DIY Tube Amplifier

md_tube.jpg
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

Related:
md_tube5.jpg
Firefly PCB - Link
md_Amp.jpg
K-502 Tube amplifier kit - Link


Recent Entries

Comments

Oldest comments listed first.

Posted by: TD on February 13, 2008 at 4:07 AM

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

Tubes are soooooo 20th century!


Posted by: Monk on February 13, 2008 at 7:19 AM

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...


Posted by: Chris G. on February 13, 2008 at 8:04 AM

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."


Posted by: SQ on February 13, 2008 at 8:35 AM

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...


Posted by: DN on February 13, 2008 at 10:08 AM

@ 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.


Posted by: Jason on February 13, 2008 at 10:14 AM

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:

http://www.headwize.com/projects/cavalli2_prj.php

Also, people make kits for it:

http://www.glassjaraudio.com/category.sc?categoryId=3

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.


Posted by: Monk on February 13, 2008 at 10:36 AM

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


Posted by: Z on February 13, 2008 at 10:41 AM

@ 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?


Posted by: MadScott on February 13, 2008 at 11:24 AM

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.


Posted by: David Feather on February 13, 2008 at 1:15 PM

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.


Posted by: TD on February 13, 2008 at 10:58 PM

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.


Leave a comment


Subscribe to MAKE!Subscribe to MAKE Magazine!

Subscribe today, save 42% and get web access to MAKE free. MAKE Digital Edition is available only to subscribers.

$34.95 / 1 year
(4 Quarterly Issues)

Subscribe now


Void your warranty, violate a user agreement, fry a circuit, blow a fuse, poke an eye out. Make: The risk-takers, the doers, the makers of things... Welcome to Make: Online!


CRAFT Maker Shed Maker Faire MAKE television
Holiday Gift Guides from MAKE
Gifts for Dads
Science and Chemistry
Gifts Under $20
More guides: Santa Claus Machines, Geek Toys for Grown Up Girls & Boys


Check out all of the episodes of Make: television

Alex Rider Dream Gadget Contest
Make: Science Room

Connect with MAKE

Be a MAKE fan on Facebook MAKE on Facebook
Visit our Facebook page and become a fan of MAKE!
MAKE on Twitter MAKE on Twitter
Follow our MAKE tweets!
MAKE Flickr Pool MAKE on Flickr
Join our MAKE Flickr Pool!
    make_tips on Twitter




    Maker SHED

    Advertise here with FM.

    Why advertise on MAKE?
    Read what folks are saying about us!

    Click here to advertise on MAKE!



    Subscribe to MAKE Magazine!

    Make: Online authors!

    Gareth BranwynGareth Branwyn
    Senior Editor


    Phillip TorronePhillip Torrone
    Senior Editor
    | AIM | Twitter


    Becky SternBecky Stern
    Associate Editor
    | AIM | Twitter


    Marc de VinckMarc de Vinck
    Contributing Writer
    | AIM | Twitter


    John ParkJohn Park
    Contributing Writer
    | Twitter


    Sean RaganSean Ragan
    Contributing Writer
    | Twitter


    Matt MetsMatt Mets
    Contributing Writer
    | AIM | Twitter


    Dale DoughertyDale Dougherty
    Editor & Publisher
    | Twitter


    Shawn ConnallyShawn Connally
    Managing Editor
    | Twitter


    Goli MohammadiGoli Mohammadi
    Associate Managing Editor

    Kip KayKip Kay
    Weekend Projects
    | AIM | Twitter


    Collin CunninghamCollin Cunningham
    Contributing Writer
    | AIM | Twitter

    Adam FlahertyAdam Flaherty
    Contributing Writer
    | AIM | Twitter



    More contributors: Mark Frauenfelder (Editor-in-Chief, MAKE magazine), Kipp Bradford (Technical Consultant/Writer), Chris Connors (Education), Diana Eng (Guest Author), Peter Horvath (Intern), Brian Jepson (O'Reilly Media), Robert Bruce Thompson (Science Room)

    Suggest a Site!

    Current Podcast

    itunesdl.gif Weekend Project: Beetlebot Simple robot from your parts bin that avoids obstacles. Thanks go to Jerome Demers for the original article in MAKE, Volume 12. To download the Beetlebot video, click here or subscribe in iTunes. Check out the complete Beetlebot article... More...

    Get the Make: Online sent via email
    Enter your email to receive Make: Online each day:



    MAKE Fascination video series brought to you by Dow

    Make: Education
    MAKE: en EspaƱol MAKE: Japan
    Important please read


    Subscribe to MAKE Magazine!

    Recent Posts from the Craft: Blog