John Curl's Blowtorch preamplifier part II

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I peek, and I discard maybe 90% or our exprinents, or partially discard 90%, Point is that there's no precise tool for sound quality, which is better better linerity or a smoother phase shift?? Or maximum extended bandwith vs a better impulse response...?? Not so easy but choices that leads to performance of products later released for sales, This listening and selecting happens if not every day, then every other day.

Maybe it quite obvious that with speakers I has to be that way. But for sure if you look at electronics there are similar choices to be made, like needed capacitance, or how to set the output impedance, should it be slightly negative or posetive, how will you evaluate that without listening, and that is not enough you have to listen over a broad range of speakers and make choices.

For me engineering is the tools behind the path to get to my/our goals. Goals that with this type of products can be nothing short of listening and sonic performance and not numbers.

In the end of the this is not something you can put into a group or make ab testing on, for me it's clear, I'am behind the product, my name is used and I make the choices, why hide your choices under the excuse of a testing group. Trust in your ears and you expirnce is the only way forward.
 
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In the end of the this is not something you can put into a group or make ab testing on, for me it's clear, I'am behind the product, my name is used and I make the choices, why hide your choices under the excuse of a testing group. Trust in your ears and you expirnce is the only way forward.

Certainly if you are selling high end the designer is a major part of the product. JC didn't become 'The Legendary John Curl' by hiding.
 

I´m sure he must have experimented and found what works best, but it is a bit objectionable to not apply analog riaa eq before conversion.

Quote:
"The signal is digitized “dry,” i.e. without prior RIAA
EQ, at a sampling rate of 192 kHz and 24 bit resolution.
Digitizing the un-EQ’d phono signal means that
the highest frequencies are almost 40 dB louder than
the lowest. This taxes the headroom of the mic preamp
and requires it to be noise free (which the ULN-8 is).
It is definitely not recommended to record a dry phono
signal with 16-bit resolution."
 
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It just makes more sense to compute in the analog domain for such a huge attenuation (-40dB at the highest frequencies!)

Isn´t he throwing away A/D resolution when converting the signal directly from the cartrige?

hint. Vinyl doesn't have 24bits of resolution. The limiting factor is overload from the ticks and pops not the RIAA. There is a thread on this.
 
hint. Vinyl doesn't have 24bits of resolution. The limiting factor is overload from the ticks and pops not the RIAA. There is a thread on this.

Worse and a seemingly unappreciated effect, if one has loudspeakers on in the room as a record with a stylus on it can also make a fairly sensitive microphone for airborne sound and especially mechanical vibration.

I would be interesting to make a "difference" recording like this one below made from the difference between the original recording and the MP3 version.
Instead, to do one of a record, with loudspeakers on at normal level and no sound in the room to hear the difference.

What's lost making an MP3;

https://vimeo.com/107845118


Alternately, the curious can take an old record, turn the platter motor off and set the needle on the stationary record. Turn the volume up to normal, now, all you have is the microphonic part of the record player.
 
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To deny the possibility that the test situation itself was the cause for not being able to reject the nill hypothesis would be a total ignorance on perception and psychoacoustice testing as well.... :)

Of course. Part of the test setup would also be a calibration with a know difference and a null cal.
Funny how this starts to look like a routine scientific procedure :)

Jan
 
You guys can believe anything that you want. IF you think that a null test will answer your questions about audio, then believe away. I found different, 35 years ago. Null tests remind me of an old test for 'witchcraft' that threw the suspected person in water, while bound. If they floated, it PROVED they were a witch, if they sank, then they would drown, but God would sort them out.
When these early 'blind' tests were first evolved, a great many mistakes and biases were added in, to get the result desired: A null result. In fact, an extraordinary result is usually thrown out, because it does not fit in the presumption that the test was not possible to pass. I am sure that neither I nor almost anyone else would pass SY's blind test. Perhaps Michael Fremer could, but SY would probably throw his result out, as being 'untypical'. There is no winner here, nor any real resolution of what we can hear with ABX and similar tests, when it comes to serious appreciation of audio quality.
 
It just makes more sense to compute in the analog domain for such a huge attenuation (-40dB at the highest frequencies!)

Isn´t he throwing away A/D resolution when converting the signal directly from the cartrige?

This is even more of a red herring than the Pure Vinyl guys presented it as. In reality the surface noise fully dithers a 24 bit converter under almost all circumstances. The digital RIAA can be better than .0001 dB and requires no bespoke capacitors.
 
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