valve

Replacement Valves for Munchkin Cups - 3 Pack
$2.95
Kids love our Munchkin cups so make sure you always have some replacement valves on hand in case one comes loose or you lose it during washing. These patented, one-piece, easy to clean silicone valves fit all Munchkin spill-proof cups. They make drinking easy because the liquid flows through the valve only when your child takes a sip. That's why moms love our cups almost as much as their kids.

Valve Handbook (McGraw-Hill Handbooks)
$131.00
Offers complete coverage of the operation, application, and pros and cons of today's newest smart valves with digital positioners and actuators. Also includes updates on HART and FieldBus valve technology. For mechanical engineers. Previous edition: c1998.

Portal: Still Alive [Online Game Code]
$15.00
Portal has won many awards since its launch in 2007, and when you play it, you'll agree that it deserves them. It's ingenious and compelling, a masterpiece easily at home in an all-time greatest games hall of fame list.

Despite many recommendations from friends, I initially avoided getting this game for two reasons. Don't make this mistake! It's a fantastic game, and neither of my concerns proved to be important.

First, I thought Portal was a first-person shooter (FPS), and I don't like FPSs or games requiring lightning fast reflexes, so I almost skipped it. Portal was originally released as part of "The Orange Box". The Orange Box was a disc-based game for Windows, Xbox 360, and PS3 which bundled 5 games in 1. The other 4 games in the bundle were well-known FPSs which had been released previously (Half Life 2, 2 add-ons for Half Life 2, and Team Fortress 2). In that company, one might assume that the 5th game in the bundle, Portal, was also an FPS. In fact, Portal is not an FPS at all, but a first-person 3D puzzle game, and one of the most original and ingenious puzzle games in years. Each level introduces you to new game elements and increasingly difficult puzzles, with many wonderful "aha!" moments. Fast reflexes aren't required, but brains definitely are. Others might assume that, as the "fifth wheel" in The Orange Box bundle, Portal would be a give-away title not worth trying to sell or advertise. Nothing could be further from the truth. Despite the obvious success of Half Life 2, many game players and critics alike would argue that Portal is the strongest game in The Orange Box bundle.

Once I knew I wanted to try Portal, I again delayed my purchase because I wasn't sure which version to get. Should I get "The Orange Box", which costs more, comes on disc, and contains 4 FPSs that I probably won't play? Or should I get "Portal: Still Alive", which costs less, is downloadable, and comes with a few extra puzzles but no bundled games? The answer is: it doesn't matter, either choice is great, and it's up to personal preference. If you also like FPSs, The Orange Box is definitely a great value. I personally prefer not having to keep a disc in the drive, and will gladly take even a small amount of extra puzzling content over an FPS, so this downloadable version was best for me. See my comment on this article for a detailed list of differences between the two versions. Regardless, don't let indecision about the platform/version hold you back, like it did me. You can't go wrong with either one!

Now, I want to briefly describe the game and what makes it great. The premise and basis of all the puzzles is that there is a new technology that allows you to open "portals" between virtually any two flat surfaces. Imagine opening a magic door that connected the wall in front of you with the wall behind you -- you could look through this door and see your own backside. Now what if you opened a magic portal connection between the floor and ceiling -- and stepped through. Now what if you open a portal connection between walls at different angles and jump through -- your momentum will carry through but gravity will shift your ballistic trajectory. The possibilities are endless and mind-boggling. Fortunately, the game eases you into the concept, along with other game elements, and by the end you're an expert, ready for the major challenges ahead. (Once you solved the game, try looking at online videos of pros playing the game; you'll be blown away by what experts can do with portals.)

But the other great thing, which isn't common for puzzle games, is the understated but excellent plot and backstory. Throughout the levels, you get a few hints that something bigger is going on here, and that maybe beating the levels shouldn't be your first priority. I'll avoid spoiling it and leave it at that. But I can't help but mention the superb cherry on top, which is a very gratifying end credits scene with a catchy original song, which you'll probably want to view/listen to over and over again. You can find this song and its lyrics online (and in games like Rock Band 2), but they won't make sense or carry any emotional weight until you've solved Portal. I'm also told the plot ties in with the larger Half Life universe, but as I don't like first-person shooters, I didn't catch those references.

I can't recommend this game highly enough. If you haven't played it yet, run, don't walk, to enjoy this treasure.

Valve Amplifiers, Third Edition
$62.95
The second edition of this book was the first book on tube amps I ever read. I borrowed it from the local library. I can not say that I understood all the concepts then, but for some reason whenever I had returned the book to the library there was something I had to look up, so I bought the third edition.

There are not very many good tube books out there, you can believe me because I have read everything from the 1956 RCA tube manual to most of the modern books on the subject.
This book is not perfect. It has the tendency to hide a lot of information in the text instead of making a clear presentation from point A to point B. It assumes that you have read all the preceding chapters and have them fresh in your head because there are explanations on things in chapter 13 that is based on stuff in chapter 3 with no references what so ever.

That said, I think this is probably the best place to start. It has lots of information that is relatively easy to grasp.

If you are more interested in guitar amplifiers, then I would not recommend you to start with this book. It has all the basic information you need to design a guitar amplifier, so it is not bad reading, but I would recommend you to buy "The Ultimate Tone" series (probably start with volume 3)by Kevin O`Connor instead. Because it explains more of the guitar concepts, such as how to make distortion sound good.

If you want to design tube amplifiers I recommend this book. Even though I have many tube books this is the one I always come back to when I want to look something up.