Kegger KT88 UL PSE?
- Thread starter whoaru99
- Start date
Ironically the measuring, the marking, (I did it on graph paper first) then the drilling, (I did everything with the smallest bit and then opened to appropriate sizes.
A small holesaw and a nipper for the IEC fuse jack.
I thought that was more difficult (tedious?) Than the actual build.
Most of the work , none of the glory
A small holesaw and a nipper for the IEC fuse jack.
I thought that was more difficult (tedious?) Than the actual build.
Most of the work , none of the glory
whoaru99
Epic Member
Yeah, the round holes were easy, but I wasn't on my game when I did some of them with the UniBit. Went just a hair too far and some of the holes ended up with a bit of uneven chamfer around the holes. Should have thought to do them from the back side then the outside edges would have been square. Will be fine with paint and tubes installed, just a lesson learned.
The IEC power inlet I used a drill bit with closely matching radius in all four corners, then connected the dots with a coping saw, and finish fit with Dremel.
I need to figure out how I will do the one-side-flat hole for the fuseholder though.
OTOH, the paint match of the repainted Hammond choke end bells looks like a respectable, although perhaps not perfect, match to the Edcor OPTs (I think they are actually powder coated). To me it looks closer in match in person. Angle/reflections/lighting is tricky.
The IEC power inlet I used a drill bit with closely matching radius in all four corners, then connected the dots with a coping saw, and finish fit with Dremel.
I need to figure out how I will do the one-side-flat hole for the fuseholder though.
OTOH, the paint match of the repainted Hammond choke end bells looks like a respectable, although perhaps not perfect, match to the Edcor OPTs (I think they are actually powder coated). To me it looks closer in match in person. Angle/reflections/lighting is tricky.
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primosounds
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I just started using a Greenlee hole punch. It is so much easier than a unibit. I used it on a steel chassis and it was like buttah.Yeah, the round holes were easy, but I wasn't on my game when I did some of them with the UniBit. Went just a hair too far and some of the holes ended up with a bit of uneven chamfer around the holes. Should have thought to do them from the back side then the outside edges would have been square. Will be fine with paint and tubes installed, just a lesson learned.
The IEC power inlet I used a drill bit with closely matching radius in all four corners, then connected the dots with a coping saw, and finish fit with Dremel.
I need to figure out how I will do the one-side-flat hole for the fuseholder though.
OTOH, the paint match of the repainted Hammond choke end bells looks like a respectable, although perhaps not perfect, match to the Edcor OPTs (I think they are actually powder coated). To me it looks closer in match in person. Angle/reflections/lighting is tricky.
The IEC socket is still a pain. I just trace out the outline and hand cut with the Dremel. Then finish with some files. I don't try to make a really precise opening since the receptacle will be held with 2 screws and the outlet is in the back where no one really looks.
For the fuse holder, i drill a small hole, roughly the distance between the flat and the diameter of the fuse socket. Then use a round file and a small flat file to get it to the right dimension. It takes about 5 to 10 minutes. Faster with aluminum.
I am starting to like the chassis work more because i realize it is quite hard to make it come out looking really good.
whoaru99
Epic Member
The IEC receptacles are a bit of a story too.
While I ordered two nice EMI-filtered Corcoms, I inadvertently picked rear mount instead of front mount. The cutout/hole work is fully exposed, if not highlighted, by the fitment of the receptacle into the hole (but, yes, on the back).
On the fuse holder, I did the primary hole like you described just hadn't settled on if I would try to file, Dremel, saw, or what combination thereof to achieve the flat and final ID.
While I ordered two nice EMI-filtered Corcoms, I inadvertently picked rear mount instead of front mount. The cutout/hole work is fully exposed, if not highlighted, by the fitment of the receptacle into the hole (but, yes, on the back).
On the fuse holder, I did the primary hole like you described just hadn't settled on if I would try to file, Dremel, saw, or what combination thereof to achieve the flat and final ID.
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Yeah I got the IEC with the fuse built in.
I figured it'd save me a hole.
Also, between Greenlie and Ideal you can get carbide tip holesaws that fit tube sockets
(I know they're not standard trade sizes)
I mic'd the sockets then web searched then special ordered but they work great and if need be can drill stainless
I figured it'd save me a hole.
Also, between Greenlie and Ideal you can get carbide tip holesaws that fit tube sockets
(I know they're not standard trade sizes)
I mic'd the sockets then web searched then special ordered but they work great and if need be can drill stainless
whoaru99
Epic Member
Another thing I need to look into is a doubler plate for where the toroidal power transformer mounts. The chassis doesn't appear to sag, but it does flex a bit around the mounting bolt if you wiggle the transformer. Remember, the way the AnTek toroid cover is the made, the outer diameter cannot touch the chassis or it causes a shorted turn. It is designed about 0.050" "short" so the cover doesn't touch. As a result, you don't get the 5.5" diameter bearing on the chassis for stiffness/anti-rocking. Only about 1" diameter of the mount in the center actually bears on the chassis. http://www.antekinc.com/content/CA-xxx.pdf
Probably will try about 3-3.5" square piece. I'll put a hole in the center for the mounting bolt and bushing, then a screw or rivet in each corner to tie the doubler to the chassis. That should all stay hidden under the area covered by the toroid.
Probably will try about 3-3.5" square piece. I'll put a hole in the center for the mounting bolt and bushing, then a screw or rivet in each corner to tie the doubler to the chassis. That should all stay hidden under the area covered by the toroid.
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You might add a thin layer of rubber between the plate and chassis to provide some vibration/electrical isolation. Easy to purchase on that auction website.
whoaru99
Epic Member
For added measure of electrical isolation against shorted turn, I made an insulated bushing and washer arrangement of the style typical for mounting transistors to heat sink. But, that did raise the toroid cover by another 0.010" or so for the insulating washer. Didn't help the rocking any, but pretty much eliminated any possibility of shorted turn from cover touching the chassis.
If you use the full rubber layer and only cut the holes needed for wiring and screws it will be stiffer.
whoaru99
Epic Member
Yeah, I have only three holes for the transformer. The center mount ~1/2" and two 5/8" holes to accept 1/2"id snap bushings for the primary and secondary leads (they exit the toroid 180-deg apart.
If you go back to the picture in post #62, you see the small black area at the center of the toroid? That is the only area that actually bears on the chassis.
primosounds
Powered with pure tube sounds.
If you don't have them, get some nice Nicholsen or German files. The euro ones are quite expensive and the Nicholsen last a lifetime if you care for them.
Is your chassis made of wood sides? You will need to use a rasp for enlarging holes instead of a file.
whoaru99
Epic Member
I don't know who made them, but I have a set of I suppose what I'd call jeweler's files I bought at Radio Shack many years ago. I don't use them too often but they do come in handy and seem to keep an edge. I usually keep the small flat one in my tackle box for sharpening fish hooks. Does a splendid job of that.
The chassis is full aluminum box, but I think I will eventually add a wood or some other sort of wrap to the chassis. Probably just the sides, maybe the front too, but leaving the back where all the connections are as just painted aluminum.
The chassis is full aluminum box, but I think I will eventually add a wood or some other sort of wrap to the chassis. Probably just the sides, maybe the front too, but leaving the back where all the connections are as just painted aluminum.
blabla_19_d
New Member
Great progress... cant wait to see the finished product. By the way, does this amp need an active preamp or a passive vol control will do?
Great Job
Great Job
