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I want to learn how to build a tube amp..

Discussion in 'Amps and Cabs [BG]' started by TylerDurdenPSSC, Jan 26, 2012.

  1. As the title says, I REALLY want to learn all there is about tube amplifiers in order to build my own this year.

    Not because nothing on the market floats my boat, but simply because they fascinate and intrigue me. I've never had better tone than through a vintage tube amp, and I'd love to reproduce that through my own capable hands. (That, and I don't have the $1500+ to just buy one either, lol.)

    This an in-depth project, that I've been eager to tackle for around two years now.

    Any links to literature, threads, or even people I could pm/call/E-mail for tips and suggestions?

    I'm shooting for something in the 100-200 watts range in the long run. Considering starting out with something in the ~50 watt range for my first build.

    Thanks for any and all constructive input!!!
  2. This venture is going to take a long time. I've been working with tubes for more than fifty years. Am I knowledgable? Certainly. Do I know everything about them? Not even close. I really doubt if there is anyone who meets that description. We're all still learning every day!!!
  3. kiwifrogpossum


    Jan 26, 2012
  4. And that is something I am 100% perfectly okay with!!! =D

    I figure; I love bass, and am a mediocre hobbiest at best... (maybe I'm short-sticking myself here, haha.) And man am I also a gear/tech junky! So then, what better to-do!

    Some people collect coins, cars, stamps... Girlfriends... Etc. I like to collect knowledge, I love to learn.

    I've been thinking about trying to break into the gear industry as a rep this year to pursue what I love, and I figure this could be a good test to see how much I truly love the field.
  5. Hhi.

    What Paul said.

    Here's a decent site to start from IMHO: AX84.com - The Cooperative Tube Guitar Amp Project

    And here's well more than a years supply of reading and learning from literature:

    Technical books online

    Personally, I'd say shooting for 50W from ground up as the "first" will only end in misery, 1-5W amp or just a pre-amp is much more satisfying first project.

    I'd also stay away from any kits, unless on the upper end of the spectrum, a lot of short-cuts there.
    And assembling a kit will teach You just that, how to assemble a kit. Doesn't necessarily teach You anything deeper than that.

    Modding an existing amp as a first project isn't such a bad idea either.

    But, as always with tube amps:


    Good luck.

  6. rust_preacher

    rust_preacher Supporting Member

    Dec 17, 2009
    I concur with "safety first". These projects are best done with your left hand behind your back. Don't even start before you know what I mean.

    I have built just one full tube amp and that took me several years to complete. The electronics part was actually easy, but the construction got to be something of a nightmare. The most difficult issues deal with the chassis and the transformers. You have to have reliably dimensioned and built-to-spec transformers, and a tried-and-true layout for the mechanical parts. Then you can have the chassis built. Be sure you have every little bit of the constructional details figured out before you have the chassis bent, welded, stamped, and drilled. It is much easier and safer to mount the transformers and tube sockets when you don't have to drill or whittle corners or whatever that creates metal dust particles that tend to get to hazardous places. Be sure that the layout is such that you can assemble the electronics from just one direction and where all electronic components can be accessed without taking out the wiring, mounting strips, or other parts physically (this means that you must be able to poke at every solder joint from the top).

    When you have these points worked out, I would say you are two thirds of the way there. For the actual circuit design, I would learn from the masters and do what they did at their time and whom everyone is more or less emulating for vintage tone. Leo Fender built his first designs from an RCA application note published in the 1940s.

    I hope you have a lot of fun with your project, and that you learn along the way, and eventually get to play though a rig you have built to your exact preference.
  7. I've actually been glancing over a few kits in the $300 range, so as to familiarize myself with the assembly process.

    I was also thinking about what I love in a tube amp in total. What kind of controls I want, layout, how easy it would be for others to operate without given direction, etc.

    I have always followed the KISS method in life, and have found it to be a successful method as well. I also find beauty in miniminalism. Over-complication is just that, over-complicated.

    I've given thought to also "cloning" the V4B at first as well. (Being my to-date favorite tube amp.) Then taking that design further by tinkering and changing this'n'that here'n'there.
  8. BogeyBass


    Sep 14, 2010
    Basically you need to understand how much voltage and current you need for the power transformer

    And depending on what tube and number of tubes what impedance and power handling you need from the output transformer.

    you can goof around with free goober designs from the net, or you can look at already established designs.
    My opinion you aint gonna reinvent the wheel, Fender Sunn Ampeg already figured it out long time ago.

    tube type is a preference for builder but I highly steer you towards beam tetrodes 6L6 6550 7027 or KT88

    6l6 x 4 80/100watts
    6550 x 4 160/200 watts

    good quad 6l6

    Bassman 100
    Bassman 135

    good quad 6550/7027/KT88

    Sunn Model T
    Ampeg V4B

    General Electric/RCA tube Data sheet will show you what voltages, current and impedance you need to get a push pull class AB1 amplifier its the most common for high power tube amps. the 135 and Model T being ultra linear, bassman 100 and V4B are not.

    6L6-GC , 6550 and attached 7027 the only data sheets you will ever need for a 100 to 200 watt bass amp. Look at voltages and current for a fixed bias AB1 pair on those sheets, double the current and half the impedance for a Quad for your transformers.
    Preamp design and output topolgy already done with the models I gave you.
    Good luck alot more to it, but a good start.

    Attached Files:

  9. bb5000


    May 30, 2006
    Sundsvall, Sweden
    I guess that I took the "crash course". I ordered the Weber AB200 kit in Nov 2009, studied the subject (mostly safety procedures, first startup etc) and started building when the kit arrived by mid-Jan 2010. Spent a couple of months with troubleshooting & tweaking, because the power transformer didn't follow the original specifications. Since then I have read a lot of books on the subject and I've joined a lot of forums where tube amps are discussed.

    Start with a small kit + read up on safety.
  10. As mentioned above, AX84 has a lot of great info. I don't attest to have a lot of experience building from the ground up, but I have found that it is much more cost effective to buy amps in disrepair (depending on the state...) and get them up to spec with new components. You learn a lot in the process, and to me it's a much more rewarding to take something that might just barely work and return it to its former glory.

    My current project amp is a 1965 Guild Thunderbird. It's going to be a pain in the ass to work on because it's got four reverse-mounted PCBs inside, and the tube sockets are on the boards. Picked it up for $160 though, so the overall cost burden is kept low. Same with my SB-12. Picked it up for $300, and everything was bone stock. Replaced caps, fiddled around with a bunch of other stuff, and it's running smooth thanks to helpful people in the Portaflex thread and a few other forums. My advice would be to either start really simple, or buy something that needs fixing. Get some experience under your belt and then dive in to the more complicated designs.

    Other sites to check out:
    Tube amp parts, Guitar Tube amplifier building supplies, Tube amp Information, Guitar amp parts
    Allen Amplification - Quality Tube Guitar Amps, Kit, Parts, and Repairs
  11. gerryjazzman


    Dec 31, 2006
    New Jersey
    From the Technical Books Online link that T-Bird posted, particularly look at the "Radiotron Designer's Handbook, Fourth Edition".

    Also, look at some of Kevin O'Connor's books (London Power Press):

    Tube Amp Books - Tube Amp Kits, Tube Amp Books from London Power

    Lots of practical knowledge to bridge from the theoretical, targeted at musical instrument tube amp design and construction. Some books are beginner level:

    Tube Amp Books - - Ready Set Go!

    Tube Amp Books - - Tonnes of Tone

    Tube Amp Books - - TUT - The Ultimate Tone

    up to more advanced topics.

    Also Morgan Jones's Valve Amplifiers Book:

    Amazon.com: Valve Amplifiers, Third Edition (9780750656948): Morgan Jones: Books

    Geared more towards Hi-fi, but lots of fundamental information about tube circuit design, components, etc.
  12. Just by glancing over a few of these pages... Awesome info guys!!! Thanks a ton!!! This is more than enough to keep me busy during my weekend away from the misses and work!!!

    Keep it coming!!! Lol.
  13. Interceptor


    Mar 29, 2005
    Madison, WI
    I've been learning for a long time, just like BassmanPaul. I'm just a few years younger. I've had projects work out great, and I've had a few clunkers. I think I learned more with the clunkers.

    My favorite references have been an RCA Tube Manual and my trusty 1968 ARRL Handbook. The guy I learned the most from was a "RADAR Man" from WWII who was also a ham and took me under his wing fixing televisions as a youth.

    I strongly suggest getting a copy of the RCA Tube Manual and an older ARRL Handbook. Hooking up with an old ham is also highly recommended.

  14. Luckily there's a great little HAM place about 20 miles from home. I've been planning a visit sometime soon.
  15. I'm probably going to try building a Fender champ clone (not a kit though) this summer, hopefully. My goal is to build my whole rig and my bass, but I think that might take a few years, if not decades... :p
  16. I had returned to this thread to suggest that the Tyler do just what post #16 from our Irish brother suggests. It's a simple project without too many stability issues and a fairly low B+ voltage. I've built a couple of my versions of the schematic using old obsolete amp combos. Both sound great with a skinny string or even a mic and a harmonica.
  17. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Even though I'm not a tube amp guy, I've done a lot of DIY electronics projects. In my view, safety is only one reason to start small. Another is that a smaller project will let you develop your soldering and debugging skills on smaller and less expensive components.
  18. JimmyM


    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Ya, I couldn't imagine debugging an SVT as a beginner!
  19. You wrote that you want to build a 200 W amp but think a 50 W should be your first build.

    A 200W amp will really only be marginally more difficult than a 50W amp. The difference in building a 200W amp being a beefier power supply (but in concept the same supply), a beefier output transformer (wired exacty as you would a 50W), and the fact that the push-pull power amp has multiple tubes in parallel instead of just one tube for each side.

    Even a 50 watt amp is too much for a first build.

    The major step in complexity comes between single-ended cathode-biased amps (single power tube, usually less than 10 watts), and push-pull fixed-bias amps (power tubes in push-pull pairs, all the higher power stuff typically 18 watts and up).

    Probably the best first build is something like a 5F1 tweed champ. Once that was build and de-bugged you could mod it into a 5F2A tweed princeton, and then a AA764 blackface champ. Just starting with a AA764 would be a reasonable thing to do.

    This will teach you basic layout, laying out wiring, twisting heater wires, high voltage safety...

    THEN you can step up to a push-pull like a blackface princeton or an 18 watt Marshall...

    THEN you will have enough experince in trouble shooting to attempt something like the Weber AB200 MOABA.

    Weber Original Design Kits scroll down to AB200

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