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Old 9th May 2012, 06:44 PM   #5301
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I asked a colleague of mine, a professional electronic designer, as well as a professional audio recordist, about the THAT1510-12. The answer was that it is very good, BUT not great. Better can be done with tubes or discrete. Good enough for portable, battery powered stuff. Doesn't surprise me in the least.
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Old 9th May 2012, 07:08 PM   #5302
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Some of this might still apply . Hope it helps .

5.1Precision BJT matched-pairs for Current Sources & Voltage Refrences
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Old 9th May 2012, 07:44 PM   #5303
a.wayne is offline a.wayne  United States
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Quote:
Originally Posted by john curl View Post
I used to make my own master tapes from the board with my Ampex 15 ips 1/2 tr recorder. Unfortunately, the tapes were all lost about 20 years ago, in a firestorm.

A shame , My first experience listening to mastertapes in an Hi-Fi setting was at Peter Mcgrath's ,(78 or 79) funny seeing it being revitalized again today .



Old time sumting come back again ...



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Originally Posted by dvv View Post


Kid all you want to, Godfrey, but whoever tries them, DOES remember them for a long, long time.

They are NOTHING like the stuff from Heinz cans. No less than 3 types of meat in them, of which two must be smoked beforehand. Lots of carrot, onions and some paprika (not hot). No less than 6 hours on the stove, as slow as you can manage it.

Way back, while we were (dad, mom and I) in Ankara, our best "customers" were the Brits, winning hands down, and followed by the Americans. Both are grossly misrepresented, in my view. The Brits are the next best thing after ideal guests - exceptionally tolerant, they take their time about it, they don't stuff themselves. Americans, as opposed to the idiot stereotype, may not have much of a cuisine (also untrue, but that's another story), but they sure as hell know to recognize good food when they are served some. And unlike many others, they are always willing to try something new, with extremely few exceptions.

Of course, after one of mom's lunches or dinners, everybody knew the Brits wouldn't be coming to work the next day, too preoccupied with ice on the forehead and Alka Seltzer in their tummies, but, to their credit, they NEVER failed to turn up again.

Americans seem made of sturdier stuff, they could take it without casualties.

Which makes both a host's Dream Team guests.

Germans and Austrians not counted, they are practically locals, they can take anything in their stride. And what with the number of Serbian restaurants in both countries, chances are they are already well versed.
Sounds like you had your fair share of Bully Beef ...

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Originally Posted by john curl View Post
Well, what I try for in designing audio is to get as close to the 'live' experience as possible. It hasn't been possible to do so yet, in my experience, (and others) with IC's.
Why my IC150A sounded Live ...
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Old 9th May 2012, 07:48 PM   #5304
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Worth trying .

Try BCV 61 and 62 as current mirror in Self type amp ( protected by VAS so 30 V OK ) . Better than transistors I have hand matched ( good Vce ) . Very good if VAS Vbe is < 0.6 V . I use 22R as a starting point for re ( x 2 )

http://www.farnell.com/datasheets/775182.pdf

Worth trying with That's matched pairs . BTW Self amps do not work exactly as simulation . Current mirrors especailly . I add 4R7 to VAS emitter to help that ( not local feedback , a little gain lost ) . Also although I do not know where someone says the input stage noise is not optimum due to resistor values choosen in the same designs .

Last edited by nigel pearson; 9th May 2012 at 08:00 PM.
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Old 9th May 2012, 08:26 PM   #5305
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Especially for D V V .

Extreme Low Noise Preampifier

This theme was covered by the predecessor of the That's chip .

This man compares a blameless amp with a previous Naim amp . Interesting reading . Not what I expected . Musicality and sweat !
http://www.pinkfishmedia.net/forum/a...p/t-37966.html

Last edited by nigel pearson; 9th May 2012 at 08:43 PM.
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Old 9th May 2012, 09:35 PM   #5306
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Nigel, do you know that I made that noise spec in a commercial product in 1973? It was the Levinson JC-1.
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Old 9th May 2012, 10:12 PM   #5307
a.wayne is offline a.wayne  United States
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Interesting interview on U-boob with Mark discussing his early years and that Pre-amp ...

another : http://www.youtube.com/watch?v=sKtPmthrdYw





...

Last edited by a.wayne; 9th May 2012 at 10:25 PM.
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Old 9th May 2012, 10:17 PM   #5308
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I didn't John . I heard some Red Rose speakers once and liked them . That was Mark I beleive ?

D V V and I like BF transistors and this seems another endorsement . Seems that performance was out there .

I was told a special Philips TV driver transistor had the best ever Rbb noise ( we called it that , no idea if it's correct ) . Philips required the TV chassis numbers before supplying as they were fed up with us lot buying them ( no idea which ) . TO126 I think .

I learnt about noise from the mic chip we have been discussing . It was the RS spec sheet ( before That's about 10 years ago ) .

Lehmann of Black Cube told me it is the Re if the internal LTP that adjusts gain on the differential input pair on those chips . Johnathan Carr says not .

I added some 2N4403 to an op amp . Lower noise and easy biasing as it was a bipolar input . However the sound was less detailed .

BTW it was Julian Vereker who taught me about noise in about 1976 . His pre amps were not good in that and it did concern him . Not bad for a mechanical engineer JV .

Last edited by nigel pearson; 9th May 2012 at 10:35 PM.
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Old 10th May 2012, 04:52 AM   #5309
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Mark did an interesting interview, but he did not mention me or the products that I designed for him. He is the 'same old Mark', a little more humble than he was for a number of years, and actually quite likable again. He used to be like that when I first worked with him, but he changed a lot as his company powered up. Now he is back to normal.
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Old 10th May 2012, 05:51 AM   #5310
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Nigel, the problem is that we are discussing 'throwaway' designs, rather than anything with some sophistication.
I have been using the 2N4403 in circuit designs since 1968, or 44 years ago, and it is a bit behind the times, except for 'throwaway' designs. Today, we would use a low noise jfet for the input or a device with an even lower rbb'. We would try to make everything direct coupled, and get rid of input and output caps, etc, etc.
I might be wasting your time, here, but wouldn't you rather discuss more sophisticated circuits?
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