Yes, you read that right, and yes, I've taken my pill, so I'm not as crazy as I seem (?). We've talked on multiple occasions about the flexibility of the Raspberry Pi, but someone came to the fabulous conclusion that the only thing missing was turning this popular mini computer into a tube amplifier. It's the 503HTA, a hybrid amplifier by Pi 2 Design, which can be connected in four different models of the Raspberry Pi without difficulty.
Imagine you've invested a significant amount of money in your new headphones, but now you feel you need a little more hardware up to the task. I'd guess a Raspberry Pi would be the last place you'd think to look. After all, there are many specialized amplifiers out there, and although the Raspberry Pi is used in a great number of projects, the idea of creating an amplifier with it doesn't appear on any priority list. However, what we must not forget is the brilliant expansion capability of the Raspberry Pi. Just like with Arduino hardware, a compatible module can transform a Raspberry Pi into something completely different, and that's what brings us to the 503HTA, a hybrid tube amplifier that sits on top of the mini computer.
Technical Specifications
According to the official information, the amplifier uses a 12AU7 or 6922 tube, but thanks to its multiple adjustment options (including switches to change gain) it should be possible to install other similar tubes. The amplifier can be connected to headphones with an impedance from 32 to 300 ohms using a 3.5mm output. It is based on the well-known Bravo V2 amplifier (with several modifications incorporated, including the use of an IRL510 MOSFET), it has Nichicon MUSE series capacitors for audio applications, and despite its compact design, I'm sure several electronics enthusiasts will be able to replace components and alter components if necessary. The compatible Raspberry Pi models are A+, B+, 2 B, and 3 B.
Funding and Availability
From a technical point of view, it's not the first time someone has tried to arrange a meeting between a Raspberry Pi and tube technology, but the 503HTA makes the process of acquiring the amplifier much simpler, or rather, that is its intention. Its creators turned to Kickstarter to finance the construction of the amplifiers, and they have already received more than $78,000 against a base of $20,000. The campaign started at a price of $99 per amplifier, but after that option sold out, now interested parties will have to invest $119 with worldwide shipping. First deliveries, between July and September.
