John Curl's Blowtorch preamplifier part II

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Scott,
Some of that equipment looks like it is vintage my birthday in the 50's. You say it all works... Does that mean that the owner, if not you, needs to turn that equipment on, on a regular basis to keep the electrolytic caps happy? If yes how often would that need to be? Real questions here......

These are all bona-fide WWII vintage and all suspect parts have been replaced , they have a wonderful vintage sound. Every time I turn them on they work beautifully, one here on the left is an unlabeled secret project (I don't know the details). I'm not showing more than 10% of this stash.
 
Fas42, thanks for the link with JA and Enid Lumley. That was Enid all right! The best ears I ever had as a friend. She used to visit Karen and me about once a year, and she would 'adjust' my hi fi to sound its best. She was amazing!

Did she hang the wet towels everywhere, considering that large sheets of cloth can get quite electrostatically charged there might have been something to this.
 
Did she hang the wet towels everywhere, considering that large sheets of cloth can get quite electrostatically charged there might have been something to this.
I know exactly what she was working to counter, this is one of the biggest bugbears to knock off. The frustration this has caused over the years has been immense, if not dealt with well this kills the quality like nothing else, for me ...

Frank
 
I'm curious whether her "awakening" was a steady process, or an epiphany. For me, it was the latter; after the usual, steady tweaking, one day the sound quality just floored me, it was a revelation! The shades just fell away from my eyes, it was a "I don't believe the sound can get this good!!" moment. Of course, it was highly transitory, shortly after that the quality dropped back to normal and so since then I've been chasing that, the end of the rainbow thing ...

Frank
 
The worst contacts that I ever came across were sealed mercury relays in an ABX box.
Anyone have a copy of the original Moncrief article? IM very limited & HE, when such claims are investigated, they are often (always?) the result of wonky procedure .. not Blind etc.

JC's letter has hints of this but we really need to see the original article .. from various 'proofs' that he has posted recently.

That's the beauty of Scientific Method; someone else should be able to repeat your test and get substantially the same result.
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The real issue is whether these wonky contacts would mask the differences between Blowtorch and an evil 4558 device.

But as we are doing ABC rather than ABX, the need for instant switching is lessened though some of my true golden pinnae would appreciate its convenience. As each subject is tested separately, the use of a switch box may be at the request of individual subjects.

We have the technology to get around wonky contacts!

The source is fed via a "hand crafted by virgins from solid Unobtainium" wire wound pot specially selected by JC himself to BOTH Blowtorch and the evil 4558 device. They feed matched Parasound A21s or some other choice device of JC's.

Switching is done by trained monkey ... I mean highly qualified engineer switching the speaker cables.

Anyone care to add important details or suggest how it can be done better?
 
jay said:
I have written several times that some people (including me) need to listen to a new system for a long time to decide if it is the sound that I like or not.

Also, it is not always apparent if one sound is different with others. Assume that even the golden ears are not accurate. So why risk your choice based on your poor golden ears? The point here is, some think that when the measurement tool (aka golden ears) cannot measure, why bother with the options because they should be equal. This is wrong.

Listen for preamp A for 1 month. Then change to preamp B for another month. You should be able to feel the difference. One day is not enough because who knows if your body is tired on that day, you're not in the mood, etc.
Jay, you bring up a very important point about the time-scale in which small differences can be detected. Here is one extreme.

If we brought an evil 4558 device to chez Curl and openly connected it to JC's supa system it is likely his Golden Pinnae friends would take less than 5mins. to declare it sounding terrible compared to Blowtorch. All sighted of course. :D

JC, in fact would take less than 0 secs. to declare he can hear all sorts of faults .. even without listening.

.. as he has declared there is no need to conduct tests he considers important on HIS designs cos he KNOWS they are FAULTLESS. And if he does conduct eg the Hirata test on Blowtorch, the results must remain secret for secret reasons.

When the curtain is drawn, lights dimmed or other means to make the test Blind are engaged and the contenders are re-allocated to A, B or C, some of the Golden Pinnae will indeed take less than 5min to declare they have positively identified Blowtorch from its superlative qualities compared to evil 4558.

But 5min is far too short a timescale to pick up differences of this sort regardless of the prowess the Golden Pinnae believe they possess. Here, in an attempt to prevent these worthy people from shooting themselves in the foot and making utter fools of themselves, I always insist they go through the protocol of the test which includes
  • at least 5 pieces of music OF THE SUBJECTS CHOICE
  • which must include at least one each of
    • simple voice(s)
    • complex
    • complex with voice(s)
    • soft
    • loud
  • he spend at least 30min comparing the 3 contenders
Note there is no requirement for any genre or even for the examples to be acoustic. The important criteria is that it be music the subject enjoys. BTW, Stairway to Heaven is often chosen as it meets several of the above for a 'pop' fan.

Remember, the aim of the exercise is actually ...
kindhornman said:
to find a system that involves the listener in the music and makes you happy? If I listen to some loudspeaker that someone else tells me in a dbx test is the best and after a few hours I can no longer listen to the sound because of some fatiguing phenomena like a titanium dome tweeter with lots of upper frequency hash is that a good test?

On a test of electronics like Blowtorch vs evil 4558, my true golden pinnae would probably take between 30min & an hour to establish a difference and up to half a day to select a preference.

But this isn't the important time-scale. Let assume that this hypothetical test has 2 of A, B or C assigned to Blowtorch and the other to evil 4558. I expect a true golden pinnae to say he "likes one and prefers it to the other 2 which are similar" (though he probably won't say they are the same) BTW, he is NEVER told that 2 presentations are the same. He has to assume even the possibility that all three are the same. [*]

The chances of this result being pure chance are 1/3. For greater statistical significance, we would have to test him another 2x making 3 tests in all .. each of which may take 1/2 a day. The assignments of A, B & C may be changed between the tests. If he produces, the same result on all three, it is highly likely he isn't deaf and his opinion is worth listening to.

The 1/2 day time limit is based simply on the performance of my true golden pinnae, logistics & cost. I make the possibly false assumption that people who take longer are probably not worth listening too.

I believe this sets a practical upper limit to the time-scale.


[*]Of course if he assigns very different descriptions to the 2 presentations of Blowtorch, he is spared further testing.
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john curl said:
Be careful, Frank, or you will be elected the next Enid Lumley. May she rest in peace.
I'm sorry to hear that JC. I take it you would have proposed her as competent to ensure Blowtorch performs at it's best and also as a true golden pinnae if you were to lend your spare Blowtorch to us. :mad:
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Because some Blind ABX tests often come up with NULL results doesn't mean Blind Tests cannot be refined to improve their resolution. I've spent much of my previous life attempting this with some success.

I certainly don't find it
jay said:
... hard to believe that to some extent ears can go far beyond measurement.
and have in fact done a lot to demonstrate this .. but in controlled tests which can be repeated by anyone versed in the art.

More listening tests please instead of
.. I have been doing this for 30 yrs, won a zillion awards, don't need to do ANY tests on my stuff cos its perfect, yus are all deaf & idiots etc.
 
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