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After some rounds of trial and simulation, I thought I’d put together a rough guide for setting the 300B operating point, mainly to make life easier when dialing things in. Given static operating currents: 34.3 mA → Rk = 2160 Ω, Vgk = –73.7 V, Grid pot = 10 kΩ, set around 10%. 23.8 mA → Rk = 3200 Ω, Vgk = –75.8 V, Grid pot = 10 kΩ, set around 10%.   Plate voltage check (with Va = 0 V target): At 34.3 mA → Plate Voltage = Va – Vk = 0 – (–325.9) = 325.9 V. At 23.8 mA → Plate Voltage = 323.8 V.   By matching these points against the 300B characteristic curves (see the red-line markers in the attached graph), the theoretical Vgk comes out roughly between –70 V and –75 V, which lines up with the measured –73.7 V and –75.8 V. From the curves, the 34.3 mA point looks more linear. Pushing current further could be even better, but that depends on whether the EL34 can handle it safely and whether the PSU has enough overhead.   All of these measurements are under a ±400 V supply. The 300B datasheet gives a max plate voltage of 400 V (though some manufacturers claim 450 V). On the XL build, with 400 V rails, the plate voltage is about 335 V, and still within a safe zone. I haven’t confirmed the behavior at 450 V rails, but I’d expect plate voltage around ~380 V, which starts to get a bit risky. If anyone’s interested, I can run tests at 450 V and report back the voltages at each node.

Wow, they've made replicas also for Stax... What a life's today's life!

That's better...  

Silksong crashes Steam, Nintendo eShop on release day — highly anticipated indie video game took six years to arrive and is already one of the most played games ever on Steam. My (sainted, octogenarian) mother asked me about Silksong today.  Its launch was so big that the type of news she listens to covered it.

I went back to 2010 this week.  I didn't buy and bitcoin or, ahem, play any classic 8 bit Nintendo games.  I did blow the metaphorical and some of the actual dust off my PowerShot S95.  (More on that in a minute.)  It took me a couple tries to get it going.  It took me even longer to figure out how to use the damn thing.  The S series of PowerShots (S95 to S110 or so) have dual physical wheels, which is the best.  I had to work to remember exposure compensation.  I also had to set the time, date and things like picture style.  All of this took some futzing.  Unfortunately, about 10 years ago during one cold and miserable winter, I got depressed and left the S95 on its back for six months (while running the wood stove).  The meant it got some killer sensor grime, which I cannot clean.  In broad daylight the dirt is invisible, but indoors the dirt specs are a curse.  This is a shame as the S95 has an F/2 lens and works quite well in low light.  With that said, I took a stroll through downtown Edgartown and snapped a few street shots. The best second hand store on MV was on this street for decades.  Now it's a boutique that sells  uber-expensive skin care products.   Downtown Edgartown is still bustling with "shoulder season" people.  The kids are back in school, so now it's blue haired retirees and buses full of people with name tags.  It's a PITA to navigate around them, but TBH I cannot blame them.  The weather is perfect here this time of year.   The four trees in front of this house are of historical significance.  That thing on the other side purports to be a Volkswagen.   Looking down toward South Water St.  That farthest point is Chappaquiddick.   Built in 1703(!), this is one of the oldest buildings on the Vineyard.  I quite like it, but the modern signs in front of it are ugly AF.   This is the only shot I posted that I don't totally like.  For some reason I shot it wide open (F/2) and there's significant smearing in the upper corners.  As I mentioned, I'm just getting re-acquainted with the S95 after a decade.  Also what's happened in the interceding 10 years is that my vision has deteriorated sufficiently that I can NOT read the controls of the camera without my glasses on.  This makes all aspects of photography more complicated.   EDG harbor with Chappy in the background.  There's not one but two catamarans in this shot.  One is the famous Mad Max and the other is even more strange looking, somehow.  My mother was friends with a Swiss woman who owned a farm on Chappy.  (That is a huge deal.  Chappaquiddick isn't that big, and the island itself is eroding.  Land on it is very precious.)  She was born in 1924 and refused to accept the idea that Mad Max was a real boat.   A kid dropped their heart glasses and some kind soul put them on top of a mailbox in case they came back looking for them.   This sweet dog was waiting patiently for his mistress.  He turned to look at me just for a second before she returned.  The S95 is fast enough that I caught him the moment his head turned.