John Curl's Blowtorch preamplifier

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#18,881
stinius said:


Gerhard

Good point, but anyway JC will never answer my first question so the conclusion seems to be that if you take a lousy signal, compress it, modulates it, use a class C amp and an antenna to transmit the signal to another antenna demodulate the signal and it “sounds” better then a SACD.

Strange, isn’t it?

Cheers
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Perhaps not so strange.

Although "better" is someone's subjective perception and opinion.

The clear difference between the SACD and the broadcast (perhaps even of the same program material) is going to be in the harmonic spectra. The two have very different spectra of distortion. One of them might be perceived as more pleasing.

Also the FM is sent through a processor to prevent (at minimum) over deviation of the signal.

And given that it is Frequency modulation the Class C part plays little role... at least that is what they would have us believe...

Otoh, perhaps the FM tuna in question is a Marantz 10B (I think that is the one with toobers and a scope?), and maybe that is why the FM sounds so goooood? 😀

Again I did not consult with Curl on this... 😎


_-_-bear
 
#18,886
I now have a Marantz 10 vacuum tube tuner. In the past I had a Marantz 10B tuner, much the same, and I have used solid state Marantz 20 tuners (not as good), Fisher 200B darn good, and a number of solid state tuners, that mostly stay in the closet.
Of course, FM is not perfect, and MOST programming is very poor, BUT 'The Prairie Home Companion' and certain low power FM jazz stations sound wonderful. It just goes to show what is possible, when people actually care, or are led to believe what is possible with a very old medium.
 
#18,894
syn08 said:


All these are bad for the sound?
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For FM, especially. Varactors change own capacitance with signal, also with signals of neighboring stations, RF interferences: they are right on the front where almost is no selectivity. It causes frequency modulation. PLL heterodynes add jitter, also modulating frequency. Ceramic filters have sharp resonances that cause parasitic amplitude and phase modulations. All this results in distortions.
I once made a FM tuner, very simple, that phase locked on the frequency of the tuning station directly, it was kind of FM-modulating feedback. Very simple, but very clean.

Edit: something like this one, the same principle:

An externally hosted image should be here but it was not working when we last tested it.
 
#18,895
Steve Dunlap said:
First, let me state that I am not saying blind testing is invalid. I have however participated in blind tests with unexpected results. These were not listening tests, but show just how easily people (including me) can be fooled.

The first blind test of this type came about when a master chef I was taking classes from flatly stated that no one in the class could tell the difference between Coke and Sprite while blindfolded. Of course we jumped at the chance to prove him wrong. The results were 50/50, the same as guessing.

The second test of this type was even more bizarre. We were to tell the difference in 5 different liquors. The 5 were vodka, gin, tequila, bourbon and rum. They were placed in our hand in shot glasses, randomly. All we had to do was identify each one. Only one person out of 14 got 3 correct. She didn't taste them, just smell.

I don't believe for a second that I can't tell these differences when I know what I am tasting. Why were the results so poor in a blind test?
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It's dangerous to apply experiences across taste and listening, blindfolded taste tests are notorious. Gordon Ramsay does one on his show where trained chefs fail at the most obvious ones. They can't tell scallops from pork. OTOH I did not lose a bet that I could tell Stoli from Absolute even after having "some" of each. The key was to only smell them.
 
#18,898
Not to talk too much about it, I have found that subtlety exists in audio design. It may not be easily provable, and it might not even be important in every application, or situation, but I have found it almost impossible to precisely tell when something like wire selection can make a serious difference, and when it is just an exotic wire where something cheaper might do as well.
However, when I am working on my best designs, I consider everything that I can. It doesn't hurt, usually looks better, and it tends to win listening comparisons.
With cheaper designs, I try to give guidelines to avoid really bad components, and just accept that cheaper wire, connectors, etc are probably going to effect the sound, somewhat, but that's what it sometimes takes to make something affordable. I am associated with a whole range of designs, and I hope to make any design that is connected to my name, at least OK, sonically. This has little to do with measurement.
 
#18,899
john curl said:
Not to talk too much about it, I have found that subtlety exists in audio design. It may not be easily provable, and it might not even be important in every application, or situation, but I have found it almost impossible to precisely tell when something like wire selection can make a serious difference, and when it is just an exotic wire where something cheaper might do as well.
However, when I am working on my best designs, I consider everything that I can. It doesn't hurt, usually looks better, and it tends to win listening comparisons.
With cheaper designs, I try to give guidelines to avoid really bad components, and just accept that cheaper wire, connectors, etc are probably going to effect the sound, somewhat, but that's what it sometimes takes to make something affordable. I am associated with a whole range of designs, and I hope to make any design that is connected to my name, at least OK, sonically. This has little to do with measurement.
Click to expand...

You a professional, John. More, you are well known professional. That means, you have to design for your customers.
In 1979 (or 1980, I don't remember) my boss went to a closed professional exposition of Electronics ministry. He took my microwave alarm system and a "Kremlin Pill" that one lady in our laboratory was working on. Coming back he told stories about new devices, technologies, that he saw on that expo. However, there were things that were popular among the public that had right to be there and see what is very new, but the most knowledgeable people were circling around one humble military pult... It was a very exceptional pult. It had knobs, LEDs, buttons... It had blue LEDs!
They managed somehow to create a party in a room of hotel, and when the representative of that enterprise that made a pult was drunk enough he asked them to swear they don't tell the secret... The secret was, their customer (one military ministry) did not want to hear that blue LEDs don't exist yet, they wanted them! So, they made miniature bulbs of a blue glass....
So, if your customer wants a directional cable, you have to respect the customer... You are a professional, it is kind of cross you have to carry...
 
#18,900
This is not true in my design world. I help make better audio designs. NOBODY tells me what wire to use or what direction. You are mistaken, as are so many others about me, and most other audio designers as to their duties in hi end audio. Keeping an open mind is a good thing. Putting your opinion of what I do, without ever working with me, is potentially slanderous.
Of course, there are the audio cynics out there who appear to be brainwashed by lots and lots of negative info about audio design. What amazes me, is why do THEY care?
Is there an equal number of people trashing autos, cameras, and telescopes on the internet? Have I missed something?
 
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