I want to build a tube amp

fast14riot

fast14riot

Joined
Oct 27, 2010
Messages
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With winter coming up quickly here I'm in need of a new winter project. I'm a low budget audio kind of guy, I like to tinker, I can solder (electronics), and have never owned any tube audio equipment. So, I thought about building a tube head phone amp as my first project. I found some schematics and sparse instructions for low voltage, single 12AU7 amps but I am having a difficult time following many of the write-ups because they assume most have a background in electrical engineering (or at least more than I have).

Does anyone have a good site or book recommendation with very thorough, hold-your-hand step by step instructions? I fully admit to being a newb to this stuff, and know that even low voltage tube applications can still have dangerous potential, I also will be sure to check and double check all safety precautions when doing a project like this.

Ideally, I would like to keep the project around $50, which I believe is very feasable.


-Xander
 
shunsui said:
Google is your friend. I've seen more basic instructions for tube guitar amp electronics over the years.
You might find this an interesting beginning project.

http://diyaudioprojects.blogspot.com/2009/11/diy-vacuum-tube-prototyping-board.html
Click to expand...

I've been googling a bunch, the less expensive tutorials are a little more advanced than me currently and the kits I see being touted as great are $300 and up. I don't need a premade enclosure, I can do that, but some very thorough instructions and part lists would be excellent.

flatblackcapo said:
Xander, hit me up homie. I know just the man you need to talk to. If I can just find his phone # :D.
Click to expand...

Kevin, I figured you might know someone who's into this stuff. Anyone I know? I swear I'm going to buy you a rolodex for your phone numbers since you oppose mobile phones and all!


-X
 
the best budget tube headphone amp I've seen (as in actually listened to the amp, and walked through the circuit and build process) is the Pete Millett (big name guy - with some serious high budget amps out there) designed "Starving Student" amp. It's a tube/mosfet hybrid, which goes a bit easier on the transformer (saving money). And is a simple schematic.

http://www.pmillett.com/starving.htm

Highly recommended for a first tube scratch build. There are probably kit versions available, but you should be ok doing it from the plans too. Lots of forums out there with step by steps on this one.
 
Here is a great site for what you are looking for, it was a hobby of mine. I found my system and now just listen to what I have. What I learned is that the sound of most stuff is subjective and that at a certain dollar level you reach a point of diminishing returns ie. a slightly better sounding set up is hundreds to thousand dollars more.



http://www.head-fi.org/
 
liamstrain said:
the best budget tube headphone amp I've seen (as in actually listened to the amp, and walked through the circuit and build process) is the Pete Millett (big name guy - with some serious high budget amps out there) designed "Starving Student" amp. It's a tube/mosfet hybrid, which goes a bit easier on the transformer (saving money). And is a simple schematic.

http://www.pmillett.com/starving.htm

Highly recommended for a first tube scratch build. There are probably kit versions available, but you should be ok doing it from the plans too. Lots of forums out there with step by steps on this one.
Click to expand...

Bingo! That is what I'm looking for. Great suggestion! The info over at head-fi and support for the PMillett starving student amp looks to be exactly the stuff I need. I have a materials list now and plenty of reading material to get going on this! Now to find some tubes.


-Xander
 
Check out any of Craig Anderton's books for a breakdown, he doesn't get into tubes but covers the basics nicely.

Be on the lookout for old reel to reels, Hammond organs, etc as you can find many nice components for free. Transformers and other parts can cost some cash new but are easy to find used.

Remember anything can shock you even on a non plugged in amp.

You might need a variac for some projects, they are easy to come by these days... if not a local shop can probably help out. You won't need many tools.

Parts-Express has some good stuff... same with the flea market, pawn shops and Radio Shack.

I mostly know small guitar amps but a 12xxx series sounds like a good start, the tubes are very easy to locate.
 
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Thanx Daniel. I forgot that you were into tube stuff at one point! I've been thinking, rather than the 12AU7 tubes I might go for some RCA 6J6 tubes. I'll have to look at the specs but I think they might work well in a low voltage amp.

Long term goal for me is to get a mini-system put together from tube equipment built by me. I figure the head phone amp would be best to start, then probably a preamp for my turntable. Next a SS FM tuner, probably a multi transistor, and of course a power amp. I think that should get me rockin and rollin with a cool system.

Now if I could just get my house to sound better, th hard wood floors and lathe/plaster walls really make it sound hollow.


-X
 
There are some easy room treatment options out there too... diyaudio has some threads on it. I'm on at Head-fi and DIYAudio with the same username as here. Feel free to shoot me a note if you have questions.
 
I imagine you aren't going to get too ambitious with your first build, but I have a wonderful book on tube amps that has schematics for classic amps like a fender bassman, vox ac30, etc. Let me know if it would interest you.

I play out of a vox ac30 usually.

BTW. does anyone here do any digital recording? I need some advice about hardware for a workstation build.

Some toys.


 
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^ Incredible setup! I like it... I want every pedal, lol!

I used to produce a bit of music for myself and friends, I always wanted a couple of Neve single channels running direct into the computer... Pro tools and Reason for most of the rest. It has been a while! you can go so many ways with a setup but these days with good mics and decent isolation you can do a lot


Xander that sounds like a plan! What style are you going for? exposed tube? :D

I have a book somewhere on building rooms for sound, I'll try to find it. Some minor treatments will go a long ways.

Long ago I was in this punk band where we all lived together... we had a place with exposed rafters and covered them with mattresses, the walls with egg crate foam, doors with sleeping bags and more, it was hilarious and didn't do much!
 
Liamstrain- SWMBO has to approve any room decor additions, I know pretty much how to deal with it thoug. I think installing a muffler on the wife will do wonders to my istening experiance though, lol!! :p. I don't know if I'm going to join another forum, but I will be in touch with you if I have any questions, thanx!

KNaB- Nice gear! Though, I'm not a guitar player, just a listener. But, I have no idea of the differences (if any) between guitar amps and typical stereo amps. Still learning about this stuff... if the book you have covers construction and theory it might still be worth the read though.

DFK- turns out the 12AU7 or 6J6 tubes won't be direct replacements in the Millet Hybrid linked above. I will just stick to the 19J6 he designed it around to maintain the simplicity of the circuit. I'm going to go point to point wiring with exposed tubes and heat synchs, volume and 1/4" output on the front and power switch, power in, and RCA in on the back. Probably a common ground plane as well.

I had some buddies back in the day who had almost an entire house done that way, it was kinda creepy to tell you the truth! I don't think Brandi will go for mattresses stapled to the walls!

Mostly I have just oriented the speakers towards the large windows opposite the stereo and open them to quell some of the echo, my neighbors are both 90+ and can't hear anyways, so no complaints!

Ideally, I think a lower output system will eventually be the plan, maybe 10W with just a single pair of 5" speakers, found some cool designs reported to be very nice sounding and cheaper t build than buying the Epos bookshelf speakers I want!


One question before I start ordering though, will 22awg solid core wire work for building this amp? I have a spool of some old high purity solid copper wire that I normally use for making my own speaker cables, I believe it is phone wire. Not sure if multistrand is better or not.


-Xander
 
fast14riot said:
Liamstrain- SWMBO has to approve any room decor additions, I know pretty much how to deal with it thoug. I think installing a muffler on the wife will do wonders to my istening experiance though, lol!! :p. I don't know if I'm going to join another forum, but I will be in touch with you if I have any questions, thanx!

KNaB- Nice gear! Though, I'm not a guitar player, just a listener. But, I have no idea of the differences (if any) between guitar amps and typical stereo amps. Still learning about this stuff... if the book you have covers construction and theory it might still be worth the read though.

DFK- turns out the 12AU7 or 6J6 tubes won't be direct replacements in the Millet Hybrid linked above. I will just stick to the 19J6 he designed it around to maintain the simplicity of the circuit. I'm going to go point to point wiring with exposed tubes and heat synchs, volume and 1/4" output on the front and power switch, power in, and RCA in on the back. Probably a common ground plane as well.

I had some buddies back in the day who had almost an entire house done that way, it was kinda creepy to tell you the truth! I don't think Brandi will go for mattresses stapled to the walls!

Mostly I have just oriented the speakers towards the large windows opposite the stereo and open them to quell some of the echo, my neighbors are both 90+ and can't hear anyways, so no complaints!

Ideally, I think a lower output system will eventually be the plan, maybe 10W with just a single pair of 5" speakers, found some cool designs reported to be very nice sounding and cheaper t build than buying the Epos bookshelf speakers I want!


One question before I start ordering though, will 22awg solid core wire work for building this amp? I have a spool of some old high purity solid copper wire that I normally use for making my own speaker cables, I believe it is phone wire. Not sure if multistrand is better or not.


-Xander
Click to expand...

My mistake. I saw the title and didn't read through the first few posts and assumed you meant an instrument amp. I get excited when instruments and guitars are the topic of a conversation. Regrettably, I don't know much about stereo amps, though I love tubes. My gf's dad is into hi-fi stereo gear. All i know is that his setup sounds amazing and NAIM is emblazoned on much of thevequipment.
 
Xander, for some local help hit up Uncle Spot in Lodi. The owners name is Ron he's a good guy that is super passionate about what he does and would be cool about offering help.
 
fast14riot said:
One question before I start ordering though, will 22awg solid core wire work for building this amp? I have a spool of some old high purity solid copper wire that I normally use for making my own speaker cables, I believe it is phone wire. Not sure if multistrand is better or not.


-Xander
Click to expand...

Should be fine. I usually go a bit thicker gauge in tube amps, but in a hybrid circuit (and a small one) should be no issues at all. Single core is better for PTP, IMO. You don't need the added flexibility of multi-strand.

I've got a couple of back-loaded horn speakers in the works that the wife has pre-approved (take a look at the Frugal Horn designs for a nice option), if you have a good wall (or corner) to put it near. They'll run nicely off an 8-12 watt tube set up, and sound pretty damn glorious if you can pair them with a powered sub.
 
KNaB said:
My mistake. I saw the title and didn't read through the first few posts and assumed you meant an instrument amp. I get excited when instruments and guitars are the topic of a conversation. Regrettably, I don't know much about stereo amps, though I love tubes. My gf's dad is into hi-fi stereo gear. All i know is that his setup sounds amazing and NAIM is emblazoned on much of thevequipment.
Click to expand...

Lol, I've been guilty of thread skimming before as well! But, I do know that guitar amps basically work like a phono preamp (I think) but if they are interchangeable between systems I do not know. Either way, tube projects have drawn me in like a moth to the warm dull glow of the tube!

flatblackcapo said:
Xander, for some local help hit up Uncle Spot in Lodi. The owners name is Ron he's a good guy that is super passionate about what he does and would be cool about offering help.
Click to expand...

Good stuff bro, I'll check him out.

liamstrain said:
Should be fine. I usually go a bit thicker gauge in tube amps, but in a hybrid circuit (and a small one) should be no issues at all. Single core is better for PTP, IMO. You don't need the added flexibility of multi-strand.

I've got a couple of back-loaded horn speakers in the works that the wife has pre-approved (take a look at the Frugal Horn designs for a nice option), if you have a good wall (or corner) to put it near. They'll run nicely off an 8-12 watt tube set up, and sound pretty damn glorious if you can pair them with a powered sub.
Click to expand...

Good to know. My preference for this wire is that its high purity and I have some ideas for making this a classy little piece of kit. Also, its so much easier to map a layout with solid core wire, it stays where you put it!

This is the speaker project that caught my eye, single 4.5" full range drivers and a tuned box. Would be quite nice for a simple small tube set-up I imagine!

http://www.pmillett.com/jx92s.htm


-Xander
 
Head-if.org is the bladeforums of the headphone world. The DIY sub forum will have exactly what you're looking for and more. I've built one of the millet based amps, it was fun and is listenable, sort of :)
 
Sounds like fun!
I'm on my second tubed preamp - they really can be magical. But I don't have the nerve, or steady hand, to build my own.
I've had great luck and service from at the tube store and upscale audio, but their prices may be a bit high for your plan. Plus I don't see any 19J6's (sounds like they're getting scarce.)

I have a couple headphone amps that others made for me - a cMoy and a PA2V2. Though both are solid state (and portable), with the right headphones the cMoy brings me most of what I appreciate about tube sound. If I were going to build a first headphone amp, I'd probably start there. If I managed to not blow anything up, I might move to a more ambitious project. But my skills lean more toward the mechanical than electrical. (I have replaced blown transistors in two solid-state amps in my past life, but one of those I blew when I mis-wired an interconnect.)

I wish you luck in your endeavor and look forward to an update on how tough the build really was, and how it sounds.
 
I've been lurking over on head-fi for almost a week now, its just the last thing I need is to join another enabling group, err, forum. The Millet looks to be my ideal shot for a first tube build, but after a bit of searching the 19j6 tubes are scarce! There are a few old repair shops still around town I plan to investigate tomorrow, hopfully I can score a couple pairs. If not, then I guess I'll do the work around design on the Millet for the 12AU7 tubes, those are easy to find.


Still open to ideas for other simple inexpensive tube designs, but the Millet Hybrid looks like the best candidate so far.


-Xander
 
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