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Old 11th June 2012, 06:07 AM   #23851
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On other subjects: There has been a hi end show in Newport Beach at the first of this month. I did not go, but I was 'represented' there by a number of products.
Besides phono, analog tape appears to be coming back, especially at these hi end shows. I am not really surprised, and I might outline, just as a tutorial, what analog tape reproduction entails, in future inputs.
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Old 11th June 2012, 09:52 AM   #23852
gerhard is offline gerhard  Germany
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Quote:
Originally Posted by john curl View Post
KTSR, I need a REAL box instrument with knobs and switches.
R&SUPV Audio Analyzer (Rohde & Schwarz USA - Products - Test & Measurement - Audio Analyzers)

They are affordable if you don't insist in the newest Version and work stand-alone.

I had an ap2712 in a mixed signal wafertester, that was NO fun.

Gerhard
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Old 11th June 2012, 02:05 PM   #23853
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Originally Posted by gpapag View Post
I googled for IEEE Std.1050 and I found the 1989 edition in pdf.
Well written and carefully worded document. Thanks jneutron for pointing to it.

In there, I read something (one of the things at least that) I didn’t know. That low – impedance circuits are less susceptible to capacitive coupled noise and crosstalk .
Susceptibility to external influence is generally broken into two categories, when the victim has an impedance below 377 ohms, and when it is above 377 ohms. That is the free space impedance for planar wave propagation.

Above, capacitance is generally the domimant, below magnetic dominates. I believe that was also included in the Tom Van Doren link I provided earlier.

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May be this is the reason that high package density modern CPUs are designed for lower voltage supply than the previous generation CPUs which were less densely packaged.
I kind of think it's more for dissipation. These puppies are getting harder and harder to keep cool, and the capacitive energy storage of the gates goes as the voltage squared. (cmos)

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Originally Posted by Bonsai View Post
". . . inductance of the wires (14 nH for some reason . . . "

That seems incredibly high. Bonds even on the old DIP packages are a fraction of this.
Hey, I'm gettin old. I read it back in the early 80's when I did chip and die stuff. And honestly, I've no idea how they measured it, nor where the return path was. I had to characterize bonds for capacitance out to .025 pf, but not inductance at that time..

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Originally Posted by john curl View Post
Besides phono, analog tape appears to be coming back...
Very cool. What size/speed?


jn
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Old 11th June 2012, 02:58 PM   #23854
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Originally Posted by scott wurcer View Post
We tried a Shibasoku before AP was around, very nice instrument that should be very cheap used. I agree that the AP can be very non-user friendly at times (you actually have to RTFM).
My AP System 2 came with a quick start guide. Useless, had to read the manual to start. Then played and reread it. Still have to look at it.

Before the System 2, I used my own dual oscillators and notch filter. By selecting components I was able to do better than 10 PPB! But as it was a very tweaked one off, it was not suitable for sharing results.

The Panasonic is popular because you can get one for under $2000!

But the freak'in issue is still what is it that you need to measure!
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Old 11th June 2012, 03:36 PM   #23855
1audio is offline 1audio  United States
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Quote:
Originally Posted by gerhard View Post
R&SUPV Audio Analyzer (Rohde & Schwarz USA - Products - Test & Measurement - Audio Analyzers)

They are affordable if you don't insist in the newest Version and work stand-alone.

I had an ap2712 in a mixed signal wafertester, that was NO fun.

Gerhard
Affordable is relative. The cheapest R&S I have seen was in the $5K region. There is a "broken" one on eBay for $2500. And while self contained its still not John's idea of knobs.

At that price I would stretch a little further and get the SRS SR1.

The Boonton is similar to the Panasonic in operation. The Boonton generator is completely isolated and the control input is via optoisolators. Essentially the equivalent to the transformer isolation of the AP.
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Old 11th June 2012, 03:47 PM   #23856
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Quote:
Originally Posted by john curl View Post
analog tape appears to be coming back, especially at these hi end shows.
I though the best of the tape manufacturers had pulled the plug long ago, especially when VHS vanished.
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Old 11th June 2012, 04:10 PM   #23857
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Originally Posted by scott wurcer View Post
I though the best of the tape manufacturers had pulled the plug long ago, especially when VHS vanished.
If it were commercially practical it would not be interesting to audiophiles. If hard to find raw material is required and there are lots of moving parts its irresistible. I still don't understand the appeal of vinyl transfers of digital files when the original file is available. But phono and tape head preamps are interesting intellectual exercises.
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Old 11th June 2012, 04:56 PM   #23858
brianco is offline brianco  Ireland
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There are - at least here in the UK - quite a few first generation master-tapes doing the rounds.

For exhibition purposes a good tape coupled with the visual impact of a big reel to reel will draw a lot of interest which - if a silver disc were playing in a transport - may well go to another exhibitor!

So, if any would be exhibitor wants a few master-tapes (at collectors' prices or a top MC cartridge or arm) for the up-coming shows, then just send me a PM!
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Old 11th June 2012, 06:11 PM   #23859
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true enough. One thing that shut the tongue waggers down in the world of audio, and audio rags and audio threads..is when John Atkinson related a story. First in the magazine (stereohile) and then on the stereophile forum . . . A story about RF engineers 'tuning' the copper bus in order to match/tune correctly. (out at a given transmitter)

They did it, this micro adjustment, by whanging on the copper bus, with a hammer.
Not quite accurate, KBK. The story was about the late Stanley Kelly, whose first job was working in the UK's radar team in the 1940s. Yes, he was tasked with hitting copper bus bars with a hammer. But this wasn't to tune them to a transmitter, but simply to increase their conductivity to the specified figure.

Stanley was a superbly imgainative engineer. I remember him showing me how a ceramic capacitor could be very microphonic.

John Atkinson
Editor, Stereophile
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Old 11th June 2012, 07:12 PM   #23860
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Posted at Jun 11, 11:11
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