John Curl's Blowtorch preamplifier part II

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Try NZ rump, my wife scorns all else, having originated from there, ;). Very simple marinade, cooked in a straightforward manner, melts in your mouth ... :)

What's bizarre is that a local butcher gets it in, in batches ... and sells it for almost half the price of the Australian stuff - I just don't get this overseas food trade thing ... :confused:
 
Try NZ rump, my wife scorns all else, having originated from there, ;). Very simple marinade, cooked in a straightforward manner, melts in your mouth ... :)

What's bizarre is that a local butcher gets it in, in batches ... and sells it for almost half the price of the Australian stuff - I just don't get this overseas food trade thing ... :confused:

Need to source it, plenty of NZ lamb here never a problem.
 
Try NZ rump, my wife scorns all else, having originated from there, ;). Very simple marinade, cooked in a straightforward manner, melts in your mouth ... :)

What's bizarre is that a local butcher gets it in, in batches ... and sells it for almost half the price of the Australian stuff - I just don't get this overseas food trade thing ... :confused:

Don't you know? If it's foreign, it must be exotic somehow :D

I know a few people who think that Ikea is a status brand FFS :rolleyes:

Buy local, unless of course it's rubbish :dead:
 
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Hi everybody, what is going on?

John I interviewed two guys yesterday from MIT. They were good kids and I would hire either of them as trainees. They showed me a class project where they did a common emitter npn amp with cascode. They both recognized the cascode was a common base amplifier but when I asked them how to use a pnp in this location they were lost.
 
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John I interviewed two guys yesterday from MIT. They were good kids and I would hire either of them as trainees. They showed me a class project where they did a common emitter npn amp with cascode. They both recognized the cascode was a common base amplifier but when I asked them how to use a pnp in this location they were lost.

They need a first edition of Shilling and Belove. Tubes, PNP's, Fets and early IC's.
 
Well I spent a bit of yesterday with JJ and among the discussion was why records are perceived as having greater dynamic range than CDs.

There are two issues. At the low level the shape of the noise floor differs. At the high end the distortion mechanism from records is similar to that of ones own ears.

So from an informed perception viewpoint records do have a greater dynamic range.

Or as Rocky and Bullwinkle would tout "Sometimes what you measure ain't what you hear."
 
There are two issues. At the low level the shape of the noise floor differs. At the high end the distortion mechanism from records is similar to that of ones own ears.

So from an informed perception viewpoint records do have a greater dynamic range.

The noise floor decreases with increasing frequency which is nice. I don't see how the distortion mechanism being similar to our ears would help. When I hear a live performance I'm also hearing the distortion mechanism of my ears. Adding additional distortion wouldn't be a good thing, or help dynamic range. If the distortions are non offensive, which seems to be the case with LP, it wouldn't hurt percieved dynamic range.

One other thing that might help perceived dynamic range is that in analog systems there can be significant recorded information below the noise floor. And the ears are good noise filters.
 
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There are two issues. At the low level the shape of the noise floor differs. At the high end the distortion mechanism from records is similar to that of ones own ears.

So from an informed perception viewpoint records do have a greater dynamic range.

Or as Rocky and Bullwinkle would tout "Sometimes what you measure ain't what you hear."



This explanation - to me - makes your post one of the most valuable on the entire site regarding such matters. :) Thank you.
 
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At the high end the distortion mechanism from records is similar to that of ones own ears.

I have never heard my ears mistrack!. Ring yes. My wife is convinced I have a very sophisticated filter in my hearing that selectively removes certain important sounds but never mistracking. When I hear mistracking I'm pretty convinced its external to my ears.
 
Demian,
I am not sure that what you call ringing in the ears is not something that I have also experienced many times. I have never looked at the actual db level that it happens at but I have always experienced what I would call distortion in my ears over a certain level of sound, almost as if they are crackling or attempting to attenuate extreme sound levels. It is obvious that it is in my ears at that level and not from the speakers, just to much level as far as I have ever been able to tell. I have had my ears checked and I do not have any perforation in my ears or any hearing problems but do seem to have an upper spl limit where distortion becomes evident.
 
I'm a Northerner, and I always wondered how loud 'loud' was. Way back when I was a teen, I decided to find out.

So I opened the window (no screen) on the field/woods side of the house and sat about 8 feet back, and fired a .308, from inside the house.

Holy mother of god that's loud.

Teh interwebs sez:

Rifles ........................... 156-167 dB Peak.

Ouch.

Regarding digital vs analog, Lynn Olsen has a great two part article (most of you may be familiar with it already) on why delta sigma DACs are ...not so hot (to be polite about it).

http://www.positive-feedback.com/Issue65/dac.htm

(I've stuck to ladder dacs, after doing everything possible to get the delta sigmas to work. Kinda reminds me of the dilemma with digital amps: SS... DD. A free running oscillator? really? flopping about doing...whatever? I gave them a both a shot (for a very long time, trying anything and everything), but I can't get the noise out, the flaw is in the design fundamentals.

It's that same problem of thinking that the low level distortion is unimportant. In engineering terms, yes, it is unimportant. In human hearing terms, it's almost the only part of the signal our ears use, and it is vital.

The future (and emerging present) of 'high end' digital is in custom ladder dac design and execution. No delta-sigma design is worth bothering with.
 
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