John Curl's Blowtorch preamplifier part II

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I'd be surprised if soon you couldn't sell a piece of equipment that doesn't use a smps with load balancing in both the US and Europe the way things are going. The days of kilo weight transformers will be a thing of the past with energy conservation requirements. Pro Audio amps are lightweights compared to what you guys are talking about and many have over 1,000 watts of output power.
 
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Sure, but you're not guaranteed those volumes starting out.



Have you listened to the current versions across all of the models?



But equity is something that it built. It's not something you're guaranteed from the start.



Much the same can be said of older males in a different market, where they are known to spend massive sums of money on that which technically, is garbage.



And that's different from "high end" audio how exactly?

se

You are not that important that I have to take you seriously. Lighten up.
 
We are gentile about it here and produce lightweight lossy cabinets cos the men in white coats at the BBC told us this is best. Or was that the man in a white coat who gave me my meds? I get confused.
I'm not sensible to this kind of humor.
I remember a time were we one of my friends was building a huge movie mixing facility in an big old theater. With a big wall, very isolating and heavy, between the studio and the space bahind. Enclosures were adjusted in this wall. I had the idea to listen to the back of the enclosures for a try. Very revelating to listen.
Isolation require mass, that the first thing. You know, we have an experience in isolating studios from control rooms. And there is always a compromize between mass (absorbsion) and thickness (rigidity). Do you want to build your enclosures with foamed concrete ?
The second is, when the membrane is accelerating on side, the chassis of the speaker do the same, the other side. And, there too, mass helps to reduce amplitude.
Now, about the BBC guy's arguments, who says they are experienced enough to avail against laws of pysics ? And, you know, the guy in white coats, he could be me ;-)

Last, I was managing at a time a big PA system (rock'n roll tours). lightness was a requisite.
 
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Many would disagree with you. But big and heavy sells high end.
Nothing to do with "high end", and nobody can disagree. No wall can isolate totally. It just provide attenuation. Double-it (with different resonances), you double attenuation ... an weight.
Now, if you have the recipe to build a very mat and dull enclosure in paper, I' am VERY interested.

And, if you says that we can have better results with the same weight than wood panels with well designed plastic molds, and non flat forms, I will be to the side of Kindhornman to agree. Not very easy for a DIYer.

Oh, ribbon's boomers ?
 
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but heavy and stiff sells expensive things.
You are boring. I don't sell anything. And prefer as cheap (and light) as i can.
My best DIY enclosures were made this way: panels of particleboard, stiffened by steel "L" profiles screwed in it and irregularly spaced. Painted with Rubson Liquid Rubber. And floating with a sand isolation in a armed concrete external one. Pretty heavy, but you could hit-it with a finger, it was sounding like your house external wall. I used the bass speaker to figure out where was the main vibration nodes of each wood panel at various frequencies.
Great care was done for internal dumping, panels of fiber-wool in a cross between all the dimensions in the center.
Any comment ?

For my studios walls, i preferred foamed concrete. BECAUSE they were very light, indeed, to make a box in a box (with different masses).
 
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Allready, around 1970, we were looking for new forms and materials to build better enclosures. In the company i was working for, we build those monitors in composite for ORTF (The French BBC ;-)
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while my friend Joseph Léon (Elipson's founder) was building the one on the edges (in fiber reinforced gypsum ).
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Notice that, to my knowledge, he was the first to align vertically the speakers to have them phase coherent, and to use dome tweeters ( in fact from a Mélodium microphone).
 
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diyAudio Member RIP
Joined 2005
It is easier just to separate the power transformer from the signal chassis, and get distance to work for you. That is what is done with the Blowtorch, JC-2, Vendetta Research, and most other low and mid level signal handling products.
Yes, with B fields distance is your friend. As transformer radiation at low frequencies, we are always in the near field and the magnetic signal is falling off with the cube of distance, which helps a lot in a hurry. There is a good discussion in Fish's book.

Keeping loop areas small elsewhere of course also helps.
 
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