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Discussion Starter · #1 · (Edited)
I'm embarking on my first scratch build, having done a kit amp at this time last year (build log starts on post 9 here http://www.guitarscanada.com/showth...-Built-Or-Running-a-TriWatt&highlight=Triwatt ). I looked at a lot of kits from a lot of makers, but then decided to go a little off the board and build the AX84 SEL. The AX84 project is single ended (single power tube), the SEL is an evolutionary step in the design and build. The complete project docs are in this link: http://www.ax84.com/sel.html

So, I've used about 4 different sources to get everything together, including our very own WCGill, thanks Bill. Most of the parts are in, the transformers having arrived today. Digikey rocks, on price and on delivery! The last thing I am waiting for is the circuit board and turrets and tools, which should land any day - I ordered blank 12" x 3" board and way more turrets than I'm going to need, plus a staking tool kit. I found this video very educational on the process!
[video=youtube;iYtQC4UBysE]http://www.youtube.com/watch?v=iYtQC4UBysE[/video]

So here's what's on hand...




I've taped up the chassis in anticipation of drilling it. I also have my heatshrink, and some tubular wire wrap that I may or may not use.


Can't get much done without a plan, can we?


And right now I'm laying out all the parts in the areas they'll need to go, double checking my spacing before I start marking up the chassis for drilling/cutting.




I'm not nervous about drilling the round holes - I have step bits and holesaws that should do me for pots, light, bias measure points, fuseholder, and so forth. Dremel will be fine for the transformer holes. I am still scratching my head trying to figure out how to do the small squares, like the switches and power socket. I imagine using a dremel cutoff wheel is going to result in ugly oversize cutting lines. If I drill then use a hacksaw blade, well I see that going badly too. Jigsaw? Dunno.

*EDIT* after doing some reading, I think it's drill the corners then a nibbler or even the dremel if I'm careful not to hit the surface outside the holes.


EDIT photobucket is being goofy, I can see and have links for 6 pics but only 3 are showing up still 12 hours later
 

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I am still scratching my head trying to figure out how to do the small squares, like the switches and power socket.

EDIT photobucket is being goofy, I'll check back in an hour see if all 6 pics show up.
Very much looking forward to following this thread and hope that the pics show up soon.

Re: "square" holes ....I am no expert, but when I have needed to do these in the past, I have drilled a hole and used a hand file (with a 90 degree "edge") to make it square....certainly not a fast solution, but easy to control and maintain accuracy...along with being satisfying in a Zen sort of way.

Cheers

Dave
 

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Discussion Starter · #4 · (Edited)
I reloaded all my pics to photobucket with changed names, then came here to add them but now they all show up but for 1, of the transformers. I added it with the changed name, it still doesn't show up.

Dave, yeah, I'm pretty much resigned to drilling the small holes and filing, though I'll probably do some dremeling where I can get away with it.

I'm pretty much ready to cut/drill the front panel. I have the rear laid out but am going to do that last, after I get my turret board (and, I forgot, bias pot that goes on back panel) and lay out the transformers and see how everything fits - my concern being the speaker inputs interfering with other parts inside. There's tons of room on the back, so I can move them around as needs be to leave room to work inside the chassis.
 

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Discussion Starter · #9 ·
Good news and bad.

Good: Turret board, turrets, turret staking tools, bias pots, standoffs, couple more lights arrived. I believe (and I have to double check the parts list, but) I have everything to go from start to finish.


So, I taped up the layout and started whacking away with a hammer and punch, so the drill bit doesn't wander when I start making holes.


Got done that and realized I didn't pay close enough attention when I bought the turrets - they require a #32 (.1160") bit. 1/8 is too big, 7/64 is too small. And I could have just had one thrown in with my order for $2.25 ARRRGH. What are the odds my local Lowes, Home Depot, or Sears is gonna have a #32 bit? I fear not good, but I'm gonna jump in the truck after supper and go looking =(
 

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Discussion Starter · #11 · (Edited)
Ugh, gotta buy a whole set, #1 to #60 at Lee Valley $69.50.

Vadsy! Yer a genius! Never heard of Century, but I well know Acklands and Greggs, guess I'll wait until tomorrow.

Turns out my buddy has one. I should be in business by 8:30.
 

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Discussion Starter · #12 · (Edited)
HURRAY FOR DREW! He bailed me out, lent me a bit set that has a #32 in it. Perfect.

All right, that video in post#1 really is magic. I just followed along step by step.
Drill


Swage (Yay! First turret!)


A couple hours later thinking I'm done. Oops, looks like I gotta go do a couple more (see arrows). The ones with X's through them, I can't see that they are used in the layout.


Again, as per the video, I very cleverly labelled one side so I didn't end up with a mirror image reversed laid out board.


And that's it for tonight.
 

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Discussion Starter · #13 ·
Didn't do that much today, drilled those 2 holes I missed on the circuit board and installed the turrets. Started marking up and cutting the chassis. Cutting aluminum is so much fun, oh joy.


Got it just right. Have to clean up the holes where the wires are going thru, maybe grommets too.


A 3/4" step bit all the way thru is perfect for the 12AX7 sockets, and a 1 1/4" hole saw is perfect for an 8 pin power tube socket.


And did the holes for the mounting of the circuit board.


Lots more chassis cutting and drilling to go.
 

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Discussion Starter · #14 ·
Spent most of my day biting my fingernails watching football and hoping my picks this week would take me back into sole first....I've had it all year, but gave up the solo lead last week and got tied. I'll be in front going into the final week, so it seems to have worked even if I have no fingernails left.

In between halves and at random times, I did the rest of the drilling and cutting of the chassis. I just finished test mounting all the components except the board. It's starting to look like something now.


Just left of the power input are the black and red bias test points and the bias pot between them.




The only place I messed up is exactly where I predicted I would, the small square openings. I'm sure no machinist lol. I went slow and a bit at a time but still ended up with sloppy cuts and oversized openings. I'll have to figure some way to shim the power and standby switches into the faceplate. If that's the worst problem I encounter before it's running right, that won't be bad at all. But I should have used a jigsaw as was recommended above.


I suppose I could buy some larger switches and recut...we'll see.
 

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Discussion Starter · #15 ·
Puttering away. Did all the lead bending for the circuit board last night, still have to trim them - nothing soldered yet. Digikey shorted me some 220K 1/2W 5% resistors, I went and bought 100 locally - fortunately they're only $4/100.


While I was there I bought some slightly larger switches to try cover up the worst of the botched holes. They are a very tight fit but look much better.


You know that junk drawer full of - hell, I don't even know what's in mine. I went rooting around in there and found some rubber grommets that are a perfect fit for the tranformer wire holes. Hurray for junk drawers and small victories! Also, you can see that the nuts holding the switches down actually touch, but there won't be any electrical connection other than what is intended.


So, I did a 'final' chassis parts installation...then realized....well, read the note. I have no way of mounting it in a headshell yet. I don't really want to drill with the parts installed, as aluminum chips could get somewhere they don't belong and cause a future short that would be miserable to track down. Cursing, I put the project aside to go wrap presents.
 

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So, I did a 'final' chassis parts installation...then realized....well, read the note. I have no way of mounting it in a headshell yet. I don't really want to drill with the parts installed, as aluminum chips could get somewhere they don't belong and cause a future short that would be miserable to track down. Cursing, I put the project aside to go wrap presents.
Just something to consider...I have seen this used before:

If you are going to "hang" the chassis from the top of the head cab (Fender style) with the controls across the front, have you considered mounting it by installing two pieces of wood (or metal) like drawer slides underneath the bottom of the chassis and along each side of the inside of the head cab. That way, you should be able to slide the chassis in and up tight to something that stops it at the front of the cab. You could then make something very simple that would not permit it to slide backwards but would be easily removed when you need to remove the chassis in future. You could likely use the same concept if you are going to mount the chassis Marshall style on the bottom of the head cab with the tubes facing upwards.

Either way, it is important to have enough room in the height of the inside of the cab to be able to change tubes easily.

Cheers

Dave
 

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Discussion Starter · #18 ·
Mike & Dave,
Merry Christmas.
I haven't got so far as to plan out a cabinet, but have options. My son is a professionally trained cabinet maker, though he doesn't do it for a living. He lives here and we certainly have all the shop tools here to do the job if we have the motivation. My brother owns steamcomusic.com and makes Voltage speaker cabinets, they have done headshells on commission before, so I could always talk to Kevin.

Right about space for the tube, but look at the size of that mother (the perspective is a bit skewed but not very much). The headshell would have to be HUGE to allow for a tube change, so I think it'll be 'just big enough to get it in the box loaded' and worry about tube changes after.
 

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Just something to consider...I have seen this used before:

If you are going to "hang" the chassis from the top of the head cab (Fender style) with the controls across the front, have you considered mounting it by installing two pieces of wood (or metal) like drawer slides underneath the bottom of the chassis and along each side of the inside of the head cab. That way, you should be able to slide the chassis in and up tight to something that stops it at the front of the cab. You could then make something very simple that would not permit it to slide backwards but would be easily removed when you need to remove the chassis in future. You could likely use the same concept if you are going to mount the chassis Marshall style on the bottom of the head cab with the tubes facing upwards.
@Keto...I'm curious as to your thoughts on the above. I type pathetically slowly and that took me most of Christmas to complete.

Seems like you have plenty of resources to help you get a nice head cab made.

Cheers

Dave
 
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