Building Tube Amps As Business (repost from Careers)

Wow I think building amps is SO cool. I myself was thinking of doing that someday... But first I'll try and build one from a kit ^.^

Have you decided on a design yet? Personally, I really like the 50's retro look. Here is a good example of a retro-looking amp that looks awesome:
http://www.emerysound.com/Stagebaby.html
Here are a couple of others:
http://www.electrosonicamplifiers.com/standards.php

Don't they look great? :shock:

Oh yeah, nice looking indeed. The amp model I'm starting with will be in a mini-head sized cabinet, covered with tweed, although those willing to pay extra and make a deposit for a custom-built amp can have other coverings, as well as other options like Heyboer or Mercury Magnetics transformers or boutique coupling caps, etc. The front/rear control panels (bottom-center, like a Marshall with tubes upright on the chassis) will be chocolate--brown with cream lettering and markings with cream chicken-head knobs.

As I get some amps sold and have the $$$ to work with, I'll be expanding the cosmetic options available to include such things as exotic-wood cabinets, etc. I also plan to expand the models and designs available.

I have a design for a higher-powered amplifier I'm itching to build which uses 2 807 tubes in the power amplifier, which I plan on being switchable between Class A @ about 32 watts, or Class AB1/2 which can produce upwards of 80 watts from a pair of 807's. I was introduced to the 807 many years ago as an amateur radio operator and builder, and I love the way they sound. To me, they sound sort of like a 6L6/5881 on steroids, with the power of a 6550 or KT88, but much warmer with an extremely warm overdriven sound. They have a "plate cap" at the top of the tube where the plate is connected. Here is a pic of the 807: (The ruler is in *centimeters*, not inches! :lol: They're about 8 inches tall.)

The sign says: Successor to the 6L6, much liked for transmitters.

And for those interested, here's the RCA datasheet for the 807:

http://datasheets.electron-tube.net/sheets/084/8/807.pdf

Cheers!

Strat

I've always thought 807s are extremely cool.

New Russian ones are still available, quite inexpensively.

That's easily doable. I have an amp I built that runs a pair of cheapo Russian 6L6s well past 80W, with 500V on the plates and screen grids in an ultralinear configuration in Class AB2, biased very close to Class B.

I've always thought 807s are extremely cool.

New Russian ones are still available, quite inexpensively.

That's easily doable. I have an amp I built that runs a pair of cheapo Russian 6L6s well past 80W, with 500V on the plates and screen grids in an ultralinear configuration in Class AB2, biased very close to Class B.
Yeah, I agree, they are a very cool tube (no pun intended). They're also built like a tank, as I used to push them in transmitter and modulator service to the point that the plates back-lit the radio table in a happy cherry glow on a regular basis. I tried running a guitar through an old 807 AM transmitter modulation amp a long time ago, and was very impressed with the sound even at that early stage in my guitar playing life. I also always got compliments from other radio operators on the air on the quality and warmth of the audio, as well as the punch of the old AM shortwave rig that used the 807s in the modulator.

I'm going to try running the 807s in the guitar amp at 600 volts as per the manual and see how they sound, and may end up lowering it depending on the results. That 80 watt output rating from the 807s in AB2 I'm sure is very conservative based on my experience with both the way tube manual ratings compare to the real world, and also my years of working with the 807. I'm quite sure as a guitar amplifier they could easily produce 120 watts plus without breaking a sweat figuratively speaking.

If I decide to build a tube bass amp, the 807 will be one of the first tubes I'll try in that role. I'm sure a push-pull AB2 quad or sextet of 807s would really rattle some teeth! :lol: I can't even *imagine* how loud a guitar amp with four or even six 807s would be! :shock:

>EDIT: Hey! I just had a thought...maybe I could build a guitar head with eight 807s and call it the Nigel Tufnel model! :twisted:

Cheers!

Strat

Hams have pushed a single 807 (or 6L6) past 100W in Class C CW service. Mostly in the "good old days" following WWII when they were available as surplus, really cheap. If you buy generic Russian tubes in bulk, they're about the same now, relatively. If you toast 'em, throw 'em out and put in some more.

On the topic of building amps and since you two seem to be very knowledgeable about the subject... can you recommend any books that explain how tube amps work and how to build them?

I found this book on Amazon and it looks quite good and the comments are generally very positive. Do you guys have any other suggestions?

Right off the top of my head, I'd say one of the best all around resource books is "The Tube Amp Book" by Aspen Pittman (the guy that owns Groove Tubes). It's not so much a DIY type book, but it has a wealth of information on tube amps including tons of schematic diagrams and much general and practical theory.

I'd recommend it as a first step for anyone interested in tube amps as a do-it-yourself-er, someone trying to diagnose problems, general care and feeding of tube amps, musicians wanting to understand what they're playing through, or anyone interested in the history of tube amps, as it will provide background to help in understanding some of the more "nuts and bolts" type technical books and tube amps in general. Plus, it also has many beautiful pictures of some very famous and some of the more exotic and obscure amps. They also include a CD, if I recall correctly, with tons of schematics in the more recent edition(s).

It also contains information on amp makers, parts suppliers, and sources for amp building info.

If you're considering trying your hand at building an amp, a kit might be a good place to start. Weber and Hoffman both have pretty good kits with all the parts you need, even cabs and speakers. They have detailed layout diagrams of where everything goes as well as schematics. They also have forums for help if you get stuck or have a problem or question.

Cheers!

Strat

Thanks for the advice stratman.

I was thinking of buying a kit from AX84.com and try to do the P1 project. I've already checked out the Weber kits and they're a bit expensive for me. Although I would LOVE to try my hand at the 6O100 (I think it's an Orange clone?). But yeah... it's pricey aaaaaaaand it looks very complicated to build, just looking at the schematic gives me a headache.

Well, did you see the 'Smokin Joe' series of kits in Webers' site? Pretty much the same thing. The Smokin Joe I kit is a single EL84 like the kit at AX84. There's also the Smokin Joe II which is a pair of EL84s. They're available as head or combo.

The one thing I noticed that you should take into account in price comparisons is the Weber kits include *everything*, including the already-covered cab (you can choose many styles/colors of both tweed, tolex, and the grillcloth for combos), which the AX84/Doberman kits do not. The Doberman kit chassis is *un-punched* which means you'll need to have some sheet-metal skills and tools, as well as the ability to do the layout for all the various holes for screws and tube sockets, transformer cutouts, etc. Also, the Doberman kits don't include the front and rear faceplates, which the Weber kits do. The Weber kits also include the wire and cabling required. In the case of combos, Weber also includes the speaker. Weber *does* offer options to add extras, or to remove things you don't need too.

One option you could choose if coughing up that much money in one go is a problem, is to look at Webers' chassis kits. You can order most all the kits' offered as chassis kits, then order more stuff later. If you look at the top of the Weber Kits web page, there's a link to a Bill Of Materials which lists all the parts used in every kit they offer. With that info, you can start with a chassis kit (the chassis number is listed in the Bill Of Materials document for every kit), then order more stuff as you can afford it.

The Bill Of Materials is found here:

http://www.webervst.com/kits/bom.xls

Just right-click on the link and choose "Save Link As...", and then it can be opened with either MS Office or Open Office.

Weber chassis kits can be found here:

https://taweber.powweb.com/store/chassis/chord2.html

Overall, I've been quite impressed with the thoroughness of Webers' kit offerings, as a newcomer that orders a standard amp kit will be able to assemble the stuff he/she receives and have a complete amp, with a nicely-covered cabinet and attractive faceplates all marked and with knobs, ready to play when finished even including the tubes and fuses, which people will look at and go "Wow! Nice amp!" instead of seeing some cobbled-together-looking science experiment that doesn't look quite 'done'.

Cheers!

Strat

I've never read any of the modern guitar amp books and can't say anything about them. Old electronics books from the 1950s era are good resources for tube circuit theory. Tube manuals like the RCA Receiving Tube Handbooks are invaluable resources. Tube era electronics repair books and ARRL handbooks for amateur radio from that era are very useful on the practical end.

Thanks for the detailed info stratman. I'll look into it. I kinda wanted to build my own chassis and cabinet but I realize that maybe I should try something easier the first time around. I think putting all the electronics together would be enough of a challenge for now!

And thanks for the tip Ricochet. I'm sure I can find some old electronics books on eBay :D

Thanks for the detailed info stratman. I'll look into it. I kinda wanted to build my own chassis and cabinet but I realize that maybe I should try something easier the first time around. I think putting all the electronics together would be enough of a challenge for now!

And thanks for the tip Ricochet. I'm sure I can find some old electronics books on eBay :D

Well, the chassis layout requires non-trivial knowledge of amp design. It's not just a matter of being able to measure and punch some holes. You need to understand what circuitry needs to be close to each other, and what needs to be kept far from each other, capacitive and inductive effects, transformer orientations, grounding and ground-loop effects in a chassis, etc. Just because you can fit all the parts onto the chassis without mechanical problems doesn't mean it's correct or will result in a good-sounding or even stable amp that won't take off and oscillate and possibly damage itself.

I would highly recommend a first-timer to have the layout done for them for the above reasons. It takes a good amount of studying and practical experience to learn all the things that go into laying out an amp for low noise, stability, and quality sound.

The cabinet is a much easier undertaking as to the design knowledge required, and if you feel confident you have the tools and skills to do a good job, I'd say go for it. All the Weber amp kits have the option to be ordered without the cabinet with a significant cost savings.

Cheers!

Strat

Well then, no chassis building for me, at least not for now.

Thanks for all the info! I can't wait to get started on this project :D

Oh and good luck with your business stratman. Post some soundclips if that's possible!

I've been busy building custom tube guitar amps and now have 8 amps plus two in the design/build stage (one is an octal amp I call the Roctal, and the other is a jazz amp with 7868 tubes).

My latest is a tweed 6V6 combo that's similar to a Matchless Spitfire with an extra gain stage and paper-in-oil caps.

I have two of my amps on consignment at a local guitar shop, but am worried that they haven't sold. Like you, I'd use the cash to build more amps.

I'd love to find a boutique shop that would carry my amps.

We're on similar paths. I've been contemplating getting a set of chassis punches, and sheet metal bending tools.

Check out my little web site for photos and sound clips:
http://www.naturdoctor.com/Chapters/Amps/Ampersand.html

Ron