kevin gilmore

just ordered all 25, thanks...

You can't measure the bias at the front panel connector without a real VTVM. Digital meters are way to low in impedance...

Of this you can be sure. I'm now a permanent member of the instrument modeling shop in addition to everything else, and well the NC toys and bridgeports... There is no limit. Even at home i have a mill and a lathe, a precision (.0001) drill press and a 1 foot shear. But really drilling holes that way is all sorts of very dangerous. Those hole saws are for wood. NOT FOR METAL. Go and get a couple sizes of chassis punches. Not very expensive. Definitely not expensive compared to 30+ stitches to your stomach when the chassis lets loose. You can find the chassis punches (greenlee's) all over the place, and at hamfests for $5 each. I have a dozen different sizes at home, most are older than I am, and will last forever if you don't do something really stupid with them.

not quite but close. pete used an off the shelf switching transformer with 2 secondaries. one was used for the filaments.

The completely backwards approach. I have something and want to use it. Pencil tubes not really suited for this. Send the tubes off to pete millet and he can put them in his whacky portable for you. Not going to be cheap. You are going to need the switchers he uses to raise the B+ to something like 48 volts. Then use the solid state buffers to drive the headphones. 48 volts and 1.5 volts both come off the switcher.

He edited the first square wave but did not edit the second. Pretty pathetic he can't even proof read his own crap. Anyone with any brains would take what he has said about VD power cords and Rudistor and assign it to the garbage can where it belongs. Kind of funny actually. And yes, driving real equipment with square waves is going to make all sorts of extra noise, and some equipment might actually seriously overheat. There are some UPS's for computer use that actually do put out square waves, they come with warning signs to use on switching power supplies only. When you get into the 10kw+ range, efficiency makes a very big difference.

this from a man who posted a shill review of the new psaudio powerplant and somehow turned the specs into square waves. For which i corrected him, and he said it was a typo. TWICE So how do you get from SQUARE to SINE as a typo??

And the clear king of spl is the koss esp950 box. runs off of + and - 600 volt power supplies. Actually clips within a few volts of those rails, so about 2350 Vpp stator to stator. srm 212 and the srm 252 running off the power brick at nominal voltage are + and - 325. Run them off of the battery and you get + and - 350 srm-001 on a fresh battery +550. sinks pretty quickly to +500.

Yes lets post as many schematics for ray as possible. I've never seen the jones designs (well at least not by that name) That national design has some significant bugs in it...

Will scan sra3s schematic later today unless someone else wants to do it.

I'm not sure that even ray has decided which schematic to steal. But the one on the tubecad site that uses 5687's seems to be perfect. Take a B52, make a different circuit board, and change the output jack mounting plate, and leave everything else the same. Major changes to the power supply section. Bang Zoom and a ray samuels electrostatic amp. Gotta be $6500 or more. A better question is which schematic he is going to steal for the solid state version.

The stax SRX circuit is all tubes. The stax SRA-3S circuit is a solid state/tube hybrid. It was the first fully dc coupled amp that stax made. One is not an outgrowth of the other, they are just plain different. There is also very little that is the same between the SRA3S and the SRM-T1 on which all the current amps are based.

Mikhail and i have talked about a great number of things over a significant period of time, at least 5 years. Certainly have discussed the all tube dc coupled thing and why he should not have put the thing into production. I'm sure there was some discussion of the BH in there but never in relation to anyone wanting a special amplifier to drive he90's. As far as the ES1 mikhail needs to figure out who he is talking to and when. This is the problem when you throw marketing BS at someone like hirsch who knows absolutely nothing about what is being discussed, and makes comments based on that. Same thing with Earl. I don't know why mikhail has to hide behind all this mystique bullshit. For example the "EXTREME has no interstage coupling capacitors" thing. Which is true, but then compared to other amplifiers who also have no interstage coupling capacitors. And the ES1 which has no output capacitors but does in fact have interstage coupling capacitors. Or my favorite, "i put 4 capacitors in parallel in a proprietary technique" Or the "its patent pending"... I'm not saying ray or peter are any better. In fact peter is probably the biggest liar of the whole bunch. I believe the miniature power supply for the portable is solved. I posted about it over at that "OTHER" site. The supplies are made by bear. http://www.bearpwr.com/products_DC.shtml I'm messing with a way to do the bias that does not eat up an extra .1 watt. Still the best idea would be to have someone wind me some custom transformers to my specs.

With appologies to Mikahil... I thought about it a while and can't let hirsch's massive pile of bullshit above stand. Mikhail building a blue hawaii. In his dreams maybe and nowhere else. While others with absolutely no experience or the knowledge of when not to do something stupid have acutally built blue hawaii's, mikhail just is not capable of this. His knowledge of solid state and even high quality solder joints is somehow lacking. I just recently had a singlepower square wave run thru my hands, and all i can say is that this thing is a massive un-inspiring absolutely poorly built circuit from the 1970's. I don't even have to say anything about the price, as anything over $100 would have been a ripoff. Fact is virtually all electrostatic headphones have roughly the same voltage, current, capacitive ratings ... The lightest of the light to the heaviest of the heavy all fall with ratings of no more than 2:1. Far less than the range of numbers you see in dynamic headphones. capacitance, 30pf for the sr-001 to about 150pf for the older koss units inductance, non-existant, completely dependent on the lengh of the interconnect cable. resistance, in the 10's of megohms minimum. Fact is that electrostatic headphones are a really easy to drive consistent lagging load. What some headphones need is more voltage swing, and there are plenty of solutions to that. He90's were limited to 500 volts of bias and about 500 V peak to peak stator to ground anyway. For an electrostatic amp to sound like shit on one pair of headphones and sound glorious on a completely different set of headphones would be a very hard thing to do. And as for the ES-1 and ES-2 they are both nothing more than a 30 year old stax sr-x circuit with different tubes. Verified by a number of people. Absolutely nothing new, absolutely nothing different, absolutely poor construction...

You are not an idiot, and i believe you know how to use a calculator. f = 1 / (2 * pi * r * c) (3db point) So for 300 ohm headphones f = about 11hz with 50uf want the same thing with 32 ohms headphones, guess how much

Hirsch back to being the biggest Singlepower shill again, acting like the Wizard in the Wizard of oz trying to distract the audience with bullshit. Same thing as sacdlover recently trying to convince people that the extreme and the woo audio are completely different when they are exactly the same. See people hear one thing and then try it apply it to something completely different. With tube OTL amplifers DESIGNED FOR DYNAMIC HEADPHONES, (every one of them except for mine) you need output capacitors. Because of the impedance of those DYNAMIC headphones the ratings on those caps have to be something in the range of AT LEAST 200 microfarads. To make a really good cap (ala the audio note caps) that value with silver foil and teflon would end up with something the size of a large garbage can. And don't even ask how much it would cost, as no one would ever build such a thing. FOR ELECTROSTATIC AMPLIFIERS designed for ELECTROSTATIC HEADPHONES the numbers are completely different. Omega2 headphones are a 170 kohm load at 10khz. An output capacitor of .1uf is absolutely plenty for a frequency response absolutely flat between 20hz and 20khz. You can make (and in fact buy) really good audio note caps that value. You will still not like the price. Comparing an ES1 with or without OUTPUT capacitors to an equivalent OTL dynamic heaphone amp is without any meaning. No the ES1 does not have any OUTPUT capacitors. It certainly does have coupling caps at the input of the OUTPUT stage. How good those caps are depends on how much money you want to spend. I'm sure mikhail will even use the gold foil caps if you throw enough money at him. Yes the best amplifier in this case would be all tubes, and completely DC coupled input to output. It is very expensive to do it this way, lots of extra parts, and lots of power supply voltages. If you are completely whacked you can even do the whole thing (all 3 stages) with DHT's. Mikhail has made a good business out of selling ES2's at $15k to $20k. I wish him continued success, and i'm sure that the limited number of customers at that pricing level are absolutely thrilled with the result.

Noise comes from a lot of different sources. A resistor generates noise all by itself due to the temperature. This is called johnson noise. The only way to reduce this noise is to lower the temperature of the device, and many ultra low noise preamps put much of the active circuitry on a peltier element to acomplish this. Output devices generate noise which among other things is dependent on the amount of current flowing thru the devices. Then there is shot noise, also dependent on the amount of current thru the device. All things being equal, an output stage biased at 200ma is going to have a lot more noise than an output stage biased at 10ma. Its not the B22 as such that is the problem. Same thing using a Dynahi as a preamp. Regardless of what gain you use in your b22 the output stage noise will still be there. One of the reasons i parallel many smaller devices is to get the noise level down.

So out of college, my second speaker system was tripple stacked quad esl 56's with decca ribbon tweeters. Owned a pair of KLH model 9's for a few years till the tweeters blew up. Had a pair of accoustats for quite a while too. My first surround system was 4 x quad esl 63's. Hardcore ESL nut ?? You Betcha

Very expensive. If you found someone to build one of these for you and did up the power supplies to the level of the rest of it, its going to be $10k. At least 2k in parts (i'm probably way low) if you build it yourself. DHT amp for electrostats is easy. Going to need a fork lift for the required power supply. First person to show they are serious by putting $15k in a bank account and i'll publish the schematics.

But its way more fun to trash about $600k of instruments to salvage the connectors. Think of it as therapy In this case a micromass quatro 2 and a micromass maldi (now owned by waters). The qstar is next.... I now have 6 x 6 inch turbo pumps and controllers... And a pair of 12 inch pumps. Time to make some electron tubes by hand...

So you take a modern source with an output impedance of 50 to 200 ohms, add a tube buffer and the result is something with a minimum output impedance of 2200 ohms, and probably more. Yep sure is going to add that tube distortion and frequency response to what was a pretty clean signal.

I was going to keep it as a backup, but the difference is so great i don't see how i could use that old thing ever again. Of course I'm spoiled. Ebay they are going for about $1000, so the first offer of $800 or more gets it. Comes with 5 EXTREMELY USED batteries with no more than 25% capacity left. Would work great as a studio camera powered by the included brick. And you will need your own lenses. No compactflash cards or lenses included. Fully up to date firmware. Fully supported by photoshop cs2 or cs3 in raw mode. firewire connection very problematic from the very start. May work with an apple firewire connection.

hurry: The Black hatters still have a couple left in stock, doubt they will last the weekend. I was on the waiting list for 5 months... http://gilmore.chem.northwestern.edu/dsc_0011.jpg Same lenses i had from the other camera. That is the great thing about buying the right lenses the first time. And the second time and the 3rd time... 17-35 f2.8 ED-IF-AF-S 28-70 f2.8 ED-IF-AF-S 70-200 f2.8 ED-IF-AF-S-VR 105 f2.8 macro (the old one) 2X teleconverter Will buy the new PC lens once it is actually available. And probably the new ring flash setup, although my old ring flash actually does work in i-ttl mode with this camera, would not with the old camera which made it virtually impossible to use. I'm actually planning on making some money with this, just like i did with the last one, so its not really a toy.

Got my new Nikon D3 this morning. I just don't know how i lived with my old kodak slr/n for so long... Pictures tomorrow... 7 hours to charge the battery from empty...

The 727 is supposed to be a similar design to the 717 with the output stage dissipating about 3 times the power, therefore a more extended high frequency and low frequency response. If it really sounds much worse, there certainly could be a number of reasons, but i would be surprised if on a casual basis anyone could tell the difference between the two. Unless stax made some kind of horrible mistake.