Why, oh why, oh why do people toss out awesome retro hardware?? Luckily, [Dino] visited the junk depot himself at just the right time. Even though you’re not supposed to take things others have dropped off he poached the retro portable turntable that was just sitting there. He cracked it open and figured out how to turn it into this great tube guitar amp without going to all that much trouble.
The original turntable used to be where the front grates are in the image above. The guitar amp version sits the case on end, which works perfectly since the carrying handle is now on the top. This orientation would have put the amplifier hardware upside down, so [Dino] pulled it out and flipped it around. The speakers for the turntable were made to sit separately and be connected with wires. But they also doubled as a lid for the unit. This makes them the perfect size to fit side-by-side in the void left by the turn table.
[Dino] records his own music for the build video after the break using his new hardware. Sounds great, looks great, and it was saved from being needlessly buried in the ground. Fantastic!
Continue reading “Junkyard tube-amp gold!”
A few years back, [Gio] decided to try his hand at building a couple of tube amplifiers.
The first amp was more of an experiment to see how well a DIY single-ended tube amp would sound. The amp is based off the 6T9 design created by Spare Time Gizmos, and incorporates a pair of 6T9 vacuum tubes, hence the name. He wired things up in an afternoon, then got busy drilling holes in a baking pan, where he mounted the amp. Bear with us for a second, it’s not as bad as it sounds. The amp actually looks pretty good mounted in the dark black steel, and this sort of enclosure is far cheaper than most DIY amp enclosures. He says that he was sure to be extra careful in isolating all of the electronic components from the metal chassis.
The second amp was built to test the performance differences between Pentode-mode and Ultra-Linear mode configurations. While both amps share a substantial amount of the same components, his UL amp benefits from slightly better capacitors and an uprated power supply, not to mention a more conventional case.
Both amps sound great, according to [Gio], but should be paired with efficient speakers for the best experience. He does note that the ultra-linear amp is the better choice, mounting options aside.
The researchers at Brookhaven National Laboratory are looking for a way to harden photomultiplier tubes. In order to make a more durable tube the researchers decided it would be a good idea to first observe how the tubes are failing. So they got their hands on an old torpedo test bay and smashed some bulbs inside of it. Check in after the break for some high fps bulb smashing.
Photomultiplier tubes are used in massive quantities to detect the highly elusive neutrino particle. The problem is when you have 50,000 photomultipliers submerged in pressurized water the the collapse of just a single bulb can cause a shock wave of destruction. This is what happened in japan in 2001 when a maintenance worker unknowingly compromised a single bulb in a 11,000 bulb array. When the tank was repressurized that single compromised bulb caused them to lose 7,000 more.
Continue reading “Imploding Vacuum tubes for science”
[Tristan Chambers] picked up an old speaker box some friends acquired at a yard sale. It didn’t have any inputs, and there weren’t any tuning knobs like a radio would have, so it’s a mystery what this was originally used for. [Tristan] traced out the circuit and figured out where he could input audio signals which allowed him to hook up an iPod, but it was mono and not very loud. He ended building his own vacuum tube preamp from a schematic he found on the Internet so that he could use it with an electric guitar. As the video after the break shows, the box not only puts out some pretty good sound but it’s nice and loud too.
Continue reading “Guitar tube-amp from junk hi-fi”
[Alessandro Lambardi] had some vacuum flourescent displays that he pulled from junked VCRs. His latest project is an experiment to use one of the VFDs as a headphone amplifier (Wayback Machine Cache). This means he’s trying to use them as vacuum triode amplifiers, aka vacuum tubes. He did get it to work but as he suspected, the output is fairly low power. It may be possible to use this setup as a preamp and build an actual tube amp to use along with it.
Update: Thanks to [Fallen] for mentioning that we’ve covered this concept in the past.
Quick quiz, what came before transistors? Why vacuum tubes of course. If this clock doesn’t make you thankful for the luxury of integrated circuits, nothing will.
We had never heard of using Neon Lamps as logic circuits, and they definitely produce a much cooler effect when counting.
And finally, we’re just suckers for a good Nixie Clock. The scope clock is also pretty interesting.
[Gio] enjoys using vacuum tubes in his projects. He designs the circuits using a CAD program but was finding that there is no substitute for actually building a prototype before heading to a final design. To make this process easier, he built his own tube prototyping station.
At the top of the board he’s got three different sizes of tube sockets with the pins from each wired as common. The nine pins from the sockets break out to a terminal strip where they can be interfaced with a solderless breadboard. For added versatility he’s included terminals to tap into some RCA jacks, as well as a 100 kOhm variable resistor. We’d bet this is not something that you can find ready-made, but it sure does look a whole lot better than a workbench full of components alligator-clipped together.