kevin gilmore

Time to show off my bottom (err... panel) http://gilmore.chem.northwestern.edu/t2chassis12.jpg Top and bottom of the power supply box will look similar.

So on the original T2, there are a lot of .5 watt resistors on the bottom of the board, lots of holes, lots of internal heatsinks, tubes completely inside, no ground plane of any kind, and the exterior gets to 55C. The inside gets to more like 75+C. On my T2, everything that generates more than .5 watt (with 2 resistor exceptions) is mounted directly to the heatsink. While more holes in the board is probably going to be a good idea, the tubes generate thermal flow that will pull air thru the unit. A thermal design program i'm playing with basically indicates that more holes is not always a good thing as it reduces air flow. I gave the board layout to the master (justin) and he will do some cleanup. Otherwise in less than 2 weeks i'm going to send the boards out.

The file is in a place i can't get to from here at the moment, but i'm pretty sure i can convert it to dxf format and send it to you... Tomorrow, first thing. You do know that nothing in this world is ever perfectly flat

You get that look with a specially made fly cutter, taking off about .00005 inch. MOAR HOLES http://gilmore.chem.northwestern.edu/t2chassis11.jpg

There is another school of thought. The school of minimum distortion. Each tube has a particular set of curves and distortion at various voltages and currents. There is no one rule that fits all. You can usually figure it out from the plate curve characteristics but not always. Triodes are much easier to do this with. Typically 60% power is the right number. Tetrodes and pentodes, and especially beam power tetrodes have to be tested, but generally the numbers end up 90% of full power.

I have no idea how to do that. But i do know someone that does... yep, fits perfect, the 9 pin sockets are flat with the top and the octals stick up about .125 http://gilmore.chem.northwestern.edu/t2chassis10.jpg New top panel with MOAR holes on monday

I think the T2 will be on the front panel with an understated look... Otherwise it ends up looking like the overblown crap from my friend in skokie... What i want to see is what the surface looks like from the high pressure water cutting machines. In the end i will probably still machine it... Nothing seems to beat the perfect edge of a sharp carbide bit. Still have no idea whether i'm going to anodize or power coat... Have a couple of small pieces of the extrusion to send out for testing... Found a company that will polish all the pieces, they do a lot of work for Fermilab... Relatively cheap too, but they just polish stuff, they don't do the rest of it.

Drawing in DXF format or it will never happen Same number of posts here as there

But milled holes are so much prettier... .005 countersink... Fine... More Holez... Shop is getting a brand new laser cutter next week. Evidently it can cut at the rate of 1 inch per second in .5 inch material. Much faster in the .125 stuff i'm using. So i think one more circle of holes around each tube, then ... well i don't know yet, creativity is zero at the moment... Quite exhausted... And stinking of that milky white water based machining lubrication crap.

http://gilmore.chem.northwestern.edu/t2chassis9.jpg tomorrow i'll drill holes in the fake circuit board and mount the sockets and see what that is going to look like. So far i'm very happy. It really does not need more ventilation holes as all the hot stuff is on the heatsink. May add some more holes to make it look purdy... 32 machine minutes to do this including the edge...

CMC--Teflon Tube socket the last time i looked, the prices at pcx were $21 each... At $19 each the group buy turns into more trouble than it is worth. You can buy them from ebay too, 2 for about $32 I already have enough for 2 amplifiers... 4 of each of the sockets are required... 4 x 6ca7 4 x 6dj8

well i like the socket prices http://gilmore.chem.northwestern.edu/cmc091023.jpg but something whacked with the shipping charge. (round 7...)

Last time i checked, balanced P&G were about $580, but the price has likely gone up.

More info on the teflon sockets when i get it. Maybe someone else can do the group buy, otherwise i'll do it. At some point soon i may need a bigger house So they say measure twice and cut once. I kind of believe in measuring about 12 times and cutting once. (especially with these prices on the circuit boards) http://gilmore.chem.northwestern.edu/t2chassis7.jpg http://gilmore.chem.northwestern.edu/t2chassis8.jpg

The language barrier is killing me, but if someone wants to do a group buy on the sockets, we can get the 9 pin ones for a bit less than $14 each, and i still don't know how much the 8 pin sockets are.

http://gilmore.chem.northwestern.edu/t2chassis6.jpg

Every one of the electrolytics needs replacing. The yellow ones and the silver ones. The orange ones are not electrolytics and do not need replacing. All cracked resistors obviously need replacing.

Remember that there are 2 chassis, another identical one for the PS. The circuit board that goes on the inside is 12 x 16. I think the resulting chassis had better be 15.4 wide x 16.7 deep x 2.96 high (plus feet) (plus tubes) (plus about an extra .35 for the neutrik jacks) Still less cubic inches than a dual maestro chassis...

Show me what you got... Be creative... autocad 3d drawings in dxf format please... or solidworks, or cativa.... no lines <.025 inch please.

Starting to think about a completely custom machined knob... Anyone with some ideas ?? The deep engraving is going to be sweet.

I love it when a plan comes together no errors yet, and i think i can probably sail thru the rest... http://gilmore.chem.northwestern.edu/t2chassis1.jpg http://gilmore.chem.northwestern.edu/t2chassis2.jpg http://gilmore.chem.northwestern.edu/t2chassis3.jpg http://gilmore.chem.northwestern.edu/t2chassis4.jpg http://gilmore.chem.northwestern.edu/t2chassis5.jpg current BOM such as it is http://gilmore.chem.northwestern.edu/t2parts2.xls I'm doing a custom radius cutter for the outside from a single blade carbide bit, edm'd for the surface i want. (because I CAN! ) hand drill??? what are you guys nuts??? i'm going to cnc the stax jacks...

I can also make them round and threaded just like the real stax thing. But the diameter is going to have to increase a bit. Time to learn how to cut threads on the NC lathe...

I cheated. Justin came up with the idea. I did not think it was going to work, but it did. I used the macro lens and took a picture at as close as i could get and still have all the pins in the picture. Then i suck the thing into featurecam and tell it the measured dimensions of just 2 of the pins. And it calculates the rest... And damm close too. PDF's of that connector are just plain not available. If this did not work, i could have used the new nikon microscope at work which has guaranteed flat optics and a reticule for exact measurements. justin's way was boatloads quicker. I'm open to suggestions. The harder the better.

So as we all know the amphenol stax connectors are less than ideal, and the real stax ones are generally unobtainable. so i got these guys to sell me just the pins from these sockets CMC--Teflon Tube socket and i evidently got the measurements right on the first try. (well to .0001 anyway) http://gilmore.chem.northwestern.edu/staxc1.jpg http://gilmore.chem.northwestern.edu/staxc2.jpg Was thinking of a dual stax connector made out of some crazy hard wood. Need to find the electrical impedance of hardwoods... Anyone know?? If i can get some more machine time this week i should have a finished amp chassis by saturday.

So thats 9.1 channel surround sound balanced