John Curl's Blowtorch preamplifier part II

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About this Bybee thing that controversy is boring, at the end. I don't believe in it more than most of you. But, if i had to evaluate it, i should first proceed to an attentive and honest listening. Can we perceive any change ?
If the response i "NO", why to even measure-it ?
If the response is "Yes", and measurements don't show nothing, time to ask ourself questions.

But it is certainly not with the purpose to demonstrate it is BS before even to open the box that we gonna get an objective evaluation.
 
It came in a little zip lock bag, not a box, just for the sake of accuracy. You will be even less pleased with my measurements on the HOT headphone accessory, which appears and acts like a jack and a plug wired together.

I found Ed's earlier posts. Not in this thread. Hilarious- he refused to show what his test setup was or what the repeatability was. How convincing.
 
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What does Jack Bybee believe this nanotube thing does anyway? I skimmed through the paper from Science about the quantization and ballistic transport but still have no idea how a bundle of nanotubes would affect a signal passing through them.

The resident Canoga Park audiophile does have some in his system. He's an interesting mix of hard science by early education and... IMO a certain credulity. When there was an amplifier "shoot-out", once an intermittent cable was discovered and replaced, he immediately found the contending amplifier to be better than his, and purchased it on the spot. Talking to the designer about his creation I began to fear that there were parasitic oscillations due to too-long wires to the DMOS output devices and in the absence of damping resistors. Whether this accounted in part for the preference I have no idea.
 
A couple of more inputs re Bybee. Ed is this your graph?
 

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I discovered a local electronics shop. It's almost a museum. Tons of NOS stuff, a wall of tubes, etc.

There was an "RF detector probe" kit for an oscilloscope. It was old and faded, but it said it would work at 300KHz to 250MHz. How useful do you think this would be in tracking down RF in an amplifier?

Might be a demod. or detector probe. Good to track modulated RF signals.


-RNM
 
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Who was it here who suggested the difference in CD vs HD Download might be jitter? Please stand up and take a bow.

Requestioning the whole record/play CD process got a lot of people frustrated with me. The call to BenchMark and the reminder here about F.O. and jitter helped turn on the light bulb.

BTW - the output of the CD player is from the Sony CD via optical port/cable.

Got more tests to go and do re jitter.


:)



THx-RNMarsh
 
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About this Bybee thing that controversy is boring, at the end. I don't believe in it more than most of you. But, if i had to evaluate it, i should first proceed to an attentive and honest listening. Can we perceive any change ?
If the response i "NO", why to even measure-it ?
If the response is "Yes", and measurements don't show nothing, time to ask ourself questions.
And that's pretty well the core of any of this sort of thing. The number one step is whether you, personally, can hear a change occurring - dump this nonsense about people's hearing being easily fooled; if that's the case throw all your expensive hifi in the dumpster, and buy a cheap midfi from the local electrics - you won't notice any difference, really, and will quickly get used to it ... ;)

The questions to ask if measurements don't show anything are: am I trying to measure the right thing? Is the equipment sensitive enough to pick anything up? Is there a time dimension to the behaviour; does it change over time, for any reason? And, etc ...

I see a lot of very primitive measuring of extremely basic behaviours using very precise and sophisticated equipment talked about here - not the smartest way to get real answers, IMO ...
 
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Come on Frank, what is wrong with using highly sensitive test equipment to look at anything unless you get lost in the minutia? I wouldn't think it would be very practical to use an electron microscope to look for a simple bacteria but I suppose you could do that.

Perhaps someone with access to a flame photometer could find out if there are some hidden elements in one of the BB devices but I highly doubt that they would find anything.

As Christophe has stated if you can't hear any difference who care what it is suppose to do anyway? Jan stating the it shows no phase shift or FR changes and Sy showing only resistance at a miniscule level would seem to be fairly conclusive evidence that there will be no change anywhere in the system. Put the thing in the chain and measure the final result with and without at the speaker terminals and use your differential software to find a difference, if you can't find one how can you possibly hear anything?
 
Steven, the test equipment is fine, but one needs to create the right type of measuring regime to get meaningful results - a few times I've mentioned several ideas I've had for test signals, ways of going about stressing equipment to get real numbers - but there has been zero interest, so far.

I'm not in a position for doing this myself, but others are - in the meantime, I rely on my ears to give me answers.
 
I discovered a local electronics shop. It's almost a museum. Tons of NOS stuff, a wall of tubes, etc.

There was an "RF detector probe" kit for an oscilloscope. It was old and faded, but it said it would work at 300KHz to 250MHz. How useful do you think this would be in tracking down RF in an amplifier?

Does it scan?

My favourite tool for RF was a Spec An. with a fet probe. You can just poke around in those NE/SA602 chip set FM rx's, see the LO's, you can tell if the amplitudes are appropriate even though it's not calibrated, inject a signal and follow it....
 
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Hi Richard,
Nice link. All kinds of information in one spot. Some of the links in that page require membership to the AES, and another to a University (or the link is broken maybe).

I think it is important to note that the 75 R coaxial connection is coupled via a transformer in most equipment. There is no chassis to chassis connection at all.

-Chris
 
If something is only detectable if the tester is using rapid switching (and/or short snippets) then the practical relevance is questionable. If you can´t remember you´ll not miss something the next time.

I don't know if what I'm going to say is relevant to your discussion but...

When we listen to A for a second then to B, we don't always put A into our memory then check whether B is similar to A. Instead, we already familiar with C and it is pretty well stored in our memory then we just need to know if A or B is similar to C. So we don't need to "store" A and B into memory at all.

The above is implemented in a DBT or in speaker design. What we need is to listen to specific lyrics of a specific singer (usually female vocalist) of specific music. Some "sound" even already registered very well in our memory since childhood. This how consistency is possible.
 
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Well, it doesnt seem to do enough of anything to be of personal interest. I would be more interested in the 'active' one to measure. But only if I got to test it without paying for it. I have been quite effective in removing noise with more conventional methods.


THx-RNMarsh


This is one of the ac line filters i designed for mfr. The bottom line is -100db.... the filter drops below that and doesnt come back up until >1MHz. The cut starts at -6dB at approx 400Hz.

It is one of several such filters in one chassis.... seen in # 67144, above. [They sold a lot of them before the financial crash of the USA and world. Was UL approved etc]



View attachment dual xfmr filter response.pdf




THx-RNMarsh
 
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Do you have ideas/advice on how to economically retrofit better than Toslink optically isolated links to existing gear ?.
'Economically' is the hard part ;)
For short distances nothing beats transformer isolated coax. Good transformers are a must.
If it absolutely has to be optical, you might try these (ST type). They are common, but not cheap. Make sure that you have enough current available for the transmitter.
 

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But Richard, you showed me my first CRAY computer. '-) decades ago. Remember, the letter was written 20 years ago, and the development done, perhaps 40 or so years ago. The computer time was used for development, not measurement. I have the measurements made in 1995, and they show little, if anything, and THAT is what I am warning you about.

OK. I remember our first Cray and subsequent super computers for high energy physics research. But not much about the multiple nano-tube construction removing all or part of the 1/f noise. That would not need a network analyzer then but some really, really low noise tests..... using something like 10 each 2sk170 in parallel IPS, minimum.


THx-RNMarsh
 
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'Economically' is the hard part ;)
For short distances nothing beats transformer isolated coax. Good transformers are a must.
If it absolutely has to be optical, you might try these (ST type). They are common, but not cheap. Make sure that you have enough current available for the transmitter.

I think the relatively slow signal rise time of the transformer would be a source of increased jitter.


THx-RNMarsh
 
I discovered a local electronics shop. It's almost a museum. Tons of NOS stuff, a wall of tubes, etc.

There was an "RF detector probe" kit for an oscilloscope. It was old and faded, but it said it would work at 300KHz to 250MHz. How useful do you think this would be in tracking down RF in an amplifier?
It will work, but I recommend you build yourself one or two dedicated sniffer probes: it costs very little and is much more convenient than an actual detector probe. You can sneak it everywhere without fear of causing shorts, to pinpoint accurately the source of an oscillation.
Have a look here:
http://www.diyaudio.com/forums/equipment-tools/256426-sig-tracer-probe-rf.html?highlight=rf+probe
http://www.diyaudio.com/forums/equipment-tools/264871-oscillation-sniffer.html?highlight=rf+probe
 
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