Pair this kit with a Raspberry Pi for the DIY headphone amp of your dreams

Hybrid Tube Amp for Raspberry Pi
For a long time, standalone DACs (digital to analog converters) and headphone amps were something only audiophiles bothered with. Now, with the resurgence in popularity of headphones, they’re getting more popular — but they still aren’t cheap. A new project on Kickstarter, however, has both audio enthusiasts on a budget and hardware nerds excited.

The 503HTA Hybrid Tube Amp by Pi 2 Design looks similar to other kit-based tube amps, but this one has a trick up its sleeve: it uses a Raspberry Pi — supplied by the user — for its brain. The kit itself is HAT — hardware-on-top — compliant in size, and is compatible with any 40pin Raspberry Pi models.

The board uses a 24-bit PCM1502A DAC to drive a 12AU7 tube gain stage capable of driving headphones from 32 to 300 ohms. Output is switchable between approximately 2V, 4V, and 6V — though this will vary based on the tube used — to tailor the amp to specific headphones. The 503HTA also includes Output Relay protection to prevent audible “thump” sounds when the power is turned on.

Early-bird pricing had the kit available for $99, but that has already sold out, as did both $110 tiers. At the time of this writing, a $120 tier is available, but is limited to 100 backers and is quickly running out. When that happens, backers will have to spring for the $150 tier. Both of these tiers offer the amp itself, power supply, acrylic case and mounting hardware, and a choice between a JJ 6DJ8 (ECC88) or JJ 12AU7 (ECC82) tube. Additional tiers are also available, offering a pair of kits.

The initial funding goal for the 503HTA Hybrid Tube Amp was $20,000, and only a few days into the campaign, it has already raised more than 250 percent of that original amount, nearing $55,000 at the time of this writing. Pi 2 Design has introduced one stretch goal, unlocked at $75,000, which will add a pair of adapter cables with each kit shipped: one 3.5mm to 1/4-inch to allow high-end headphones to be plugged in, and one 3.5mm to stereo RCA to allow the amp to be plugged into other stereo gear.

The campaign will come to an end on Monday, June 6, leaving potential backers plenty of time to pledge. For more information, see the campaign page on Kickstarter.

Home Theater

Puro’s kids headphones don’t just sound great, they help prevent hearing damage

Puro Sound Labs' PuroQuiet headphones are a pair of noise-canceling over-ears that are designed for young listeners, allowing them to jam out to their favorite tunes, but limiting volume to avoid long-term hearing damage.
Trash

Experience true immersion with these top-notch PS4 headsets

You don't have to stick with a shoddy headset because it came bundled with your console. These are the best headsets for the PlayStation 4, whether you're in the market for virtual surround sound or merely a comfortable build.
Trash

The best MP3 players of 2018 cram tons of music into a small package

Want to go for a run, but your phone is weighing you down? Don't sweat it. Can't fit your whole music library on your smartphone? No worries. Check out our list of the best MP3 players, and find one that works for you.
Gaming

How do Nintendo Switch, Xbox One X compare to each other? We find out

The Nintendo Switch is innovative enough to stand apart from traditional consoles, but could it become your primary gaming system? How does the Switch stack up against the Xbox One?
Trash

Looking to get into shape? Snag one of these fitness trackers

Looking for your first fitness tracker, or an upgrade to the one you're already wearing? There are plenty of the wrist-worn gadgets available. Here are our picks for the best fitness trackers available right now.
Home Theater

From the Roku Ultra to the Fire TV Cube, these are the best streaming devices

There are more options for media streamers than ever, so it’s difficult to pick the best option. But that’s why we're here. Our curated list of the best streaming devices will get you online in no time.
Home Theater

Amazon’s free Spotify competitor is here. Just ask Alexa

Just ask Alexa to play your favorite song. Amazon has launched a free, ad-based music streaming service to compete with Spotify's free tier on its popular Echo devices, aiming to bolster subscriptions to Amazon Music Unlimited.
Home Theater

The best TVs you can buy right now, from budget to big screen

Looking for a new television? In an oversaturated market, buying power is at an all-time high, but you'll need to cut through the rough to find a diamond. We're here to help with our picks for the best TVs of 2019.
Home Theater

Throw away those EarPods -- we dug up the best headphones in every style

Trolling the internet for hours to find headphones is no way to live. Instead, leverage our expertise and experience to find the best headphones for you. Here are our favorites, with all the features you want.
Home Theater

Still listening on tinny, muffled TV speakers? Try one of our favorite soundbars

You no longer have to sacrifice sound for size when selecting home audio equipment. Check out our picks for the best soundbars, whether you're looking for budget options, pure power, smarts, or tons of features.
Deals

Walmart deal drops the price of the 55-inch TCL 4K Roku smart TV to just $338

Was last weekend's Game of Thrones streaming experience lacking? Look no further than this 55-inch TCL TV, which features built-in Roku functionality, and can be had at Walmart for just $338.
Music

YouTube Red is now YouTube Premium. What's changed, and should you subscribe?

Thanks to Google, YouTube Red is now YouTube Premium. We explain what exactly a YouTube Premium subscription gets you, how much it costs, and break down if it's a good choice for you.
Product Review

Now that every speaker has Alexa, don't you want the best? Get the Sonos One

To compete in smart speaker space, Sonos could have just made a better-sounding Alexa speaker, but the company has a reputation to uphold, and went much further. Our Sonos One Review reveals how Sonos does Alexa better than Amazon.
Product Review

It sounds like a Sonos, but the Beam pulls one trick none of its siblings can

Sonos makes really good surround sound speakers for home theaters, but they’re expensive. A cheaper model with great sound would be a win. The Sonos Beam is that speaker, but were too many corners cut to make a more affordable product?