John Curl's Blowtorch preamplifier part II - Page 3407 - diyAudio
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Old 2nd February 2013, 09:30 AM   #34061
BV is online now BV  Slovakia
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Try to make Your own measurements with EVB for PGA, and after then make conclusions . I used PGA for short period, and I must leave it, because listeners complained "something is wrong", measurements confirm this.. I wrote my experiences to manufacturer with measurements results, no response. Really, something is strange... , But believe , or not, it is Yours decision.
I am not "begginer" , I can make preamp with results as posted in attachment
Attached Images
File Type: png 1k.png (14.8 KB, 208 views)
File Type: png CCIF.png (16.2 KB, 206 views)
File Type: png THD-F.png (18.6 KB, 208 views)

Last edited by BV; 2nd February 2013 at 09:39 AM.
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Old 2nd February 2013, 10:28 AM   #34062
fas42 is offline fas42  Australia
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At least part of the story appears to be that people get used to a certain quality of distortion, and they expect it to be always present, as a mark of "normal" sound reproduction. So for them any system that doesn't display these characteristics is somehow not correct, even though it may actually sound more like the real thing than what they prefer. I have been surprised many times by what some people prefer, a somewhat artificial, hyped up presentation that has to be at exactly the right volume to sound "right", and which immediately sounds unpleasant if anything except the "correct" recordings are played. Each to their own, I guess ...

Frank

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Old 2nd February 2013, 10:29 AM   #34063
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Oh, please, BV and PMA, don't justify, i'm not thinking anything negative about your expertise, on the contrary. And i believe your experience. That's why i was arguing, trying to understand why i prefer those CIs to pots on my system, and not you on yours.
May-be we are not searching for the same things, listening to the same kind of music, may-be our enclosures do not present the things the same ways, who knows ?
I use horns and fast amps (current feedback) , love jazz etc. What are your systems ?

About THD measurements, as long as they are not awful and reveal a failure, i do not care too much about them.
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Old 2nd February 2013, 10:44 AM   #34064
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fas42, any musical instruments produce its own harmonics. H2 & H3 are always present in the original signal.
Little HD does not change the sound more than if the mike was positioned a little aside. The risk is, if HD is too high, the texture of the instruments begins to change and the whole scene to be monotone (or awful). (h2 and H3, high order is more perverse)
It is the IM that i fear much, as it brings noises betwwen the instruments and blurs the signal, plus the lack of instant dynamic witch kill the life.
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Old 2nd February 2013, 11:55 AM   #34065
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Each nonlinearity causing simple harmonic dstortion will always produce IM product with complex signal, you can not separate this. IM is very "nonmusical" and changing harmonic contents of original signal. And simple THD20 reveal a lot, and CCIF19+20 a lot more.
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Old 2nd February 2013, 12:04 PM   #34066
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Yes, there is a non-linear transfer function that is both frequency and amplitude dependent. Thd and ccif only help to visualize non-linearities. These non-linearities should be minimized as a necessary condition. And we have methods how to zoom and reveal the non-linearities.
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Old 2nd February 2013, 12:10 PM   #34067
SY is offline SY  United States
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Quote:
Originally Posted by BV View Post
According Levinson preamp, how do You know, they used PGA?
They didn't use PGA (nor have I tried it myself). They used MDAC, which you said (I quoted you twice) was easy to distinguish from relays by measurement and listening. Then you said it wasn't easy to distinguish from relays by measurement and listening. So... my congratulations were for correcting your initial incorrect statement. I don't know about PGA, but MDACs are a superb way of avoiding the well-known issues of mechanical analog volume controls.

Quote:
It has nothing to do with "instinctively rejection..
If you inferred that I was talking about you, my apologies. I wasn't.
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Old 2nd February 2013, 12:40 PM   #34068
Bonsai is online now Bonsai  Taiwan
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Quote:
Originally Posted by PMA View Post
I vote for manual rotary stepped attenuator or relay resistor network. And blue Alps 10k is also sonically better than any PGA.
6moons audio reviews: Esoteric C-03


6moons audio reviews: Esoteric C-03


ESOTERIC Stereo Linestage Preamplifier C-03 | ESOTERIC COMPANY

Still winning accolades 4 years after they first started using the PGA23xx

Leave you preconceptions out of this. When well implemented, it's an awesome chip.
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Old 2nd February 2013, 12:45 PM   #34069
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I don't care about magazine reviews. Not enough info to get complete view.
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Old 2nd February 2013, 01:07 PM   #34070
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You don't care about a lot of things, PMA, including measurements - selectively, of course.
Still waiting an answer regarding the NCore measurements, for instance.

In other news, I'd be happy if my favorite music tracks were recorder using something like this.
I'll be even happier the day I get it for my own system. Yeah, PGA2311s and 5532s inside. Sad really (that competitors with better "ingredients" can't do much better).

Some measurements here (using google translate).
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