Which book or source for tube amp building?

U

Uncle Thor's Hamer

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Let's start with me being an electrical engineer by degree, and many years of tinkering with electronics.  I remember opening up and messing with transistor radios at age 10.

But there is a vast difference between Engineer and Technician.  Mini-rant here:  Technicians are not Engineers, they are Technicians.  I hate how everybody is now some kind of "engineer".  Auto mechanics, air conditioning technicians, telephone repairmen, etc are all suddenly Engineers!  It demeans the education required to become a engineer, and it demeans the practical knowledge and skills required to be a technician.

So, I can (and have) designed numerous analog and digital circuits as a hobbiest, mostly many years ago.  Those were built way back before computer aided circuit board layouts!  I've got a couple of tube amp designs on paper.  But I have none of that practical knowledge how to select actual physical components.  E.g. a carbon resistor or a wire wound?  And why?  Which kind of capacitor, and why?  What placements of components are asking for noise which might not be intuitively obvious?  How about grounding strategies?

Is there a book or other resource you'd recommend which addresses the practical aspects of selecting components and assembling them?  I don't need electrical design help, just the practical knowledge a technician would have.  Because they don't teach Engineers how to actually make it work!

 
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Gerald Weber has a series of books that have good info in them. Check out 'Dave Funk's Tube Amp Workbook'. Some people like Kevin O Conner's 'Ultimate Tone' series. If you get ready to actually build, pm me and I'll go through how to lay out your PT and OT with a set of headphones for quiet operation. 

 
Another idea, and it could be fun, would be to examine examples of a variety of classic tube amps. Circuit design, component selection, even the materials used for the chassis and cabinets all play into the sound of an amp. I remember some conversations with Gary Croteau years ago when I was younger and dumber than I am now, when he was working on the first of his Juke amps. He was talking about how he was taking the circuits from some of his favorite classics and combining them into his own unique design. I wish I’d payed more attention as his amps are seriously cool. 

 
HamerDave said:
Another idea, and it could be fun, would be to examine examples of a variety of classic tube amps. Circuit design, component selection, even the materials used for the chassis and cabinets all play into the sound of an amp. I remember some conversations with Gary Croteau years ago when I was younger and dumber than I am now, when he was working on the first of his Juke amps. He was talking about how he was taking the circuits from some of his favorite classics and combining them into his own unique design. I wish I’d payed more attention as his amps are seriously cool. 
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The tweed 5F6 4x10 Bassman (and possibly the JTM 45) have been well covered over the years, and there's lots of info about them online.  One amp that I don't think has been dissected enough (or, at least, I couldn't find that much 'nuts and bolts' info on) is the Marshall 18 watt.  I had joined the 18Watt.com website a few months ago, but I didn't find much there at the time that I couldn't find elsewhere online, and it wasn't comprehensive or very organized there at that time...and oddly enough, I couldn't find anything there on the VHT 18-watt handwired 'Standard' series of amps. which IMO is just a 18-watt Marshall-style amp with the 'TMB' (Treble/Middle/Bass) mod, and master volume control mod, factory installed.  I need to go find my log-in info and check what new stuff is going on there...especially since, just by looking at the innards of the Marshall 18-watt types of amps, they all seem to me to be pretty basic and really simple, maybe deceptively so...but they sound REALLY good.

This is from the 'welcome'/preface to the 18 Watt website:

18Watt.com was created and primarily exists for the purpose of discussing the Marshall 18W amplifier, as well as amplifiers based on or derived from the original Marshall 18W. So we can talk about anything from the original Marshall amp, to all kinds of variations, using parts of the original design combined with other ideas. The field is almost limitless, provided there is at least some clearly recognizable part of the original 'DNA' there - such as the preamp, PI or power amp. There's also a few other close members of the 18W's family, Watkins' Westminster and Dominator (which the 18W derived from), Marshall's 1930 10W Popular and the various Marshall 20W amps, including the 2061 that are covered here. For other kinds of amps, there are many great forums already out there on the net, which will usually be the best source of information. If you would like to discuss other amps on this site, be sure to post them in the "That's Not 18 Watts" Section. 

 
Actually, the 18W has been documented. Or to be more precise, a specific specimen was documented. About 16-17 years ago, when 18W.com was a yahoo group. I can probably dig up the schem/layout.

I always thought the tremolo channel sounded best, but I never used the trem.

 
DaveH said:
Actually, the 18W has been documented. Or to be more precise, a specific specimen was documented. About 16-17 years ago, when 18W.com was a yahoo group. I can probably dig up the schem/layout.

I always thought the tremolo channel sounded best, but I never used the trem.
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I forgot about how the Marshall 18 watt amp DIDN'T have a ton of circuit variations like Fender did with their amps.  The earlier Watkins amps supposedly fit in there by rough association somewhere, but I'm not sure where exactly, or with what.  It just amazes me how something so simple can sound so good!  Especially when there's literally TONS of tube amp turkeys out there. 

I had bought a Mojotone Marshall 18W kit amp head here on the board that HFC member Fractal had built a couple of years ago, and that's been my amp yardstick ever since.  The VHT handwired 18W 'Standard' heads I've got ain't half bad either...in fact, I haven't had the urge to get anything boutiquey (or anything else amp-wise, for that matter) since I got both of those amps.

 
DIYaudio forums are full of info, including some level of cork sniffing.  It is a little intimidating there tbh.  I'm not looking to do anything too far out from any of the well known brand name amps.  But I do want it to be mine, not a simple exercise in soldering a kit together.

 
I like your discussion of Technicians versus Engineers.  I worked for General Electric from 1985 to 1988 as a test technician.  The engineers would send us sub-assemblies for tank simulators to debug and ask us what to do to make it "work".  Then, I moved to Martin Marietta (now Lockheed Martin) as a test engineer.  It was a step above debug technician.  I worked on Patriot, Hellfire and Copperhead programs.  The engineers would decide what they thought would work and we tried to make it work.   Only a few of the old guard that didn't have EE degrees worked in design.  Most of them were on the mechanical side.  I couldn't create, but I could make the creations work.  Peace broke out and layoffs forced me to get a second degree in accountancy in my early thirties.  That death and taxes thing...

Tube amplifiers are a totally different world.  Lots of amperage and voltage.  Components and how they shape the sound is a "science" no college degree or digital design education/experience can teach you.  It's real voodoo.

 
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For the "technician" type information, the "Technical Discussion" section at http://ampgarage.com/forum/ can be very useful, as can the Hoffman amp forum dealing with "tube amp building, tweaks and repairs". Since you are an engineer and undaunted by the math, Merlin Blencowe is an author you might try. Start with his online topics presented here http://www.valvewizard.co.uk/index.html and then decide which book to buy. Any of the books are worth reading if you want to understand tube theory and practical amp circuitry. As mentioned earlier, the Kevin O'Conner books are also good.

Good luck, building amps can easily become addictive. 

 
Start with a kit. That will give you some hands on experience while you investigate the 'how-to' websites.

Maybe a nice little Champ clone...

Also, check out London Amps' website. He does some odd stuff that may tweak your interest.

 
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