Baking pan tube amp sounds better than you’d expect

baking_pan_tube_amp

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.

[Thanks, Philippe]

[via RetroThing]

555 Two-fer – Baby swing upgrade and a Headphone tube amp

baby_swing_tube_amp

[Jason] sent in two 555 timer driven items that were worth sharing, both of which are entries in the 555 Design Contest.

The first item is a circuit that automatically resets an infant swing. [Jay], who built both items, has an infant swing for his daughter that spins a mobile and plays music. It’s great but it only works for 7 minutes and 15 seconds before a button push is required to trigger it again. He found this limitation to be annoying, and as I have owned the same swing, I can echo his frustrations. He probed the swing and found that a 5v pulse was required to reactivate the mobile, but it had to be sent after it turned off to have any effect. He put together a simple circuit that would do the button pushing for him, as you can see in the video below.

[Jay's] other entry is a headphone tube amp using a quartet of 6DJ8 vacuum tubes. The 555 timer in the amp is used to drive a FET and the hand-wound transformer he built for the amp. You can see a video of the amp in action below as well.

The projects are lacking a thorough write-up, but he does provide schematics for both the swing reset switch and the tube amp for those looking to replicate either item.

[Read more...]

Poddwatt: Tube amp with mp3 in mind

poddwatt

[Bruce] has designed a push-pull tube amp that has enough gain to connect to a portable audio player. The design is closely related to his OddWatt offering from a few years ago. The new amp has many redesigned circuits and the new hardware choices drop the price tag of the parts by about $50.

This little wonder pumps out 5-7 watts and [Bruce] is please with the end result. It doesn’t put out quite as much low-end as the KT88 amp we saw last year, but compared to some other iPod speaker solutions this provides stellar audio.