John Curl's Blowtorch preamplifier part II

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When it comes to double-blind testing: I KNOW that I can be easily fooled by it.

The thing is, John, that you have it backwards.
Most people have enough understanding of perception to know that it's the peeking and knowing the context that fools you. Blind testing removes this so you cannot be fooled so easily anymore.

jan
 
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I believe a good approach to start with is that mentioned some days ago now; injecting some carefully controlled distortion into one version of a track, and determining the audibility of that - how it depends on the precise nature of the distortion, and levels thereof ...

We're all looking forward to your experiment, your posted files, and your report of the results.
 
Frank, I have the full Waves Diamond production bundle, which I believe is calculated at 64bits. i'll try and find some time this weekend to get something done if there is demand. what specific type of distortion does the crowd think is most suitable? (check the plugins list in the link for details) actually I do need to doublecheck that it still works with Lion, havent used these plugins in a while. regardless I definitely have something of high quality that will work in logic.

actually just checked, wont work in lion, i'm seeing if I can get an 'update' ;) I do have various other plugins that will suit though, not quite as nice
 
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Optional extras would include phase-shifting the distortion or delaying it a few mS, to de-correlate it.

this bit is easy

but wondering how to model a rectified signal in an audio program, so we are talking about the diode effect appearing like clipping on a positive, or negative going swing only, ie flat-tops correct? totally flat is no worries, but getting the diode reverse recovery + transformer stored energy effect i'm not sure. i'll check what the various distortions look like
 
but getting the diode reverse recovery + transformer stored energy effect i'm not sure.
I wasn't thinking of anything fancy like that, just a simple arithmetic operation like abs() to get a perfectly rectified version.

It's not a realistic representation of the sort of distortion you'd get from an amp, but rather a semi-worst case kind of distortion, with a wide spray of HD and IM products. The idea being that if you can't hear that at say -60dB, then you probably can't hear more benign distortions at the same level either.
 
Moving forward, I've got hold of a nice little distortion effects plug-in for Audacity, which allows me to specify the transformation function by B-spline waveshaping - extremely flexible. This is the sort of thing that can probably replicate just about any real-world behaviour you can think of - should have a lot of potential ...

Most interesting distortions do not have a static transfer function applicable at the output only. One of the most important and simplest is the input pair transfer function. This can not be applied a posteriori in this simple fashion so these tools have limited use.
 
Frank, I have the full Waves Diamond production bundle, which I believe is calculated at 64bits. i'll try and find some time this weekend to get something done if there is demand. what specific type of distortion does the crowd think is most suitable? (check the plugins list in the link for details) actually I do need to doublecheck that it still works with Lion, havent used these plugins in a while. regardless I definitely have something of high quality that will work in logic.

actually just checked, wont work in lion, i'm seeing if I can get an 'update' ;) I do have various other plugins that will suit though, not quite as nice

WOW! You must be making some good money in music production to justify the price for the whole bundle (well over $2000, for those who don't know).
Lucky you. I can't :-(
 
You can't really find 2nd or 3rd harmonic distortion apparent, until the distortion on music peaks are about 10% or so. Vinyl or analog recorders would never work, otherwise. You have to go for 5th, 7th, 9th, 10th etc. That is where the action is. We have ALWAYS lived in a world of distortion on reproducing music, yet some of the 'deviant' characteristics of a specific amp or preamp can be noticed, either as 'missing some information' or adding an irritant. This is what hi end audio designers hope to minimize.
 
exactly what it was for their audio stuff

Mr Russell,

identical looks and model number under two different brand labels, is not differentiating and positioning a brand for a particular market segment, just adds to the confusion. (e.g. SU-V900 integrated)

Yamaha stuck to one slice of the audio market, merely came up with some special models on occasion, for media attention and pushing sales of the volume items. (e.g. Centennial X10.000 line in '87)

Technics developed some really exciting stuff ; TH400 ribbon tweeter, SL10/15/1200 turntables, a couple of interesting cartridges, the 200lb SU-A2 preamp and Class A+ SE-A1 power amp duo, that even today looks exciting.
For the SOTA stuff, Technics couldn't get production in order and up to speed, eventually pulled the plug.
And in the high volume market, they came up with AA, New Class A, whichever label that might just as well be stuck to a washing machine.
Very confusing marketing, imo, almost as if Technics was the experimental & fck-up division of Matsushita.

(In my street, I've got a couple of neighbors with an itch to copy eachother. If one exchanges car model, the next follows a couple of months later, and the next, think Cayenne, currently Panamera. One may move away and be replaced by someone with a Bybee type spouse. Another is temporarily forced to downgrade to company registration diesel, due to a dip in the economic cycle, but none will pick a Lexus with the looks of a Toyota. Interesting to observe though. Aargh, cars again !)
 
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Subtlety Distorted Distortion...

You can't really find 2nd or 3rd harmonic distortion apparent, until the distortion on music peaks are about 10% or so. Vinyl or analog recorders would never work, otherwise. You have to go for 5th, 7th, 9th, 10th etc. That is where the action is. We have ALWAYS lived in a world of distortion on reproducing music, yet some of the 'deviant' characteristics of a specific amp or preamp can be noticed, either as 'missing some information' or adding an irritant. This is what hi end audio designers hope to minimize.
+100%

Dan.
 
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