kevin gilmore

I'm thinking that just 2 more people need to appear here, then we will have the top DIYers of all time all in one place...

The food at the chemistry department is very lame. However we have lots of 200 proof drinkable alcohol... Just for fun i will be bringing a special bottle of water to CJ... It is absolutely pure to 9 digits. And priced accordingly. I doubt that we could even get a reservation at this point even if we were nuts enough to try.

It tastes exactly like what you put in it. And its fun when it goes squish. I've tried chilling them and that works great too. So a whole batch of about 50 proof half size golf balls, would get you drunk in a hurry. The biggest trick is to let the sodium alginate mixture sit for about 4 hours to get rid of all the bubbles. The stuff does not disolve easy. And you do have to weigh out the ingredients carefully. For stuff that contains high amounts of calcium, you do it in reverse i.e. you deposit the sphereoids into the sodium alginate solution instead of depositing the spereoids in the calcium carbonate. Another chef trained at el-bulli has a place in chicago. http://www.alinea-restaurant.com/ The 23 course dinner with wine parings is about $500 plus tip (per person) We could do a CJ run saturday night...

So after seeing the 60 minutes last week, and already knowing all the liquid nitrogen cooking tricks, the chemist in me idecided to try my hand at the ravioli/caviar things with the sodium alginate. Yesterday's try was a complete disaster, but today came out almost perfect. As with all of this kind of stuff, technique is all important. Its helpful to have a stash of USP grade chemicals to pull this off... So i present mohito caviar, and mohito ravioli http://gilmore.chem.northwestern.edu/mg1.jpg http://gilmore.chem.northwestern.edu/mg2.jpg Maybe we can have birgir show us how to do this...Correctly

stop messing around and use 4 of these... http://gilmore.chem.northwestern.edu/powertube.jpg The filament current alone is killer.

I used national semiconductor parts for the regulators. They work fine. They are 20+ years old. I have enough for many more years to come.

The mingus is fantastic. There are a couple of areas where they had a bit of trouble with the master tapes but it sounds way better than it should for something from 1963. Sweet.

They are pressed in austria. Have not had time to listen today, cleaning up from other software disasters. This is very unusual, normally i drop everything for new music.

Just got in the 4 impulse sacd titles. See you at the fair out of the cool coltrane mingus mingus mingus mingus mingus All of these have stickers that say SACD only. The stickers are wrong! The titles are all hybrids...

A milestone was reached today. I just shipped Inu the top and bottom plates, so he now has a complete chassis set. (less the knob and a 6 pin stax jack) So if he hauls ass a bit, he might have his built by CJ2010 On friday the vendor that is doing the polishing and anodizing is picking up two complete sets of chassis (less the knobs) so production is well underway. On a lighter note, my first experience with a 4D mill doing the preamp chassis as one single piece turned the block of wax into a big mess. The machines idea of 90 degrees and mine seem to disagree If there is going to be a next batch of boards, i'm planning on a pair of single piece chassis for my second T2. Everyone needs 2 x T2 !

Well personally i like the look of black, with shiny stainless steel screws. Some may even want to add washers...

I'm back to machining the edges of the tops and bottoms. Really does not add that much extra time or expense. The laser cut edge sample i did not like. Should finish the 3 sets by monday, 3 of the 4 pieces are done. Without finishing, the current cost estimate for the 2 fronts, 2 backs, 4 heatsinks, 4 angle brackets, 2 tops, 2 bottoms and 2 stax jacks is $987 plus shipping. No idea how much the knob is going to be yet, the first one i made by hand, need to learn how to use the NC lathe.

If everything goes right (and it probably won't) i should have 5 sets of tops and bottoms by friday afternoon. Already have at least half of the fronts/backs and heatsinks done. I know that at least 2 of you want to do your own finishing, If there are any more that want the chassis unfinished speak up now... Could get a couple of chassis out in a week or two. (no knobs yet)

The amp boards will be available seperately so you can build a preamp using all mechanical switches.

I still have to get T2 chassis parts done... Did another 20 fronts and backs on friday, will do another 20 or so this week, still waiting for top/bottom material. This is easily another 8 month project. Although the first one will be going inside that monoblock chunk of aluminum. Definitely NOT going to be done for CJ. The touch screen makes all the sense, and would be completely reprogrammable. By the time i would add all the buttons and knobs, and the circuit board for them, plus all the extra machining time on the front panel, the display ends up costing less. I believe that this is the first of many new things from me that will have OLED controllers.

I've been looking at various different interfaces (knobs, buttons, remote control...) and i think i have decided on this as the complete interface. With the remote control and touch options. SparkFun Electronics - Active Matrix OLED 2.4" with Touchscreen Reasonably priced, active matrix OLED, built in i2c drivers for the preamp control stuff, and IR input. Single part complete controller. Any comments??

Output impedance is less than 1 ohm. Should drive anything.

better at 1.7mb http://gilmore.chem.northwestern.edu/baseboard3-3.jpg bigger at 6.5mb http://gilmore.chem.northwestern.edu/baseboardpro.pdf both smaller than the above version. Now for the important stuff. charles hansen says he found a non-multiplexed vacuum fluorescent display for use in his preamp, he says it generates way less digital hash. Which certainly makes sense. Anyone have any idea who makes his display. its 1 line of 16 characters, and is VF. Power supply coming along nicely. lm317/337 in first stage, same thing as current limiters in second stage, third stage will either be series regulated, or shunt regulated, have not decided yet. All the resistors will be the surface mount thick film, vishay or equivalent, completely non-magnetic and non-inductive. (and not super cheap, but not super expensive either)

how i hate photoshop. If anyone has any better ideas to take a multi sheet pdf and stack the pages with some transparency to make something that shows up without being 10mb... http://gilmore.chem.northwestern.edu/baseboard3-1.pdf

uploaded struts spreadsheet. http://gilmore.chem.northwestern.edu/t2parts3as.xlsx

Except when bridged is used as balanced. Lets take the input of the T2 for example. The two hot wires both go to seperate deck on the attenuator. The other end of each of the attenuator decks is ground. Therefore a truely balanced 2 wire input signal coming from a transformer has both wires referenced to signal ground thru the resistance of the pot. Now the T2 also as a switch that can tie pin 1 to signal ground. For hum and noise reasons signal ground IS NOT chassis ground. Chassis ground is strictly tied to earth safety ground. If you want to you can drive the T2 with an unbalanced signal by using one of the neutrik unbalanced to balanced converters. In which case rca ground is tied to both pin 1 and pin 3 inside the connector. For this you have to set the switch to connect pin 1 to circuit ground. The same thing is exactly true for the input of the preamp. Now the output of the preamp should be considered as a bridged output referenced to signal ground. In which case only 2 wires are needed to drive the input of a transformer. The problem comes in with the input compliance with respect to ground. In this case chassis ground. transformers are good for at least 100 volts of compliance, most solid state gear can handle less than 15 volts of compliance. the RSA protector for example is a bridge output amplifier.

The preamp in question is both balanced and bridged. It will take a 2 wire balanced input. It will take a 3 wire balanced input. It will take a 2 wire unbalanced input. It will output both 2 and 3 wire balanced output. And 2 wire unbalanced output. Same as krell and ayre, and levinson. The T2 will take a 2 wire balanced input. But because there are only balanced input connectors, pin 1 is connected to signal ground so that you can supply an unbalanced input. Clear as Mud!

The aluminum is recycled. Still it takes lots of energy to melt the stuff down and re-purify and recast. At the prices ayre is charging, he probably does not make too many of those things. They sure are nice however. The blowtorch's were also machined out of a solid block of metal. and then they still have an end plate. What a complete waste of materials.

I have studied the JC design for many moons. I have synthesized it over and over and tweeked it over and over. Which is how i improved on the original. Nope, not using the renasys devices Yes i certainly am going to use the lsk389 and lsj109 My version swings 8 volts peak to peak (unbalanced) from +/-20 volt power supplies. (may go to 24 volt supplies) At 8 volts peak to peak the second harmonic is down 81db. The 3rd harmonic is below the 120db resolution of my instrument. At 2 volts peak to peak (unbalanced) the thd is about .005% I know how to get the second harmonic down another 4 or 5 db. But as many already know, its the sound that i'm after, not the numbers. The problem with cmos switches is well... they are cmos switches. I know that levinson uses cmos switches in their silly priced preamp, on an arlon board. But i think that gold cross point relays sound better. I was planning on using the omron small signal relays. But sealed reed relays would be better, but are also much much bigger. Will see what i can get to fit. Yes i think i have a pretty good servo. And its not in the audio path anymore. Although you might argue that the common mode servo in JC's original is not in the audio path because it is DC, except when you go balanced input. I've pulled out my schematics for my phono stage from 30 years ago. I'm pretty sure i can source equivalent parts for everything, so at some point there will be a phono stage. OH look, there is the lsk389 and lsj109 again... An exact copy of the vendetta phono preamp should be a snap. But in a seperate box with a seperate power supply. .2 pitch OK, glad you said something now because i'm going to start laying out the board tomorrow. Can't wait to see the price on teflon or arlon circuit boards. Just wait till you see how silly the power supply is going to be.

Invert phase, sure why not, the blowtorch had it. Just 2 more relays... Maybe we can get to 50 pieces per board and get a price break.