John Curl's Blowtorch preamplifier

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Well, the 'truth' can be valuable, and I knew that it would create a reaction. I had almost forgotten how people felt about 'break-in' and directionality, but they are 'real' in my world.
When it comes to the 'sound' of the BLOWTORCH, this is where it sits.
For years, I used a Levinson JC-2 preamp, thinking that it was enough for just about anyone. Then, I began to both hear and MEASURE its limitations.
I applied what I heard in the JC-2 to the JC-80, and tried again to make the world's greatest preamp. I did pretty well too: All fet, 3 chassis, P & G studio faders for volume controls.
This unit got raves in Japan, it made preamp of the year. Owned and used as a reference by many audio reviewers, including Dave Wilson, etc.
Yet, I found that I could hear even the JC-80 in the audio path, so it is now in the closet.
YES, I went direct, WITHOUT any line preamp for about 5 years. I used a Vendetta SCP-2 phono stage, but I individually plugged whatever source that I had directly into a dual potentiometer, of the highest grade, including a P & G dual volume control and a Spectrol dual 20 turn wirewound (I like it best) with only 1/2 meter of premium connecting cable to the power amp inputs. I liked this a lot, and this was my version of a 'straight wire'.
When I started making the BLOWTORCH, I was skeptical that we could make something as good as MY 'straight wire'. However, when I put it into operation and lived with it awhile, I found that it really did sound as good as my previous 'straight wire' or even better!
Why, I think it is because the pots are now shielded and BUFFERED, and the buffer can better drive the cable a reasonable distance, and the input wires can be significantly shorted. The output impedance is 1Kohm at ALL frequencies of interest, and doesn't change with volume control setting.
The 'physics' of break-in is about as mysterious as 'sustain' in ballet. You know it when you see it, or hear it in this case. If I was so pig headed that I denied that 'break-in' existed, I would make a complete fool out of myself at CES demos, etc. , where we try to take sound reproduction, seriously.
 
Edmond Stuart said:
>polarized in the right direction.
:bigeyes:
Does that mean perpendicular on the earth magnetic field in order to eliminate adverse interference? :scratch2:

Thought it would be too much for you. 😀

Explain this one, when I change phase at both speakers (positive out to neg in) I can clearly hear a difference in sound but when I change phase digitally on the CD Player it is quite hard, if not impossible, to hear a difference.

André
 
Andre Visser said:
Edmond, you mis the point that I'm trying to make, the only difference in sound when I change polarity at the speakers seems to be the current flowing the 'wrong' direction through the cables and XO unless you have a better explanation.

André


André,

Have you tried to investigate this? Have you, for instance, checked by sucessively changing the phase at the CD-player, the preamp, the power amp, the speakers, and in each case do a proper test to record your findings? With multiple listeners, blind, different kinds of music? How many listeners did hear it, how many not, etc.
If not, you're just giving us an anecdote, and you can't be serious that anybody makes an effort to 'explain' an anecdote??

Jan Didden
 
it is 'beyond' them

Andre Visser said:
Edmond, you mis the point that I'm trying to make, the only difference in sound when I change polarity at the speakers seems to be the current flowing the 'wrong' direction through the cables and XO unless you have a better explanation.

André

Hi André,

So you didn't change the phase of the speakers, instead, you only changed the 'phase' of the cables (whatever that may be), right? Yet you can hear a difference. At least for me, this is most amazing. Clearly I'm missing something, for example, a solid explanation for this phenomenon.

Regards,
Edmond.
 
janneman said:
Have you tried to investigate this?........
Jan Didden

Jan, a few years ago I've heard the claim that absolute phase doesn't matter so me and a friend tried for ourselves by changing the polarity on both speakers several times and we found that there were a very noticeable difference in sound, so my believe was that it do matter. Then later I've read an article written by Doug Blackburn where he also stated that you can hear a difference when changing cable polarity on the speakers but not if you change polarity in the digital domain. I've tried that later with an EmmLabs CD player with polarity inversion and, as said, it is not easy to tell the difference.

Sorry for the anecdote then, please don't bother to explain.

André
 
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