Le the drilling begin...2A3 build finally underway.
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squirrelnest
Lunatic Member
Great project.....keep us posted with your progress (pics)
Goldleaf is going to be busy then, because he's going to build the KT120 PP amp with me. By the way, I found him first, but I'll let you borrow him for a while
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Even though the prevailing wisdom would be 2.5-3K OPTs, Dennis is adamant that I should go with 5K primaries. I've got a pair or both 3K and 5K, so I can play with it if I get motivated enough.
And I've used the 5K Transendars before as replacements on a 45 amp I have. However, the design is someone elses, so eventually I may need to build another one from scratch and see how they compare....
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Got talked into...
...letting a friend of mine use this chassis as a demo for potential mass production of chassis for Dennis. Here's the CAD image of the cutting layout...
and the CNC system by Shop Bot...
This buddy of mine works for the company and has his own set up in his garage.....:thmbsp:
...letting a friend of mine use this chassis as a demo for potential mass production of chassis for Dennis. Here's the CAD image of the cutting layout...
and the CNC system by Shop Bot...
This buddy of mine works for the company and has his own set up in his garage.....:thmbsp:
goldleaf
Super Member
We'll have a nice contrast between Allans' and my version because I am using Tomiko iron. My SE OPTs have 5K and 3.5K taps so we can test how it sounds both ways. The 2 of us also have quite a few different pairs of 2A3's - NOS and new production. Should be fun. Only complication is I have to redraw the drilling pattern to fit.
I love my Shopbot in my garage. Though you can (carefully) cut aluminum on it, I have not yet. What I do is cut a template out of wood and place over the chassis and drill thru the holes.
Figures....
Here's the partially cut chassis on the Shop Bot. unfortunately, the bit broke half way through, and it was the end of the day, so it will get finished first thing in the AM. Dig the rounded corners on the PT cutout...:thmbsp: You may also notice the change in the PT bolt holes. I had to modify the originals, since the PT is a little asymmetric, and I measured it wrong the first time around. Hopefully I got it right this time....
Not the similarity to the layout on my 6L6 SE amp, built off of Dennis' layout, although I drilled this one by hand.
Here's the partially cut chassis on the Shop Bot. unfortunately, the bit broke half way through, and it was the end of the day, so it will get finished first thing in the AM. Dig the rounded corners on the PT cutout...:thmbsp: You may also notice the change in the PT bolt holes. I had to modify the originals, since the PT is a little asymmetric, and I measured it wrong the first time around. Hopefully I got it right this time....
Not the similarity to the layout on my 6L6 SE amp, built off of Dennis' layout, although I drilled this one by hand.
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Dunno. This is in the Shop Bot plant in Durham....
The finished piece with the mask partially removed
The bare chassis with some additional work done to it. I think I measured some of the holes too small, and I also didn't account for the larger size of the 4 pin sockets. Live and learn. Where did I put that step drill bit?....:scratch2:
The bare chassis with some additional work done to it. I think I measured some of the holes too small, and I also didn't account for the larger size of the 4 pin sockets. Live and learn. Where did I put that step drill bit?....:scratch2:
Ready for paint...
Here we are with all the cut outs deburred top and underneath, the surface scuffed with 240 grade sandpaper, and the surface wiped with alcohol to remove any fingerprints/grease. I also rounded the corners to clean up the look a little..
Here we are with all the cut outs deburred top and underneath, the surface scuffed with 240 grade sandpaper, and the surface wiped with alcohol to remove any fingerprints/grease. I also rounded the corners to clean up the look a little..
Initial coat of paint underneath. It's too cold and windy to do any more today, but I wanted to get a look at this paint and decide if I wanted to do the whole thing in this color....:scratch2:
