John Curl's Blowtorch preamplifier part II - Page 571 - diyAudio
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Old 13th August 2010, 06:37 PM   #5701
iko is offline iko  Canada
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Everyone likes to make some statement, Jacques chose his. The worst that can happen is that he'll be forever and only remembered for this choice. To each his own.
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Old 13th August 2010, 06:38 PM   #5702
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A small aside: My future wife, a young violin student was late for her master class with Zino Franciscatti and was in the elevator with an older lady, who happened to be the sponsor of the institute she was attending. Apparently, being late, she was nervous, and kept muttering Sh--, Sh--, Sh-- to herself. Overhearing, the mature and stately benefactor corrected her, saying: 'No dear, it's Merde'. ;-)
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Old 13th August 2010, 06:38 PM   #5703
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Originally Posted by PMA View Post
Cal -
really?
After reading that I get the impression it is as widely used as it is in English, sometimes referring to feces and lots of the times for other things. Perhaps my friends are more polite than others. Don't know how that could be though, they're French.

Oops, did I just say that?
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Old 13th August 2010, 07:07 PM   #5704
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Originally Posted by Jacques Merde View Post
Uh, oh. I'm on the police radar now

Je ne comprende pas Jacques Merde.
While we are on how things translate why is it that no one can translate "je ne sais pas?"



I am going a bit crazy as today is being spent build RCA stereo to mono adapter boxes! Used to be a Y cord was fine, then RDL made an STD-10K combiner, so all of the large projects call for it to be used. As these are $40+ I build a small metal box, mount 3 RCA jacks (cosmetic gold plated) and wire two resistors. As the jacks cost me 19 cents, the resistors a penny and I can make boxes for 75 cents a pound, the two dozen I need justify my waste of time.

That is because the design professionals judge the sound system with their eyes. A metal box combiner is bigger and must be better than a plastic box, which must be better than a Y cord.

The other issue that keeps getting missed is we prefer to hear what we expect. Way back I remember when Scully tape decks were all the rage. They replaced the older Ampex 350's. The Scullys were modern and solid state. They even had an optional distortion canceler circuit to compensate for magnetic tape saturation.

I remember listening to a record one time and noticing the Scully sound on it. Checking the liner turns out I was right, it was recorded on a Scully. (Sy not sure, is this an accurate test?)

Of course if you were to put a good working condition Ampex up against the equivalent Scully, I suspect virtually everyone would pick the Ampex as better sounding.

But in the day Ampexs got dumped wholesale, today they are still treasured.

So when someone tells me they like the sound of carbon composition resistors, or some such, they really aren't wrong. But I would not let them guide me.

So John it is possible that the golden ear reviewers prefer the sound of discrete components over I.C.s.

Of course on the other hand some people considered cables to sound better sending signal one way than the other. Absolute nonsense, I thought, surprised me so much I (Can't mention the physical reaction here Jacques) when I found I was able to measure a difference. Yes it was a ridiculously small difference. So were the golden ears right or was it coincidence?

Of course there is a small power amplifier we keep around here that has 5-10% 2nd order harmonic distortion at full power. It is interesting to demo it to people and compare it to a popular model that is RATED less than .05% at all levels. Virtually everyone prefers the higher distortion one.

Oh yeah I also like to play a 30 khz tone through a small tweeter, everyone says they can't hear it. But then when I turn it off and back on most can tell when it is on. A few question if they are hearing sub-harmonics. I let them use any of the analyzers we keep around to see if they can find it, so far no. (The 30 khz level is about 75 db, looking for 10 or 15 it is below the noise floor, but that doesn't mean it is not there and the ear can pick signal out of noise. (An example of where the ear is better than instruments... maybe))

Well break time over...
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Old 13th August 2010, 07:14 PM   #5705
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Originally Posted by simon7000 View Post
(Sy not sure, is this an accurate test?)

.
Nope, but it's absolutely plausible, just as I have no problem distinguishing between a large diaphragm condenser mike and a small diaphragm one.
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Old 13th August 2010, 07:26 PM   #5706
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I was told 'pure hearsay' that the Scully machines suffered from an oversight where a solenoid relay was located too close to the tape path, and this created problems. I never used a Scully, myself, so I don't know.

Last edited by john curl; 13th August 2010 at 07:42 PM.
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Old 13th August 2010, 08:00 PM   #5707
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. . . it went for review at 'Stereophile' . . .
. . . Later, 'The Audio Critic' tested another . . .
How interested are such reviewers in things like schematics, parts lists, and taking off the cover/looking inside? Perhaps their reviews are much more "blind" than if any of us were reviewing John's designs?


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Last edited by johnferrier; 13th August 2010 at 08:14 PM. Reason: have i asked yet, if i know you Jacques Merde ?
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Old 13th August 2010, 08:27 PM   #5708
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The reviewers did not know what was inside the amps, specifically, when they listened to them. I, unfortunately, told them, after the fact, that the main difference was the IC.
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Old 13th August 2010, 08:43 PM   #5709
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Originally Posted by john curl View Post
The reviewers did not know what was inside the amps, specifically, when they listened to them.
Really? It was beyond Dick Olsher's capability to look inside, see a dreaded opamp at the input, then draw his conclusions?
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Old 13th August 2010, 09:06 PM   #5710
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Really? It was beyond Dick Olsher's capability to look inside, see a dreaded opamp at the input, then draw his conclusions?
Actually reviewing is a really tedious process after the novelty wears off. Looking inside and seeing the I.C. case doesn't particularly tell where the part is in the circuit. They could be used for metering etc.

I suspect it is quite plausible that he can hear a difference between an I.C. opamp high gain feedback circuit and a low open loop gain discrete circuit. His preference would seem to be discrete.

Now if there was training involved, for example he used to look inside, that could have tuned his bias. So if the review sells your product... You should be more successful following the pied piper.

Unfortunately I cannot build a discrete opamp exactly the same as an I.C. There are some things available in both technologies that can be used to advantage.



As to large diaphragm vs small diaphragm condenser mic, when I do an arena, ballpark, or stadium, the required mic is almost always a miniature condenser headset. I also provide a large diaphragm condenser. Sometimes I get complaints the announcer cannot be heard. These usually turn out to mean he cannot be understood. Also turns out they can't be understood even from a recording. For some funny reason it is much less of a problem with the large diaphragm mic.s. Although some announcers who use them do turn their heads or "eat" them.
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