Milbert Amplifiers

Guitar amps using traditional audio output transformers (i.e., magnetic filters) inescapably transform tone into something no longer what was played. While sonic magic comes from active components (tubes, electron valves), audio transformers impart homogenizing sonic shadow, having traditionally been necessary evils in tube amps. Until now.

Mating any desired combinations of power tubes near-perfectly with any speaker(s), the Milbert GAGA tube guitar amplifier brings musicians closer to their musical truth and ecstasy. GAGA eliminates transformers to unleash tubes and dramatically unveil tone in thoroughly unique ways that can be measured, heard, played and enjoyed.

Begun decades ago first written several years ago and last updated in February 2016, what follows is an organic white-paper with relevant quotes from Mr. Dumble and other industry icons and cultural luminaries, that incorporates additional information, sources and clarifications as humanity progresses; includes DIY tests. PDF synopsis.

Necessary evils in typical tube amps, traditional transformers always filter the sound. Since almost no one has ever played tubes without that significant veil, essentially all ideas of "good tone" (and what begets it) have been jaded by sonic shadow.   Using innovations specifically made to convey maximum tube tone, GAGA finally realizes with tubes what no one thought possible: The verifiably purest possible tube tone and performance, without traditional audio output transformers or massively paralleled power tubes. Unlike all others, GAGA is a thoroughly new kind of tube amplifier for guitarists and musicians.

"Freed from 'driving' an homogenizing metal bulk, the output tubes really shine. It's shocking how different various tubes actually sound, once unleashed, and the sonic benefits hardly end there."

GAGA eliminates all traditional power magnetics and the ubiquitous audio output transformer to unleash maximum tube performance and Clarity of Tone^™ Hearing is believing, playing is proof. »

"Beyond mere weight reduction, removing the audio output transformer from power tube amplification brings numerous audible improvements, including magnified detail resolution, dynamic accuracy, and thorough tonal de-homogenization."

GAGA is a new kind of amplifier and understanding what it can do requires new words. » Its transparency, purity and clarity leave 'clean' in the tonal dust. GAGA puts you as close as you can get to you, the instrument, and the tubes - only louder, purer. Measured and shown below, this is important as accomplished musicians, instructors, mavens » and masters exhort 'starting with a good clean tone'. In the world of guitar amps - nearly all rooted in decades-old designs and ideas - GAGA is meaningfully unique, resoundingly fresh and delightfully de-homogenizing. GAGA lets you break completely free from the old tones, emulate them, or mix your own unique tone from among literally hundreds of thousands of possible tube combinations. There is no other guitar amplifier anything like GAGA.

What good tube "tone" looks like

Left drawing - The Ideal

Idealized tube response curves: Each curving line shows how much plate current flows at one grid voltage and some fixed plate voltage. Notice the relatively straight, defined, evenly-spaced lines: Deviation indicates unfaithful amplification - an impossibly perfect tube would exhibit no curves at all. Drawing shows only the upper, "push" curves. ("Pull" curves would mirror down and to the left.)

Middle photo - GAGA being Ideal

The complete "push-pull" response of four 6L6 tubes used in GAGA. Notice the relatively straight, defined, evenly-spaced lines: You've seen them before, in the ideal drawing, and they indicate faithful amplification, accurately conveyed tube characteristics, subjectively superior clarity of tone. Guitar books, websites, instructors and accomplished musicians readily acknowledge the crucial need to 'start with a good clean tone'. Contrast the next photo, showing unfaithful response of the same tubes measured in a high-quality amp which nevertheless imposes significant corruption.

Right Photo - The Sonic Blender

The same 6L6 tubes used in a tube amp having a superb-quality traditional audio output transformer ("stock" ones often perform worse, hence the upgrade aftermarket). Obvious is perhaps what is variously described as lost impact and power, dulled nuance, deflated dynamics, confused or falsified tone - or munge, flub and smear. Apparent wilt also reveals magnetic delay that further slows traditional amps, and this changes with frequency - more evidence of homogenizing 'sonic blending': You don't sound like you anymore but what the transformer makes you sound like.

"Transformers tend to smear the sound and limit the frequency response, and while many manufacturers wind great transformers, there's no transformer like no transformer at all -- something that becomes clear when you hear...bass as deep as that from a solid-state design, but with levels of detail and tunefulness that most solid-state amps miss. The difference is not subtle." »

Luke Manley (Manley/VTL) » "Multiple output taps [present in typical audio output transformers as 4-, 8- and 16-Ohms] are inherently a serious compromise in performance. Inactive winding-segments are inevitable in a tapped transformer and result in additional leakage inductance that affects high-frequency response." GAGA completely avoids this.

Malcolm Moore explains bandwidth » "For a guitar, the audio spectrum needs are wide. ...The lower open E string has a fundamental of about 128 Hz, and significant harmonics are the second, fourth, sixth and eighth meaning the spectrum here extends to 1,024 Hz. On the twelfth fret on the upper E string the fundamental is about 1,024 Hz, and the spectrum extends to about 8.192 kHz. On the 21st fret the fundamental at C# is about 1,722 Hz, and the spectrum extends to almost 14 kHz! The...frequency response needs to be virtually flat from less than 100 Hz to greater than 14 kHz to faithfully reproduce the vibrations from the guitar strings - before anybody starts to play with the audio spectrum, develop distortion, or introduce echo and / or reverberation." From this perspective, speakers having significant roll-off above 5 kHz combined with amps that presumably don't do much better no doubt caused need for the popular "bright" switch and various "equalizations".

Manley Labs: "The downside with iron [audio transformers], and there is always a downside, is ... time smear ... with sounds that have lots of energy (and tightness)..." »

Regarding magnetic lag, hysteresis and "loopy" distortions: "... B [X-axis] is the notation for magnetic flux density and H [y-axis] is magnetic force. Plotted together, they graphically illustrate hysteresis ["magnetic lag"]. A large separation between the magnetizing and demagnetizing curves [i.e., a "fat" loop] shows much hysteresis, and a small separation [i.e., a "narrow" loop] approaches the ideal of no hysteresis." - Line-level transformers in High-End Audio, Mark J. Medrud, Design Engineer, Jeff Rowland Design Group, Inc., 17 March 1995. GAGA suffers no magnetic hysteresis and therefore conveys with immediacy, clarity and impact the purest-possible tube characteristics.

R. G. Keen, geofex.com, Output Transformer Q&A, on various magnetic distortions including uncorrectable loop glitch: "Inherent (or Iron) Distortion: ...iron in a transformer has to be driven to a certain magnetic flux level to couple signals to the secondaries. ...the nature of the iron itself ... is non-linear. ... Excess Distortion: [Around] the crossover point where one tube turns off and the other tube carries all of the power load ... there will be a glitch in the output waveform [that] can not be biased away. [Inferior] output transformers often have this kind of distortion and sound "harsh"." »

Torroidal-core transformers have been used in some amps seeking to alleviate these and other problems, but they also face inevitable limitations. After all, bigger or "better" audio magnetics in different shapes are still audio magnetics. What's needed is a new way to connect tubes and speakers.

GAGA offers a new way forward.

Conclusion of Measurements

Most musicians have not yet experienced faithful tube amplification without the wide-ranging penalties always imposed by traditional magnetics. Tube performance in GAGA demonstrably meets its ideal. What conveys is the purest-possible transfer characteristics of the tubes and audio signal without any magnetic munge. Toward the goal of maximizing musical ecstasy, GAGA finally provides with tubes a widely-acknowledged, preferable sonic 'starting point', to which distortions and effects - electrical and magnetic - may then be added to taste:

R. G. Keen, geofex.com, Output Transformer Q&A: "You can model any transformer ... you can accurately model everything about any transformer. There are no mysteries hiding in there. The component values are all measurable, and to a certain extent predictable from the start. Any transformer can be copied..." »

Hear and Prove it to Yourself

Ideas for further research -

CAUTION SHOCK HAZARD - Do not allow an unloaded, open-circuit condition or speaker-disconnect during testing, as an induced, undamped, high-voltage flyback may cause electrical arc, physical damage or harm, shock hazard, death. High-voltage can be damaging and deadly. These tests should only be performed by a qualified electronics technician. Proceed at your own risk.

• Put two identical audio output transformers back-to-back at the output of any transistorized amp. Connect all identical plate windings between first and second transformers and carefully insulate these connections for high-voltage (which may exceed 400 volts or more, depending upon the transformers used). Feed the amp "backwards" into the first transformer's Ground and 8-Ohm taps. Connect speaker as a normal load across Ground and 8-Ohm taps on second transformer. The two transformers are now in series between amp and speaker, the second reversing the voltage gain of the first. Confirm noticeably worse sound and performance. Move the amp's global feedback to the output of the second transformer, with appropriate network as necessary. Confirm sound and performance still worse than with no transformers present. This demonstrates audio output transformers do not add "magic" or desirably interact with speaker and cabinet to improve tone or performance, even if "corrected" with global feedback. This is why traditional tube amps never use two audio transformers, because the negative impact upon tone and performance would be audibly if not measurably worse.
• Repeat above scenario except with tube amp substituted for transistorized amp. Play signal through added transformers to confirm the sound and performance degradation versus plain amp. Move global feedback to output and confirm no improvement.

The above tests demonstrate that adding audio magnetics does not improve performance and instead causes audible and measurable degradation. We've done these tests, but you don't have to take anyone's word for it - you can prove to yourself: The magic of amplification comes from the electron plasma of tubes; there is no magic in bulks of wire and metal. So what happens when the metal is taken out of the way? Naturalness, dynamics and totally tubular tone leap forth unbridled. If you think we're exaggerating, try it; floor yourself by discovering how much your tone is jaded by transformerized tube amps.

• Effectively eliminate the audio output transformer by comparing GAGA to a traditional, transformerized tube amp. Note GAGA's dramatic unveiling of dynamics, articulation, organic dimensional naturalness, purity, and heightened sensitivity to different tubes, guitars, and players. Beyond mere weight reduction, removing the audio output transformer from power tube amplification brings numerous audible improvements, including magnified detail resolution, dynamic accuracy, and thorough tonal de-homogenization.

Mr. Dumble's Good Tone via Hot Plasma

Perhaps "good tone" involves vacuum tubes' hot plasma, electron cloud and space-charge as the sources of magic, and not bulks of metal wrapped with hundreds or even thousands of feet of wires having inumerable crystalline lattice fractures, magnetic domains, and better-known drawbacks including frequency limitations and phase anomalies?

Mr. Dumble: "The more fragile harmonics can survive in a vacuum tube; [whereas] they seem to be eliminated or squashed in a ... crystalline lattice. ...the physics of it: electrons [i.e., the sonic qualities represented by their infinitesimal analog motions] can survive in a free-space vacuum..." [versus being homgenized and "digitized" by discrete forces and effects] youtube

Electron Movement through Solids - Energy Bands and Semiconductors - http://youtube.com/watch?v=KYYWZhsgVPc -- Materials vary greatly in their ability to conduct electron flow. A "digitalization" may take place that has bearing on sound quality and overall performance, fidelity and response.

Not to beat it to death, but metal and semiconductor solids appear to intrinsically counter sonic smoothness -- Modern Physics Lecture 27, Introduction to Energy Bands https://www.youtube.com/watch?v=T8WCr5axQXM and Modern Physics Lecture 28, Mechanism of Conduction in Metals https://www.youtube.com/watch?v=hflMR6_FJPk. Electron movement through hot plasma in a vacuum tube is not affected by (and needs no "feedback" correction for) these distorting domain quantizations.

Further into esoterica, certainly Dr. Judy Wood and John Hutchison's "Hutchison Effect" (i.e., dramatic state-change, if not modern alchemy, of solids and the total levitation of heavy objects, inexplicable by common science) reveal otherworldly effects of modulating fields within high-voltage gradients. Doesn't this describe conditions inside vacuum tubes? Looking further back for magic in a vacuum reveals the (Sir William) Crookes (cathode ray) tube (CRT), developed by a Golden Dawn / Theosophical Society member purportedly in part to communicate with 'the other side'; further back appears the mysterious Dendera lightbulb of ancient Egyptian high technology, presumably illuminated by aetheric or pyramidal earth energies, much of which still beyond our present understanding. All this makes it clear we still don't know precisely what's going on, how or why - in fact, the exact definition of magic. More wonder.

Faraday's fibrous magnetic "scraping"

"Farady felt strongly that action at a distance is not possible thru empty space, or in other words, "matter cannot act where it is not." He considered space pervaded with lines of force. Almost everyone is familiar with the patterns formed by iron filings around a magnet. These filings act as numerous tiny compasses and orientate themselves along the lines of force existing around the poles of the magnet. Experiment has indicated that a magnetic field does possess a fibrous construct. By passing a coil of wire thru a strong magnetic field and listening to the coil output in headphones, the experimenter will notice a scraping noise. J. J. Thompson performed further experiments involving the ionization of gases that indicate the field is not continuous but fibrous ("Dielectricity and Matter", 1906)." - Eric Dollard and video This led Thomson to develop the concept of the electron as a discrete charged particle. More than one-hundred years later we have never actually seen an electron.

Obviously, the part about magnetic fields possessing "a fibrous construct" that makes "a scraping noise" when in motion does not in any way bode well for the magnetic steel chassis nor for the bulky magnetic steel transformers commonplace in traditional tube guitar amplifiers. Published research (Menno van der Veen AES papers, see below) reveals that, among over 90 tube + transformer topologies tested, traditional audio magnetics always smeared fine detail, audibly and measurably.

More detail by Eric Dollard, who describes his apparatus and experience in hearing fibrous magnetic scraping: http://youtube.com/watch?v=TttHkDRuyZw at 1:57:45 into video

Even Tesla disdained metal ... and patented ways around its need

In U.S. Patent 568,178, Tesla revealed air cores are better suited to manifesting the 'negentropy voltage gain effect' than iron cores.

"...while many manufacturers wind great transformers, there's no transformer like no transformer at all...The difference is not subtle."

Transformers are known to substantially color the sound

An audio transformer is a big, homogenizing filter. Ongoing research reveals serious measurable and audible drawbacks with what has, until now, been a necessary evil in tube amps. Custom-wound and/or heavier magnetics may arguably improve low-end power handling, but usually at the expense of high-end phase angle (manifesting as impact, "air" or "edge"), frequency roll-off and other factors, not least of which are cost and weight. Regarded as a kind of black art, even superb audio transformers always present complex, inescapable (and worse, unique per-device and therefore unreproducible) trade-offs, explored below. Let's start with common knowledge:

"Output transformers also have a reputation for coloring the sound..." --Howard Davis, Electro-Harmonix, Pigtronix »

"...transformers can distort and color the sound...a change in the output transformer...can make a huge difference in tone..." »

"...it is the output transformer that can dramatically affect the tone of your amplifier since audio signal is actually passing through it." --John Chappell, et al., "Guitar All-In-One For Dummies" »

Transformers "set the sound" of an amp and limit its tonal palette

It's known that an audio output transformer largely (and often individually and uniquely) sets a characteristic 'sound' -- a filter that can never be turned off. How desirable an inescapable effect may or may not be ultimately plays out in ears and minds. Some people may play an amp for its "sound", but not all "identical" amps sound the same because not all "identical" transformers sound the same because not all "identical" transformers (with their hundreds of laminations and tens of thousands of windings) end up being made the same. The situation parallels that of cymbals. Or guitar bodies. Or diamonds. Uniqueness at every level (in metal alloys and hammer blows, or grain orientation and crystal cuts) ensures unlimited, unique (and confounding) variety. This is no doubt also true of vacuum tubes, although vacuum tubes are far easier to change for tone and feel than are output transformers!

"...I was amazed at how different [transformers] sounded, even [those having identical] specifications..." »

"The large, heavy output transformer...introduces harmonic distortion, particularly at low frequencies...like the many pounds of transformer weight, this distortion cannot be eliminated when it is NOT desired." -- Howard Davis, Electro-Harmonix, Pigtronix »

"I didn't realize that tone was so much a part of the amp." -- Paul Reed Smith, Vintage Guitar Magazine, November 2011, pg. 26

The serious technical limits of traditional audio output transformers

Technically, parasitics skew phase and mangle impact », magnetizing current and core saturation rob power », and detail evaporates ». Inescapable magnetic bloat inherent to audio output transformers audibly and measurably manifests as distortion » : munge, flub, smear ».

GAGA circumvents the magnetic roulette and instead maximizes pure tube tone while eliminating weight, bulk and other traditional limitations. GAGA unveils and intensifies the character of whatever tubes are inserted, allowing unlimited customization.

With GAGA "...'the sound' of the amp is no longer coupled to the transformers." »

Advanced power supplies and patented ZOTL Technology in GAGA provide idealized impedance matching and power conversion, without all the weight and limitations of traditional audio frequency output transformers and bulky power magnetics.

"... pure tube tone with no Iron to lug around." »

Freed from 'driving' an homogenizing metal bulk, the output tubes really shine. It's shocking how different various tubes actually sound, once unleashed, and the sonic benefits hardly end there.

"Like inferior speakers, tube amp output transformers distort the low bass, muddying it and cutting the fundamental." -- Howard Davis, Electro-Harmonix, Pigtronix »

"Transformers tend to smear the sound and limit the frequency response, and while many manufacturers wind great transformers, there's no transformer like no transformer at all -- something that becomes clear when you hear...bass as deep as that from a solid-state design, but with levels of detail and tunefulness that most solid-state amps miss. The difference is not subtle." »

"A preamp stage driven nonlinear produces clipping behavior with substantial asymmetry, meaning higher levels of even-order harmonics. Depending on the gain structure of the amp, it is possible that multiple preamp stages will clip. Because the common-cathode gain stages used in tube amps are inverting, a signal that is clipped in two successive stages may appear more symmetrical as a result of the clipping in the second stage. In that case, odd harmonics will be added to the signal. Power amp stages have much more complex reactions when driven into nonlinearity. Because the signal is coupled through a transformer, there is the possibility of core saturation. Additionally the power supply ("B+") DC voltage may begin to sag, causing a type of compression. The onset of nonlinearity is affected by the amount of negative feedback in the design. Zero-feedback designs enter nonlinearity earlier and more gradually, whereas designs with negative feedback tend to stay clean longer but clip more abruptly. A power stage driven into nonlinearity will often lose high frequency bandwidth as it is driven further into clipping, then recover the bandwidth as it comes out of clipping. This has a profound effect on the tonality and dynamics of single notes vs. chords." »

"... transformers epitomize...obstacles to high fidelity: Abruptly limited bandwidth [short-changes] both the ends of the frequency spectrum [with] smeared transients. Limited power bandwidth in particular [hampers] output transformers, resulting in compressed dynamics, masses of harmonic distortions from hysteresis(1), low-frequency saturation(2), phase distortions and more. ...the gross distortions of power output transformers... (1) Hysteresis, in this case, refers to the tendency of the magnetic flux in a transformer's core to not respond precisely to the magnetizing force of the current in primary coil. For instance, the predilection of the core to stay slightly magnetized even when the current in the primary coil has ceased. [In other words, "magnetic inertia."] (2) The upper limit of a transformer's core to contain magnetic flux is called saturation. Above saturation, additional magnetic force causes little increase in flux density. The flux density in a transformer's core is inversely proportional to frequency of the signa1 applied to the primary coil: Halve the frequency and the flux density doubles. [In other words, "magnetic compression."] ... (5) B is the notation for magnetic flux density and H is magnetic force. Plotted together, they graphically illustrate hysteresis. A large separation between the magnetizing and demagnetizing curves (a "fat" loop) shows much hysteresis and a small separation (a "narrow" loop) approaches the ideal of no hysteresis." [GAGA has no magnetic audio loop at all.] -- Line-level transformers in High-End Audio, Mark J Medrud, Design Engineer, Jeff Rowland Design Group, Inc., 17 March 1995 »

It's pretty clear what's been going on with audio power magnetics. Let's next examine some research directed precisely at audio output transformers.

At the 118th convention of the Audio Engineering Society, Menno Van der Veen presented his paper ( PDF | archive ) detailing a universal audio output transformer system that "includes all possible [90+] variations in topologies." [excepting GAGA's ZOTL Technology, which was not included in the study] With good technical discussion it demonstrates how audio output transformers inescapably impose compromises.

Summarily paraphrasing Menno van der Veen's Low Level Details in Output Transformers research paper (presented at AES 122, May 2007): Failing to accurately transfer low-level signals, audio output transformers inherently smear details and obscure fidelity. Some effect is always present, and excellence is in detail. Transformers, according to this extensive research, subdue excellence.

M. Hawksford wrote, in May 1986 (Hi-Fi News & Record Review, p.53): "Low-level threshold phenomena ... set bounds upon the ultimate transparency of an audio system." Reasoning and research confirm what ears can already hear.

"Ideally, a transformer stores no energy - all energy is transferred instantaneously from input to output. In practice, all transformers do store some undesired energy: Leakage inductance represents energy stored in the non-magnetic regions between windings, caused by imperfect flux coupling. Leakage inductance delays the transfer of [energy]...the main cause of...problems... Mutual inductance represents energy stored in the finite permeability of the magnetic core and in small gaps...Mutual inductance and leakage inductance energy causes [arcing] voltage spikes...resulting in...damage or destruction..." -- Texas Instruments »

"Pro audio" people agree.

"Phase distortion not only alters musical timbre, but it has potentially serious system headroom implications as well. ... Even ultrasonic phase distortions caused by undamped resonances can excite complex audible cross-modulation products in subsequent nonlinear (any real world) amplifier stages. Low-frequency phase distortions are often described as 'muddy' bass and high-frequency phase distortions as 'harshness' or mid-range 'smear'. The complex cross-modulation products are usually described as 'dirty' sounding and often are the cause of 'listener fatigue'." -- Glen Ballou, Handbook for Sound Engineers, p. 605

"The downside with iron [audio transformers], and there is always a downside, is ... time smear ... with sounds that have lots of energy (and tightness)..." -- Manley Labs

Purity, Tree-of-Life, Kabbalah, Ascension

Ancient mystery schools and religions place high value on purity, consistently recognizing its primary importance as the necessary first step in the Tree of Life, as related by no less than Manly P. Hall. The next step is communication and intelligence; then emotion, affection, beauty, love, sincerity, truth, the sublime. Ascension and transcendence requires Purity. It follows that if you play transformerized amplifiers which inescapably filter your tone from the outset, where can you ultimately go? You begin stunted, disadvantaged, handicapped.

Eustace Mullins points out the ancient occult link between healing or health and purity.

William Henry (35:25 into interview with Art Bell) describes the gnostic pursuit for purity, as revealed by Jesus in the Pistis Sophia.

Again and again, across religions, teachings, pursuits of Truth, esoterica and luciferiana, we find this consistent theme of "purify", "begin with purity", "purity first", "purity foremost". Are they all wrong, or is there maybe something to it?

David Cherubim details the religio-spirituality of the guitar: "Guitar playing is a Spiritual Art, for it is a musickal form of both Magick and Alchemy."

"When an honest man is confronted with the truth that he is wrong, he will either cease to be wrong or cease to be honest." - Mark Twain

"Great things are not accomplished by those who yield to trends and fads and popular opinion." - Jack Kerouac

Tonal Apotheosis

Broad, deep examination concludes that audio output transformers negatively affect sound and performance.

Consider how various data - over long periods and across genres - consistently relate purity and excellence.

We've shared others' and our own research into how and why GAGA amplifies most faithfully to get musicians closer to their truest tone.

We've also detailed how you can explore and verify simple but revealing listening tests for yourself using any amp - proving with your own ears and equipment that traditional audio output transformers are never better and always lessen the sound quality and tone.

GAGA is a new kind of tube guitar amplifier, fundamentally and resoundingly unique among all others, and while 'new' isn't always better, sometimes it is.

We invite you to transcend.