Milbert GAGA-90 Transformerless Tube Guitar Amp

CHEEZOR · Post by **CHEEZOR** » 02 Jan 2010, 21:04

Has anyone seen the milbert amps at http://www.milbert.com/guitar? Check out the feature list. It has some cool ideas. Does anybody know how it works under the hood?

teemuk · Post by **teemuk** » 03 Jan 2010, 18:35

Read the patents. They can be found from the Milbert's website or by Google Patents search.

soulsonic · Post by **soulsonic** » 05 Jan 2010, 00:41

That looks like a brilliant design!

If it turns out to be a winner, I may end up saving my money and actually purchasing one because it looks like they've accomplished everything I've been looking for in a tube amp.

Greg · Post by **Greg** » 05 Jan 2010, 03:52

Interesting design.
It looks like the sound clips are gone from the website.. Any more anywhere ?
Has anyone heard it ?

I see the Milbert guy was banned from HC for registering as another member to spam his product..

http://acapella.harmony-central.com/sho ... 953&page=2

A lot of people feel that an output transformer is a major contributor to the tone of a good tube amp.. so I'd love to hear clips of this thing.
If it really does sound good it'd be great to have an amp that light.

teemuk · Post by **teemuk** » 05 Jan 2010, 23:25

I listened the clips while they were still online. Sounded as convincing as any other decent tube amp.

The amp was kind of voiced towards the generic smooth and sustained blues and hard-rockish tonal palette, which is really not my thing so I wasn't really thrilled of the tones. My reaction was more like "meh, sounds like any other similar tube amp voiced that way".

So it wasn't bad or anything - considering how much hate amongst tube purists that design will likely generate.It was actually pretty convincing and should definitely appeal to people digging that kind of archetypal bluesy tube amp tone.

Greg · Post by **Greg** » 06 Jan 2010, 23:37

I wonder why the clips were removed, and there seem to be none anywhere.
I did a bit of a search for more info..
The builder seems to be pretty elusive.. he makes a post on forums, but doesn't reply to any questions..

He was called out on one of the amp forums after making a post.. they basically said that the members were very amp and tech savvy, and expected more than smoke and mirrors.... so instead of telling everyone how great it was, let's see a working example and let's hear the thing... no reply.

teemuk · Post by **teemuk** » 07 Jan 2010, 18:35

I had an impression that the amp is still pretty much on prototyping stage, hence shortage of clips; there's no-one but the designer (who has the prototype) to record them.

The website at the moment of writing shows that they're at the stage of designing a cabinet and a proper chassis for that thing. (The protype looked quite trashy). Might still take months before they even release a commercial version - if ever. Quite a lot can change during that time, maybe that's why the pulled out the clips. Maybe they're redoing them... Maybe they're holding up for Winter NAMM...

The website is quite often updated with new content (e.g. the last update was today). Just keep on the look if the soundclips happen to reappear.

CHEEZOR · Post by **CHEEZOR** » 08 Jan 2010, 03:31

I heard the sample clips while they were still up, but I didn't really care for the sound they were going for. I imagine that there are quite a few possibilities with this amp if you can mix ad match tubes. I also didn't care for what the guy was playing. I'm hoping to see it in person at the NAMM show (if it is there).

drbob1 · Post by **drbob1** » 05 Jan 2012, 02:12

This stuff is pretty dense for me, here's the patent:

http://davidberning.com/technology/patent5612646

And the advertising fluff:

http://milbert.com/gaga/details#measurable

Basically it seems, if I'm reading it right, like the power tubes drive a digital switching power supply that directly drives the speakers. It's not, as the adverts suggest, directly driving speakers with the tubes with no transformer, but a solid state transformer that uses minimal iron and windings to minimize phase shift, EQ changes, and time smearing. It's apparently been out since NAMM 2009 with no buzz, no clips, no video... Milbert is somewhat respected in tube home stereo, but I'm not sure that equipment is using the Zotl technology. Anyway, what do those of you with better technical chops than me think of the whole thing?

Shiny_Beast · Post by **Shiny_Beast** » 05 Jan 2012, 03:01

without looking I'll guess no one is going to care about it enough to matter untill the patent wears out lol.

phatt · Post by **phatt** » 05 Jan 2012, 08:38

Look at Valvetronics (Korg)
Concept is vaugely similar.

Unless I've missed something,,,Be aware that Gaga wanky is only quoting Triode connection of 6L6 Not Pentode connection.

Valvetronix came and went with hardly a flutter and my guess is this will be the same.
Next?

Phil.

DrNomis · Post by **DrNomis** » 05 Jan 2012, 09:39

Interesting concept, but I'm really interested to hear what the amplifier technology actually sounds like....

teemuk · Post by **teemuk** » 05 Jan 2012, 14:34

It's apparently been out since NAMM 2009 with no buzz, no clips, no video

It's not "out", they are still prototyping it.

And, there were clips at the site. About a year ago (if I remember right). For some reason they were removed.

And there is "buzz" about it, this is who knows how manyeth thread about them I've seen. Likely there will be even more buzz if they ever actually start to sell that thing in larger scale.

drbob1 · Post by **drbob1** » 05 Jan 2012, 15:23

Actually I'm not sure there's any connection between the Valvetronix system and this. The Valvetronix system, like the H&K Machine series, uses an output tube (12AX7 for Korg, EL84 or 12AX7 for H&K) to drive a dummy load. In Korg's case they did use an OT, I'm not sure if H&K did or not, but in any case they derived an AC signal to drive a SS output stage. Milbert argues that their output stage is not an amplifier per se, but an impedance matching system... I think they're wrong, but it's not as simple as an AC signal being amplified, it's a very high voltage signal driving some kind of gates/mini-transformers that then modulate what appears to me to be a digital switching power output of some kind. I don't have enough theory to be able to say with certainty that's different but it seems different...

And yeah, their's two issues: how does it sound and is it worth $2k? There have been very innovative products before (Maven Peal's Sag, London Power's highly configurable output stages, Pritchard's SS amps for example), but none have offered enough improvement in sound to capture the imagination of the masses, at those price points. Maven Peal is out of business, London Power soldier's along and sells a few amps but mostly licenses parts of his technology to other companies, Pritchard must sell a few but I still don't know anyone that owns one. And how about the "new" Mullard tube that was going to be low noise, high gain and revolutionize tube construction? Didn't work that well out of the box for guitar amps and production never really got off the ground.

Another thing that makes me think this may not be what it's being hyped as is that the technology has been available for home stereo for years, and in my research of tube stereo units several years ago, I didn't hear any buzz about it at all. I suspect it's one of those things that sounds great in theory, but fails to advance the art in practice...

phatt · Post by **phatt** » 11 Jan 2012, 07:51

@ *drbob1*
Well put.

Yes I got sucked into some of the hype on Korg stuff a few years back but on testing it was pathetic !! (And that is being kind).

Even some of my early attempts at stomp boxes would leave it for dead.
It's just a modeling rig with a fancy output section.... Next?

I'm not up to speed on all this stuff but Search for posting on SS guitar by *Teemu* he seems to have a good grasp on this stuff.

All the names you drop I've searched a fair bit but yes most of them just don't seem to capture the imagination of the general players.
Bluetone Amps was another one ,,, good but just never caught on.

The closest I've heard is KMG's stuff but the Actives are hard to source for me so not really worth the effort.

I've been using a hybrid for a long time and it's covering my needs.
Phil.

MilbertCom · Post by **MilbertCom** » 06 Jun 2012, 17:52

"Milbert argues that their output stage is not an amplifier per se, but an impedance matching system"

The impedance matching apparatus ("ZOTL") is not an amplifier, and that's not an argument - it's made clear in the patent itself that it is not amplifier; if there's any argument it comes from misunderstanding the technology and patent. New technology is sometimes confused by old terms that inadequately describe. We detail the differences at http://milbert.com/gaga/technicals Basically, it's not (the typical "hybrid" approach of using) tubes to boost signal that then 'hands-off' to solid-state for amplification -- with ZOTL the tubes are doing 100% of the audio power amplification. The rest of the circuitry is for power conversion...like a transformer converts (transforms) power but does not amplify audio power. We think of ZOTL as a new way to more perfectly connect power tubes and speakers - a much more ideal transformer - and the measurements and performance support that.

There's a bunch of fresh clips and jams from the June 2012 NY Amp Show (w/ bass and drums) up at http://milbert.com/gaga#clips
Pigtronix used a GAGA D-60 in their Ultimate Pedal Demo video.

Also, regarding this "...the technology has been available for home stereo for years, and in my research of tube stereo units several years ago, I didn't hear any buzz about it at all. I suspect it's one of those things that sounds great in theory, but fails to advance the art in practice..." In fact, David Berning's high-end equipment that pioneered ZOTL Technology is winning awards all over the place, from years ago to present day. 2011 Absolute Sound! Editors Choice Award. Hi-Fi+ 2009 Product of the Year. 2012 Amp of the Year. Reviewers have been writing about spiritual / near religious experiences for years - dozens of full reviews (and links) here http://davidberning.com/reviews and a bunch of quotes here http://milbert.com/gaga/reviews

"I had many listening hours with these amplifiers that bordered on the spiritual..." —Quadrature Z review by Hi-Fi+ Magazine, Issue 60, October 2008

GAGA began shipping in Dec 2011. Announced April 2012, "little sister" GAGA D-60 (domestic mains, 60 watts power) is also now shipping.

phatt · Post by **phatt** » 07 Jun 2012, 09:03

At *Milbert*, I quote from Your link:

"Using patented ZOTL (Zero-Hysteresis Output-Transformerless) Technology™, an award-winning
technology renowned in esoteric high-end audio"

The very moment I read the words, *hi end audio* I lost interest.

When will you tecky folk ever pick up on the simple fact that the greatest amplified sounds
emanating from any electric guitar that is overdriven is simply because of LIMITED BANDWIDTH.

**It's about what you DON'T hear that makes it sound great and now you want to add more.**

A girl does not wear her wedding dress to a mud wrestling contest and nor do people who actually understand Guitar sound want more friggin hifi bandwidth.

If they do need that there are a garzilion 20/20 band SS rigs out there to choose from already. (and likely cost far less)

No points for guessing I'm only a hobby geek with limited knowledge but I have one major advantage over highly qualified technicians.
I'm a musician.

I spent years trying to work out why certain things work and others don't.

Without hesitation my first answer to kids trying desperately to chase great guitar sound is;
Limit your Bandwidth or you will be forever frustrated buying gear. (and likely broke)

Don't get me wrong IF this idea works as well as claimed then start building top notch Bass rigs where the extended bottom end will obviously be very useful. And hit the hifi market as some of those guys are worse than us guitar players. LOL

Sorry I've lived far to long to fall for the more is better than less mindset. (Often clouded in hi tecky words that few player will even understand)

As I'm sure you are well aware you can make Valve Amps (with output transformers) that perform insanely good Dead flat frequency response that can rival a lot of hifi SS power amps.
So what? When guitar bandwidth is relatively narrow?? All the good stuff happens between 100Hz and 4kHz.

A short story;
Marshall was close to broke at one point and just to get a product out the door he used the cheapest **LOW FI* tranformers and made the front from plastic. Those Amps became known as the *Plexi* and are now worth a small fortune.
I don't need a university degree to work it out.

If you want great guitar sound build basic lo fi circuitry.

I wish you well,, Phil.

Adding, For the sake of the punters who may not grasp it here is a frequency response chart of all the instruments.
Note the guitar bandwidth in relation to other instruments. Note the outer limit of useful range is only 5kHz

Note that Pipe Organ delivers the broadest frequency band.
(ps I forgot the site where I found this pic so if I breach any copyright please let me know)

DrNomis · Post by **DrNomis** » 07 Jun 2012, 10:09

When you play an electric guitar through a full-range Hi-Fi system, the guitar can sound thin and weedy, aside from the usual impedance issues, the pickups in an electric guitar tend to produce a midrangey response, now, have you ever noticed how Fender Amps tend to have alot of midrange scoop, and alot of Bass and treble boost?, well this works with the natural midrangey-ness of the pickups to produce a brighter and fuller tone, the amplifier becomes part of the guitar as a complete musical instrument....

RnFR · Post by **RnFR** » 07 Jun 2012, 14:08

a lot ofthinner brightness could be due to the fact that most of those types of amps have speaker systems with a tweeter/horn. remember, guitar speakers limit bandwidth as well.

diagrammatiks · Post by **diagrammatiks** » 07 Jun 2012, 14:18

sorry but hifi doesn't necessarily just mean frequency response.

Of course some people prefer the saggy slow transient and recovery response of lo-fi and under performing transformers...

but not everyone.

Also just because the response capability is there doesn't mean you have to use it.

There's much more frequency shaping in the circuit itself then the actual transformer.

The extended response means that the transformer operates safer, cooler, and more reliably through the actual used frequency range.

also just to be fair...

classic ac30 - great transformers
hiwatt partridge - great great transformers
marshall era dagnell - fantastic
fender era schumaker/chicago - great transformers

Not as good as some of the cutting edge stuff that hifi guys like now but any of those transformers were top notch in the day and would have been found in hifi amps like quad and mcintosh.