John Curl's Blowtorch preamplifier part II

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I haven't kept up lately, but I didn't see that, no. There is a good bit of info about what frequencies might work best, but nothing about sweeps. Unless I missed it.

Oh, BTW I was joking about the dishwasher. Just in case any of you nuts decide to try it. :p
WHAT! I just put all my priceless d to d in there.....

The issue with variable freq ultrasound is I think that most transducers are operated close to or at mechanical resonance, so sweeping them may be something of a challenge and require very different electronics. Still in all, possible.
 
I haven't read that whole thread yet but there is a section where they are talking about sweeping the frequency. The answer was that the resonance that the units cover has a band width of about 3 to 4Khz at best so varying the frequency was only a small change. The preferred minimum frequency was 60Khz and up. Rotation speed is anywhere from 1 rpm to 1rph.
 
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Oh, BTW I was joking about the dishwasher. Just in case any of you nuts decide to try it. :p

Slightly OT, but I have used the dishwasher to clean vintage equipement for many years with only one problem: on some vintage test equipment (Lambda power supplies of note) the process sometimes peels off the chassis paint.

But audio equipment comes out sqeaky clean and fully operational.
(I don't use any detergent, though).

jan
 
any of you nuts

I wasn't.

If you clamp a warped LP and spin it at high speed, it straightens out.
Spin it fast enough for some time, and residual shear stresses are a goner.
Et voilà, perfectly flat pancake.

Not for the faint of heart, but less off the rocker than sticking an LP in the microwave, or in exotic incubators as e.g. DF1/DF2.

Just in case.
 
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Of course, you can recognize a vinyl record. But for the rest of us, it is the sound quality that we can't get from digital, that we appreciate. We tend to ignore the minor ticks and pops.
I love the 'rest of us' while the whole world had turned to digital apart some nostalgic or old retrograde.
I'm unable to recognize a correct digital copy from ANY original (analog or numeric), while i cried each time i listened to the vinyls made from my master tapes.
The difference is so obvious than even a deaf can hear it.
I can recognize any analog copy made on tape (on the best studio mastering machines), and specially when the original source is digital (no hiss).
While all the blind test we made in recording studios between any sources and digital copy with all the people pretending something negative about a so colling 'digital sound' produced the same results: impossible to discriminate.
Of course, you can notice very little differences due to the analog parts of the two systems if they are not the same.

Now, that 'YOU' prefer the kind of sound distorted by the vinyl is 'YOUR' problem.
You can also prefer horse carts to cars.
 
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We had, in France, local vinyls made from American records. The difference with the 'import' vinyls was obvious. I have, may-be ten records with the both versions.

Each mastering room had his own 'signature', it was a little like lutherie, reason why we traveled sometimes across the oceans, in order to had our records cut here or there.
Who cares anymore with this ?
 
It's more like film vs digital.
For naturalness, films wins every time.
Again, it is a question of culture.
I was photographer too, during a part of my life, and have created, and manage, a photography site about 'street-photography':
Street photo et Cie. Site et forum sur la photo de rue..
So, i'm very involved in this question.
We were used (and loved) to the way the film was dealing with the light, but, nowadays, when you compare live the colors of a landscape with the photo you just shot on your digital full frame body, you can be VERY surprised by the color's fidelity.
Now, some people like to play with excessive added sharpness, but it is not to blame to the digital process.
The gain in sensibility and definition brought by digital is just amazing.

There is a negative effect about dynamic on our digital sensors ( in constant improvements): if the digital is perfectly 'flat', compared to the analog, it breaks brutally near full black and whites. While the film was smoothing the transitions in an agreeable way, giving-you the feeling of an increased dynamic.

Now, you can process your digital photos with softwares to get very similar results to various films, each ones with their own signatures.
It is VERY similar to the sound domain, reason why this is, may-be, not too far from the topic.
 
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Thanks Brad. See the common base and common emitter version of prof. Marshall Leach head amp
Moving Coil Cartridge Head Amps

MC phono cartridges will work into a direct short, if necessary (summing input), so cap loading is a VERY SMALL problem.

George, I don't think it's very significant

Thanks JC and SY. I run some sims for DL-103 with 3 to 1 variation of C. Results agree with SY calculations. I wonder then how can the nonlinearity of the input capacitance can have an effect in the audio band. I’ll wait for the data.

Regarding record cleaning fluids, remember this
I'd be more worried about the alcohol leaching out the plasticizers, making the material more brittle

George
 
Esperado,
I listen to both formats, the great CD recordings I can't fault, but sometimes they have just waited to long to transfer the information to CD and the sound quality is just not there, the old material as we spoke of weeks ago has been compromised by age and mishandling the old analog tapes and remastering doesn't bring the music back it seems. Then I would rather listen to the album, clicks and pops and all.. Two different sounds but both enjoyable. Today in America the album is making a strong return, yes much of that is nostalgia such as the cover art and the liner notes, but it is growing and saving the record stores. Actual CD purchase volume keeps dropping off, today it is digital transfers mostly as MP3 that people are doing and I just don't like the atrocious sound of most of that media, blame it on the engineers or the record companies who don't want you getting the high rez material, I don't know, but I can tell I am listening to an MP3 when I hear it. Lately they have upped the film rate on a new movie and the reaction to the more realistic color and clear edges have been very disliked it appears. Just as you said in digital photography that you can emulate the look of film there is either something we have come to expect or a real preference for film saturation. To me it is no difference from preferring Kodak film over Fuji film, the color spectrum has always been different and though the Fuji was more vivid I always preferred the Kodak. You could say let them eat cake, but I would rather say let them chose from the buffet.
 
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