DIY Tube Amplifier

DIY Tube Amplifier

This kit may not be within the price range of a lot of DIY electronic junkies, but it would be a lot of fun to put together. The kit retails for $780 and should be available in March of 2008. You better brush up on your soldering skills before you try to put this one together. – [via] Link

Firefly PCB – Link
K-502 Tube amplifier kit – Link

22 thoughts on “DIY Tube Amplifier

  1. TD says:

    Now that’s GREEN! I wonder if I can get a power supply to run one in my Hummer.

    Tubes are soooooo 20th century!

  2. Monk says:

    You may have a point there, Tubes are old school. But they do sound nice.

    Your point of power draw is right on the money however. Wasting energy to be retro-cool is a dumb idea. It’s like having flames come out of your tailpipe by running the fuel mixture fat (rich)… cool looking, but kind of stupid really…

  3. Chris G. says:

    They may “waste” more energy as heat than a solid-state device, but tubes are still the gold standard for audio work, both for recording and reproduction.

    Energy efficiency is not a criterion for me; sound quality is. And the average incandescent light bulb wastes far more heat energy than even the most high-powered tubes a builder is likely to use.

    When they invent something better, I’ll use it. I could give a toss about “retro-cool.”

  4. SQ says:

    Yeah, and now you’re going to tell me vinyl sounds better, too. Do you know who I should call to buy the Brooklyn Bridge? I have this idea to set up a toll booth…

  5. DN says:

    @ SQ: Sorry, properly maintained analog gear, whether playing tape or vinyl records, is much higher fidelity than digital.

    There isn’t even any significant disagreement about this among audiophiles or recording engineers. If you have reliable, credible information that says otherwise, I’m sure we’d all be happy to hear it. It certainly would be news to a lot of people.

  6. Jason says:

    Another fun tube project is the SOHA – it’s half tube, half op-amp amplifier for headphones. It can be built for around $70 if you source the parts/pcb yourself:

    Also, people make kits for it:

    One advantage of the SOHA is you’re not dealing with hundreds of volts typically present in a lot of tube amplifiers, so it’s a good entry-level project.

    Another inexpensive option is the Little Dot line of tube amplifiers – those can be found on E-Bay. They’re made in China, but sound great for their ~$200 price. Granted you’re just buying the amp, and not really making anything.

  7. Monk says:

    I won’t argue the audio quality of tubes, I’ve never been a fan of digital. However I do think that a tube amp, with the big transformer et all does consume more power than a comparable solid state device.

    I’m working on using less power at the homestead, not more. So far got the monthly kilowatt down to 187kw

  8. Z says:

    @ DN
    There also isn’t any significant disagreement among audiophiles that the scientific method is useless… you know, things like how double blind testing should bow down to personal observation. Hence $5000 digital interconnects and power cables that even recording studios don’t use… not to mention $500 wooden knobs, magic foils, magic rocks, etc. As far as recording engineers, I haven’t seen any evidence that actual professionals hold the same biases toward tubes (and vinyl, etc) as audiophiles, but perhaps you could give a reliable, credible source for that claim?

  9. MadScott says:

    Cute project but *way* overpriced!! The parts count doesn’t justify this at all — it looks like they’re trying to get into the tubie sucker market mentioned by @DN above.

  10. David Feather says:

    Transformer size has little to say about the power it consumes in general. What matters is how the circuit it’s in operates.

    The main current draw in tube pre-amps are the heater circuits. Imagine a bunch of little light bulbs running at 5V, 6V, 12V, etc. Power amps need to drive low impedance speakers (generally somewhere between 4 and 32 ohms per driver). Solid state or hollow-state, that speaker needs the same power behind it to make it sing.

    Then it’s on to arguing the merits of current controlled voltage sources vs. voltage controlled current sources.

    As to analog vs. digital, open up a new file in your favorite open-source audio editor: Audacity. Generate a 15 kHz or higher sine wave at “CD quality.” Zoom in on the waveform. Does it still look like a clean sine wave? Ideally, in the analog world, it would.

    Now Audiophiles are just funny. Some people have more money than sense, no matter their hobbies. I can say many of the same things about photographers, artists, computer “gamers,” auto enthusiasts, or musicians.

  11. TD says:

    You vinyl and tube junkies have it all wrong with your newfangled contraptions. My Edison cylinder player is “da shiznit” – constant linear velocity recording and playback with no electronics to get in the way of pure, accurate reproduction. The vast majority of tube nutz have NEVER heard a cylinder player, the same way most of todays CD kiddies have never heard vinyl. You don’t know what you’re missing.

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