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John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
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Old 10th March 2011, 05:10 AM   #10921
abraxalito is offline abraxalito  United Kingdom
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Centre-tapping does indeed make all the difference to my earlier advice. Nice one
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Old 10th March 2011, 05:11 AM   #10922
Steve Eddy is offline Steve Eddy  United States
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Originally Posted by abraxalito View Post
Oooh se, its great when you get all philosophical Yes it is still a transformer ontologically, but no its not one existentially. Any help?
I transform, therefore I am.

se
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Old 10th March 2011, 05:15 AM   #10923
Steve Eddy is offline Steve Eddy  United States
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Originally Posted by abraxalito View Post
Centre-tapping does indeed make all the difference to my earlier advice. Nice one
Well, there are also the so-called "grid chokes" which have massive amounts of inductance.

se
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Old 10th March 2011, 05:21 AM   #10924
abraxalito is offline abraxalito  United Kingdom
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So they're chokes, ergo they don't count. 'I choke, therefore I am (not)' doesn't have the same ring about it.
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Old 10th March 2011, 05:31 AM   #10925
Steve Eddy is offline Steve Eddy  United States
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Originally Posted by abraxalito View Post
So they're chokes, ergo they don't count. 'I choke, therefore I am (not)' doesn't have the same ring about it.
Has marketing done any focus group testing on this yet?

se
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Old 10th March 2011, 05:39 AM   #10926
abraxalito is offline abraxalito  United Kingdom
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Marketing would need to know what answer you wanted, a priori. Then they'd apply some techniques like this one :

http://users.aims.ac.za/~mackay/probability/survey.html
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Old 10th March 2011, 06:27 AM   #10927
wrinkle is offline wrinkle  United Kingdom
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Originally Posted by scott wurcer View Post
I have to agree with jcx in this case "no signal no noise" does not really apply the noise in the system is a signal. At thermal equilibrium the eddy current losses will be accounted for, i.e. if I take a transformer and resitively terminate it at both ends the losses will show up in the resulting input/output terminal measurements.

Which is another way of saying I have not observed a transformer losing the ability to pass a low level signal even to the point of the thermal noise of its terminations.

This also brings back fond memories of the guy down under that wound 300,000 turns of wire on a bundle of rebar and measured the Schumann resonance (pico-Teslas)
In support of your claim about working down to low levels, EM Electronics range of miniature amplifier modules for high resolution temperature measurement and calorimetry. Resolve micro degrees with Thermocouples. measures down to picovolts with a transformer front end, thats lower than most here.

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Old 10th March 2011, 06:46 AM   #10928
Soundminded is offline Soundminded  United States
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I find it rather puzzling that people who fret about what kind of capacitor to insert in a signal path at any signal level don't have the slightest compunction to inserting a transformer in the signal path and one with a ferrous core in it at that. To make matters even more bizarre, they are ready to insert it at the very lowest signal level in the circuit where any noise and distortion it introduces will be amplified with the maximum gain possible. This where the alternative to what is just one more atavism that pervades and characterizes audiophiledom is obvious. Where I come from that is not called engineering.

At the very least, the problem of providing adequate signal levels for modern amplifiers should be solved where the problem is created in the first place, with the people who manufacture MC cartridges. If they can't provide a suitable signal best suited to the peculiarities of their own product, why is it the responsibility of the preamplifier designer to invent a one size fits all solution especially when there are so many variables among alternative MC cartridges?
 
Old 10th March 2011, 08:18 AM   #10929
jan.didden is offline jan.didden  Europe
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You guys may want to read this:

Distortion blind test

jan didden
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Old 10th March 2011, 08:48 AM   #10930
SY is offline SY  United States
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John Curl's Blowtorch preamplifier part II
Quote:
Originally Posted by Steve Eddy View Post
Well, there are also the so-called "grid chokes" which have massive amounts of inductance.

se
Or a transformer whose secondary is connected to a grid of a pentode (not uncommon). The voltage is taken from the secondary, but essentially is unloaded.
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