# Is what Mr. Dumble says true?



## bcmatt (Aug 25, 2007)

Do we have a physics expert that can confirm if Mr. Dumble's comments are accurate about why the harmonics are better in tube amplifiers?
http://www.youtube.com/watch?v=iVTj08qTwGw


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## starjag (Jan 30, 2008)

I am not sure about the electrons, but Dumble certainly looks all rock and roll with that bandana. The other videos in the series appear to be more about effects than tubes amps. Where is Dumble now?


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## bcmatt (Aug 25, 2007)

Ya, that bandanna is so hardcore.


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## devnulljp (Mar 18, 2008)

I wonder what happens to all the electrons as they pass through all the solid state parts of the amp other than the tubes...sounds like voodoo to me. I'm sure his amps sound great and all, but I think he's talking out his ass--not to say he can't hear what makes an amp sound great, but I doubt he actually knows how it's doing it beyond _this_ bunch of parts sounds like _this_.


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## zdogma (Mar 21, 2006)

Did you see the video of Henry Kaiser that goes with it:

http://www.youtube.com/watch?v=l1qCczGgSxw&feature=related

I don't know about fragile harmonics, but that just sucks. Dumble himself sounds fine.


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## Big White Tele (Feb 10, 2007)

zdogma said:


> Did you see the video of Henry Kaiser that goes with it:
> 
> http://www.youtube.com/watch?v=l1qCczGgSxw&feature=related
> 
> I don't know about fragile harmonics, but that just sucks. Dumble himself sounds fine.


Can you imagine how that would have sounded with out tubes???


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## Big White Tele (Feb 10, 2007)

devnulljp said:


> I wonder what happens to all the electrons as they pass through all the solid state parts of the amp other than the tubes...sounds like voodoo to me. I'm sure his amps sound great and all, but I think he's talking out his ass--not to say he can't hear what makes an amp sound great, but I doubt he actually knows how it's doing it beyond _this_ bunch of parts sounds like _this_.


He's been known to build his amps while eating Cheesburgers, so it blows the Tone Glove theory...


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## mhammer (Nov 30, 2007)

The world is chock full of people who, if you only examine the product, "know what they are doing", but if you ask them to explain it, all confidence goes out the window. Not a sin, but rather a fairly regular human occurrence. Did YOU ever get a decent explanation from your auto-mechanic, family doctor, dentist, lawyer, music-store sales rep, sex-ed teacher, parent? It happens.

Dumble makes exceptional amps. As a person, he is not exceptional.


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## Guest (May 28, 2008)

Big White Tele said:


> He's been known to build his amps while eating Cheesburgers, so it blows the Tone Glove theory...


Hehe. Damn. They'll never sell now. If I could get Dumble too endorse them I'd be able to charge $20,000 a pair. And sell the first batch of 100 to John Mayer!


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## Wild Bill (May 3, 2006)

bcmatt said:


> Do we have a physics expert that can confirm if Mr. Dumble's comments are accurate about why the harmonics are better in tube amplifiers?
> http://www.youtube.com/watch?v=iVTj08qTwGw


He's been trippin' on the brown acid, I suspect!

The audio harmonics themselves do not exist in the electron flow anyway. The electrons are just a medium for the amplifier to work. The flow has been modulated by an audio signal but in itself is not audio. So any harmonics are NOT fragile!:smile:

Other media can be used to amplify. Fluidics, even a flame envelope! Only when the final result is converted back to audio as in a loudspeaker pushing air do we have audio harmonics. These harmonics are not "fragile" - they are as strong as the moving air makes them. How fragile is moving air?

"Man, I'll bet there's enough cosmic energy in this bag of granola..."


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## bagpipe (Sep 19, 2006)

This is probably a bit childish, but it made me laugh. There was a thread on Harmony Central a few years ago, discussing the merits of Dumble amps. Someone posted the picture of Dumble from this PDF document:

http://schematicheaven.com/howard_dumble.htm

There was much discussion about how great or not the tone was, SRV used one so they must be awesome etc. Anyway, someone eventually posted this comment about the picture:

"He has a severe case of Dumble toe"

That was it for me! :banana:


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## starjag (Jan 30, 2008)

Wild Bill said:


> He's been trippin' on the brown acid, I suspect!


As always, Wild Bill to the rescue 

Say you have two speakers of similar characteristics, one driven by a tube amp, the other by a solid state amp. A guitar is connected to both amps via a A/B/Y box using the Y option. All cables used are of similar characteristics.

You strum a chord and notice that the speaker driven by the tube amp produces certain harmonics that are not produced by the speaker driven by the solid state amp.

Certainly, those harmonics where there in the natural string vibrations when the chord was strum. And those string vibrations were converted to the same electron flow that fed the two amplifiers.

So is the issue how the electron flow travels in different media? Or how different media amplifies (or not) an electron flow at different stages before it hits the speaker? What happened to the electrons in the solid state media that did not hit the speaker to produce those harmonics?

Okay, now I will stop taking acid myself


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## greco (Jul 15, 2007)

The tone is in the cheeseburgers


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## mhammer (Nov 30, 2007)

Whatever the basis of Dumble's tone, if you've ever heard one live, you become an instant believer. He may be ornery and a crackpot and desperately in need of a personal trainer and style consultant, but the man *knows* tone. I had the pleasure of hearing Sonny Landreth torture a Dumble at Bluesfest here a couple years ago (and happily he is returning this year), and became convinced.

Similarly, many worship at the altar of the late Ken Fischer, and apparently he was not always God's gift to sociability either. Like I said, it happens.


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## Wild Bill (May 3, 2006)

dr_iggi said:


> As always, Wild Bill to the rescue
> 
> Say you have two speakers of similar characteristics, one driven by a tube amp, the other by a solid state amp. A guitar is connected to both amps via a A/B/Y box using the Y option. All cables used are of similar characteristics.
> 
> ...


Ah, this is a different situation! Both amps reproduce the harmonics. Their circuitry however is very, very different.

Tube amps run what's called a push-pull circuit most of the time. Each output tube amplifies one phase of the signal waveform. (Think of it as the top half of the wave and the bottom half. That's not strictly true but it serves as a working man's model. The two halves are combined in the output transformer.

This circuit tends to reduce odd harmonics. Even harmonics might actually be enhanced!

Solid state amps don't use output transformers. They use what's called a push-push circuit, where the transistors work in phase. This means they tend to reduce even harmonics and enhance the odd ones.

The two circuits are doing exactly the opposite thing to any musical note. A musical signal is full of harmonics, sometimes called overtones, of different amplitudes. This is what makes a violin A sound different from a piano A, or an A blown from a horn. The shape of the signal is not a simple sine wave ~ but something very bumpy and complicated.

So it's not the fact that you're using tubes or transistors to amplify the signal. It's the circuit. If you used a Champ, which is a Class A single-ended amp, it would sound more like the transistor amp, as long as you kept the volume down in clean territory. You CAN build transistor push-pull amps! The very first ones were done that way 'cuz no one knew anything but tube circuits.

As Gilda Radner said : "It's always something!"

:food-smiley-004:


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## Wild Bill (May 3, 2006)

mhammer said:


> Whatever the basis of Dumble's tone, if you've ever heard one live, you become an instant believer. He may be ornery and a crackpot and desperately in need of a personal trainer and style consultant, but the man *knows* tone. I had the pleasure of hearing Sonny Landreth torture a Dumble at Bluesfest here a couple years ago (and happily he is returning this year), and became convinced.
> 
> Similarly, many worship at the altar of the late Ken Fischer, and apparently he was not always God's gift to sociability either. Like I said, it happens.


Mr. Dumble pioneered a new form of overdrive circuit. I smile when I see the "Dumble" kits being sold on the Net. I guess folks don't realize that there were a NUMBER of drastic revisions to his circuits! The kits seem to be based on only one of them.

More than just the OD circuit, Dumble understands how to "tweak" the voicing of an amp to suit a particular player. He changes wiring and parts values at the drop of a hat. He also will use higher than necessary tolerance parts so that they have an odd and scary looking value, to further confuse those guys who don't know their theory but only how to parrot and copy. The amp he built for Reuben Ford is no doubt different from the one owned by Larry Clarke or the one built for Carlos Santana.

Most of the masters understood how their circuits worked and how parts values changed tone. Ken Fisher, Gar Gilles, Pete Traynor, they all knew. Younger guys like Andy Fuchs keep the flame alive.

It's why when I build a custom amp I usually chat with the player for a while to get a feel for his usual style and desired sound and of course, his usual guitar and pickups! This means a few changes are involved.

We stand on the shoulders of giants!:smile:

:food-smiley-004:


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## Stratin2traynor (Sep 27, 2006)

bagpipe said:


> This is probably a bit childish, but it made me laugh. There was a thread on Harmony Central a few years ago, discussing the merits of Dumble amps. Someone posted the picture of Dumble from this PDF document:
> 
> http://schematicheaven.com/howard_dumble.htm
> 
> ...


LOL!! That is nasty! I bet you camels bow down to him.


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## Wild Bill (May 3, 2006)

Paul said:


> Speaking of.....whatever became of the amp you were going to build for our friend from April Wine???


Barely started, I'm afraid. This has not been a good year personally. A lot of sickness and eventually death on my wife's side of the family. Then I had a heart incident and it seemed every time I turned around there was another doctor's visit, leading to a quadruple bypass operation. I've been home for 8 weeks recuperating and I've started some amp work but I'm still kinda slow.

Bench pressing Twins? I can't bench press a Champ!:smile: Still, I'm getting stronger each day, more and more. I think the operation worked!

At the rate I'm going I expect to start back in to David's amp in the next week or two. 

As promised, there will be pictures...

:food-smiley-004:


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## rhh7 (Mar 14, 2008)

Pulling for your speedy recovery, Wild Bill. Do I understand you correctly, that a solid state amp which was designed as a push-pull might sound very much like a tube amp?

Seems possible then, to have an amp which would sound almost as good, without the expense of tubes...or am I missing something?

Thanks a million!


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## Hamm Guitars (Jan 12, 2007)

rhh7 said:


> Pulling for your speedy recovery, Wild Bill. Do I understand you correctly, that a solid state amp which was designed as a push-pull might sound very much like a tube amp?
> 
> Seems possible then, to have an amp which would sound almost as good, without the expense of tubes...or am I missing something?
> 
> Thanks a million!


 
I'm sure Wild Bill will be along to answer this for ou, but I'll add my 2 cents as well....

Solid state power amps are designed to deliver clean power - they strive for low distortion levels and extreamly low harmonic distortion levels. They are not designed to break up musically, as they are not intended or designed to be used in that manner. Over driving a power amp (ss) results in clipping, which does not sound good. If you are over driving a solid state amp, you need a more powerful amp for the given application.

Back in the 80's MOSFET power amps were popular. These tended to break up more gracefully than other types of transistor power amps, and you would see them used in guitar rigs and so forth.

So to recap, Solid State Power amps are designed to be as transparent as possible, and should not be driven into clipping. They are made to do what they do best, amplify and not colour the sound.

With that being said, there are differences when it comes to the sound of power amps, for a large part it is dependant on the slew rate of the amp as well as the class and quality of the design. A QSC MX1500 (pretty much a 'classic' as far as power amps go) is a good example of what an amp sounds like with a low slew rate. They sound great for subs, the low end and the mids, but nothing to write home about when used as a horn amp. A yamaha PD2500 has a high slew rate, and is great for highs (as a horn amp), and not so great anywhere else (but definately still usable).

For the most part, the differences of the sound of individual amps can be overcome with changes in the way the system is set up and graphed. The most important factor is that you have enough headroom and don't run out of clean power.


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## mhammer (Nov 30, 2007)

Wild Bill said:


> Barely started, I'm afraid. This has not been a good year personally. A lot of sickness and eventually death on my wife's side of the family. Then I had a heart incident and it seemed every time I turned around there was another doctor's visit, leading to a quadruple bypass operation. I've been home for 8 weeks recuperating and I've started some amp work but I'm still kinda slow.
> 
> Bench pressing Twins? I can't bench press a Champ!:smile: Still, I'm getting stronger each day, more and more. I think the operation worked!
> 
> ...


I had my own triple in 2000. Even if one is still feeling like you might have a chest explosion à la John Hurt in "Alien" if you have to fart, I am pleased to report that there is considerable life afterwards. And if I might add a bit of kiss and tell..."That's what SHE said!" :wink:

Funny bypass story. Two actually.

Woke up from the surgery in post-op, with tubes up the wazoo as I'm sure you're aware, and shaved like a Vegas showgirl. I was groggy and stiff...and itchy. My wife, bless her soul, is at my bedside and asks "Is there anything I can get you or do?". I motion to her to lean in, which she does. She thinks she is going to get some sort of deep profound message, but I mumble "PLEASE scratch my balls. They are SO itchy. I can't reach them and I can't ask the nurse to do it." The nurses hear this and of course keel over laughing. My wife, wonderful woman that she is, reaches under the blankets nonchalantly, and "applies treatment to the afflicted area".

Second tale.

Some 8 weeks post-op I'm driving around when I feel this really irritating prickly sensation on my chest. Given that the cutting of the sternum means the nerves do not grow back flawlessly, one is bound to have some bizarre sensations, and I had plenty (I still have an area along about 1" of the wound where if I touch it it feels like someone is tuggin at my armpits rather than a sensation in the middle of my chest). I figured this prickly sensation was simply one of those, and that I would have to get used to them as the price for being alive, and kept driving. But the prickly sensations were REALLY irritating and interfering with my ability to concentrate at the wheel.

Finally, I stopped the car and got out because the pins and needles sensation on my chest and belly was driving me nuts. And that's when I found out that the poppy I had pinned to my shirt pocket (it was late October) had slipped off the pocket and slid to the inside of the shirt, where the pin had been repeatedly jabbing me in the gut. Apparently, the pins and needles sensations *were* literally pins and needles.

Less funny story. Before I had the bypass, I was functionally limited to about 100yds. Walking the 2 blocks from my office to the bus home (VERY slowly), I would have to stop halfway and "nitro up" to make it the rest of the way. Now I can run for the bus for blocks and push the car out of a snowbank and, uh, "be a better husband".

Our respective swimsuit-model careers may be over Bill, but it's good to be here and good to have you with us. :food-smiley-004:


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## Wild Bill (May 3, 2006)

mhammer said:


> Given that the cutting of the sternum means the nerves do not grow back flawlessly, one is bound to have some bizarre sensations, and I had plenty (I still have an area along about 1" of the wound where if I touch it it feels like someone is tuggin at my armpits rather than a sensation in the middle of my chest).
> 
> Our respective swimsuit-model careers may be over Bill, but it's good to be here and good to have you with us. :food-smiley-004:



Thanks, Mike and Andy! I'm at that 8 wk point and am experiencing those chest sensations you mentioned. 

As for Paul's question about a solid state push-pull amp, it would not sound exactly the same as a tube amp. The reason is that transistors tend to be long on current and short on voltage ratings. So they might be run on 80 volts max. This would mean you'd have to wire up that output trannie with battery booster cable gauge wire. It would end up kinda big!

FETS can run on high voltages similar to tubes but they also turn on and off with characteristics different from tubes. So you might get something similar but not truly the same.

What's more, one of the biggest cost savings between tube and solid state designs is eliminating the output transformer. Put it back in and tubes again look like a better deal.

Tubes and transistors are just very different in the way they operate. It makes the most sense to use them where appropriate. 

:food-smiley-004:


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## Adicted to Tubes (Mar 5, 2006)

So basically what everyone is trying to say here is that because tubes are inefficient,dated devices,and require antiquated output transformers to power speakers,is the real reason they sound better than solid state amps.
As far as guys dumping on HD,you go on camera and get asked some general question about why tube amps sound better than solid state and lets' see what you say.He gets a 10 second answer and he says something short and sweet and people get all judgemental about his knowledge level.
Fact is he makes great amps that pro's love and we can't afford and we get all freaked out.Those clones out on the market can sound great.I build a version called an 'Overdrive Rocket' and it's getting some attention by some great local players.
The bottom line? Dr D was brilliant for his time and made some inovative designs work very well.We are just now unravelling some of his secrets and applying them to guitar amps.Maybe Randall Smith found out earlier but frankly Boogie amps are stale and lifeless compared to a Dumble.
Why are tubes still number one for guitar Amps? 'Cause they still sound better than the best solid state amps.

www.claramps.com


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## bcmatt (Aug 25, 2007)

Adicted to Tubes said:


> So basically what everyone is trying to say here is that because tubes are inefficient,dated devices,and require antiquated output transformers to power speakers,is the real reason they sound better than solid state amps.
> As far as guys dumping on HD,you go on camera and get asked some general question about why tube amps sound better than solid state and lets' see what you say.He gets a 10 second answer and he says something short and sweet and people get all judgemental about his knowledge level.
> Fact is he makes great amps that pro's love and we can't afford and we get all freaked out.Those clones out on the market can sound great.I build a version called an 'Overdrive Rocket' and it's getting some attention by some great local players.
> The bottom line? Dr D was brilliant for his time and made some inovative designs work very well.We are just now unravelling some of his secrets and applying them to guitar amps.Maybe Randall Smith found out earlier but frankly Boogie amps are stale and lifeless compared to a Dumble.
> Why are tubes still number one for guitar Amps? 'Cause they still sound better than the best solid state amps.


It was never my intention to dump on Dr. D. If I didn't value his amp-designing abilities, I wouldn't have brought up the discussion in the first place. I merely wondered if his explanation was correct enough to use myself to explain to people. However, I was a bit nervous about suggesting that the nicer harmonics came from allowing electrons to live easier in a vacuum. This post has helped me to confirm that I "probably don't want to go there".


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## Wheeman (Dec 4, 2007)

For what its worth:

I've got a solid state (Marshall 10-watt) and tube amp (Fender Hot Rod Deluxe 40-watt). My cats like to sleep in my room because it is the warmest one with the most sun throughout the day. They know the difference between the tubes and the chips. Playing either amp at the same volume, the cats only bolt out of the room with its through the chips. On the other hand, I can play the tube without a hitch and at a louder volume. 

If my cats agree, there must be something to it.


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