dsavitsk

EAS-400

The other main reason is that the Heeger case is a little bigger which means that the power transformer can have a slightly thicker core which will run cooler and dissipate heat a little better. Now, I will say I am less concerned about heat than Tom -- it's hot, no doubt, but it is tube amp. They run hot. I also think with some venting added to the top and bottom of the case, and some strategic holes in the PCB, everything will run OK. There's just no airflow right now. The Heeger cases look nicer, and are more solid, too.

200mA should be good. Tom drew up a template at one point ...

B&H is definitely my first choice (except for Tamarkin) for anything camera related. Sales tax in Chicago is 10.25%. Burbs are only slightly better.

200V is too low. The PT is rated at 200VAC. Unloaded it runs at ~275V or so which is what the parafeed caps will see before the tubes start conducting, so I wouldn't use anything lower than 300V.

R4L and R4R set the CCS current. Each should drop ~1V at ~13mA. In a pinch, for the CCS transistors, cut some little sinks out of a disposable pie tin.

You aren't building two?

Plentiful, cheap, and it looks like the right size to me. As for caps, I also like the paasonics better, and we'll probably use those for the kits, but I wouldn't go out of your way to order them from Digikey unless you are getting other stuff there, too. The influence they have in the circuit is pretty minimal. Edit: It looks like Mouser is starting to carry Panny caps 667-EET-HC2G101BA is 100u/400V TS-HC which can replace the recommendation above.

Here's a start to the parts list (double check that the parts look reasonable) -- everything is Mouser, with some Digikey options for caps in (). The only things not available from Mouser are perhaps the little heatsinks, though some little screw on ones are likely fine, the parafeed caps, and the tubes/sockets (which are available from Tom.) Oh, and see the choke note below. C1 10u/400V 661-EKXG401ETD100MJ2 C1L 0.1u 505-MKP4.1/630/10 C1R 0.1u 505-MKP4.1/630/10 C2 100u/400V 661-EKMM401VN101MP30, (P6843-ND) C2L 4.7u/300V Clarity Cap SA from e-speakers C2R 4.7u/300V Clarity Cap SA from e-speakers C3 100u/400V 661-EKMM401VN101MP30, (P6843-ND) C4 4700/16V 598-SLPX562M025A1P3 C5 10u 647-UPW1H100MDD1TD D1 1N5062 78-1N5062-TR D2 1N5062 78-1N5062-TR D3 1N5062 78-1N5062-TR D4 1N5062 78-1N5062-TR D9 512-1N4448 D10 512-1N4448 J1 550-22302 J2 161-4221-E 161-4221-E J3 DD21 693-DD21.0111.1111 + 693-4301.1405 Q1L BC558 512-BC558BTA Q1R BC558 512-BC558BTA Q2L MJE350V 512-MJE350STU Q2R MJE350V 512-MJE350STU R1 250K/.5W 594-5073NW270K0J R2 200/1W 594-5073NW200R0J R3 200/1W 594-5073NW200R0J R5L 60K/1W 594-5073NW62K00J R5R 60K/1W 594-5073NW62K00J R6L 60K/1W 594-5073NW62K00J R6R 60K/1W 594-5073NW62K00J pot 688-RK27112A00CC choke 546-154H (Hammond 154H -- only 2 left at Mouser!, but digikey, radiodaze, PartsConnexion, AES, etc all have this, or just use a resistor for R2)

I've gotten a request to do so, so later today (?) I'll post some "recommended" parts, particularly for places where the parts list is confusing.

Toroids have wider bandwidth and let through HF noise. Split bobbin EIs have a narrower bandwidth and don't, and are thus better for audio.

An EU meet close in time (and perhaps proximity) to E.T.F. might make a trip more possible.

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