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Milosz

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Posts posted by Milosz

  3. T2 knob turning

    in Do It Yourself

    Posted

    Depleted uranium makes nice knobs. Hefty feel. Be sure to use beryllium copper tools though, don't want sparking.

    Uranium makes sparks when struck / scratched / tapped just right with a steel tool, and the sparks are burning uranium metal- and while the uranium is mostly depleted of radioactive isotopes it is not FREE of them, and inhaling a little u-235 oxide vapor / dust is a bad thing, strong alpha emitter....induces lung cancer...

  7. The ultimate DIY? A Stax SRM-T2!

    in Do It Yourself

    Posted · Edited by Milosz

    Mouser delayed part of my order due to lack of stock for the umbilical connectors; those are now in stock but fulfillment of my order waits arrival of Xicon 449k 1% 0.5w resistors. Must have been a run on 449k resistors.... confused.png

    It begs the question: How can Mouser be out of stock on resistors...?

  9. Audeze LCD-3

    in Headphones

    Posted

    Seems that Audeze got wiser. Still despite the price LCD-2 sold like hot pie.

    SOLD LIKE HOT PIE? Love that expression!

    (Love me some hot pie, too!)

    I second the opinion of the LCD-3 appearance - those chrome bulwarks have to go! Too gaudy! Why not just encrust them in zircons, for the luva mike?

    Also, I do not like the wood. A dark wood would look better in this application IM(NS)HO, or at least a "honey colored" wood.

  10. Crafting Thread -- Ask Questions About Casework and Whatnot Here ...

    in Do It Yourself

    Posted

    you could try to weld something onto the tap and use that to extract it. But you might just end up kind of arc welding the tap into the hole....

    if you can get any sort of grip on the tap, you can try heating the aluminum to a few hundred degrees in your home oven and then dripping some freeze-mist on the tap (or butane, or "Canned Air" CFC liquid- be careful with any flammables)

    That might make it possible to remove it....

    The other possibility is to carve out the aluminum around the tap with a small Dremel tip, then grab the tap. You'll have to fill in the hole you carved out.... can be done in various ways, including inert gas welding.......

  11. The Quad thread

    in Speakers

    Posted · Edited by Milosz

    My ESL-57's do many things right. I have them in a fairly small room, a narrow room, and they are about, but not quite, midway placed in the length of the room; in this configuration the bass can be pretty amazing for speakers that are said to have no output below ~50 Hz. The bass "punch" and proper tone, with no sluggish overhand makes me wish all speakers could make bass like that, only more so.

    But it's really the lower midrange to lower treble that shines. I think it's a result of a very good frequency response evenness across this critical region, combined with that utterly fantastic transient behavior especially in the lower part of the mids. Quad ESL's can portray music with so much BODY but yet without chestiness or other unpleasant effects. This is hard, I think, for most box speakers to do; if the speaker has enough energy in the low-mid/mid region it tends to excite the cabinetry and get trapped by the mass of the whole business- there's blur and overhang, the energy at these frequencies tends to "pile up" and the speaker will sound 'boxy' or even downright woolly. So I think to avoid this, many speaker manufacturers opt for lower output levels at upper bass / lower mid frequencies, since the whole apparatus of their cones and boxes seems to conspire to store and then re-radiate the energies in this sonic realm. The result may be a speaker which measures flat - the stored energy compensates for the reduced driver output at these frequencies - but yet lacks body or weight in the upper bass / mids. I think a flat steady-state measurement hides the important things the ear listens for in terms of transient behavior. The ear doesn't care that the average intensity of sound is constant across frequency- what the ear wants is the right balance of sound at every instant.

    So, yeah, the upper bass and mids have all the warmth, body, palpabilty and so on that they really need to convey music; and the treble, while not perfect, is no slouch either.

    DYNAMICS, however, are limited. Electrostats just don't do what horns or good dynamic speakers can do in terms of dynamic contrast and range. In a small room, a pair of ESL-57's can play pretty loud, satisfyingly so, but they do not reproduce the full dynamics of real instruments.

    But the colorations of horns, and the boxiness of cone / dome systems really don't satisfy me. I will gladly live with the dynamic limitations of the ESL-57's in exchange for all that they do right.

    I also have a setup with tri-amped Magnepan MG 3.6's using a DEQX; this gives very satisfactory results, in many ways besting the Quads; and although this system approaches the upper bass / midrange rightness of the Quads, the Quads are still noticeably better in this regard.

  14. The ultimate DIY? A Stax SRM-T2!

    in Do It Yourself

    Posted

    I am using [2 pieces] times four of their HSG-07XX heatsink, which are each 7 inches long, for a total of 14 inches. Two pieces on each side of the amplifier and two pieces on each side of the power supply. This is not as long as the entire PCB, but it does "cover" all the transistors.

    I am having them cut to 3.5 inches height. I am going to be using a piece of 90 degree "L" aluminum as heat spreader; the transistors will be mounted to the aluminum on the horizontal face and the vertical face will mount to the heatsinks, similar to K. Gilmore's original. (I only hope my aluminum "L" heat spreader is thick enough to transfer the heat efficiently.)

    I am drilling and tapping them myself, I haven't used their service for drilling and tapping so I don't know what file format they want. Just a guess, I bet they can probably take AutoCad .DXF or .DWG files, most everyone working with machining has some software that can read these.

  15. The ultimate DIY? A Stax SRM-T2!

    in Do It Yourself

    Posted

    Nice! (on both counts)

    Cant wait to see the finished goods.

    Thanks. The Hagerman has a more old-school look, more of a DIY looking casework. The T2 will look sleeker, I hope. The wood is bubinga, which has some pinkinsh color to it that nicely compliments the copper. I found out you have to use a special lacquer - Incralac - on copper to keep it shiny. Regular lacquer lets in too much oxygen.

    The heatsinks are from Par-Metal, they have some pretty decent prices. We'll see how it goes.....

  18. The ultimate DIY? A Stax SRM-T2!

    in Do It Yourself

    Posted · Edited by Milosz

    Thanks.... I've got a copy of Autocad around here someplace.... maybe I'll make a file- should be able to do so from your numbers; hmmm, even Visio ought to be able to handle something as simple as this, and export a .dwg or .dxf, hmmm

    Hmmm.

    Of course I can always just position my (unstuffed) PCB on the sheet of copper I'm using for a top plate, and using the tube socket center holes in the PCB I could drill pilot holes through the copper plate; then use these for punching. I have to use Greenlee punches, as I have no CNC mill. I guess I could use a step drill for the smaller holes.

    I have all the sundry parts, and now my chassis design is coming together.....

    I am guessing that I will be at a point to apply power in January~February.

    That timing is fortuitous - it will be quite cold here in Chicago at that time; so it shouldn't be a total loss, any fire that may start when I first power things up will not go to waste.....at least I will be warm.

  21. The ultimate DIY? A Stax SRM-T2!

    in Do It Yourself

    Posted · Edited by Milosz

    Yep, use the PEEK screws, you don't want to have a metal screw.... 900v can pretty readily arc through one of those insulating shoulder washers you'd normally use at lower voltages to insulate the mounting screw from the TO-220's tab.

    PEEK is polyetheretherketone, a fairly high-strength plastic. You can't tighten PEEK screws to the same torque you'd use with a steel screw, but PEEK is tougher than other plastic screws- nylon, derlin, etc. and you can get them pretty tight before they fail.

    Max torque for the PEEK screws is about 21 oz-in or about 1.5 kg-cm.

  23. The ultimate DIY? A Stax SRM-T2!

    in Do It Yourself

    Posted

    I ordered the rest of the stuff -all the passives etc- the other day. The BOM I was working off specified Xicon resistors, I guess this was Kevin Gilmore's BOM.

    Also, my practice has always been to give parts a little "longer legs" up off the PCB ground plane if voltages are more than, say, 200 V.- unless it's a VHF, UHF or microwave circuit. Insurance.

    I've got all the parts now except the chassis and the STAX SOCKET. The chassis, I have ideas.

    But where to get the STAX 5 pin socket?

  24. The ultimate DIY? A Stax SRM-T2!

    in Do It Yourself

    Posted · Edited by Milosz

    Ahhhh OK, IXCP10M90S is the correct part number. Yeah I had come across IXCP10M90S and was trying to find a datasheet for IXYS10M90S to see if the two part numbers had the same characteristics.

    My BOM shows IXYS10M90S, I wonder if there is an updated DIY T2 BOM someplace that I missed seeing.

    IXYS is the mfg name, I see

    Getting closer to having all the parts; I have the transformers, most of the silicon, will be ordering the passives tomorrow.....

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