What makes Dumble style amp sound better?

[vibratoking]

I don't agree that objects have the ability to transform themselves over time. Yes, things change due to environment. Did Pearly Gates sound great in 1965? Probably. Does it sound any better today than the day it was made 1959? I doubt it. I have played new Les Pauls that sounded better to me than vintage ones.

Magical thinking doesn't normally advance technology. Stearing a novice builder in the direction of 'seasoned' iron on the premise that it is part of the Dumble magic is wrong, IMO. I was just pointing out that there isn't even a definition of what seasoned means in this sense. I know you are not doing the stearing, but it has been mentioned in this thread. There of plenty of other useful things to focus on when considering a Dumble build, especially for a hobbyist.

My $0.02. Respectfully.

[talbany]

Magical thinking doesn't normally advance technology

Why do we have to think of it like some magical thing?

Example: We know time has an effect on electrolytic caps and tubes, they eventually go bad and are no longer efficient and working properly..This generally causes the amp to (for most ) sound bad, so we change them and maintain the amp... We don't refer to that part as having Bad Mojo or no magic left etc..
Do we ever consider that aging of some components (especially transformers) might have appealing qualities, (we are dealing in sound not performance) we now label this as mojo or magical properties and it has to be proven to us when in fact some just might prefer the sound of an output or power transformer that is just not as efficient as it was when it was new (especially an amp with built in overdrive).Why is this so hard to believe...IMO there is really nothing to advance

I agree...Seasoned Iron is purely a taste thing and not needed to build a good sounding Dumble style amp!!

Tony

[CHIP]

I've built a number of great sounding amps in the last decade, never sold one.
One I didn't build is a '64 Super Reverb and it's the only one with "seasoned iron".(It came with it.)
And that particular amp has no more magic than the ones I've built.
That's my observation.

[rdjones]

Without getting into those areas that one has to believe in for it to exist, (magic, Mojo, etc.) seasoned simply means it has been subjected to numerous heating-cooling cycles, and has developed a 'patina' of rust on the exposed untreated surfaces.
It's possible that the cycling can drive off moisture and other initial or residual manufacturing impurities.

There's also the reliability factor where expected lifetime (MTBF) is greater after a certain "infant mortality" period, which is well before the attainment of 'seasoning'.

IMO seasoning cannot take place without extended use.
Whether such seasoning can lead to any tone or other improvement will remain up for debate.
I believe that an audible difference, if any, will be orders of magnitude below other more well known processes of break-in of other components, particularly speakers.

reddog

[Smitty]

IMO, the only way one can conclude that output transformers do not have different permeability at different frequencies after break-in is through an inadequate understanding of metallurgy and magnetism. At rated power the laminations in the core actually move. Have you ever listened to your power transformer 'hum'? It's vibrating as the magnetic field expands and collapses.

Take an iron nail and bend it back and forth until it breaks in two. Then tell me it hasn't changed. It changed as soon as you bent it the first time. It's not some magical thing that happens as time passes its the process of changing the metal through stress. The more you do it the more it changes.

Same goes for capacitors. The dielectric actually moves.

Think of the process as similar to breaking in new leather shoes or a baseball glove.

These changes are different than changes in the oxide layer which are environmental.

[talbany]

Here is another thread that discusses this and others have noticed it as well..These are mostly peoples opinions but we should consider them noticed..I generally have the same findings as the OP..

https://tubeamparchive.com/viewtopic.ph ... 15768b0f4a

Tony

[vibratoking]

IMO, the only way one can conclude that output transformers do not have different permeability at different frequencies after break-in is through an inadequate understanding of metallurgy and magnetism.

I have taken several courses on electromagnetic fields and theory, but my understanding must be inadequate. Perhaps you can correct my thinking with something other than bent nails? Maybe you can explain the quantitative theory regarding the frequency dependence of permeability and how it changes after break-in? I assume that theory will also define exactly what break-in is. I am always open to learning.

[lovetone]

Could some of this be that old transformers where wound in a different way which might effect the tone?

I have read that for Hifi the primary winding has a better frequency response with more liner response when the winding is split up into sections one wound over the other.

I guess a test would be to install an old output transformer, have a listen to the tone and capture a spectrum analysis of the output and then install a new one of the same. That way you would see any difference on paper and might hear any difference in tone.

Take it a step further, burn the transformer in for a few hundred hours and check the results.

Just an idea for someone with the gear to do it.

[bluesfendermanblues]

Could some of this be that old transformers where wound in a different way which might effect the tone?

I have read that for Hifi the primary winding has a better frequency response with more liner response when the winding is split up into sections one wound over the other.

I guess a test would be to install an old output transformer, have a listen to the tone and capture a spectrum analysis of the output and then install a new one of the same. That way you would see any difference on paper and might hear any difference in tone.

Take it a step further, burn the transformer in for a few hundred hours and check the results.

There's a Professor at Regenburg University in Germany, Manfred Zollner, who has made a lot of test of what matters in guitar tube amps. He has build a test setup with 7 different Output transformers. He and his student couldnt hear of measure any difference between ordinary Hammond and the like and very expensive mercury magnetics etc. Only the very cheap ones from Conrad.de (the german equivalent to Radio Schack) did have a poorer sow end.

I don't know why this thread has developed into a consensus, that 'what makes a dumble sound different?' is due to seasoned iron.

I have several fender amps with old 60' Iron and none of these sound anything like my three dumble amps either clean or in OD.

IMO what makes a difference between Dumble's amps and the rest is schematic design, voltages and carefull construction and selection of components and not the transformers. IMO, Any medium quality transformer (with the proper wattage) will do the job.



Just an idea for someone with the gear to do it.

[talbany]

A simple Google search brought this up for me...There is no marketing reasoning why Sergio would lie about "seasoned iron" also this is common knowledge in the amp manufacturing world IMO..
So judging by what a major transformer manufacturer suggests as well as some members here, if seasoned iron is something that you are interested in learning about my advice would be to do some empirical testing on your own first...Get some 20-30 year old iron (same type same brand) and put it on one of your ODS's and see if you can tell...Listen when you change out an old replacement transformer and see what you hear..If you notice a difference and want to take it further do some frequency analysis and some blind taste tests with some local players see if they notice (Ken Fisher did this)..Do some research on the cause and effects of aging in regards to bobbin material,interleaving type,humidity,patina,rust (which can be a good thing) core magnetism and the breakdown on insulation material and how heat effects power transformer regulation over time,.
Much of the info resides out in Google land...I think there has been enough evidence here to support an investigation, if you want to dig a bit deeper in the world of guitar amps...IMO Some things are better heard and proven on your own..Here it is

http://www.mercurymagnetics.com/pages/n ... nes-02.htm


One final, and perhaps most important point, which Mercury Magnetics™ vice-president Sergio Hamernik added: “The transformer in a 30-year old amplifier will sound characteristically different as it ages compared to a new replacement, even if the replacement is built with the same materials.” And while the component materials and manufacturing methods used by Mercury Magnetics™ are made to the exact same standards as the originals (Sergio also added “Every turn, every layer, is copied and blueprinted exactly, including any original manufacturing anomalies found during our rewinding process of the original, vintage specimen), Sergio emphasized that the ToneClone™ series transformer will still sound different, but “like the original did in the amp when it was new” and not like the tone of the aged 30-year-old transformer. Since much of our favorite tones were recorded at least 20 years ago, perhaps this isn’t such a bad thing?

Sergio did suggest breaking in the new Axiom® transformer with 20 to 40 hours of hard playing time. He also said that this break-in period will get the transformer about halfway there to that 30 year seasoned tonality. Thermal cycling and running magnetizing currents through the transformer (playing the amp) will definitely sweeten things up in that period of time.

Good Luck with your tests!
Tony

[Smitty]

IMO, the only way one can conclude that output transformers do not have different permeability at different frequencies after break-in is through an inadequate understanding of metallurgy and magnetism.

I have taken several courses on electromagnetic fields and theory, but my understanding must be inadequate. Perhaps you can correct my thinking with something other than bent nails? Maybe you can explain the quantitative theory regarding the frequency dependence of permeability and how it changes after break-in? I assume that theory will also define exactly what break-in is. I am always open to learning.

Because I understand it myself does not mean that I have the ability to 'correct your thinking'. I wasn't aware there was a 'quantitative theory regarding the frequency dependence of permeability and how it changes after break-in'. Sounds like troll bait to me.

I typically don't bite on the deductive-is-the-only-type-of reasoning bait. As a practitioner I don't limit my reasoning to pure deduction. I also include inductive reasoning (seems especially appropriate for transformers).

So if you can accept that permeability is frequency dependent, that permeability is affected by continued physical stress, and that the operation of a transformer applies physical stress to the laminations, you can conclude (though inductive reasoning) that the frequency response of a transformer will change after use.

Which part are you struggling with?

[Zippy]

IMO, the only way one can conclude that output transformers do not have different permeability at different frequencies after break-in is through an inadequate understanding of metallurgy and magnetism.

I have taken several courses on electromagnetic fields and theory, but my understanding must be inadequate. Perhaps you can correct my thinking with something other than bent nails? Maybe you can explain the quantitative theory regarding the frequency dependence of permeability and how it changes after break-in? I assume that theory will also define exactly what break-in is. I am always open to learning.

Because I understand it myself does not mean that I have the ability to 'correct your thinking'. I wasn't aware there was a 'quantitative theory regarding the frequency dependence of permeability and how it changes after break-in'. Sounds like troll bait to me.

I typically don't bite on the deductive-is-the-only-type-of reasoning bait. As a practitioner I don't limit my reasoning to pure deduction. I also include inductive reasoning (seems especially appropriate for transformers).

So if you can accept that permeability is frequency dependent, that permeability is affected by continued physical stress, and that the operation of a transformer applies physical stress to the laminations, you can conclude (though inductive reasoning) that the frequency response of a transformer will change after use.

Which part are you struggling with?

Where is the physical stress coming from? Are you suggesting sufficient physical stress to change the physical properties?

[talbany]

Where is the physical stress coming from?

Vibration..

Tony

[Zippy]

Where is the physical stress coming from?

Vibration..

Tony

Understood. Has that been shown to be true? My degrees are in applied physics and materials science, and I've not read papers regarding high cycle fatigue effects on electronic effects. That doesn't mean they don't exist. In fact, I'm happy to help with a literature search, if someone thinks there is a reason to believe it has a basis.

I think the mechanical stresses and temperatures are too low.

I could believe there is some magnetic order from manufacturing that becomes more random with age, but I don't know how strong that effect could be on the coupling, or whether it would be in such frequency ranges that don't matter in this application.

[NickC]

Where is the physical stress coming from?

Vibration..

Tony

I've heard of clinical studies claiming that plants grow better when exposed to classical music.

God only knows what stress rock-n-roll puts on a transformer.