A new type of tube guitar amplifier

but, i'm no luddite.

Same here. I play an amp with four channels, channel-assignable rectification, channel-assignable output wattage, channel-assignable FX on/footswitchable FX, three preamp modes per channel, and enough preamp gain to kill puppies. I just don't think the guy who designed this amp really understands what guitarists are looking for. ;)
 
Hmm. A lot of talk about how awesome its specs are, and not much about how it sounds.

About halfway down their page I found some clips. Listening now through Skullcandy earbuds, I'm not blown away. The stereo micing ("Right channel: Shure SM57 dynamic microphone placed 12 inches off-axis below and in front of Marshall 4x12 with Vintage 30 speakers, in anechoic / dampened room. Left channel: AKG C-3000 studio condenser microphone set 2 meters away in same room.") just makes the whole thing sound odd, and the focus is mostly on cleaner tones.



This worries me, TBH. This guy is a high fidelity stereo amplifier developer, and is trying to leverage that into amplifier design. Yet, for the past 60 years of electric guitar, part of the sound of rock guitar HAS been the very innefficiencies in an amplifier circuit. A Marshall plexi is nowhere near full frequency - that's half the point.

I fully agree - firstly, why are they using a c3000 at all, secondly why that panning thing going on with the mics, it should be a mixed demo track not an unmixed paired mic tracked project ready for mixing.. can't tell a thing from that without mixing it myself which I just don't have enough interest in to bother doing.

and no transformer = less of the guitar tone we know and love, and hifi does NOT equal good guitar tone. I'm sure it's a great hifi amp.

but there are several reasons why recording engineers and musicians prefer classic transformer-balanced gear. certain transformers make music sound warmer via the particular response anomalies and distortions generated by those transformers.

Also, the output transformers in some tube guitar amps are part of the reason why "tube watts" sound louder than "solid state watts" in guitar amps.

This guy needs to research the history of great sounding guitar amps I think before he tries to sell his amp designs.

I'm sure he's a good engineer, but he either has no concept of what generates great guitar tone, or he doesn't care or doesn't like what we feel is great guitar tone which kind of makes his amp designs moot either way.
 
laughing out loud at you, mshilarious. :D
man, you seem like you've got some kind of axe to grind.
it's kinda like watching a psychiactric exam, on screen.


wrong.

Patent 5,612,646 Output Transformerless Amplifier Impedance Matching Apparatus
MARCH 18, 1997

but point taken. it's not brand spanken' new.


ok, let's see your patent on something.
LOL again.....

you're kind of nit picking about somethign that he basically got right, aren't you? in other words, he's not "wrong", but you certainly like the sound of saying that he's "wrong" don't you?

and why would he need to have a patent on something to understand the basic flaws in a patent?

You're really defensive about this amp -- did you design it?
 
huh? he's totally right, I agree with Drew.

heheh
and i agree with me. :D








look, no one's 'got it right', or 'got it wrong'.

you don't know what you're dealing with, til it's in hand, and you can actually play it.

my point is, for all the naysayers, yourself included, you JUST DON'T KNOW.....
until you have it in hand.

so why throw a turd in the punch bowl?



and i'm not nit picking here, i'm pointing out some fact versus fiction.
based on the evidence in hand, which is mostly technical.



like i said before:
yep, the specs are not what's gonna sell this thing.

it's the sound

and, the feel.
 
and, hopefully, we'll see....
if it's got the 'sound' and 'feel'.


meanwhile, i'm rockin' with my vintage boogie.
and that's enough for me.



hey, i'm just throwing some new info out there for anyone who's interested, and some of you guys are reacting like somebody shoved a cattle prod up your ass.

heheh

and i don't know why................
 
and, hopefully, we'll see....
if it's got the 'sound' and 'feel'.


meanwhile, i'm rockin' with my vintage boogie.
and that's enough for me.



hey, i'm just throwing some new info out there for anyone who's interested, and some of you guys are reacting like somebody shoved a cattle prod up your ass.

heheh

and i don't know why................

I enjoyed checking out that amp. I am envious of that guy, he is trying something he believes in. Many people think they know how everything should be and constantly criiticizes anyone with new and different ideas.
Thanks
VP
 
You know, wasn't the last time we saw a "new and improved" alternative to tube amps that was "lighter and more efficient" when companies first introduced solid state amps?

I mean, just sayin'...
 
It's true I've been in a foul mood for quite some time, but I had no reason to take it out on you, therefore I apologize.

I am going to make another long rambling post which I cannot reasonably expect anyone to read, so other than one technical correction to your rebuttal which I shall make first, feel free to skip the rest of the post.

The term of a patent runs from the application date, not the date of issuance. The patent in question has an application date of August 30, 1995, and expires twenty years from that date, not the date of issuance in 1997. If you think briefly about the consequences, you'll see why that is (it used to be 17 years from issue, but it didn't use to take the USPTO three years to issue a patent). Therefore, the patent is fourteen years old, more than two thirds the way through its life.

Long rambling part:

Next, about patents in general. It's true, I have filed for no patents. Thinking back, given that somehow in 2001 a person was granted a patent for balanced guitar wiring, strangely in the great scheme of things I could have also been eligible for a patent. Nevermind that I think his original patent could probably be challenged on grounds of prior art and being obvious. His circuit described in the patent had several shortcomings; I published a circuit that improved those aspects. Now, were I to use a balanced guitar circuit, I would have to license his patent, but anyone using my circuit would have had to license both patents (until his expired first, then just mine, etc.)

Except I had no intention of doing that, because in the natural order knowledge is and wants to be free. So I just published a white paper and declared my elements of the circuit design to be public domain.

That wasn't even that clever of an idea; I've had better ideas but those had clear prior art, so . . . anyway, let's talk the silliness of the modern patent system for a minute. I used to have a friend who is a patent attorney. His biggest client was the parent company of Titlest. He spend a good chunk of his career filing patent applications for golf ball dimple patterns. Are there hundreds of potential golf ball dimple patterns? I imagine. Are there hundreds of useful golf ball dimple patterns? I don't know, but I do know that Titlest doesn't sell hundreds of different golf balls with different dimple patterns.

What does that mean? It means they aren't filing these patents because they believe each new dimple pattern is the best ever. It's a form of corporate mutually assured destruction is what is it.

But I don't accuse our diligent amplifier designer of such foibles. Unlike dimple patterns, he has a single good, workable concept. Unlike the balanced wiring one, I think his is actually a novel idea. I even suspect I would like his amplifier, probably much more than you would. I never claimed his patent was bogus.

But what it is, and solely is, it's a brilliant technical solution to a marketing problem. As I argued before, there are prior art solutions of hybrid design that accomplish these same goals:

- no output transformer
- tolerant of various loads
- open-circuit tolerant
- short-circuit tolerant
- regulated power supplies

The problem is if you put a transistor in the "audio path", it's not a "pure tube amp". He has staked out a marketing position that his arrangement of MOSFETs still comprise a "pure tube amp". But as I and many others have argued, guitarists really do want output transformers and their nonlinearities.

I think hybrid design has a lot of potential, but it has to overcome the "stigma" of being a hybrid design. Let's consider these hybrid designs:

(for purposes of this discussion, each stage should be considered to consistent of one or several active elements, along with accompanying passive elements)

a) preamp tube --> transistor

This is the typical hybrid design. I built one and I rather enjoyed it. But purists rightly point out there is no power tube distortion, transformer saturation, nor rectifier sag.

OK, let's move on:

b) preamp tube --> power tube (dummy load) --> transistor

This is slightly more clever, but more expensive, and all of the power in the dummy load is wasted. Oh well, we now have power tubes pumping, and at any volume (because a pot can be placed downstream in a buffered transistor stage).

I should note at this point the amplifier is capable of all of the performance traits of the ZOTL, it just lacks the marketing cachet (presuming that purists accept the ZOTL as all-tube).

c) preamp tube --> power tube --> transformer (dummy load) --> transistor

Now we have spend even more money and weight and power than it would take to build your basic tube amp, but we can drive the output any way we require.

However, we can reconsider the output transformer design--given that it doesn't really need to drive an 8 ohm load, we could make the dummy load on the secondary more compatible with smaller and cheaper transformer design. Also, we'd only really need one or two power tubes, yet still have whatever wattage output is required via the power transistors. Does anybody want to own a Fender Champ plugged into a solid state Marshall? I dunno.

d) preamp tube --> transformer --> power tube (dummy load) --> transistor

Now things are getting interesting. Once we decide that our goal is to saturate a transformer, we realize that it's much easier to saturate a small transformer than a large one, and it won't take nearly as much power. Do we need a transformer in that part of the circuit? Of course not, but if it accomplishes our sonic goal, who cares?

Our transformer has now dropped from an $80 unit to maybe $10, and would only weigh a few ounces. The power tube(s) is still screaming away into its dummy load, and we are listening at bedroom levels (sorry, if you want speaker breakup I can't help you)

Let's keep going:

e) preamp tube --> transformer (dummy pot load) --> preamp tube --> pot --> preamp tube --> pot --> power tube --> transistor

Now we can independently set preamp tube and power tube overdrive and transformer saturation (we could even make parallel/series signal paths if we wanted, multiple channels, etc.)

But all of that presumes that in the future people will use guitar amps. You want an invention? Here you go, best of all under current law I don't have to build a prototype to patent it:

f) guitar --> onboard FET/ADC/bluetooth --> iPhone of each member of the audience that receives discrete signals from various members of the band, and according to their preferences applies DSP processes to mix the band as they like. The audience may also participate with their own instruments, or simply wave their iPhone as their instrument. All data is transmitted in a MIDI-type format, such that audience members may select not only the guitar tone they'd like to hear, but even assign completely different patches from what the actual instruments are. Imagine going to a concert and bringing your guitar so you can jam along, but instead of a metal band you decide you'd like to hear them as a gamelan strangely accompanying an Indian classical trio, with you on sitar. If you choose to broadcast your data, other audience members may incorporate your playing at their discretion. No loudspeakers anywhere, just earbuds (and ambient sounds of acoustic instruments). Of course, it doesn't have to be just live, or in just a single location, thanks to the interwebs. And people who can't play an instrument can bring their guitar hero ax to trigger various modifications of the live data coming from the band.

That, my dear Gonzo, is the guitar amplifier of the future!
 
I enjoyed checking out that amp. I am envious of that guy, he is trying something he believes in. Many people think they know how everything should be and constantly criiticizes anyone with new and different ideas.
Thanks
VP
Why do you have to wade in and make it personal? Up until your post the criticism had been of ideas and gear, not of people.
 
Let's have some more discussion on whether this is a "pure" tube amp. Here is the patent schematic for reference:

http://www.freepatentsonline.com/5612646.pdf

This will mainly be a "marketing" rather than technical discussion, about the concept of a "pure" tube amp.

OK, the tube anode at 71 and the cathode at 73 go to parts 56, 57, . . . 58. And what are those parts? They are solid state bridge rectifiers. That's right, your power tube signal must pass directly through solid state diodes. A lot of them! Note on pg. 6 that in a typical application there would be twenty rectifiers/secondary windings! Then it goes across transformer 52-55, into another transformer which carries the HF oscillation but also what looks to me as a MOSFET power amp output. It's rearranged a bit, but I think that feature is a marketing ploy intended to limit power output to what is available from the tube. Ordinarily (without the HF oscillator) you'd have the audio signal off the tube/transformer to the gates rather than as a load.

In other words, if you wanted to simply reduce the size of a transformer required by doing the HF oscillator carrier thing, you could do it without loading the tube with the speaker. You would simply hook that second transformer to the gates of the MOSFET power amp (which would leave that transformer essentially unloaded, or with whatever fixed dummy load you required) and not the output. Of course, then the entire scheme wouldn't be necessary.

Anyway, you can argue all day long about whether the audio passes through the MOSFETs or not (I don't see how it doesn't, but whatever), but it is not disputable that your power tube is hooked directly, in series, to twenty solid-state bridge rectifiers (which is forty series diodes). Is that better/worse/indifferent than passing from a power tube directly to a class A MOSFET output? You purists may decide . . .

Note: biasing details omitted from simplified schemo below:
 
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