TomB Posted June 25, 2010 Report Posted June 25, 2010 OK - first step ... it was late and I didn't realize the templates weren't plotted to scale. That's now been fixed.
n_maher Posted June 25, 2010 Report Posted June 25, 2010 Any chance of you sending me the cad file? Or are you using something else to draw these?
Nebby Posted June 25, 2010 Report Posted June 25, 2010 In case anyone else went with the switch that I looked up, it has a different cutout shape than the one pictured in the end panel drawing. The plastic is also bright red. Thanks for the info WRT the heatsink, I was looking at the heatsink and the PT, wondering how to get a good thermal connection between the two In any case I'll be glad if
TomB Posted June 25, 2010 Report Posted June 25, 2010 Dimensioned endplates: http://www.diyforums.org/Les/construction/templates/TorpedoEndplates-dim.pdf
luvdunhill Posted June 25, 2010 Report Posted June 25, 2010 In case anyone else went with the switch that I looked up, it has a different cutout shape than the one pictured in the end panel drawing. The plastic is also bright red yeah, I ordered it and noticed the same thing
luvdunhill Posted June 25, 2010 Report Posted June 25, 2010 All of the above addresses the heat issues, except that some side holes at the tube positions could help. It depends on how much heat you're willing to accept at the coupling caps, I guess (maybe Doug can add some opinions here). Mine ran without any side holes at the tubes all day, both days at CanJam. why not just couple the heat sink to the top instead of drilling all those little holes? you have a large chunk of aluminum right there to help dissipate heat! Did you actually use the mounting holes on the sides of the PCB? They're on the drawings, so I assumed so. Are they really needed?
TomB Posted June 25, 2010 Report Posted June 25, 2010 why not just couple the heat sink to the top instead of drilling all those little holes? you have a large chunk of aluminum right there to help dissipate heat!IMHO, the case is rejecting all the heat it can already. Besides, there's plenty of clearance, even with a 1-1/2" sink. It's the corner and top slot/edge lip that interferes with the clearance of the heat sink. We also wanted to keep everything mounted to the PCB. Once we have the cases machined for kits, it won't be an issue. Did you actually use the mounting holes on the sides of the PCB? They're on the drawings, so I assumed so. Are they really needed?No. It's designed for the Hammond slots. I can't speak for Doug, but the side holes are SOP, even for slot designed PCB's. There's always the off-chance that someone will want to build their own case and then they'd be needed. With the Hammond, only the center two mouting holes are necessary with standoffs to the bottom. This supports the tubes when you plug/unplug them and reinforces the center of the PCB from the torque on the ends with the xfmrs.
luvdunhill Posted June 25, 2010 Report Posted June 25, 2010 Tom, what I meant was, installing the heat sink and then tapping the two holes in the top of heat sink and then screw the lid down into these holes. Thus using the the heat sink itself as a heat transfer mechanism to the case. I cannot find any pics of me doing this, but I've done it quite a bit with good results. However, point taken about the case already getting pretty warm.
TomB Posted June 25, 2010 Report Posted June 25, 2010 In case anyone else went with the switch that I looked up, it has a different cutout shape than the one pictured in the end panel drawing. The plastic is also bright red. Thanks for the info WRT the heatsink, I was looking at the heatsink and the PT, wondering how to get a good thermal connection between the two In any case I'll be glad ifNebby - are you saying that the switch won't work? The cutout shape means little unless the pins don't line up. Red doesn't have much to do with anything, either, I would think. If it doesn't work in the present design, though, let me know and I'll pick another one out. That won't help for those who've already ordered, but maybe we minimize the error for a few. About the heat sink on top of the case. I told a few people at CanJam, but I actually tried drilling 36 holes in the case lid above the PT on mine, but it was too hot. The heat sink works well. Assuming all series-heat transfer, the PT radiates to the inside surface of the lid, conducts to the outside surface, and then to the heat sink. If you can lower the surface temperature of the lid around the general area of the PT, then heat transfer is greatly enhanced and the entire area runs cooler. I really think the curent design reflected in the drawings have the heat issue solved. We may just add some slots on the sides of the tube for convenience when we go to production (assuming the slots don't cost too much). Same for the cooling around the heater supply sink - those will be slots/chevrons, too. It's just difficult to do much more than holes by hand (or drill press) unless we had access to Nate's mill.
TomB Posted June 25, 2010 Report Posted June 25, 2010 Tom, what I meant was, installing the heat sink and then tapping the two holes in the top of heat sink and then screw the lid down into these holes. Thus using the the heat sink itself as a heat transfer mechanism to the case. I cannot find any pics of me doing this, but I've done it quite a bit with good results. However, point taken about the case already getting pretty warm.Yes, good point. However, that's what I was referring to about clearance. The sink is not nearly flush with the lid. AFAIK, you'd to have mount the sink to the case lid instead of to the PCB, with leads from the LM to the pads, etc. Besides wanting to keep everything PC-mounted, we want the lid to be as easy to remove as possible. that's one of the reasons Doug is strongly suggesting that we may use the Heeger cases, because the entire top half of the case is easily removable, as opposed to the slide-in/slide-out arrangement of the Hammond. What happens is that so little of the tubes stick out of the top, you can't grip them very easily to remove them. With 1" diameter holes, you can just barely get a wiggle on them to finally work them out, but it's definitely not as easy as it should be.
Nebby Posted June 25, 2010 Report Posted June 25, 2010 Nebby - are you saying that the switch won't work? The cutout shape means little unless the pins don't line up. Red doesn't have much to do with anything, either, I would think. If it doesn't work in the present design, though, let me know and I'll pick another one out. That won't help for those who've already ordered, but maybe we minimize the error for a few. About the heat sink on top of the case. I told a few people at CanJam, but I actually tried drilling 36 holes in the case lid above the PT on mine, but it was too hot. The heat sink works well. Assuming all series-heat transfer, the PT radiates to the inside surface of the lid, conducts to the outside surface, and then to the heat sink. If you can lower the surface temperature of the lid around the general area of the PT, then heat transfer is greatly enhanced and the entire area runs cooler. I really think the drawings have the heat issue solved. We may just add some slots on the sides of the tube for convenience when we go to production (assuming the slots don't cost too much). Same for the cooling around the heater supply sink - those will be slots/chevrons, too. It's just difficult to do much more than holes by hand (or drill press) unless we had access to Nate's mill. The switch fits just fine on the pcb, I just wanted to note that the cutout shape was different than the cutout on the faceplate drawing. As for the color, I just wanted to put the info out there in case someone was averse to red switches Ahhh, I see now. I didn't realize the heatsink was meant to be mounted to the top of the case. I have a rudimentary mini-mill with my proxxon drill stand + compound table, but I still need to find out what's needed to clamp parts to the table and the proper way to clamp. It's still nothing compared to Nate's machine
n_maher Posted June 25, 2010 Report Posted June 25, 2010 That's it, the switch is red, there's no way I'm building this. I hope to put the big mill to use on this case, assuming it ever shows up...
luvdunhill Posted June 25, 2010 Report Posted June 25, 2010 .. it's a red double D though.. does that help?
n_maher Posted June 25, 2010 Report Posted June 25, 2010 Double D's have never held much appeal for me. I've never been afraid of air wiring though so I may go a totally different direction.
luvdunhill Posted June 25, 2010 Report Posted June 25, 2010 hm.. did I mention the legs? oh, regarding the different direction, I feel that knife switches are under-appreciated:
n_maher Posted June 25, 2010 Report Posted June 25, 2010 hm.. did I mention the legs?Now you're speaking my language. oh, regarding the different direction, I feel that knife switches are under-appreciated: They really do represent the ultimate in unsafe!
TomB Posted June 25, 2010 Report Posted June 25, 2010 For those that didn't see the latest iteration at CanJam, maybe this pic will help clear things up: No comment on switches ...
dsavitsk Posted June 25, 2010 Author Report Posted June 25, 2010 that's one of the reasons Doug is strongly suggesting that we may use the Heeger cases, because the entire top half of the case is easily removable, as opposed to the slide-in/slide-out arrangement of the Hammond. The other main reason is that the Heeger case is a little bigger which means that the power transformer can have a slightly thicker core which will run cooler and dissipate heat a little better. Now, I will say I am less concerned about heat than Tom -- it's hot, no doubt, but it is tube amp. They run hot. I also think with some venting added to the top and bottom of the case, and some strategic holes in the PCB, everything will run OK. There's just no airflow right now. The Heeger cases look nicer, and are more solid, too.
n_maher Posted June 25, 2010 Report Posted June 25, 2010 The Heeger cases look nicer, and are more solid, too. Which series are you looking at?
dsavitsk Posted June 25, 2010 Author Report Posted June 25, 2010 Which series are you looking at? EAS-400
n_maher Posted June 25, 2010 Report Posted June 25, 2010 EAS-400 Those look nice, similar to context engineering or whomever manufactures those chassis. I was secretly hoping for these:
luvdunhill Posted June 25, 2010 Report Posted June 25, 2010 No comment on switches ... Perhaps I missed the proper "turn on" then?
Pars Posted June 26, 2010 Report Posted June 26, 2010 Didn't see this in the parts list: what is IC1? LM317? Think I may be out of them, so wanted to make sure to order some more.
TomB Posted June 26, 2010 Report Posted June 26, 2010 Didn't see this in the parts list: what is IC1? LM317? Think I may be out of them, so wanted to make sure to order some more.Yep. It was in the text-parts list in one of the first e-mails I sent. It was not on my Mouser BOM, though, because I stock them for MiniMAX kits and had quite a few on hand.
n_maher Posted June 26, 2010 Report Posted June 26, 2010 My box of parts arrived yesterday, everything looks good. The balance of the parts should arrive Monday and I expect to get busy building in the very near future. Right now I'm trying to avoid the compulsion to upgrade the output trafos with the eprint units that Doug hinted at.
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