap the lady and just sand the numbers off the dice! The glue was a total waste of time, as it put bubbles in the engraved parts of the dice, which the sand paper ripped the tops off the bubbles, now I have nice little divots in my beautiful glossy black knobs! Hey, at least the fusion paint worked well! Stuff dries a little slower than they say on the can, but it has a beautiful finish for spray paint!
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November
3rd -- I ordered my power and output transformers today from Angela's Instruments. They should be here in a few days. I also started work on the new amp enclosure. I have made a template for the from and for the rear of the enclosure. Now I just need to put the holes in it... I'm a little nervous after my last attempt!
4th -- Just as I thought. I started drilling the holes for the pots on the front of the amp, and be damned if the tip of the drill bit didn't break off during the drilling of the first hole, and I ruined the front of the enclosure with a dull damn drill bit! Why is this so difficult for me to complete?!?!?! Well, back to Radio Shack for ANOTHER enclosure!
6th -- Well, I finally got the holes drilled and cut on my enclosure! About dang time! I had to drill small holes and keep boring the holes out with larger bits. Took me about an hour to do 6 holes for input jacks and pots! I hate chuck keyed drills! I also had to use my Dremel and cut out 2 rectangular holes, one for the power switch, and one for the power receptacle. That took me about an hour to do, resulting in little shards of metal in my hands and a fleck in my eye (Yes I was wearing safety glasses, but somehow!)
8th -- How long does it take to recieve parts from Angela's Instruments. I have recieved stuff mail ordered from outside the US faster than this service. I ordered the transformers first thing Monday morning, so as it would have a chance to get in the mail on Monday. Nervertheless, the wait continues!
11th -- Well, I got the case painted over the past couple of days. It was a really nasty beige color... you know, that nasty computer beige. Well, now it is chrome. I spray painted several coats on it, then topped it off with several coats of shellac to seal in the paint. Unfortunately, I didn't get some of the metal shavings off after I steel wooled the paint, so I have some raised areas in the paint, and the one of the coats of shellac bubbled up, and I didn't really feel like sanding it down to redo it... okay, so I'm lazy! I am STILL waiting on my transformers from Angela's. They said thy were shipped Fed Ex Ground on the 7th... 4 days after I placed the credit card order???!!! So, the wait continues!!!
17th -- Well, I finally got the transformers from Angela's today, and wouldn't you know it, I have to work the night shift! So is life!
24th -- Well, it's really starting to come together. I haven't been able to work on it as much as I'd hoped, but I have gotten a little bit more done. Maybe over Thanksgiving holiday I can do a little. If not, there's always the Christmas break coming up! Here are a couple of pictures for the 2 people who come to look at this site.
Amp Front Amp Above
These have all of the hardware installed on them... it's starting to look good! Can't wait to hear how she sounds!
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December
15th -- Well, I finally got to work on my amp again. I got most of the off-board wiring for the tone stack completed. I still have to connect the terminals of the pots to the caps. I am going to work more tomorrow, hopefully run my heater wires, and hopefully wrap up everything that needs to be connected underneath the board. If I am lucky, I may even get to finish the input and output jacks tonight to, but I think that is pushing it. I did learn that before you apply the hot pen to the solder, you need to be sure of what you are connecting to. During my redesign of the enclosure, I relocated the pots, so what they were showing on my layout, and what they actually were on the box were totally off. I caught myself a couple of times about to solder a wire to the wrong terminal! Luckily, I double checked before I did it and saved myself some work and some serious frustration! I'm glad I am taking my time doing this. If I was in a rush, I am sure I would have messed this thing up by now! If I can get everything accomplished that I have laid out tonight, then I can do the jacks and mains on Wednesday night, then maybe test it out before bed. I actually have to wire up one of the AlNiCo 15's that I have. I don't have a box yet, as I wanted to make sure the amp is going to work first.
16th -- Wow! I got a ton done tonight. I actually ran into a couple of problems. I got the tone stack totally done, and most of the off board connections done. I ran into the first problem when I decided to not put in the internal speaker, so I need to figure out how to wire the output jack. The other problem is a little more in depth. I am using a power receptacle and a DPST switch that I salvaged from a computer power supply. I didn't write down how the wires were connected, so I want to make sure the wiring is correct before I attach anything. Once these 2 questions are answered, I will just have to install the power transformer, and hook up the power and output jack and I will be done, and ready for testing. Hopefully I can finish this tonight. I'll be stoked and begin working on my 2 x AlNiCo 15" cabinet!
18th -- Well, I finished it up tonight. However, when I powered her up, all I got was buzzing. Buzz when Master Volume was turned up, more buzz when Master Gain was turned up, and changes in the buzzes frequency when I turned up the Low, Mid, and High knobs. Bummer... I was hoping for a clean start up! :( Oh well, time to start troubleshooting, but not before a few pictures!
From The Front From The Rear Top Down
Tone Stack Power Up Finished Amp
22nd -- Eureka! I got it working. It took a few days of rewiring, and pulling my own head out of my butt, but I got it together, and she was playing this morning. Sounded decent through one of the AlNiCo 15's. I have some tweaking to do, as the knobs don't seem to funtion properly since I rewired the input jack, but I will tweak that later. I want to start building my cab for the speakers now! Once I get the cab built, I will post some clips of my horrible guitar playing!
29th -- Well, four months in the making, but I got it built, and there are no more bugs! All knobs work as they should, and I actually got more volume out of it once I rewired the input jack and grounded it to a different location besides the tone stack. Nice and crunchy when it's cranked, but can get pretty mellow too... I still can;t believe that sound is coming from those itty-bitty tubes!
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Files
NOTE: These files are as yet untested! Use at your own risk and expense!
Check Out Schematic Here
Check Out Layout Here
Check Out Wiring Diagram Here
Check Out the Layout Template Here
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