kevin gilmore

I did eventually decide on the ohmite heatsinks, some are on their way to me. Board size increased a bit to 3.6 x 3.6 inches. the idea of multiple power supplies is something i'll think of, not so hard to do, but really i'm doing this for a headphone amp, and don't need to run the thing at silly voltages and powers. (not the same heatsinks that the wire uses) The alfet parts sound so much better than the irf parts...

in the theme of new office... http://gilmore.chem....du/dsc_2376.jpg finally cleaned up a bit, new computer, moved the printer off the desk, now room for 2 monitors, one for schematics, one for the board layout. old computer to the far right, will probably stuff with new hard drives and load 2008server on it. birgir's next care package on the desk shelf ready to be shipped out monday.

OK, so blubliss has proven that a person with absolutely no experience can build a T2 as his first electronic project ever, and get it to work without killing himself. He did however have the patience (cough cough) and read enough so that he knew what he needed to do. He also had help from a friend, and another friend in high places. The kgsshv is WAY easier to do. I had a chance to look at my notebook, because when i built my 2nd kgsshv i wrote down how long i spent on various things. I stuffed both amp boards at the same time and the total time to stuff and solder the 2 boards was 6 hours. The power supply board took an additional 3 hours. I'm sure that justin can do it in half that amount of time, but most people are likely to spend twice as much time as i did. Checking all parts before you stuff and solder them in is pretty much required unless you want to spend more time fixing it than you did building it. I've seen mislabeled resistors before, and dead transistors out of the box. The $40 transistor tester is a great idea for this, and a decent 4.5 digit DVM is also necessary. Still, there are lots of ways you can get hurt if you don't pay attention. The chassis work and wiring also takes a bit of time especially if you don't have the right tools.

you missed the slight roughness and color change bit.

Yes i saved the ebony scraps just for that purpose. But i consider that cheating. Was planning on fililng the hole that way. On the other hand its a thing of beauty as is. Very little wood is absolutely perfect. Same thing the red mallee knob. A slight roughness and color change is in the red mallee too. I have more ebony to work with, for now

unfortunately there is a lot of wasted wood to make circles. Plus i want to make a couple in the other grain direction. I can always find another piece of wood, shouldn't take more than another year. Nice try steve. You can make these yourself anyway.

I have enough wood for 5 more. Should have the 2nd one done tuesday or wednesday.

micromachining revealed cracks and roughness, will have to machine up more wood. http://gilmore.chem.northwestern.edu/ebony5.jpg http://gilmore.chem.northwestern.edu/ebony6.jpg http://gilmore.chem.northwestern.edu/ebony7.jpg

I have a 7 lb chunk of pure berryllium in my drawer at work that i was thinking of turning into a knob. I have already been told that i will not be allowed to use the machines at work to do this. And i'm not stupid enough to try this on my lathe at home. Berryllium not so bad. Berryllium Oxide, very VERY bad. I also have about 25 lbs of mercury, not sure what to do with that either. Maybe waterford crystal knob filled with mercury might be neat. There are a number of kinds of stainless steel. The screws i have are non-magnetic. All my NMR magnets are made of non-magnetic stainless. I do remember the NS100's. Good speakers, a little bright. Very yamaha sound.

This one is for steve, i found it searching for a new bigger solid state hard drive

http://gilmore.chem.....edu/ebony2.jpg http://gilmore.chem.....edu/ebony3.jpg http://gilmore.chem.....edu/ebony4.jpg i managed to find a bullseye again.Too bad its so hard to see. And also a defect inside the wood. Its rough cut, ready for micro machining

Do it the same way i did with the T2. Angle bracket to a heatsink. Lots and lots of companies do this.

Yep, the real stuff, and aged about 50 years. Tree had to be a couple hundred years old. Its very hard to find a piece big enough to make knobs out of. Yes i got clobbered both on the price, and on shipping.

Messing with the input tubes can cause significant DC output which requires a pair of DVM's and a strong heart to adjust. The T2 is not like other tube amps. Best left alone. The wood is for more knobs. At some point i'm going to try and make a knob with the display inside it. Similar to the one on my Wolf range. And it will work the same way. Or maybe like that new thermostat from the ex-apple people, except made out of ebony.

I doubt he is using stuff this good. Or this size. Or this well aged. If he is, i sure was not able to get any from him. I've been looking for a piece that size and color for almost a year now.

Speaking of phallic things, picture posted in the T2 thread. I may actually go in christmas eve and bandsaw the thing into appropriately sized cylinders, then stick in the lathe. I thought the lignum-vitae was dense, this stuff is 3 times more dense. Glad i have a new set of carbide bits.

I was not really planning on going into work next week, but this has changed my mind. http://gilmore.chem....n.edu/ebony.jpg 1500 grams, 8 x 2.5 x 3.5 inches about 50 years old.

Steve's humor alludes me sometimes. Now i see the smiley. need more coffee.

I owned an original pair of ohm-A's many moons ago. I did not think they got that low in impedance, otherwise they would have smoked the amp i had them hooked up to. Quads esl57's were 16 ohms i think, i have a pair in the basement i will have to look. Esl63's were about 2 to 3 ohms when the protection circuit kicks in. With 1 ohm speakers, the impedance of the speaker wire becomes significant.

translation: All of my products have one or more tubes in them, and are therefore not DC coupled from input to output. But wait, Lamm needs to examine the LF schematic for how to do DC coupled tube/solid state hybrid. Or he needs to talk to mikhail for how to do AC coupled fully solid state (the square wave) Bizzare specs, a power amp that puts out the same power at 8 and 4 ohms, then doubles the power for 2 ohms, and then again at 1 ohm. Anyone know any 1 ohm speakers?

Other than the T2 which is a special case, i publish the schematics and i give away board layouts that i have done. Anyone can take the schematics and produce their own boards if they want to and sell them as boards, kits, or completed units. And even the layouts i have done. I do however like to know whats going on, and kept in the loop. This is to try and avoid another trevornetwork superglue and plexiglass incident. The T2 is strictly non-commercial use only. Although the board files and schematics are available to anyone. No one with half a brain should consider building and selling T2's commercially. The north central Illinois Head Case Legal Group (that would be doug) has a significant amount of information on "FAIR USE" This would even include releasing for example a SACD DAC that takes an un-encrypted stream, with the information on how to modify specific players to generate such stream. However SONY et all won't pay attention to any of that and will sue your ass into the ground anyway. If you exactly copy a copyrighted circuit board layout without permission, you are violating copyright law. If you take the same exact circuit and do your own board layout, and it is not "familiar" to the other copyrighted design then its legal. Fact is that the LF schematic if you replace the tubes with a pair of jfets and a current source, looks absolutely identical to stuff seen in the late 1970's. So take a $50 circuit, put in a pair of tubes to make it look purdy, slap it in a box with glass windows, and abracadabra $3200 amplifer. Alex would not be the first to do this. He won't be the last either. Never mind what the distortion characteristics, or any reasonable specifications might be.

There is a missing resistor on the gates of the fets from the drive transistor, requires a cut on the circuit board and attaching a 1k resistor. schematic updated. like this http://gilmore.chem.northwestern.edu/dynapowerfix.jpg

You can be sure that there will continue to be DIY amplifiers. The current transistors will continue to be available for at least another year. ixys has 1500 volt n-channel mosfets that sound just fine. The only difference will be a stronger drive circuit to drive the extra gate capacitance. I'm playing with this now. Its really just the 3rd stage voltage gain section. Standing power will go up a few watts per channel. Whats a few watts among friends

It should be noted that pete while not mentioning names specifically says that you need at least 70 volts on 6922's to get them to operate in a very linear region. 30 volts just does not cut it and requires much more feedback. Its tricky to make fully dc coupled dynamic amps with the input tube at 70+ volts. Something alex has not figured out yet. I suggest that alex look at the T2 schematic for some inspiration.

why does the simple stuff have to get so complicated sometimes.