Building a Vacuum Tube Amplifier

[randyc]

Bits and pieces of the cabinet:



the cabinet is finger-jointed, glued and sanded:



front view (a piece of black felt is installed temporarily - to be replaced with grill cloth when speaker cabinet is built):



rear view:



cheers

[lpdeluxe]

Fine looking workmanship.

[Jazzarian]

What's with all the test equipment in the background? I see frequency generators, power supplies, meters. That's all yours?

Who did the cabinet work? Who cut the wood?


How about building a Ceriatone for your next project?

[lpdeluxe]

What's with all the test equipment in the background? I see frequency generators, power supplies, meters. That's all yours?

Yeah, isn't that cheating?

[randyc]

What's with all the test equipment in the background? I see frequency generators, power supplies, meters. That's all yours?

Who did the cabinet work? Who cut the wood?


How about building a Ceriatone for your next project?

All of the test equipment is mine, it's not a big an investment. Most of it is old and was obtained for a modest amount of money (EBay, electronic flea markets and the like). But everything is functional and it's great to have my own lab in my home.

As I said in the OP, I did all the work - it was a gift for my brother. He wanted to replace his Fender Frontman with a tube amplifier. I knew that the gift would have more meaning to him if the project was designed and entirely hand-crafted by me.

I don't have any interest in building a Ceriatone, I have too many amplifiers already (my wife complains that, since I'm retired, I have no use for more than one guitar and one amplifier). At this point in my life, now that I have the time, the fun is in building my own designs.

The tube amplifier is an anomaly, though, most of my work is solid-state (like the two high-voltage laboratory power supplies that can be seen behind the amplifier under test - they are the ones in the wood cabinets).

cheers

[Jazzarian]

All of the test equipment is mine, it's not a big an investment. Most of it is old and was obtained for a modest amount of money (EBay, electronic flea markets and the like). But everything is functional and it's great to have my own lab in my home.

As I said in the OP, I did all the work - it was a gift for my brother. He wanted to replace his Fender Frontman with a tube amplifier. I knew that the gift would have more meaning to him if the project was designed and entirely hand-crafted by me.

I don't have any interest in building a Ceriatone, I have too many amplifiers already (my wife complains that, since I'm retired, I have no use for more than one guitar and one amplifier). At this point in my life, now that I have the time, the fun is in building my own designs.

The tube amplifier is an anomaly, though, most of my work is solid-state (like the two high-voltage laboratory power supplies that can be seen behind the amplifier under test - they are the ones in the wood cabinets).

cheers

No pictures of bandsaws, jigsaws and the like? Let me guess, you picked up a CNC machine on eBay?

Ever think of designing the next Dumble clone? There's good money to be had in that. Witness Two Rock, Fuchs, Glaswerks (most excellent!!), Ceriatone etc.

[Jazzarian]

Yeah, isn't that cheating?

Yes indeed, one is supposed to just solder away until done. After which, one plugs in the guitar and everything works.

[randyc]

No pictures of bandsaws, jigsaws and the like? Let me guess, you picked up a CNC machine on eBay?

Ever think of designing the next Dumble clone? There's good money to be had in that. Witness Two Rock, Fuchs, Glaswerks (most excellent!!), Ceriatone etc.

I WISH that I had a CNC machine !!

But even without one, my shop is capably equipped, though the tools are manually operated. (Like my electronics lab, the shop is mostly equipped with older, not very expensive machinery.) I have welding, metal machining and woodworking capability, as well as the requisite metrology stuff that goes with the metalworking machinery.

No, I don't think of designing things for production, I did that throughout my career. The documentation for the 40 watt tube amplifier that I designed was offered free to anyone interested when I first built it, two years ago. (WITH all of the usual legal disclaimers of responsibility, of course.)

If you are REALLY interested in my shop, I love talking about it and I'll e-mail photographs. (I participate in several metalworking and woodworking forums too.) This website won't let me post more than four photos and I'm up to my limit.

cheers

[Jazzarian]

I WISH that I had a CNC machine !!

But even without one, my shop is capably equipped, though the tools are manually operated. (Like my electronics lab, the shop is mostly equipped with older, not very expensive machinery.) I have welding, metal machining and woodworking capability, as well as the requisite metrology stuff that goes with the metalworking machinery.

No, I don't think of designing things for production, I did that throughout my career. The documentation for the 40 watt tube amplifier that I designed was offered free to anyone interested when I first built it, two years ago. (WITH all of the usual legal disclaimers of responsibility, of course.)

If you are REALLY interested in my shop, I love talking about it and I'll e-mail photographs. (I participate in several metalworking and woodworking forums too.) This website won't let me post more than four photos and I'm up to my limit.

cheers

You're a lucky person to have to much stuff. I'm rather paranoid about losing a finger around saws. I take it you had to cut the "fingers", each one at a time? Then sand the corners "round" after gluing it together?

I've shocked myself with 3000 to 4000 volt DC and AC hi-pot testers. Good thing for current limiting.


How about designing a Dumble clone for the people here? Better yet, a rackmount Dumble preamp clone, which nobody seems to make presently.

The Ceriatone "Overtone" kit goes for about $450 to $650. Very tempting for someone like myself, although they do a great job of wiring apparently.

I too have too many amps, but I'd really like something that sounds like a Dumble.

[lpdeluxe]

I have too many amplifiers already (my wife complains that, since I'm retired, I have no use for more than one guitar and one amplifier).

I built a rack for my guitar cases out of pvc just before a friend and his family came to visit from St Louis. He later told me, "my wife really likes that guitar rack you made."

"She thinks it looks that good?"

"No, she likes the idea that there's a limit to how many guitars you can have."

Here's a shot of it (yeah, I know, I've already outgrown it -- but three of the instruments are up for sale). You can just see the top of a Pignose G40V under the air conditioner -- it's my harp amp -- and the tableau does not include my '63 Silvertone 1484, which lives in my recording room.

[randyc]

You're a lucky person to have to much stuff. I'm rather paranoid about losing a finger around saws. I take it you had to cut the "fingers", each one at a time? Then sand the corners "round" after gluing it together?

I've shocked myself with 3000 to 4000 volt DC and AC hi-pot testers. Good thing for current limiting.

How about designing a Dumble clone for the people here? Better yet, a rackmount Dumble preamp clone, which nobody seems to make presently.

The Ceriatone "Overtone" kit goes for about $450 to $650. Very tempting for someone like myself, although they do a great job of wiring apparently.

I too have too many amps, but I'd really like something that sounds like a Dumble.

Yes, I'm very lucky to have my equipment. I worked hard, had a fascinating and rewarding career and was able to retire young. I started accumulating tools and machinery when I was in my early twenties, working as a machinist while going to school, and I just keep on accumulating things.

Same with guitars and amplifiers, I never seem to get rid of anything, so the house and garage are full of "boy toys". My wife is great about not complaining, though.

Finger-jointing the amplifier cabinet was fussy, time-consuming work but it was very rewarding after everything went together with just a few mallet blows. The Western Ash is really nice wood to work - nicer than oak in my opinion and prettier.

Regarding the high-voltage power supplies, I made the cabinets for them from wood also, both because it's cheaper and faster to work than metal and because I wanted the chassis to be insulated from the 600 volts that are floating around inside.

I don't know what a Dumble amplifier sounds like, I've never even seen one. When I retired in 2001, I moved from the San Francisco Bay Area further up the northern coast of California. It's very isolated (The people up here describe this area as "the lost coast" and "living behind the Redwood curtain").

I live near Eureka and the only music store in town isn't even open on the weekends ... their stock is limited. The amplifiers I've seen there have been Fender solid-states.

I AM interested in Class D amplification, one of these days I'll get around to doing some experimentation and measurements. A lot of my background is in frequency synthesis/PLL's and some that experience could be applied to Class D implementation.

cheers

[Jazzarian]

Yes, I'm very lucky to have my equipment. I worked hard, had a fascinating and rewarding career and was able to retire young. I started accumulating tools and machinery when I was in my early twenties, working as a machinist while going to school, and I just keep on accumulating things.

Same with guitars and amplifiers, I never seem to get rid of anything, so the house and garage are full of "boy toys". My wife is great about not complaining, though.

Finger-jointing the amplifier cabinet was fussy, time-consuming work but it was very rewarding after everything went together with just a few mallet blows. The Western Ash is really nice wood to work - nicer than oak in my opinion and prettier.

Regarding the high-voltage power supplies, I made the cabinets for them from wood also, both because it's cheaper and faster to work than metal and because I wanted the chassis to be insulated from the 600 volts that are floating around inside.

I don't know what a Dumble amplifier sounds like, I've never even seen one. When I retired in 2001, I moved from the San Francisco Bay Area further up the northern coast of California. It's very isolated (The people up here describe this area as "the lost coast" and "living behind the Redwood curtain").

I live near Eureka and the only music store in town isn't even open on the weekends ... their stock is limited. The amplifiers I've seen there have been Fender solid-states.

I AM interested in Class D amplification, one of these days I'll get around to doing some experimentation and measurements. A lot of my background is in frequency synthesis/PLL's and some that experience could be applied to Class D implementation.

cheers

Robben Ford is from Ukiah I believe. Blame him for starting the Dumble craze. Everyone wants to sound like him. Amp makers all over make a buck on Robben Ford.

I've seen Alexander Dumble on the web. He is NO engineer by any stretch.

I'd like to retire near Mt Shasta, or a bit further north, in southern OR.

I've got a western ash in my front yard that grew from 8 feet tall to well over 35 feet in 8 years time. Just add water. I had no idea western ash was a figured wood like that. If one had a few acres, they might make for a nice troublefree cash crop every 15 years.


BTW, companies like Boogie (Petaluma) sell fancy maple and oak cabinet upgrades in the area of $500 to $1000, replete with fingerjoints like yours. Crazy prices or about right? I have no idea what good wood goes for these days and how many hours it takes to cut those finger joints.

[Jazzarian]

Yes, I'm very lucky to have my equipment. I worked hard, had a fascinating and rewarding career and was able to retire young. I started accumulating tools and machinery when I was in my early twenties, working as a machinist while going to school, and I just keep on accumulating things.

Same with guitars and amplifiers, I never seem to get rid of anything, so the house and garage are full of "boy toys". My wife is great about not complaining, though.

Finger-jointing the amplifier cabinet was fussy, time-consuming work but it was very rewarding after everything went together with just a few mallet blows. The Western Ash is really nice wood to work - nicer than oak in my opinion and prettier.

Regarding the high-voltage power supplies, I made the cabinets for them from wood also, both because it's cheaper and faster to work than metal and because I wanted the chassis to be insulated from the 600 volts that are floating around inside.

I don't know what a Dumble amplifier sounds like, I've never even seen one. When I retired in 2001, I moved from the San Francisco Bay Area further up the northern coast of California. It's very isolated (The people up here describe this area as "the lost coast" and "living behind the Redwood curtain").

I live near Eureka and the only music store in town isn't even open on the weekends ... their stock is limited. The amplifiers I've seen there have been Fender solid-states.

I AM interested in Class D amplification, one of these days I'll get around to doing some experimentation and measurements. A lot of my background is in frequency synthesis/PLL's and some that experience could be applied to Class D implementation.

cheers

Robben Ford is from Ukiah I believe. Blame him for starting the Dumble craze. Everyone wants to sound like him. Amp makers all over make a buck on Robben Ford.

I've seen Alexander Dumble on the web. He is NO engineer by any stretch.

I'd like to retire near Mt Shasta, or a bit further north, in southern OR.

I've got a western ash in my front yard that grew from 8 feet tall to well over 35 feet in 8 years time. Just add water. I had no idea western ash was a figured wood like that. If one had a few acres, they might make for a nice troublefree cash crop every 15 years.


BTW, companies like Boogie (Petaluma) sell fancy maple and oak cabinet upgrades for their amps in the area of $500 to $1000, replete with fingerjoints like yours. Crazy prices or about right? I have no idea what good wood goes for these days and how many hours it takes to cut those finger joints.

[derek]

Robben Ford is from Ukiah I believe. Blame him for starting the Dumble craze. Everyone wants to sound like him. Amp makers all over make a buck on Robben Ford.

Before Robben you had Larry Carlton and David Lindley (Jackson Browne + hundred others). Include SRV, John Mayer, Carlos Santana, Steve Lukather, Eric Johnson and Sonny Landreth as other celeb D users.

[randyc]

Robben Ford is from Ukiah I believe. Blame him for starting the Dumble craze. Everyone wants to sound like him. Amp makers all over make a buck on Robben Ford.

I've seen Alexander Dumble on the web. He is NO engineer by any stretch.

I'd like to retire near Mt Shasta, or a bit further north, in southern OR.

I've got a western ash in my front yard that grew from 8 feet tall to well over 35 feet in 8 years time. Just add water. I had no idea western ash was a figured wood like that. If one had a few acres, they might make for a nice troublefree cash crop every 15 years.


BTW, companies like Boogie (Petaluma) sell fancy maple and oak cabinet upgrades for their amps in the area of $500 to $1000, replete with fingerjoints like yours. Crazy prices or about right? I have no idea what good wood goes for these days and how many hours it takes to cut those finger joints.

Everything north of Willets is good retirement country - beautiful scenery, inexpensive property for the most part, and low cost of living.

The last time I bought some ash (a couple of years ago), it was around $2.80/bf. That's about 30% less than oak, looks as pretty and works a lot easier, IMO. It may very well be a good cash timber crop. I don't really know what a fancy, finger-jointed cabinet should cost but they're probably making a pretty nice gross margin on those.

As I said, I know nothing about Dumble amplifiers and, if the designer is not an engineer, no surprise there. Neither was Leo Fender, right ? I probably shouldn't say this, might get flamed for it, but designing vacuum tube musical instrument amplifiers is pretty simple stuff. (The performance parameters are indifferent - one would have to work fairly hard to screw things up.)

Back in "the day", most amateur radio operators, like Leo, could build a creditable audio amplifier for thirty bucks U.S. and a weekend's work. The parts were in mass production, available from surplus sales, CHEAP.

I'd say that a person with a rudimentary knowledge (high school level) of electronics, willing to do some reading and research on the subject and reasonably adept with tools can build a damned GOOD tube amplifier, probably for around $300 U.S. (~25 watts). Electronic test equipment is almost throwaway-cheap these days, so for a couple of hundred bucks more, one can equip a small lab bench, capable of trouble shooting these things.

It's not even close to the level of effort and knowledge required to design an equivalent performance solid-state amplifier. No offense intended to anyone who builds their own vacuum tube equipment. The success of any project can be defined by the ability to meet cost, schedule and performance goals. It doesn't take an engineer or a manager to do this, just a motivated person who knows what they want and how to get it.

cheers

[Jazzarian]

Before Robben you had Larry Carlton and David Lindley (Jackson Browne + hundred others). Include SRV, John Mayer, Carlos Santana, Steve Lukather, Eric Johnson and Sonny Landreth as other celeb D users.

Santana gave up on Dumble after 6 months, according to a story I saw. Seems he and Alexander didn't get along like he and Randall Smith. Santana is still using that '73 Mark I. He sounds better with a Boogie anyway. It's his sound.

Christopher Cross' "Fly like The Wind" features a nice Dumble solo at the end. Hard to take that "guy's" voice though.

Lukather's solo on Rosanna is another famous Dumble solo. He sold his Dumble on eBay. I actually saw it. Now he uses Rivera Knuckleheads, the perfect amp for him.

Carlton usually tours with 2 Dumbles, as does Robben Ford. I've seen recent Carlton with Boogie Mark IVs as well.

[Jazzarian]

Everything north of Willets is good retirement country - beautiful scenery, inexpensive property for the most part, and low cost of living.

The last time I bought some ash (a couple of years ago), it was around $2.80/bf. That's about 30% less than oak, looks as pretty and works a lot easier, IMO. It may very well be a good cash timber crop. I don't really know what a fancy, finger-jointed cabinet should cost but they're probably making a pretty nice gross margin on those.

As I said, I know nothing about Dumble amplifiers and, if the designer is not an engineer, no surprise there. Neither was Leo Fender, right ? I probably shouldn't say this, might get flamed for it, but designing vacuum tube musical instrument amplifiers is pretty simple stuff. (The performance parameters are indifferent - one would have to work fairly hard to screw things up.)

Back in "the day", most amateur radio operators, like Leo, could build a creditable audio amplifier for thirty bucks U.S. and a weekend's work. The parts were in mass production, available from surplus sales, CHEAP.

I'd say that a person with a rudimentary knowledge (high school level) of electronics, willing to do some reading and research on the subject and reasonably adept with tools can build a damned GOOD tube amplifier, probably for around $300 U.S. (~25 watts). Electronic test equipment is almost throwaway-cheap these days, so for a couple of hundred bucks more, one can equip a small lab bench, capable of trouble shooting these things.

It's not even close to the level of effort and knowledge required to design an equivalent performance solid-state amplifier. No offense intended to anyone who builds their own equipment. The success of any project can be defined by the ability to meet cost, schedule and performance goals. It doesn't take an engineer or a manager to do this, just a motivated person who knows what they want and how to get it.

cheers

Hey the world is your oyster. You could make custom amps AND cabinets.

Here's Robben Ford (on tour in Brazil) and Dumble.

Here's the Ceriatone Dumble clone. Kindly tell me what ya think of the pictures.
Ceriatone Amplification

[randyc]

LOL - the world would be my oyster NOW if I didn't have cancer.

cheers

P.S. Ford sounded great and the Ceriatone looked impressive.

[Jazzarian]

LOL - the world would be my oyster NOW if I didn't have cancer.

cheers

Oh crap, not what one wants after finally retiring. Best of luck with that.

[Jazzarian]

LOL - the world would be my oyster NOW if I didn't have cancer.

cheers

BTW, Alexander Dumble sells his amps to the stars in the $50,000 range. He makes them wait too. On top of that, if the stars want service, they have to kiss his ass.

Apparently he's a Hollywood eccentric type with a bad temper.