All Activity
- Today
-
Red Bull! Is you mad!? https://www.the-race.com/formula-1/our-verdict-christian-horner-red-bull-f1-exit-shock/
-
Megatron Electrostatic Headphone Amplifier
JoaMat replied to kevin gilmore's topic in Do It Yourself
I’m using a single cathode resistor. When you are using two 3300R resistors, as on your board, I guess that is equivalent to one 1650R. If you follow silk screen you will get -100V or so on output. You probably need to double resistor values. Maybe someone out there can tell more about this. -
I’m planning to use ±400 V for the supply with an anode current around 23 mA. I noticed that on Kevin’s PCB layout for the 300B, the cathode resistors are shown as two 3300 Ω parts. Do you think I should replace those with 3600 Ω instead? Also, for filament voltage switching, I’m using the pin header setup shown below(MPN: 0010897120). Each row corresponds to 2.5V, 5V, 6.3V, and 12.6V, and I also left one extra row reserved in case I need it in the future.
-
Not going to go see them on tour but that doesn't mean I can't dust off the old records and jam out.
-
Callon79 joined the community
- Yesterday
-
So sorry to hear that, Dan. Don't know what to say.
-
Megatron Electrostatic Headphone Amplifier
JoaMat replied to kevin gilmore's topic in Do It Yourself
Thanks. XGL6020 inductors are probably excellent. With TPS62913 I use Wurth 2.2uH 4.4 x 4.1 mm, which works all right. I don’t change anything when switching between 300B and 2A3 (except from filament voltage). Both tubes need 3.6K cathode resistors @20mA. EL34 needs 1.6K and EML 20B needs 0.6K. I use small daughter boards with resistors and jumpers to change cathode resistance. -
That's horrible to hear. Sorry 😔
-
-
Lulian20 joined the community
-
Taimane Because: Yesterday
-
What's the over/under on "Micro Greens" and "Foam" on the menu?
-
Dang an entire kitchen just filled with people with tweezers..
-
Yup smoker still works. I had a good chunk of it as sushi last night, sans wasabi, which bummed me out, but the fish was yummy. And the chunk of freshly smoked for supper tonight night was lovely. Also receently 10lbs of pork belly {not pictured}...
- Last week
-
No words other than I'm so sorry, Dan. That's just horrible.....
-
Holy shit. One of my closest friends from college was murdered not far from where she lived. Sunny was one of the toughest people I've ever met. I can scarcely process this.
-
I used an inductor from Coilcraft, MPN: XGL6020-222MEC. The manufacturer claims it has the lowest DCR in the industry for its class, and it’s also very compact at around 6.71 x 6.71 mm. For the output voltage selection, I set it up with a few jumpers to switch between different resistor values for 2.5V, 5V, and 6.3V outputs. If you need help calculating those resistor values, just let me know. Also, I’m curious. When you switch from 300B to 2A3, did you modify any surrounding circuit parameters, or can you drop them in directly (aside from changing the filament voltage)?
-
Figured i'd finally go through my tubes, sort them out a bit. Too many to catalogue properly in one go (which is why i never bothered) Was never quite meant to become the hoard it is, but.. left Luxman with crates worth of stuff, left ML with yet more crates, then isn't life funny when none are what you "wanted" for your then current system a few years later, so there you go buying more when they were still crazy cheap. Then you buy yet some more, because what if, right? You haven't got everything. And, yeah Sorted four 24"x16"x16" crates full of NOS tubes. I'd say 6-7 more to go; some other time. It's 23:28 and i'm spent. (actually 60x40x40 in cents, but i figure that's close enough?) So far am going with input/output/rec, US-EU/RU. It's gonna take some time. One of many things i miss dearly? Proper packing cartons. Yes, really. Nothing decent in EU. ECT/load-rated? Don't even ask, they'll think you're so funny. Not sure they know what this is down here:
-
Car was set up for qualifying and also to defend on the straights during the race. However these conditions would have required more downforce. Despite not having the best strategy and the spin, still ended up P5 with that car. While it feels like he could be soon out of the championship fight, he might still have a big effect on who comes out on top at the end.
-
Megatron Electrostatic Headphone Amplifier
JoaMat replied to kevin gilmore's topic in Do It Yourself
With help of above Mini Hot Plate I managed to build another three small regulators. Here they are on a “motherboard” with rectifiers and electrolytics to achieve 12VCD. The trimmers are for adjusting output voltage, 2.5V for 2A3 and 5V for 300B. Now I want a regulator for 6,3V and 7.5V. The buck converter above is limited to 5.5V, so might try LMQ66430. @Shawn What inductor did you use with LMQ66430? -
Part 2 just dropped: Part 1, if you don't know it:
- 2,086 replies
-
- 2
-
-
- Golf Mafia
- M Sport
-
(and 1 more)
Tagged with:
-
Fakiros joined the community
-
-
Sending a hug your way @skullguise.
-
Spent the 4th up in Maine, our condo association had a mini-parade of kids and golf carts (~ a dozen carts, several made up quite well); also a pic of my next-door neighbor Michelle and her two - used to have 4 - Samoyeds, beautiful pups! Also visited one of Karen and my favorite places, Cape Porpoise....sat and contemplated life a bit there.