Patent pending Speaker Reactance Thru (S.R.T.) attenuation technology used by Aracom

[Steve A.]

The Marshall Power Brake uses a big multi tapped inductor in a similar way. Similar enough that it may qualify as prior art.

The Power Break does not handle different impedances as the Aracom attenuator does. As a Fender guy I got the 8 ohm version of the Power Brake. [Note: that statement is not true as pointed out below by dai h. My bad!]

I did have a technical question- with an OT feeding a speaker directly there is an interaction between the two. Is that what they call reactance? After going through two transformers and the resistive bridge is that interaction unchanged? It seems to me that it wouldn't be the same. Is the interaction strictly between the OT and the first transformer- or does the speaker load have an effect on the second tranformer which is transferred back to the first transformer? Questions, questions, questions- so many that they give me a headache...

Al Capone (a fairly successful and intelligent man) once said: "Just because you think they're all out to get you doesn't mean they aren't."

Are you SURE that Al Capone said that? I did a Google search on that and the only hit was a post you made here on February 3, 2012.

(I thought that a Firesign Theater LP from the 70's had the line "just because you're paranoid doesn't mean they're not out to get you" but I could not confirm that. )

It was Joseph Heller who said in "Catch 22" which was published in 1961: “Just because you're paranoid doesn't mean they aren't after you”

Steve

[R.G.]

A moderated and healthy paranoia is one of the things trained INTO you as part of formal project management curricula; probably other training processes as well, but that one comes to mind.

If there is anything that history shows us, it's that if anyone can take advantage of others by sub/per-verting whatever is already in place, they will.

My personal response to this disclosure was "Well, yeah. What's new about that?"

That view is what make me shake my head in disbelief at anyone wanting to give more authority with less oversight to governments of any kind. It simply can't end well.

[Leo_Gnardo]

Questions, questions, questions- Steve

Questions, questions, questions plaguing the youth of America. (F.Zappa - 200 Motels)

I just can't see thousands of guitarists or hi fi nuts running out to buy this transformer contraption, Aracom or any other.

Perhaps just the "chosen few" like the one that started that awful row back in April.

And yes I have to wonder just what losses in tone & power it would incur when properly used NEVERMIND the damage that will be caused by those who don't understand it & try to use it. As in guitarists/techs who will swap input for output. Already happens plenty with power attenuators of the past & present.

Another solution in search of a problem.

[jpfamps]

I did go look a the patent. The patent researchers have done a execrable job for the last few decades. Patents that are laughably obvious to "one skilled in the art" as prior art have been awarded. It's difficult for me to believe that given the - what, century old now? - idea of using transformers to transform impedances, the idea of using two of them, one on each side of a variable resistor, would be patentable. However, I'm regularly surprised how low the standards of the patent examiners can be.

Well the cynical view would be that it's in the interests of patent office to award as many patents as possible as this is how they derive their income.

By rejecting spurious patents you would also be depriving lawyers of income from challenging said patents in court.

[Chuck H]

Are you SURE that Al Capone said that? I did a Google search on that and the only hit was a post you made here on February 3, 2012.

(I thought that a Firesign Theater LP from the 70's had the line "just because you're paranoid doesn't mean they're not out to get you" but I could not confirm that. )

It was Joseph Heller who said in "Catch 22" which was published in 1961: “Just because you're paranoid doesn't mean they aren't after you”

Steve

I'm sure I have the info on good reference... But I can't say from where?!? I must have read it from a credible source at some time or another. A google search doesn't seem to back me up. But I don't think I dreamed it.

As to the Power Brake... The inductor is adjusted at both ends of the coupling as a means of regulating reactance. That seems similar to me. And I did see a technical evaluation of the Power Brake that demonstrated how it managed an even impedance representation to both the amp and speaker (I'm sorry I can't reference where!!!). The power break does bump the frequencies at the peaks and valleys of the reactance compared to a typical speaker. But it does use a tapped inductive load to remain consistent. That seemed significant enough to mention.

[dai h.]

The Power Break does not handle different impedances as the Aracom attenuator does. As a Fender guy I got the 8 ohm version of the Power Brake.

Steve you may be thinking of the (THD) Hot Plate (which is offered in impedance specific models--8ohms, 16, 2.7). (FWIW) the Power Brake does provide switching between 8 and 16 ohms. The main load (ignoring the Ls and C meant to model the impedance rise in the highs and low freq. resonance for simplification) is a 10 ohm 100W R (this is the 8 ohm). To achieve 16 ohms, an inductance (which measures about 2.5 ohms DC IIRC) is switched in series (which seems to equate to about x4 impedance AC = 10 ohms (+10 ohm R = 20 ohms for the 16 ohms Z setting) when placed in series w/the 10 ohm R).

[Steve A.]

Steve you may be thinking of the (THD) Hot Plate (which is offered in impedance specific models--8ohms, 16, 2.7). (FWIW) the Power Brake does provide switching between 8 and 16 ohms.

I don't know where I got the idea* that there were separate versions of the Marshall Power Brake for 8 and 16 ohms but you are absolutely correct. However unlike the Aracom it does not convert impedances like plugging a 16 ohm load into an 8 ohm output, or in fact any combination of 2, 4, 8 and 16 ohms.

Steve Ahola

BTW the MPT is fairly transparent at the higher settings. When I first got it I had this crazy idea to plug it into my JTM30-112 and turned all of the controls up to 10 and the MPT to its lowest setting. After playing it for about 10 minutes getting some pretty cool sounds the amp died. One of the internal fuses popped and the 6L6 power tubes were trashed. The 6L6's were mounted horizontally and had to be very short to be able to put the tube cover over them.

I couldn't find any tubes short enough to fit locally so I decided to hammer out the tube cover a bit to fit the tubes. Not one of my better ideas- it would have been much better to leave the stock tube cover alone and make up a new one with expanded aluminum from the hardware store. I thought that one of the problems was that the tubes were mounted horizontally and perhaps when overheated some of the tube elements had shorted out. Or is that not possible.

Thanks!

Steve

P.S. I did find a site that sets the story straight on many of the quotes attributed to Al Capone:

http://www.mistercapone.com/quotes.htm

* I think it was the salesman who told me that and I never did bother to look it up. I had thought that the input was 8 ohms and that the 8/16 ohm slide switch was to match the speaker that you were using.

[loudthud]

A tube amp presents a non-linear impedance to a speaker when the amp is clipping. It seems to me that this invention does not scale the impedance in a correct mannor to lower the volume, all it does is add resistance in series with the speaker after the impedance matching provided by the transformers. Ken Fischers' Power Brake (or whatever he called it) does a similar thing, it adds significant resistance in series with the speaker after a voltage divider/load.

Without knowing the ratios of the transformers used, it's hard to know what the amplifier sees as a load when connected to this invention. I want to see the math.