Big-name tube amplifiers often don’t come cheap. Being the preserve of dedicated audiophiles, those delicate hi-fis put their glass components on show to tell you just how pricy they really ought to be. If you just want to dip your toe in the tube world, though, there’s a cheaper and more accessible way to get started. [Jenny List] shows us the way with her neat headphone amp build.
The build starts with an off-the-shelf preamp kit based around two common 6J1 tubes. These Chinese pentode valves come cheap and you can usually get yours hands on this kit for $10 or so. You can use the kit as-is if you just want a pre-amp, but it’s not suitable for headphone use out of the box due to its high-impedance output. That’s where [Jenny] steps in.
You can turn these kits into a pleasing headphone amp with the addition of a few choice components. As per the schematic on Github, a cheap transformer and a handful of passives will get it in the “good enough” range to work. The transformer isn’t perfect, and bass response is a compromise, but it’s a place to start your tinkering journey. Future work from [Jenny] will demonstrate using a MOSFET follower to achieve much the same result.
We’ve seen a great number of headphone amplifiers over the years, including one particularly attractive resin-encased example. Video after the break.
…audiophiles…
Say no more !
Well, yes. This isn’t an audiophile project though, it only cost a few dollars, there’s no oxygen free directional wotsit, and those sockets aren’t gold-plated.
Here’s Jenny’s original article on this tube amp circuit, assembling the kit and then characterizing it:
https://hackaday.com/2020/09/01/that-elusive-valve-amp-sound-for-not-a-lot-there-has-to-be-a-catch/
Damn, I should have mentioned that in the video. Thanks.
This is just such an aesthetically pleasing build!
Thanks !
I want my audio distorted and not sound like source material, because that means quality!!1
Tell me you’ve never heard good tube equipment without telling me you’ve never heard good tube equipment.
I need the like button for this one!
Valve equipment seems bad in the numbers but great to the ear’s, nobody’s can deny this fact. It’s like an old car versus a new one, the new car has better numbers in anything but the old car has a better feeling for the car enthusiast.
They do sound good, agreed, even better when they’re “played” by the musician but “Sounds good” and HiFi aren’t the same thing and if the purpose of playback equipment is the faithful reproduction of the original source then valve amps cannot even come close to being called HiFi because they add to and change the sound.
Most quality tube gear THD is at inaudible levels anyway, so it really doesn’t account for much outside “measurement races”. My main tube preamp and amp are rated at 0.08% and 0.5% respectively, and I can’t hear any more distortion with them versus my main solid state setup rated at 0.005% per component. What I can hear with the tube setup, however, is hugely better holography and more human-like vocals and a much more realistic midrange, as well as less harshness on the top end. I swapped in some Chinese KT88s and, after burning them in, vocals are eerily realistic… and stereo imaging is the best I’ve ever heard on any setup over the years. Granted, the tube setup cost more than many people spend on their cars, but I’m okay with that.
I’m not an “audiophile”, since I don’t subscribe to “cable voodoo” or use nonsensical words to describe inaudible changes in sound… but I do know how to do critical listening with reference albums and comparative listening.
“Lesser” tube gear will absolutely color the sound and change the presentation, but when you get in the high end space it’s an entirely different animal. Obviously there’s a point where diminishing returns come into play and spending another $20k doesn’t get you anything more than a handful of empty promises. Many “lesser” tube amps and preamps deliberately color the sound to make the presentation “warmer”, some even add distortion with a buffers or weird topology, but high end stuff aims for the cleanest signal path possible. Many high end tube setups don’t have a “tube sound” even.
There’s a lot of subjectivity in this space, but I’ll take the “Pepsi Challenge”, pitting my tube setup against similarly priced solid state setups any day of the week, and challenge anyone to correctly and reliably identify (much less hear) any negative audible differences on my end. At the end of the day I think the most crucial “measurement instrument” is our own ears. This craft is supposed to be about listening to your music and seeking that emotional connection, but most “audiophiles” get stuck in listening to their gear. If it sounds good to you it’s a win in my book.
Yay, word salad complete with nonsense terms used unironically while in the same response you claim to not use nonsensical terms!!!!!
Extra points for the nonsense use of the word ‘holography’ as substitute for the (deservedly) mocked and cliched ‘broadened 3d sound stage’ while also denying you’re an audiophile but perfectly describing yourself as such.
The irony is just what I needed to round off my work day with a wry smile.
i just wish i understood how the tube amp improves the sound if it doesn’t alter it
The only measure I care about is what the audio analyser says, and a good quality tube amplifier can give a good account of itself there.
This however is not a particularly good tube amplifier. For $15ish, are you surprised?
There is nothing wrong with making audio equipment with tubes.
Part of the challenge is getting good results with the design constraints of tubes and transformers.
Just ignore the audiophile lore about paper capacitors, and eliminating negative feedback.
Long time Hackaday readers will know I enjoy poking fun at audiophiles.
headphone amplifiers, and good headphones (Senns or Etymotic or something) are the absolute cheapest and best bang-for-buck dollar (euro? pound?) you can spend. For the $10 this thing will set you back- give it at try. worst case is a fun well documented project. Best case (like when I went to a dedicated headphone amp and never went back) is you listen to a record you’ve listened to a thousand times and it is way, noticeably better. thanks
Years ago I did a contract, doing technician work and a small amount of PSU work for the designer of a set of electrostatic headphones. So I spent several months sitting at a bench working and listening to a pair of 7k ‘phones. Amazing quality, but in a way they were too good. You heard far too many spitty sounds in vocals I’d kinda prefer not to.
I got one of these kits a few years ago, built it and ran it exactly once to make sure it worked. I’ll have to dig it out and try this since it’s just sitting there doing nothing anyways.
happened to have once whimsically placed a tube headphone amp between my stratocaster and my extremely cheap amp, so it was functioning as a pre amp. absolutely astonishing how much it improved the sound. noise / hum went away almost completely and the dynamic contrast became clearer. not sure what the exact reason is but i imagine the input stage on my cheap amp was creating a ton of problems that were all masked when its upstream source was willing to drive a little current.
easy to imagine the same is true about the output stage on my laptop’s headphone jack but hard to imagine toting around a separate heaphone amp :)