dsavitsk

Judging from the vague description, and from the number of parts in the internal pics, I'd wager that this is the basic topology. If so, this is basically a Melos SHA-1 built from solid state parts. If not, then someone should build this -- extra credit for adding a servo to DC couple the output [ATTACH=CONFIG]3251[/ATTACH] ... I may have to build this -- not sure why I haven't done it before

Great pictures, Grahame. It's a cow. They're all over. cows in chicago - Google Search It's the Robie House, I think. Right on the edge of the U. of Chicago campus. Robie House - Wikipedia, the free encyclopedia

I guess I am not sure the benefits of the interstage at all -- there's no "coupling" cap, but you have a big PS cap in the signal current loop instead. Further, with single feed, the transformer has to be a large steel core with a big gap which seems far from ideal. Single feed only makes sense to me when there is a need to swing higher than B+ which doesn't seem to be the case here. Parafeed lets you use interleaved Permalloy, and a smaller core. Only real advantages of the transformer over cap coupling are probably that you can use the transformer for current or voltage gain, and there is isolation from the grid of the output tube if it goes A2. And, parafeed seems better for boh of those? As I say, it's just a preference -- my ear likes nickel. I think the best way to do this is likely to use the voltage regulator tube as a reference for a mosfet shunting element. The Zout from the vreg tubes are just too high (~300R) and to my ear led to constricted dynamics. In my amp, it was OK for low level stuff, but it seemed to fall apart with big swings.

Ryan -- my terrible DSL tested at 2.5 down and .4 up (plenty fast for youtube, netflix, rhapsody) -- bring your computer over and you can test if it is fast enough. -d

Yeah, well, saying the best Chicago style pizza is a little like saying, "my favorite car, among those manufactured by Renault." That said, Medici pizza isn't too bad -- better than Gino's/Uno/Giordano's/Edwardo's/Malnates/et al. at any rate.

It looks like more or less the right way to do it. If it were me, I'd probably ultrapath the output tube with a CCS on the cathode. I might also parafeed the first stage. But, that's just my personal preference. What about keeping the tube and using a 1:2 IPT, or a 5K:10K interstage?

I like the name. How about L'espressivo Siluro. Either that or L'espressivo Salsiccia.

Best pizza in Chicago? Welcome to Spacca Napoli Pizzeria Closest thing I've had to what I ate in Naples in the U.S. Real buffalo milk cheese, and unbelievable sauce.

I'd just like to second this. Jack has made some tremendous things for me, now including a 32:32+32 OPT for use in a version of my solid state amp which is a real oddball. I wonder if a choke phase splitter would work here? Something different.

Now that CJ is over, this is pretty much top priority for us. Tom is in possession of PCBs, transformers, cases, tubes, and a few other parts, so it is really a matter of when he has some time to get everything together. Should not be too long, though. The target price for the kit is in the $300 range. That may go up or down a bit depending on how much parts cost us, but we are trying to keep it around there. It doesn't make sense to use a pot that costs 2/3 of the rest of the amp. And it's too big. And, I don't think it makes that much, if any, difference. If you really want an upgrade, I can supply you with some Electra-Print nickel core OPTs which will make a ton more of a difference. Or with one of these: http://assets.head-fi.org/6/6d/6ddc8d48_IMG_0688.JPG I hear they are nice. Anyway, I think the Noble pots have the same footprint.

It always is. Welcome. If you have nothing else to do, jump on the Blue line and head into the city -- there's not much to see in the suburbs. Downtown is nice if you want to go to a department store, but the Blue line also crosses through Logan Square (Logan Square stop) and Bucktown/Wicker Park (Damen stop) which are both more interesting, and full of better places to eat (particularly Bucktown -- which is also where Reckless Records is).

Etymotic it 7.6 miles from CanJam Hyatt Regency O'Hare to 61 Martin Ln, Elk Grove Village, IL 60007 - Google Maps

I've heard that, but even assuming oxygen is necessary, you'd have to boil for a long time to remove enough to make a difference. Indeed, practically speaking, boiling at normal atmospheric pressure is not a particularly good method of oxygen removal from water, and the oxygen returns as the water cools. Too cool of water is a much bigger problem.

It's impossible to get a good cup of tea in a hotel. You have to use the coffee maker to boil water which is a) never hot enough, and tastes like coffee, and the tea itself is terrible. Even in the restaurants, people don't seem to understand that tea needs water at a boil, and that the cup needs to be preheated. I've taken to traveling with a paired down tea ritual: + + +

Fritz Sennheiser, 98, Electronics Executive, Dies - Obituary (Obit) - NYTimes.com

Indeed -- don't try to sneak out on Saturday for a quick lunch there. Last time I went it was ~15F out and I waited on line (outside) for about 2 hours. When it is warm, there is often a guy with an ice cream truck there to serenade the line. And, there is nothing else worth seeing around - it is totally out of the way so it isn't like you can even have an enjoyable walk around the neighborhood. They close at 4:00pm. With all that, it is still worth going, and waiting.

For any guitar players, a trip to the Chicago Music Exchange is worth the time and effort, and the snotty attitude you'll get. Vintage Guitars | Chicago Music Exchange | Electric Guitars | Fender Gibson Marshall Rickenbacker | Vintage Guitar Dealer Other neat Chicago things you should see that aren't on the tourist maps http://www.garfield-conservatory.org/ http://www.hotdougs.com/ Nowhere else are you likely to find "Pear-Infused Elk Sausage with Foie Gras Dijonnaise and Mustard-Seed Gouda Cheese"

There are quite a few little record shops spread around Chicago. Off the top of my head, Laurie's Planet of Sound in my neighborhood, Hard Boiled Records in Roscoe Village (~a mile or 2 south of LPoS), Vintage Vinyl up in Evanston (which is right across the street from Audio Consultants if you need some Ayre power amps and Wilson Speakers while you're in town), 2nd Hand Tunes (also in Evanston), Dusty Groove which I've never been to, and the venerable Jazz Record Mart which is downtown. There also used to be a few more near Reckless, but I haven't been to them in years, and I don't know if they are still around.

Well, the initial 3 to 4 week estimate for winding the transformers turned into 2 months. They finally arrived last week, and the pinout was wrong. New ones are being wound, and should ship soon ... I hope. They told me it would be this week. We'll let you know. Sorry again for the delay.

Where does Rane say that pin 1 is only connected at one end? Pin 1 is connected to the chassis at both ends. You would only need to disconnect one end if one side is improperly grounded. Here is what they say is the "The Absolute Best Right Way To Do It" http://www.rane.com/note110.html

Pin 1 Revisited

CadSoft Online: Non-Profit-Lizenz

Indeed I can. The DAC is pretty simple. It is a CS8416 receiver connected to a SRC4192 upsampling to 96K connected to a Wolfson WM8741 DAC chip. The output is straight off the chip. Generally, people put a buffer, or an opamp, or at least some caps there since the output is biased up ~2.5V and can't drive a difficult load. Here, however, because the amp it was connected to (with short low capacitance cables) has an input transformer, the bias is effectively nullified. The amp thus acts as the output stage for the DAC. The amp is one of my prototypes that Tom has been listening to. It is basically a differential mosfet follower using an input transformer for a little voltage gain, and an output transformer to block offset. The fets are CCS loaded, and there is a servo that measures offset and adjusts one of the current sources to keep them in balance. The arrangement, which is fully differential (not balanced bridged) makes sure that there are no caps in the signal path, no power supply caps in the signal current loops (the "rail" caps are 0.1u per side), and no attempting to match inherently unmatchable P and N channel devices. Here is a simplified schematic: The amp is pretty much designed around, and voiced for Grados. It works OK with a few other phones, but really seems to excel with Grados. There will be a couple of prototypes at CanJam (TomB and I have a table) in nice wood and anodized cases. There will also, I should add, be a new tube amp and maybe a DAC next to it -- more on that in a few days. The long tube amp is one of our prototypes. We had been hoping that prototypers would build them, we'd make changes, and we'd have at least a semblance of the kits at CJ. Alas, the prototype transformers that I thought would take ~3 weeks took two months to get wound. They should be here tomorrow, so more on this very soon. But, we'll have the first version at CJ anyhow with kits sometime later this summer.

Digikey is carrying these now, in case that's interesting: E-Switch - PV6 Series 16mm Anti-Vandal Pushbutton Switch | DigiKey