Tuba – Vacuum Tube Headphone Amplifier – Hagerman Audio Labs

The Tuba is a world class vacuum tube headphone amplifier designed to work with either low impedance (grade) or high impedance (sennheiser) headphones. The power stage is a single-ended, feedback-free EL84 triode, para-fed into an impedance-matching transformer, offering very low distortion and huge signal headroom. An internal switch-mode power supply creates a stable high voltage for the tubes after a 30-second warm-up delay. The amp is conveniently turned on and off by pressing the volume knob in. the sounds are warm, organic, punchy and extremely non-fatiguing. fantastic with iems.

wood panel upgrade now available!

Reading: Tuba headphone amp


  • 50k ohm input impedance
  • 5/35 ohm output impedance (low/high)
  • 10hz to 150khz bandwidth ( -3 db)
  • 350 mw output power at 32 ohms
  • 7 vrms output voltage (high)
  • 6 db gain (high)
  • 3.5vrms input sensitivity
  • 0.25% distortion @ 0dbv 400hz
  • el84 x 2
  • 6 x 10 x 3.5 inches
  • 7 pounds
  • 15vdc @ 1.35a
  • 120v/240v operation
  • includes power supply & tubes

See also: What is a Headphone Amplifier? Do I Need One? | LedgerNote

scope photos show nameplate voltage at 170 vpp tube changes before start of soft cut; square wave output at 10khz into 33 ohms.

Tuba - Vacuum Tube Headphone Amplifier - Hagerman Audio Labs

See also: 5 Best AM/FM Radio Headphones In 2022 (Old School Meets High Tech)

Tuba - Vacuum Tube Headphone Amplifier - Hagerman Audio Labs


  • user manual
  • wood panel instructions


See also: High-impedance headphones: your guide to buying your first pair of audiophile cans | TechRadar

  • george dobrescu, audiophile-heaven
  • herb reichert, stereophile
  • mi, head-fi.org
  • matty, headfonia
  • bob levi, positive feedback
  • trav wilson, headphonesty
  • aa, headphones.com
  • “the combination tuba-degree created an order, naturally detailed and very musical sound that I found 100% enjoyable. the midrange tone was exemplary.” – herb reichert
  • “the tuba rewards the listener with a rich, luxurious tone, but will still be happily on par with all but the most advanced amplifiers in terms of resolution and musical insight” . – matty
  • “I used 14 pairs of headphones with the tuba, and not a single one misbehaved… my audeze lcd-x and lcd24 headphones, which were too revealing for an amp like this, so I thought — they were absolutely lovely…the tuba is much better than its price would indicate, built by a master designer and tuned for superior performance…overall performance was consistently excellent with strong, colorful imaging and undistorted power.” – bob levi
  • “unsurprisingly, the tuba is a very well mannered and never-tiring listening amp…throughout my time with the tuba, I found it to be very laid back and not – aggressive.it’s an easy amp to appreciate and listen to for long periods…indeed the tuba sounds great with very sensitive in-ear monitors (iems) like the kz zs10 pro.it has a very low noise floor and doesn’t add any hiss unwanted to playback, something I can’t say about it to most other desktop amps i use…i can happily report that the sr325 grade has never sounded better with any other amp i have tried. the relaxed sound of the amp coupled with the brighter grade signature is an excellent combination. It reminded me why I fell in love with the house sound in grade school the first time… the tuba is a unique product. It really doesn’t remind me of anything else currently available. the combination of tube warmth, courteous sound, highly efficient headphone compatibility, and cross-feeding will make it ideal for some, but not all. it certainly brings something different to the table for someone who currently owns an otl tube amp.” – trav wilson


  • “it really is an amazing amp. totally unlike any amp i’ve ever used. it quickly became my most sought after.”
  • “the tuba and stellia are an amazing pairing. the stellia sounds wider and warmer while still being very detailed. i would absolutely recommend the tuba if you have the stellia. i swapped tubes and had it on low gain.”
  • “listened all weekend .regarding what I currently use there is a very clear improvement, which I would sum up in a sense of purity in the sound (transparency, absence of noise and absence of distortions) it is extremely pleasant, detailed but not aggressive (as it should be). really impressed.”
  • “just wanted to let you know that my tuba arrived safe and sound this morning. even out of the box it sounds wonderful. it’s accurate, musical and overall very nice. can’t wait to integrate fully and see what time will reveal.”
  • “I really like I would like to convey my total gratitude to the work you have put into making a work of art. the tuba has exceeded my expectations. I have found several tubes that fit my subjective tastes and I thank you. this has been amazingly paired with my zmf verite closed ltd in leopardwood which you get with an ifi idsd micro bl”.
  • “I recently received my tuba headphone amp. I must say that so far I am really impressed. I feel like my hifiman headphones have really come to life. I am completely satisfied with my purchase.”
  • “The tuba arrived today and was very well packaged…not a single blemish on the unit. listened for a few hours and this brought my hd650 back to life… like a perfect match. Now I’m going to let these tubes burn some more. so far listening to the hd650 on the tuba has been an amazing experience. thanks again for the amazing product and excellent customer service. :-)”
  • “I’ve never had a tube amp before, but listening to it was amazing. pairs nicely with an aeolus. I’ve never heard an amp sound this good. you weren’t kidding about world class. gave me chills. It was worth the wait!”
  • “My favorite combination of all the headphones I’ve used was the clear focus on the low output, with the clear tonal balance and clarity that matches the output of the tuba absolutely wonderful. near audio perfection here with a $649 amp. the combination could be described with all those hot adjectives, but the one that sticks out is the ‘clarity’ of the combination of the two, but the ‘sound’ of the tuba makes the clear ones shine…like a lightsaber and I’m talking about a tube amp! this amp, compared to other tube amps, removes another layer of the “veil” that stands between us and a real live performance. the tuba’s most admirable trait is its clarity and its wonderful ability to help articulate everything on a recording. this clarity comes from a very quiet tube amp, when you listen you hear nothing from the amp, just the music good or bad.”
  • “i think the tuba will appeal to those who have invested in expensive items; they can use them with a portable device on the go, however, they want better amplification for these items to listen to at home. with many iems costing $1000 or more, the tuba can tap into the growing iem market and is a bargain given its build quality, performance and 10 year transferable warranty!”
  • “you have designed and built a wonderful amp and the price is so reasonable! I am amazed by its ability to reproduce the harmonic qualities of the range of musical instruments, mainly acoustic. I mainly listen to classical music and I have to say that the pianos, which are very difficult to record, sound very good and are different from each other (ny steinways, they sound different from the steinways in hamburg and the fazoli are monumental).”
  • “I just received the tuba and am listening to it as I write. You have created another winner with this amp. quiet background with great musicality and detail recovery, but completely non-fatiguing.”

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