Advantages & Features of GAGA-50

1. 5 pounds total weight - much lighter and smaller than typical tube amps, lighter than every electric guitar we've weighed, and lighter than comparably powered transistorized amps.
2. 50 watts clean output power   &   80 watts full power and distortion.
3. All tube power amplification - all analog, not "hybrid" or class D or "digital" anything.
4. Auto-Everything™

   • Play-Any-Tube™ - Mix and match any combination of "octal" output tubes for tone and power. Escape from "matched pairs" or even matched types and choose your own voicing and tonality with whatever tubes you have or prefer. Even older tubes, "worn out" by other amps, may be usable in GAGA-50 thanks to its patented ZOTL Technology that operates tubes more like tubes and less like light bulbs or space heaters.
     • 6L6, KT66, EL37, 5881, 7581, 6P1P-EV, 6P3S-E, 6P6S
     • EL34, KT77, 6CA7
     • 6550, KT88
     • 6V6, 6EY6, 6EZ5, 6P6S, 6AY5, 587, 5871, 7184, 7408, 7EY6
     Note these are the tubes we've examined; there may be others. GAGA-50 should accept any "octal" output tube, pentode or beam tetrode, having the RETMA standard 7AC style base and pinout.

     A lot more than 31 flavors: "So many types (and combinations) of tubes are useable in GAGA-50 that hundreds of thousands of tonal varieties are possible. And that's just clean; there are 7 Power-Step settings at which each tube will react and sound differently. Without figuring different manufacturers or different production runs, that's already millions of possible tonal varieties. Plus, by not having any audio output transformer to munge and homogenize the sound, nuances and colorations can sound even more dramatic. That's a hidden strength of this amp. For the cost of one new output tube players can get a geometrically growing number of new amps. There's never been an amp like this."

   • Auto-Bias - Never worry or adjust bias again. GAGA-50 automatically biases any combination of tubes for optimum performance. Traditional tube amps often run their tubes with high bias and operating currents, necessary because the tubes must drive the big, reluctant and lossy audio output transformer. But high tube plate current results in heat, noise and failure. Patented ZOTL Technology used in GAGA-50 extends tube life, markedly increases reliability, improves sound quality, and brings musicians closer to true tone.
   • Auto-Standby™ - No "standby" switch as GAGA-50 automatically controls the output tubes, keeping them, just like a race car's idling engine, ready to deliver full power and performance instantly, seamlessly, reliably.
   • World-Power-Ready™ - Plug in anywhere on Earth. Advanced power supplies, proper design, standards compliance: 90-240VAC @ 50/60Hz, RoHS, CE.
   • Drive-Anything™ - Nothing to set, match, mismatch, or confuse: Single 1/4-inch output jack drives any reasonable combination of speakers or cabinets.
   • Blow-Proof™ - Sustains dead-shorts or no-load total-opens without self-destructing - can also drive instrument cables used as speaker cables. No more fear or blown output transformers as with typical tube amps.
5. Power-Step™ - Allows full output tube distortion to be realized at any volume level without abusing output tubes or heating big resistors - not an attenuator, 'power soak' or 'hot plate'. Provides widely adjustable output tube distortion vs output volume level - get zero to full output tube distortion from half-watt to full-power volume.
6. Super-Infra-Sonic™ - Impactful, full-bodied tone with delicate, harshless alacrity: Flat frequency response across entire spectrum at full power, heretofore unattainable in tube amplifiers.
7. Uncommonly dynamic and responsive, with no overdrive hangover - Powerful and agile with constant touch response to maximize guitar+amplifier synergy and convey true tone. Per-note accuracy never bogs in overload and amplifies precisely. "This amp is fast."
8. Extended Tube Lifetimes - Years to a decade or longer of useful, working life (expected) with reduced stress and insensitivity to microphonics and aging.
9. P3 Phantom Powered Pedal System® - Provides 2 amperes of regulated 9-volt DC power to remotely power guitar pedals and/or pedalboard breakout boxes. "Another world's first."
10. Tube-buffered tone stack adjusts +/-16dB - Minimal knobs, maximal adjustment, intuitive, great tone.
11. More tube-like operation of output tubes (i.e., lower current, higher impedance) with triode-like characteristics presented to speakers, even from pentodes.

12. Patented circuitry + advanced power supplies = detail, speed and slam.
13. Superior components throughout - Includes quality components, 'above mil-spec' circuit boards, chassis-mountable power tube sockets, and point-to-point wiring where appropriate.
14. American made by experienced designers and manufacturers whose numerous other products have received glowing reviews over decades of time. GAGA-50 is sturdy and stands alone (Marshall 20-watt head footprint), or mounts in any 4U rackspace, or installs into standard cabinets.
15. Available 2010. Pricing TBA, ~$2k. Want to know when GAGA-50 is available? email list

GAGA-50 chassis front concept An input jack, power switch and four knobs. Red switch toggles 9volt P3 Phantom Power for pedals. Chassis is 1/8-inch 5052 aluminum alloy mated with 1/4-inch stainless steel hardware -- rugged and overbuilt to last. Easily removable top cover attaches solidly with four thumbscrews. 17 inches by 6 inches by 6 inches tall (plus 1-inch tall handle) chassis footprints a Marshall 20 watt head or fits into 4U rackspace.

Quotes

• "Basically, I near shat myself when I read this thing's specs." » Kuz929, 24 Jul 2009
• "I love it though when people stretch the norms, and [GAGA-50] appears to have blown them out of the water." » Stanz, 5 Sep 2009
• "That's like a fantasy version of specs. Crazy! It'll power a couple 9v pedals too? sheesh." » super56k, 22 Jul 2009
• » "And don't forget the part about being able to lift it with your pinky! I didn't believe it was possible until I tried it myself!"
• » "...i think the features are what's going to make this amp enticing. These features will probably attract a lot of people (including myself) who don't want high maintenance amps."
• » "...the features are what gives this amp a serious edge - not because they're just silly nick-nacks thrown in to fatten up the deal, but something far more important - they (claim to) solve a whole bunch of critical issues that are related to reliability. also, the ability to autobias any octal tube to the correct current is always a huge plus. for touring musicians, they can plug in anywhere in the world without a problem. and the weight..... no need for matched tubes, total safety of the power stage so that if a tube blows, the amp keeps going... "
• » "...everything i HATE HATE HATE about tube amps, this amp does away with. (i'm a tube amp snob i guess, i've played tube amps of every make and model since 1975)..."
• "Half of the music industry here is in an uproar to find out what this GAGA-50 amp is all about...the other half may be asleep." --Chris Lewis, Sep 2009
• » "...certainly one of the most innovative new products i saw at Summer NAMM. very cool..."
• How GAGA-50 measures up to the November 2009 Tube Amp Wishlist
• » "I was thinking the same thing: 'Damn. Why didn't I think of that?' The sad part is that it is so cool, I can't even pretend to not like it."
• » "I guess there is always a first.. and this is it. ...It certainly would be a step forward as it's much more practical for the mobile musician and on top of that, the most important part - the sound quality is probably pristine. Sounds like it in the clips."
• » "...i think that the next album to set a benchmark for incredible guitar sound, the way siamese dream did, will likely involve the Milbert Amplifiers GAGA-50... they've invented a way to build a tube amp that doesn't need power OR output transformers, and it apparently quantum-leaps beyond the limitations of every kind of amp that does have transformers. no i don't work for them, but after reading up on this thing, good god i wish i did..."
• » "...in the truest sense, a breakthrough in the most serious end of the audio arts. This circuit is not an incremental step, but a major leap forward in thermionics..."
• » "Wow...very interesting. This is really something new! There's a lot here to read and think about."
• » "Very interesting. I like the fact that they provide a lot of technical info ... instead of the usual vague promises of 'groundbreaking design' and 'incomparable tone and warmth'."
• » "I just read their patents and tech descriptions and it's nothing like previous OTL designs...This really is fresh..."
• » "Can you imagine the warmth and joy in a manufacturer's heart, to learn ... that people are having to invent entire new words and phrases to talk about their products?"
• » "...i find this thing totally fascinating. i've not seen ANYTHING like this before...there's nothing...that is even remotely connected to this."
• » "...this amp does offer a lot of features no one else has."
• » "Re:A NEW TYPE OF TUBE GUITAR AMPLIFIER: I just started saving again...."
• » "it's way cool. especially if you own a studio, and like the idea of multiple amp sounds out of a single amp. the way this thing is designed, means the sound of the amp is no longer coupled to the transformers."
• New 5lb 50 Watt tube amp by Milbert!
• » "...your amp is amazing -- it totally wins my 'best new innovation' award."
• » "...this is a really advanced amp based on some very cutting edge technology. it is simply amazing what can be done when one breaks from the 'traditional' design process."
• » "That's pretty cool with the impedance matching. They must put little elves with electronic engineering degrees in there."
• » "This could potentially be one insane amp just with the tube possibilities alone though, and there aren't a lot of knobs anyways so it should be intuitive to use."
• "Well, amps have been using pretty much the same technology for the last 60 years. It's time for a change." »
• "...keep going man whoever is making this stuff!" »
• "This kind of thing may take 50 pounds out of my rack. I know I am very interested in what is being done. Just what is said about the 20 hertz has me interested." »
• » "Wow. This sounds like the ultimate idiot proof amp. I like the no impedance matching and being able to run any power tubes."
• » "...if its anything like the milbert amp i used to have in my car it would handle impedence as low as 0.5 ohms..."
• » "...the selling point for me was the built in phantom power, how ridiculously small it is and the insane amount of versatility. this is gonna be one ridiculous amp..."
• "...just when you've seen everyone doing the same things in different ways, then you see something like this..." --Richard Goodsell, Goodsell Amplifiers, 18 July 2009, Nashville Summer NAMM
• "It is nice to see somebody still thinking." --Craig Anderton, harmony-central.com, 18 July 2009, Nashville Summer NAMM
• » "...I was thinking the same thing: 'Damn. Why didn't I think of that?' ...it is so cool, I can't even pretend to not like it...for sheer innovation, it is the bees knees!"
• » "The sound clips sound pretty good. Nothing too high gain, cleans are full, crunch is 70's style rock or modern pop."
• Video interview about GAGA-50, from Nashville NAMM 2009 Scroll down the right side of the flash video player, and see also the interview with Jason about the P3 phantom power pedal system.

  

• "I'm interested to actually see and play one of these. ... With traditional amps as you probably know a tube amp will tend to be forgiving of an impedance miss match but if you run it with no load....bye bye output tansformer. And a [transistorized] amp will run with no load but run it with a lower than spec'd load and it's bye bye output transistors." --layboomo, 11 Jan 2010, forums.epiphone.com
• "No transformers, any valve, auto biasing?? I'll be looking out for more on this baby..." --redstringuitar, 17 Dec 2009, tpdri.com
• "...there are a fair number of touring guys who get their sound mostly from their pedal boards, and the idea of a supper light amp that they can use to get a - good - consistent sound every night might be very appealing." --Gabriel Hoffman, 17 Dec 2009, thewombforums.com
• "...Berning's HIFI amps are very well reviewed and cost $10k+ ... All the most knowledgeable amp [designers] that have commented on this design have only one criticism I have heard: 'I didn't invent it!'" --tedmich, 30 Nov 2009, ax84.com

New technologies can be challenging

"...amps are essential to creating a great rock guitar sound and literally contribute one half of the effort. The more you understand your amp, the more passionate you become." --John Chappell, et al., "Guitar All-In-One For Dummies", »

"Just as audiophile product designers can learn from us music guys, it's time for vice-versa." --Howard Davis, long-time engineer at Electro-Harmonix, »

"To sound musically rich, go for wide range, low distortion at high volume, and desirable tone qualities." --Howard Davis, long-time engineer at Electro-Harmonix, »

If one audio output transformer sounds good, how is zero better ?

A better question might be: If an audio output transformer's limitations were truly desirable, then why hasn't any tube amp maker ever combined several, using two, three or even ten transformers all at once for sound thereby totally out of this world? ( "Output transformers also have a reputation for coloring the sound..." [»] [»] ) One reason is because output tube tone is largely what's desirable, not transformer munge, yet an audio output transformer to translate between tubes and speakers has been a necessary evil in all-tube amps. Until now.

Does the audio output transformer contribute to "the sound" of an amp?

Most likely. An audio output transformer is a big, non-linear filter that surely affects an amp's characteristic "sound", like an effect that can never be turned off. How desirable this effect may or may not be ultimately plays out in ears and minds. Players seeking one particular sound may do well with one particular amp, or suitable clone.

GAGA-50 does not necessarily attempt to clone or mimic but to provide a top-quality foundation for any tone desired with the idea that starting from purity is musically advantageous.   ("...it's crucial to attain a pure, clean tone prior to adding other effects to your signal for better overall tonality..." [» p14]))

GAGA-50 provides the characteristic tonality and warmth of whatever output tubes are inserted with an ability to turn down the total volume while retaining full tube character, touch response and addictive playability. We think musicians will appreciate its many technical merits and enjoy the build quality and unbounded tonalities available uniquely from GAGA-50.

Is GAGA-50 an "hi-fi" amp masquerading as a guitar amplifier ?

No, but GAGA-50 is an audiophile quality amplifier that is purpose-built for guitar and instrument amplification. Some of its technologies come from the worlds of high-end and mobile audio. For example, GAGA-50 shares designs with David Berning's $30,000 Quadrature Z amplifiers (which was awarded "Power Amp of the Year" in October, 2009 by Hi-Fi+ Magazine ») and several other Berning and Milbert products. GAGA-50 embodies decades of design and production experience in both the finest and most punishing environments.

GAGA-50 fulfills the most demanding applications of guitar amplification, studio recording, classical and fine instrument amplification, or use as a "keyboard" or vocal amplifier. GAGA-50 is also ideal in many ways for bass amplification as its exceptional, resilient low-frequency response provides a meaty and powerful all-tube low-end atypical to tube amps.

Not meant to undermine or mimic "classic" amps, GAGA-50 provides numerous worthwhile benefits and exceptionally pure, all-tube tonal foundation in a solid, reliable package made to maximize performance and musical enjoyment. GAGA-50 faithfully amplifies your sound depending upon what what guitar you use, tubes you install, what pedals you use, how you adjust its controls, what you drive it into, and how you play.

"If you want a classic sound, plug GAGA-50 into a classic 12 inch speaker or a 4x12 cab: Speakers will provide their same natural filtering as always. GAGA-50 doesn't load pickups or pedals strangely, so guitar tone conveys fine. If you want amplified distortions, feed pedals into GAGA-50 or run them in its effects loop, or use its Power-Step control to increase output tube distortion versus volume. GAGA-50 is made to indiscriminately play well. Our development team includes performers and industry professionals having collectively decades of experience across hundreds of different amps. Their criticism was, 'Why can't we buy this today?' We've done our homework, and we think musicians will appreciate the build, sound and performance."

Is GAGA-50 merely existing technology ?

No. GAGA-50 is a new kind of amplifier. It is patented, its own unique thing, unlike other amps. It is not solid state, not hybrid, not OTL, not class D or digital anything. GAGA-50 uses only vacuum tubes (in preamp and power output stage) to perform 100% of audio power amplification, and it does so in analog not digital fashion. It uses ZOTL Technology, a new name for a new kind of amplifier.

Most tellingly, although solid state, class D, hybrid, digital switching, OTL and various other techniques existed long before ZOTL, the USPTO agreed that ZOTL is novel and granted patent (with all 27 claims) without objection or notice of prior art.

Therefore, it is entirely accurate to describe GAGA as a new kind of amplifier, one that uniquely offers audible, measurable and worthwhile benefits, and not as hybrid, solid state, OTL, class-D or other existing term or technique as is sometimes erroneously asserted.

Why isn't GAGA-50 a "hybrid" ?

"Hybrid" describes circuits in which some or all audio power amplification is performed by solid-state semiconductors with a tube or tubes present mainly for control, feedback or filtering. [»] [»] [»] GAGA-50 performs all audio power amplification with only vacuum tubes (pre-amp and output stages). As noted in the ZOTL patent (column 2, line 29), GAGA-50 performs no analog signal processing of any kind in any way with solid-state devices. Just as a transformer transforms and is not an amplifier, ZOTL Technology converts impedances and is not an amplifier. This is explicitly noted in the ZOTL patent (column 3, line 20). Therefore, GAGA-50 is not "hybrid".

Why isn't GAGA-50 "digital" or "Class D" ?

GAGA-50 does not digitize the audio signal, nor does it pulse width modulate (PWM) the audio signal or in any way "use the switching mode of transistors to regulate power delivery" [»]. MOSFETs shown in the ZOTL patent operate at high, fixed, switching frequency, which has nothing to do with audio frequencies, and GAGA-50's output stage partially incorporates class AB_1 ("push-pull") operation, as noted in the ZOTL patent (colum 3, line 25). As explicitly noted in the ZOTL patent (column 5, line 54, and all diagrams), GAGA-50 uses only vacuum tubes to regulate audio power delivery and does so in analog not digital fashion. Therefore, GAGA-50 is in no way "digital" or "class D".

Why isn't GAGA-50 an "OTL" ?

"OTL" (Output TransformerLess) [»] refers to a technique developed by Julius Futterman in the 1950s that applies numerous output tubes connected in parallel to drive speakers, attempting to overcome fundamental incompatibilities with brute force and arguably resulting in many shortcomings including tube noise, unreliability, rather severe impedance mismatch, excessive heat, and inefficiency.

GAGA-50 uses ZOTL Technology and shares nothing in common with the OTL technique except that it is a technically superior method of obviating the audio output transformer. Regarding how ZOTL Technology is compared to OTL: "Among engineers, designers and enthusiasts there is continuing and often lively debate on this subject and, as of yet, no firm technical consensus exists as to how these designs should be classified."[»]

Can GAGA-50 be used as a bass amp?

Yes. Despite GAGA-50's 50 watts rating its unexpected performance can be surprising. Its ZOTL Technology can play flat down to DC, lower and more faithfully than any amp we've seen commercially available. The magnetic inertia and distortions ("munge") that muddy the sound and rob power are gone, so the bass performance available from GAGA-50 surprises most players: "...it doesn't collapse and fold back over on itself..."

Here's a relevant quote by Charles Hansen (Glass Audio Magazine, vol. 12, issue 1-2 / 2000) from his review of David Berning's ZH-270, a 70 watt hi-end home audio amplifier that uses ZOTL Technology:

"The bass was tight, far more so than I have ever heard on any tube amplifier. Acoustic bass was woody, resonant, and full of life. The extra harmonic richness in electric bass came through in spades, and kick drum had a lively pop...the bass never became tubby or boomy. The soundstage was spacious, wide, and deep. You could hear each individual instrument in even the most complex orchestral crescendo. Piano was portrayed as though you were standing right above the soundboard. You could hear each hammer and pedal in realistic detail. The sound never became confused, nor did the soundstage retreat even the slightest bit. This amplifier was absolutely unperturbed at even the highest volume. Complex pop music with layer after layer of synthesizer was more detailed than I have ever heard."

Will GAGA-50 be short-lived ?

No. Our BaM tube car amp (with several improvements over the years to the same basic model) has been in continuous production for almost 25 years, with no end in sight. We like to think we made it right initially and have kept at it. Not many products are still in production (let alone fully supported) after 25 years. GAGA-50 will be no less in any way.

How does a typical audio output transformer sound ?

		Figure 1 -- This is what transformer munge looks like. Visibly bloated and audibly muddying, audio output transformers magnetically munge everything. Desirable? Not likely - not one amp uses multiple audio output transformers all at once.
Some characteristics peculiar to audio output transformers are evident in this curve-tracer photograph which shows the response of a push-pull pair of triode-connected 6L6s. The diagonal loopings of the constant grid-voltage lines are caused by magnetizing current (i.e., energy wasted in making any transformer transform) while the large horizontally oriented loop shows core saturation and hysteresis (i.e., magnetic lag), causes of audible softness and muddiness, particularly in the low and low-mid frequencies where it manifests as lost impact and power. Powerful, taught and deep low frequency performance, which typical tube amps simply cannot reproduce, is commonly cited as a major benefit of transistorized amps. Patented, all-tube GAGA-50 uniquely delivers the full-bodied, rich warmth of tubes with uncommon speed and accuracy.

		Figure 2 -- This is what tube performance looks like. GAGA-50's pure, all-tube amplification uniquely provides top speed plus rich tube tone with excellent dynamics, nuance, control, impact and musicality -- "cleaner cleans, dirtier dirties".
This curve-tracer photograph shows the same test amplifier and the same push-pull pair of triode-connected 6L6s but this time utilizing patented technology instead of an audio output transformer. Comparing the photos: overall response is pure and solid as the output tubes are being operated in a preferred, tube-like manner: The tubes behave as if driving a 4k Ohm speaker, and the speaker sounds as if it is being driven by a 0.6 Ohm triode. Precluding magnetic munge while amplifying purely with vacuum tubes, GAGA-50 responds smoothly and instantly recovers from overload on a per-note basis. The result is pure tube warmth, heightened audible delicacy and nuances, full-bodied impact, sustain and slam when so driven, harshless alacrity, and addictive responsiveness, essentially bringing musicians closer to their true tone.

Play tubes, not a transformer. With GAGA-50 players enjoy the desirable tonal qualities of output tubes, in any combination, totally divorced from the inescapable limitations of audio output transformers.

• Before GAGA-50, truly changing "the sound" of an amp usually meant changing the amp.
• GAGA-50 enables maximum tonal variety via changing output tube combinations, without homogenizing limitations imposed by an unchanged audio output transformer. "An enviable palette of tone."
• Without an audio output transformer and its veiling non-linearities, GAGA-50 amplifies with heightened impact, dynamics, immediacy, delicacy, nuance, accuracy and power. "Each note sounds full bodied and stays that way. Instead of converging into munge, sustain remains rich and pure."
• Droopy, unregulated supply voltages yield droopy overload distortion. GAGA-50's advanced power supplies support full-bodied and fully powered overload distortion. "A new type of dirty."
• Tube bias in GAGA-50 does not swamp during overload, allowing for high quality, sustained, full overload distortion, yet instantaneous recovery from any amount of overload. Intermodulation performance is also exquisite, giving GAGA an uncommon agility to faithfully amplify what is played and not interject unmusically related tones.
• GAGA-50 has a single output, not several, precluding the Medusa of multiple output taps that seriously compromise performance, as inactive winding-segments, inevitable in a tapped transformer, harm high-frequency response; moreover, tapping the secondary upsets feedback and causes only parts of the secondary to be used, resulting in sub-optimal power transfer. [»]

Detailed Information

GAGA-50's Power-Step™ -- output tube overload at lower volumes

What is it? Power-Step is a control that allows players to approach full output tube distortion at variably less than full volume.

How does it work? Power-Step does not limit or dissipate power but instead changes how the output tubes respond. Power-Step does not directly attenuate the audio signal, nor is it a 'power soak', 'hot plate' or "brown" technique of limiting plate voltage to cause plate starvation. Technically, Power-Step adjusts apparent transconductance of the output tubes, adjusting current available to the speaker, and allowing output power tube distortion to be fully realized at lower than full volume levels without abusing output tubes or heating big resistors.

How does it sound? At any given volume, the result is an increased distortion at that volume. As you turn down the Power-Step, GAGA-50 doesn't play as loudly but with increasing distortion. This allows players so inclined to incrementally achieve "full blast distortion" at much lower than "full blast volume." Using various combinations of different tubes (an EL-34 push tube and a 6L6 push tube -versus- a 6550 pull tube and a 6V6 pull tube, for example) yields many tonal characteristics (and available output power levels) with any amount of output tube distortion.

How does it play? The Power-Step control, Volume and tone controls, and guitar volume and tone controls all interact smoothly and intuitively with any playing style. Power-Step is ultimately a subjective control, as each output tube and every combination thereof, coupled with whatever particular speaker(s) and cabinet, exhibits unique response, distortion, power output and tone.

How much power under what conditions? Power-Step approximate power levels, maximum distortion, from 4 EL-34 output tubes, into 8 Ohm load: (Note that removing a push-pull pair of tubes will approximately halve the available power at all steps, leaving the distortion at max.)

• Power-Step 7: 80+ watts
• Power-Step 6: 40 watts
• Power-Step 5: 20 watts
• Power-Step 4: 10 watts
• Power-Step 3: 5 watts
• Power-Step 2: 2 watts
• Power-Step 1: 1 watts

GAGA-50 Tone Stack - Baxandall: simple, flexible, high-fidelity

GAGA-50's tone stack is an improved, tube-buffered Baxandall circuit, which is simple, proven and maintains great sound quality over wide (+/-16dB) adjustment. If you want midrange "boost", turn down the bass and treble. If you want midrange "scoop" turn up the bass and treble.

See: wikipedia
See: schmarder.com
See: http://www.duncanamps.com/technical/baxandall.html
See: http://www.duncanamps.com/technical/tonestack.html on DuncanAmps:

"When designing the DDS-2250V, I had the choice of the traditional Fender/Vox/Marshall tone stack using Bass/Mid/Treble controls, or using a passive version of the Baxandall Bass/Treble tone stack which is popular on hi-fi equipment.

"On the basis that 'the more knobs, the better', I started the design using the FVM tone stack. When SPICE modelling the effects of the stack, it became apparent that the tonal control was limited. Furthermore, the effect of the mid control on everything else was more than noticeable.

"After some rough working out, it became apparent that more different tones were available using Baxandall's bass/treble combination than the FVM circuit. Not believing that two knobs gave more variation than three, I double checked everything. Whichever way I looked at it, it had to be Baxandall..."

We reached the same conclusion though we had begun with the precept of "the fewer knobs the better". We believe guitar amps should be intuitive, elegant and musical, and that generally means 'do fewer things, better'.

GAGA-50's Auto-Everything™: Autobias, Auto-Idle, Use-Any-Tube™

GAGA-50 accepts (and automatically biases) a variety of octal output tubes which may be combined for a broad palette of tonal variety. Insert four output tubes for maximum power. Remove one or two output tubes and the sound continues, albeit at reduced power output.

"The ...technology is both complex and elegant. The auto-bias circuit alone is a technical tour de force." --Charles Hansen, describing Berning's ZH270 amplifier, which lends certain technologies to GAGA-50, Glass Audio Magazine, February, 2000, page 38

Tube lifetimes usually approach and often exceed a decade in audio equipment using Berning technologies. We expect GAGA-50 will also exhibit greatly extended tube lifetimes, likely to several years or possibly a decade or more.

GAGA-50 has no "standby" switch or mode; instead, its output tubes operate at higher voltage and lower current than traditional tube amps, obviating any need for standby while offering reduced sensitivity to aging, lower operating temperatures, and consequently increased reliability and lifetimes.

GAGA-50's minimal latency and uncommonly high speed

Recovery from overload is practically instantaneous as, thanks to its patented ZOTL Technology, GAGA-50 suffers no time-dependent bias upset from interstage coupling capacitors common in typical tube amps. Not swamped by or mired in lingering distortion, players can glide smoothly or leap fully in to (and out from) however much overload they wish merely by varying playing style.

"The dynamics are amazing...It's really a joy. Gliding into and out of distortion [depends] on how I play; I don't have to touch the volume at all."

When hard playing at full overload ceases, the very next note can sound out as purely and delicately as it is played -- there is no "distorted hangover". This unique quality feels fast and faithful. Several guitarists noted how the "extremely dynamic" GAGA-50 responds with "lightning speed" and therefore "feels intimately coupled" to the guitar.

R. G. Keen may have highlighted a truth universal to amplifiers in general (and not just to op-amps) when he wrote: "What makes for a good opamp versus a bad one? I dug through the data books on the ones that people told me sound good, and came up with a common factor. The ones that sound good seem to all make a point that they recover from overdrive gracefully." »

GAGA-50's pure, powerful, wide bandwidth -- Why "clean" matters

"To sound musically rich, go for wide range, low distortion at high volume, and desirable tone qualities." --Howard Davis, long-time engineer at Electro-Harmonix, »

An amplifier should amplify purely without inserting limitations and uncontrollable distortions that can not be reduced or avoided. Yet, typical audio output transformers insert inescapable limitations: parasitic effects at upper frequencies, core saturation at lower frequencies, and magnetic hysteresis, which might be characterized as lag or smearing magnetic inertia. Together, these may act as an ever present filter, unable to be switched off or reduced, constantly coloring an instrument's true tone.

GAGA-50 amplifies purely. It has a 1Meg-Ohm input impedance, a straightforward and minimalist tube preamplifier design, and a smoothly overdriveable tube output stage, providing an experience that is highly touch sensitive and an intimate part of the overall guitar-amplifier instrument.

"Sheer volume is no substitute for tonal quality. Just as audiophile product designers can learn from us music guys, it's time for vice-versa." --Howard Davis, long-time engineer at Electro-Harmonix, »

Coming from the world of high-end audio, GAGA-50 provides near perfect impedance conversion between vacuum tubes and speakers without the loss of signal fidelity or power at any audible frequency. Reproducing full power accurately from near DC voltage to well above human hearing, GAGA-50 offers wide bandwidth unattainable with typical tube guitar amps.

GAGA-50 is designed to provide top quality vacuum tube amplification, thereby putting musicians more directly in touch with their music. Additional filtering, tone shaping, or effects may be added as desired, either with effects pedals or in the effects loop.

Amplifier Purity & Fidelity are Keys to Great Tone

"An amp has a big job to do... It receives from the guitar a signal that is quite sensitive, having started life as a tiny current produced by skinny vibrating strings and a simple magnet. The amp must then respect the tiniest nuances of those vibrating strings, because you the player know exactly what you played, and if you don't hear that at the end of the process -- coming out of the speakers -- the amp has failed in its mission." --John Chappell, et al., "Guitar All-In-One For Dummies", p. 170 »

The Need for Wide Spectrum in Guitar Audio -- Malcolm Moore

"For a guitar, the audio spectrum needs are wide. Understand that the spectral centre of our hearing is about 740 Hz and that when we listen to music, it is balanced about this frequency in a logarithmic structure, so our hearing extends from about 30 Hz through to about 18 kHz, and this is roughly about nine octaves...

"For a standard guitar tuning, the lower open E string has a fundamental frequency of about 82 Hz, and significant harmonics are the second, fourth, sixth and eighth meaning the spectrum here extends to at least 656 Hz... On the twelfth fret on the upper E string the fundamental is about 656 Hz, and the spectrum extends to at least 5.248 kHz. At the 24th equivalent fret E#’’ is about 1,312 Hz, and the spectrum extends to at least 10 kHz! ...frequency response needs to be virtually flat from less than say 50 Hz to greater than say 15 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.

David M. Brewster, "Introduction to Guitar Tone and Effects", p. 14, [»]:

"...before you attempt to use any effects or tone-shaping devices, you must dial in a flat-response clean tone on the amplifier...it's crucial to attain a pure, clean tone prior to adding other effects to your signal for better overall tonality. If you can find a clean-sounding amplifier...then anything that you add to the signal path...should accentuate what your natural [guitar] tone sounds like."

Kevin Barrett, KAB Electro-Acoustics, Stereophile magazine, March, 1998: [»] [»]:

"There are plenty of products out there to 'process' audio---expanders, compressors, bass-impact enhancers, spectrum harmonic enhancers, spatial enhancers, etc. However, an amplifier should never behave as a signal processor!"

How does GAGA-50 sound and feel?

Cleaner cleans and dirtier dirties. More dynamics. More responsiveness. More nuance. More control. More purity. More slam. More sustain. More tone. More feel. More emotion. More excitement. More music.

Notes from development

"Every time I plug into GAGA I'm smiling...it sounds like a classic, great-toned tube amp, but playing it I was immediately like, 'wow! this is alive, right there, part of my instrument.'"

"If I hit it hard, I immediately get that nice, full output tube overdrive. But then if I play soft, it's still right there with me, fast, no hangover at all."

"A chameleon? GAGA sounds so different depending on what tubes I plug in and how I play."

"Love sliding into and out of output overload, and the overload adjust is killer. Sounds rich and warm, even with power pentodes."

"I'll confirm it has speed and punch like transistors plus tube warmth and overload, and it weighs five pounds...such a thing should not be possible. Wild how changing tubes has such effect...unexpectedly rich. I agree with calling it 'pure'."

"...don't let the number of knobs...impress you. The important thing about an amp is how it sounds -- and more specifically, how it sounds to you when you play your guitar through it. Som eof the best amps in the world have very few knobs and look rather low tech. So make sure you check out an amp the way you would a guitar -- by listening to it as well as playing through it..." --John Chappell, et al., "Guitar All-In-One For Dummies", p. 190 »

Jason Robling shows off a Genuine Guitar Parts Jewelry "Saddle Bracelet", his cool Fender guitar, the pinky-weight Milbert GAGA-50, a Fuchs cabinet, and an uncommonly uncluttered pedalboard with P3's new line of phantom powered pedals.

Here's that uncommonly uncluttered pedalboard showing P3's new line of phantom powered pedals. From the left: Analog Delay, Reverb, Chorus, Distortion, Overdrive -- all pedals have P3 phantom power factory installed and may be driven by any P3 powered amplifier (currently offered as an option in any Fuchs head and as a standard feature in the upcoming Milbert GAGA-50) or by the stand-alone P3 Power Station (part of the P3 External Kit). Signal flows from the Right to the Left, while Phantom Power flows from the Left to the Right through the same cable.

Jason Robling demonstrates an uncommonly uncluttered pedalboard that uses P3 Technology. The world's first amplifier to offer P3 as a standard feature, Milbert GAGA-50 (not shown) is supplying 9-volt phantom power to all pedals. Note the nearest pedal (overdrive, foam green color) is set to disable P3-THRU, but it could be easily set to provide 9-volts to the guitar, powering, for example, a pickup-preamp mounted inside the guitar body.

Milbert GAGA-50 accepts any number, type or combination of octal output tubes and automatically biases them, giving unprecedented tonal variety while also maximizing the sonic impact of each tube. Patented technology in GAGA lets the tubes run cool enough, reducing microphonics and dramatically increasing tube life.

GAGA-50 Engineering Prototype played effortlessly, oblivious to output power tubes being changed or its output shorted or disconnected while playing hard. (Nashville NAMM, July, 2009, photo courtesy of Bobby D)

Preliminary information will change. Last updated 8 Feb 2010