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John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
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Old 23rd November 2012, 09:21 AM   #29721
kgrlee is offline kgrlee
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Originally Posted by PHEONIX View Post
Did you come here to work in Audio.
I think its called a 'mid life crisis'. With hindsight, its not too surprising I became a beach bum but it wasn't obvious at the time. I always thought I'd end up in Melbourne or Sydney.

Last edited by kgrlee; 23rd November 2012 at 09:49 AM.
 
Old 23rd November 2012, 10:07 AM   #29722
fas42 is offline fas42  Australia
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Originally Posted by wrinkle View Post
Hi Frank,

As you can see they still have free trial software available.
Microwave Office - RF/Microwave Circuit Design Software | AWR Corporation

But for a hobbyist the trial is never long enough...

Wrinkle
Thanks for the encouragement, Wrinkle, I'm starting to get the groove on what's available; haven't got hold of the trial yet, but the documentation is very enlightening. Plus, there's Agilent and Sonnet -- thoughts on those ...?

Frank
 
Old 23rd November 2012, 12:43 PM   #29723
kgrlee is offline kgrlee
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My favourite conventional big speaker is the Celestion A3 .. nearly as big as the Sovereign. ... I know the A3 is Unobtainium as are many of the ingredients (especially the cone material).
Mr. Marsh, the Celestion A3 might satisfy your taste for LF extension & low distortion. They appear on eBay now & then and you can still get them serviced.

They also look the part.

Thanks for reminding me of these, Pheonix.

Last edited by kgrlee; 23rd November 2012 at 12:48 PM.
 
Old 23rd November 2012, 02:34 PM   #29724
john curl is offline john curl  United States
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Well, its friday and I promised an exam. However, I am pretty darn sure that most of you are completely unprepared for one, as I would have expected.
You see, very few people are REALLY interested in doing or even understanding exotic measurements like the Hirata test, they just like to pick and poke at the very idea that the test might give some interesting results.
To them, audio electronics is relatively easy, and this is proven by ABX double-blind tests between one component and another, and invariably getting NULL results. They take this NULL result as PROOF that there are no significant differences in audio equipment from the mid fi level to the very best, if a reasonable attempt was to make it accurately in the first place.
This is where my colleagues and I depart from their belief. We find that a good deal of subtle difference in audio equipment is beyond both MEASUREMENT (at this time) and ABX listening testing.
This is WHY we pursue different 'upgrades' and encourage others to do so, as well.
It is a bit like getting a pretty good car, and 'upgrading' it with better tires and perhaps a new 'chip' for example, to get more 'performance'. In the old days, like 50 years ago, we used to 'upgrade' autos a bit more, with multiple carburetors, hot ignitions, different shocks, and even increasing the compression ratio and changing the camshaft. Today, we are stuck with minor external upgrades, and we hope that the auto manufacturers have done their job properly.
In audio electronics, we don't always KNOW whether a specific design is going to be a 'winner' or a 'loser'. I know that this disturbs people who want to KNOW what is what, but in audio, a measurement or two will not tell you EVERYTHING you need, even though the measurements are important to eliminate some of the big problems, in advance.
If this were not so, then we (my colleagues and I) would have surrendered to the IC's virtually exclusively, why not? For example, I listening tested the first batch of 5534's back in 1977, and I heard a difference between the IC and a discrete design, so I stuck with discrete designs for making studio boards, master tape recorders, preamps and finally power amps, when it would have been SO MUCH EASIER to use the IC's, and I would have preferred to use the IC's, IF I could make the same audio quality with them.
Now, decades have passed and even better IC's are available. That is good, and I do try to use them, and I am reasonably successful, but they will not completely duplicate a Vendetta Phono Stage, or a CTC Blowtorch. They just won't, at this time.
Moreover, the point of this tread is to talk about the ADDED factors to a great audio design, not just the circuit topology, or whether it is made from IC's or discrete. I hope to keep it that way.
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Old 23rd November 2012, 02:45 PM   #29725
Pano is offline Pano  United States
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John Curl's Blowtorch preamplifier part II
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Originally Posted by john curl View Post
It is a bit like getting a pretty good car, and 'upgrading' it with better tires and perhaps a new 'chip' for example, to get more 'performance'. In the old days, like 50 years ago, we used to 'upgrade' autos a bit more, with multiple carburetors, hot ignitions, different shocks, and even increasing the compression ratio and changing the camshaft.
I don't see this as a good analogy, John.
First: Blind testing a car's driving ability is not a good idea.
Second: Add a different cam, hotter ignition or just tires and a chip and it's pretty easy to measure the differences. Faster on the 1/4 mile or around the track or not? Would you put money on it?

Audio isn't so obvious, at least to some.
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Old 23rd November 2012, 02:48 PM   #29726
scott wurcer is online now scott wurcer  United States
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Originally Posted by john curl View Post
It is a bit like getting a pretty good car, and 'upgrading' it with better tires and perhaps a new 'chip' for example, to get more 'performance'. In the old days, like 50 years ago, we used to 'upgrade' autos a bit more, with multiple carburetors, hot ignitions, different shocks, and even increasing the compression ratio and changing the camshaft.
I remember the "over-clocking" of cars to defeat the federal polution quidelines. Anti-social behavior IMHO.
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Old 23rd November 2012, 03:10 PM   #29727
SY is offline SY  United States
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John Curl's Blowtorch preamplifier part II
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Well, its friday and I promised an exam. However, I am pretty darn sure that most of you are completely unprepared for one, as I would have expected.
Yes, we're too busy staring at the ground and drooling.
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Old 23rd November 2012, 03:58 PM   #29728
scott wurcer is online now scott wurcer  United States
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Well, its friday and I promised an exam. However, I am pretty darn sure that most of you are completely unprepared for one, as I would have expected.
How about someone taking the op-amps that registered nothing in Ron's test and seeing if anything shows up in the Hirata test before we waste any time on this.
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Old 23rd November 2012, 04:08 PM   #29729
bcarso is offline bcarso  United States
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I remember the "over-clocking" of cars to defeat the federal polution quidelines. Anti-social behavior IMHO.
Very similar IMO: the spread spectrum clocking of things to allow higher emissions, but energy harder to measure and slipping below mandated thresholds. Yet our EM environment gets noisier and noisier.
 
Old 23rd November 2012, 04:11 PM   #29730
john curl is offline john curl  United States
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Scott, you have to try to UNDERSTAND what the Hirata test measures, before you can say anything about it. It probably will NOT show a problem with a typical IC.
Interestingly enough, it shows more problems in older discrete solid state power amp designs, and few problems with tube amps. I can give an example, in future, when people are made a little more aware of the test.
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