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The Quest for >2000 Vppss
A small update on the Super Carbon debugging. Today I tried shorting IN+, IN−, and GND together at the input. The background noise was reduced, but there is still a very slight residual hiss that I can't completely eliminate. It's extremely low that you can only hear it if you put your ear right up against the headphone. Because of that, I'm starting to think the input stage may not actually be the source of the remaining noise. I'm wondering if it's possible that the compensation around the C3M0900170 devices is involved instead. Specifically, I'm referring to the 5pF capacitors C8 and C9 connected around Q10 and Q90. Could insufficient compensation there contribute to this kind of residual noise? @kevin gilmore , I'd really appreciate your thoughts before I continue experimenting.
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HC Bike/Cycling Thread
1) damn, that's a tall headtube 2) 58? 3) I can't even tell which model that is, but you're the first Allied owner I know. Neat! 4) Where are the proper pix!?! And details!?!
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HC Bike/Cycling Thread
- Yesterday
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The Live Music Thread
Dpa 4015gs -> mma-a Knoxville https://archive.org/details/jason-isbell-2026-07-17 https://archive.org/details/jason-isbell-2026-07-18 I’m jealous. I’ve wanted to see him but it hasn’t worked out for me yet.
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Songs You Came Across On Some Streaming Service And Thought Your Head-Case Buds Might Enjoy Too. No Critical Endorsement Implied. Fuck Vevo etc.
Bill Evans - Suicide is Painless (from You Must Believe in Spring)
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The Live Music Thread
A few years back I discovered a newish country singer named Charlie Crocket. I've become a big fan, and today I went to see him play at Stern Grove Festival in San Francisco. It's an outdoor, kind of natural amphitheater. Nicki Bluhm opened for him and both artists were great. It was a long day but well worth it!
- Last week
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The Official Head-Case Photography Thread.
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The Knuckledragger 3rd Memorial Slow Forum Post
- RIP someone or another
RIP Jennifer Finch, L7 Bassist and Los Angeles Punk Figure. She was also a notable photographer. I want to make a "Pretend We're Dead" joke, but I can't make it funny.- What are you listening to Part the Third
- Post what you're watching
Yes I know. But it is nonetheless exceptionally persuasive. There is a time oddity though. The AI Feynman talks about dark matter (which was around as a measured thing well before he died) and Dark Energy, which postdated his death. I'd clearly forgotten that Feynman died aged 69 (from cancer). Reputedly his last words were "This dying is boring"- Post what you're watching
- Major Forum Software Update
Thanks for the efforts, Nate. I hope there’s a solution, or that they deliver another update that fixes these issues.- The Knuckledragger 3rd Memorial Slow Forum Post
- Major Forum Software Update
I’m still working on the above. It’s sort of a known issue (main page image funkiness) but the posted solutions don’t work for the specific issue that we have. I need to join the support forum for the software platform and I’ll see if anyone there can point to an actual solution. What is supposed to work is at the “user level” where if you click your own name at the top of the main page you’ll see a Theme Editor option which is supposed to allow you to be able to configure what you see/don’t see. I haven’t found a way that productively helps with the mobile version of the site and can’t find a way to set a tiny image as the stock forum image so at least the view might condense down while we find a better solution.- Post what you're watching
Here's a fascinating (at least to me) series of lectures by one of my heroes - Richard Feynman. These are all about an hour long, and I was enjoying his engaging talks about diverse topics. For example, below. You get a flash at the beginning that I missed. But at the bottom it is Feynman Reborn, an AI Feynman, along with unmistakably his voice. There is a list of publications at the bottom (for example the Feynman Lectures on Physics). There is a series of these, and the only real hint that something is up is if you look at the background. I think that the authors of the AI Feynman left a really weird background to give a sense of the unreality of the superb AI Feynman.- Songs You Came Across On Some Streaming Service And Thought Your Head-Case Buds Might Enjoy Too. No Critical Endorsement Implied. Fuck Vevo etc.
- The Live Music Thread
- The Knuckledragger 3rd Memorial Slow Forum Post
- HC Bike/Cycling Thread
Great job Adam! You're definitely ready -- especially for a supported ride with breaks and refueling stops. Impressive progress!- The Quest for >2000 Vppss
Yes, it’s the C6 470pF capacitor in the power supply. I originally installed a 5pF capacitor instead of the specified 470pF. After changing it to 470pF, the output voltage rises very close to the raw DC input. My raw DC is about 698V, while Vout increases to around 675V, instead of regulating to the expected 600V.- HC Bike/Cycling Thread
Did a final big shakedown ride before the Marin Metric Century in two weeks. I didn’t want to see the hardest climb (Wilson Hill) for the first time on Fondo day. It was indeed a bear, but I am ready for this. The training has paid off. Should be a fun century. West Marin is pretty damn good riding when you aren’t on the major through roads.- The Knuckledragger 3rd Memorial Slow Forum Post
- What are you EATING right now?
- The Quest for >2000 Vppss
the 470pf cap is on the power supply right? the reason for the 1 meg input caps is to give a minimum stable bias for the input stage. its expecting you to put in front of it a pot, or other much lower impedance resistor. at 50k the remaining noise is far below any possible music at that level that does not significantly lower the input impedance. - RIP someone or another
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