Ever wanted to build your own tube amp?

[BrownSound1]

I was fumbling through the Internet the other night when I ran across a project that I found a bit interesting, and that was building your own guitar amp. I thought about it for a bit, and I concluded that it would be good for guitarists to do this so they could better understand the inner workings of a tube amplifier. Personally, I know how they work, but for people who have no electronics background this would be a great opportunity. Just think, you'd get an idea of how your big amp works and at the same time, you could build a really cool recording or practice tube amp.

Check out the site: The AX84(tm) Homepage (http://www.ax84.com/home.html)

I haven't built one of these yet, so I can't really say how the damn thing will do. However, I plan on building one of the models very soon. There are some sound clips on the site to give you an idea of what these little things sound like...and they have complete kits in which to build them from.

[Cathedral]

Hey, that is a killer idea cause i am pretty much tube stupid (i own a Peavey, lol)

My gear background is basically plug and play, and i was a supervisor in a cover shop and did exactly as the word suggests,
That's the vinyl and carpet covering job.
Hardware assembly
making grills for Redbear amps, Soldano, Sovtek and a host of lower end PA cabinets.

This is something i would love to learn and was the only reason i took electronics in high school.
Shame is that was never a project in school, lol, but i can assemble a circuit board like nododies business, lmmfao.

I saved that link to my favorites. :)

[twonabomber]

Originally posted by Cathedral
i took electronics in high school.


me too. haven't done too much with it since then, but it got me out of a lot of boring classes. :D

i'm thinking of building one of those 18-watters too. i found another board that has Marshall and Vox board kits, may have been a link on that site.

[Cathedral]

It was also a way to spend the last two years of high school in a vocational school, and what i remember most is the cosmotology students. that was where all the babes went to learn to cut hair, lol.

And to this day i wouldn't let anyone who took it there cut my hair.

It was almost like a scene out of "An Officer and A Gentleman".

"Mr. Baker, Why are you taking this course?"

"I wanna build amps, sir!"

Then it degenerated into more of a "Stripes" thing, lol.

[BrownSound1]

I did the same thing guys....electronics in high school, then college, and I have to deal with that shit every day. In the work fields I deal with robotics and automation.

I remember telling my instructor in high school the exact same thing about building amps...and I've yet to do it. My father is as knowledgeable about tube circuits as anyone I've ever met...so I'm going to tap that resource for this project.

[Nitro Express]

I built a home brew version of a Fender Bassman. I even bent the metal chassis myself. I used to build Heathkit projects growing up. My dad was a tottal Ham Radio geek, so he taught me a lot about electronics and has a fabulouse work bench and tools to use.

Right now we live in such a throw away society and it's getting to the point where people don't know how to fix anything. If your Line 6 POD breaks, you throw it away and buy something new. If your Marshall Plexi breaks you took it to a repair shop. Repair shops are dying off because nothing is reparable anymore, so if you play tube amps, learning to fix them yourself might be a neccessity.

Building a hand wired tube amp is traveling back in time. It's a lot different than dropping integrated circuits into a prefab circuit board. Laying it out and running the wired neatly can be a real challenge. Makes you really appreciat the old Hi-Watt amps with the military grade wiring.

Some home brew amps sound great, others have you scratching your head wondering why it sounds like shit. It's hit and miss, but you learn how everything in the chain effects the sound. a wrong capacitor or resistor value can spell dissaster. Transformers make a huge difference.

You really don't save any money building your own if you haven't done it before but it's a good learning experience.

[Nitro Express]

Mike Soldano said he lucked out because the library his mom worked at in Seattle threw away all the books on tube cirucuits thinking they were obsolete. Mike dug them all out of the dumpster and says those old engineering manuals allowed him to build some killer amps. He says most people who know anything about tube amp design are dead and the information is really hard to come by.

People laugh when they think of vaccum tubes like they are buggy whips or something but in the heyday of tubes, making good tubes and laying out good circuits was an artform. I always thought it was brilliant how RCA used a tube to split the signal into a push pull circiut. That was a huge breakthrough and allowed more powerful amps to be built. It's interesting stuff. Big transmitters still use tubes.

Ham radio hobbyiests, guitar players, and audiofiles seem to be the only people left on the planet who still appreciate what those little glass bottles can still do. Everyone else has moved on to their disposable solid state junk. LOL!

[BrownSound1]

I've seen vacuum tubes so big that they had 1/4" water cooled copper lines going around them to cool them. This was on a "shake table" that a company here has to vibrate the hell out of BIG parts. They did shake tests for the Saturn IV rocket on that damn thing...in sections of course, but we're talking huge sections. There is no way in hell that a transistor can produce the kind of power it takes to move that thing.

[Panamark]

Gotta love tubes !

Heated elements travelling through air as opposed to silicone doping.

As warm as the sun !

[Hardrock69]

Originally posted by Nitro Express
I built a home brew version of a Fender Bassman. I even bent the metal chassis myself. I used to build Heathkit projects growing up. My dad was a tottal Ham Radio geek, so he taught me a lot about electronics and has a fabulouse work bench and tools to use.

Right now we live in such a throw away society and it's getting to the point where people don't know how to fix anything. If your Line 6 POD breaks, you throw it away and buy something new. If your Marshall Plexi breaks you took it to a repair shop. Repair shops are dying off because nothing is reparable anymore, so if you play tube amps, learning to fix them yourself might be a neccessity.

Building a hand wired tube amp is traveling back in time. It's a lot different than dropping integrated circuits into a prefab circuit board. Laying it out and running the wired neatly can be a real challenge. Makes you really appreciat the old Hi-Watt amps with the military grade wiring.

Some home brew amps sound great, others have you scratching your head wondering why it sounds like shit. It's hit and miss, but you learn how everything in the chain effects the sound. a wrong capacitor or resistor value can spell dissaster. Transformers make a huge difference.

You really don't save any money building your own if you haven't done it before but it's a good learning experience.

Wow Nitro...that is wild. My dad was into Ham Radio as well, and I was one of the youngest persons in the State Of Kansas in 1972 to have a Ham Radio license (at age 12). I used to help my dad build Heathkit transmitters and receivers and stuff, that is where I got my first knowledge of electronics.

Nowadays, I do all my own electrical work on my guitars, though I leave the amp stuff to the experts who do it for a living.

It would be fun to someday build my own amp....

[Nitro Express]

My dad was an electronics geniouse. He went to MIT and was in the top 1% of his class. He was a total egghead but also was a first class tinkerer. He built his own tube hi-fi when he was in high school. I have that along with my grandad's old Philco radio. Both still work.

[Hardrock69]

Right on!

My Dad was offered scholarships to Harvard and Yale, but turned them down because he was happy at the University he was at.

He did not get into electronics heavily until he bought me a 1948 Hallicrafter's tube radio (with short wave bands and AM!). Then he remembered building crystal sets when he was a kid, and that was all she wrote. He got into electronics with a vengeance then....

[BrownSound1]

I knew Morse Code at 8 years old. LMAO Couldn't do it now to save my life. Sounds like we all grew up in similar situations.

[Hardrock69]

Yeah....it has been 30 years since my Ham Radio license expired.

[GAR]

Its all about the engineering math, otherwise it's simple componentwise..

I suggest Aspen Pittman's "The Tube Book" which is in it's 4th revision I believe and is available from mojotone.com. In it you'll find some of the basic engineering data to get started, although I have found the Hoffman amp's AX84 pages to contain usefull things as well as pre-made circuitboards for making Fender and Marshall amp clones.

[Nitro Express]

It's kinda like being a chef. It looks easy and in many cases it is but getting the end result to be what you like is real trial and error. I know my dad looks at the schematics of guitar amps and just shakes his head and goes,"All you guys want is distortion." He doesn't get the concept. He's a total audiofile and will be the first to agree tubes are the way to go but he's spending a fortune on expensive transformers handwound by some dude in Japan with silver wire and looking for tottaly distortion free sound. He really doesn't get why old Marshalls and such are so coveted. He looks at the transformers and the parts and basically says, it's all run of the mill stuff. Old but when the amp was built there was nothing special to the parts and even the transformers were cheap and nothing special. That's true because Marshall went to EL-34's from 5881's because EL-34's were cheaper to buy in the UK.

Guitarists love cheap shit that sounds like it's going to break. Audiofiles don't get us at all and we don't get their cork sniffing ways. LOL!

[GAR]

EL34's can take up to 700 volts plate voltage without a strain, and some engineering data specify up to 900 other designs!

Most amps do not run 'em that high.. even Marshalls.

Musicman's do 700 bone stock.. try finding 'em though. They made grate source-amps (hint hint).

[Hardrock69]

Ahhh..I had a 65-watt MusicMan head back int he early 80s. As a matter of fact, it was the first guitar amp I ever owned, errr...I mean bought. :D

[GAR]

Even though it is true these amp designs are 60 years old and use "run of the mill" parts, it's about the math principles that specify what parts are used.

That's the engineering aspect of it

[Nitro Express]

Plus guys like Jim Marshall and Leo Fender wanted to give musicians good value for their money. Jim Marshall got into the amplifier business because there was a demand for Fenders but they were expensive in the UK. So he made amps out of British parts based on the basic Fender design.

We're not talking McIntosh type quality here. The Marshalls and Fenders had good quality components but they were on the level of what was being put in the average hi-fi at the time. Not cheap Sears Silvertone transformers but not McIntosh transformers either.

There's just nothing in these old classic amps that is going to make an audiofile like my dad excited.

[Hardrock69]

Haha well yeah for the kind of amps we are talking about.

But has he ever got one of those old 1960s Macintosh Tube Power Amps going? Where the tubes are breathing fire??? :D

My Dad had one when I was a kid....sold it in the early 70s, and then just a couple of years ago he found one on eBay.

[ashstralia]

Originally posted by Nitro Express
Plus guys like Jim Marshall and Leo Fender wanted to give musicians good value for their money. Jim Marshall got into the amplifier business because there was a demand for Fenders but they were expensive in the UK. So he made amps out of British parts based on the basic Fender design.

did you all know Jim is a drummer?
he had a music shop which was
frequented by pasty pimply faced
boys with names like page, townshend,
beck, clapton, richards, moon, etc etc...

[Nitro Express]

Yeah, I have a book on Jim Marshall signed by the man himself. Like Les Paul, Jim Marshall is one of those old guys who "gets it". Most in their generations don't. Shit, I hear Jim is a top notch drummer but look at his students. Not only do they keep a beat they throw in some flash.

[Nitro Express]

I have a mint condition 100 watt McIntosh tube stereo amp with the matching solid state preamp. When my parents were selling their house my dad was just going to garage sale the thing. I grabbed it. In fact, that was the amplifier that first pumped out Van Halen when I first heard them. It's a keeper.

[Hardrock69]

Wow. Lucky bastid!
:D

[GAR]

Originally posted by Nitro Express
.. made amps out of British parts based on the basic Fender design.


Actually most of those tube circuits Leo Fender was basing his amps on were two decades old and come right out of the Western Electric receiving tube manuals widely available..

They're simple textbook circuits. Anyone can build them.. but not everyone can get consistent results because the tolerances of component values vary so much, capacitors for example are like, plus or minus 20 percent.

Building a tube circuit is all about following the tolerances and keeping it in the specification of the print, and knowing what to do to offset those measurements when they go out by computing a compensated value to continue.

Homebuilt amps are better nowadays because the component values themselves are much better sometimes with 1 percent tolerances if you can pay extra.

[BrownSound1]

I've got access to boat loads of Mil-Spec parts...those tolerances should be well within the specs on the prints.

[GAR]

Probably, but eBays' been pretty helpful to me for parts actually!

I've been loading up on resistors, caps and diodes for example, just got in a 5000 pcs bag of 1N4148 diodes for under $15 bucks, and the sellers - HALF of them abouts, actually get the materials by dumpster diving or from salvage from "end-of-run" assembly reels.

Radio Shack ain't got shit anymore. Someone ought to throw daisies on the casket already.. ebay RULES!

[GAR]

For those in need of assistance getting their AX84 low-wattage tube amp project off the ground, I found this flowchart to be of h e l p.

http://www.personal.psu.edu/users/j/f/jfs189/Random%20Pics/flow%20chart.jpg

[BrownSound1]

Radio Shack sucks monkey balls.

I've always loved that flowchart.

[GAR]

Digikey.com

FUCK radio shack, they're thru..