John Curl's Blowtorch preamplifier part II

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Don't ask.

Any idea/estimate what the market demand is in Thailand for such a power amplifier, Mr. Marsh ?

(had a peeping-tom peek inside the trunk of the new model V12 Flying Spur this afternoon, when the owner was unloading his groceries. The butler's remains will definitely fit, but stereo may possibly require a second vehicle. Bentley, not RR Flying Spur)
 
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Gentle men;

Now here you have my version of wretched excess. But that is about right for me. Each mono-block weights in at around 550 pounds ! Huge C-core transformer. CFA design (of course). >450v/usec. Distortion? What distortion? Power output? Cost? Don't ask. Yes, thats a class-A N.Pass amp dwarfed in the background.... and you thought That was a big size amp. These are in the listening room of Dr Kung down in Trang, Thailand (near the Malasia border).


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Well, someone had to do it.



THx-RNMarsh


RNM you are looking good! But about the amplifier, around here we don't use handles on big things we used forged hoist rings. Makes it easier for the crane to lift it.
 
I think that R. Marsh's amp puts things into perspective, just like comparing a Honda Civic to a Bentley. There IS a market for these things, and most of the CTC Blowtorches were sold to Asia as well. It is not easy or cheap to make this kind of product. It should be easier making headphones or wires. Limited production means high prices/per chassis. High cost demands attention to visual detail or else.
This MuMetal vs steel vs aluminum is a joke.
We make things out of mumetal, if significant magnetic shielding is demanded. Input transformers, analog tape heads, etc. We don't use mumetal for preamps, although we played with it 42 years ago, back when Mark Levinson was making the JC-2. Too expensive, AND it tends to distort nearby signals. It can look reasonably attractive, but anodized aluminum looks a lot better.
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.
If you want to make a non-magnetic chassis, you have several options: aluminum, copper, silver, and stainless (non-magnetic) steel come to mind.
Aluminum is relatively cheap in this comparison, and it finishes well without painting it.
It shields most frequencies very well, except for 50-60Hz where it is just better to put the power supply transformer in a separate chassis (that is why we do it) and separate the two chassis by a meter or so.
Fit and finish are very important in high end audio. The Asians especially, seem very sensitive to it, and they are our best customers.
 
Actually, Richard, I once saw and heard a power amp of a really BIG size. Milan Karan of Karan Acoustics played his home system for me, consisting of his own loudpeskers using JBL Pro drivers, a two box per side job, each box weighing in at over 100 kilos (> 200 lbs each), and powered by two of his biggest models of mono amps. Not to be outdone by the speakers, they also weighed in at about 120 kilos (250 lbs) each, and delivered 2.5 kW/3.8kW/4.2 kW into 8/4/2 Ohms.

Awesome power and ease of delivering just about anything you can think of, and then some. And, much as I respect JBL's prowess regarding their pro series of drivers (just the magnet assembly on the 15" driver weughed 12.4 kg, orabout 27 lbs, I didn't like the resulting sound much, it reminded me too much of reinforced souns systems for large audiences. Generally, I like his products, but this time I felt his speakers had let him down. I have heard such drivers put to better use elsewhere for much less money and size.
 
loudpeskers using JBL Pro drivers, a two box per side job, each box weighing in at over 100 kilos (> 200 lbs each), and powered by two of his biggest models of mono amps.
While I don't see why a power amp should be havy, nowadays (I tend to prefer SMPS for them), while, for speakers, a rigid and as heavy as possible enclosure is a must(Inertia).
 
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