John Curl's Blowtorch preamplifier part II

Status
Not open for further replies.
diyAudio Member RIP
Joined 2005
Are-you sure ? As far i'm concerned, never had any warning during the mandatory testings of occupational medicine. And, may-be a little more hearing "culture" than average people ?
I was told by a perfume creator that the "Noses", don't have a better sense of smell than the average people. Their ability to can distinguish all the components in a perfume is due to their "culture". They can recognize them, because they know them.
Alas a great many alleged experts are getting caught with their proverbial pants down of late---wine tasters being in the crosshairs at the moment. In one example adding tasteless red food coloring to a white wine that had been tasted just before resulted in a host of tasting notes mentioning whole constellations of aromas and flavors strictly associated with red wines. This is not a perfect comparison, as I doubt that their presumed consumption of a lot of wine has dulled their senses.

But in the recording and musical performance industry the constant exposure takes its toll, and the levels required for permanent hearing loss generally have been ignored as guidelines. I was particularly amused by the autohagiographic interview with one of the founders of Beats in Rolling Stone (the audio journal of record) who admitted that he has hearing loss about which his kids love to tease him, yet goes on to say that he can hear what is wrong with something from a block and a half away. That duo was particularly amusing for telling us how their product development process didn't involve armies of people in white lab coats and carrying clipboards, like the normal audio companies.
 
Alas a great many alleged experts are getting caught with their proverbial pants down of late---wine tasters being in the crosshairs at the moment.
What would had been interesting should be to give them to test the white wine just after ;-)
Your example was a trap, and when a trap is well done...
I have seen some blind test (some like-it in the forum) where some "Sommeliers" were able to recognize the wine, the "cépage" and the year of several wines. Of course, well known wines. Like you could recognize the Rolling stones "Satisfaction" at the very first notes.

To be true, i don't pretend to have the same audition than an average person. And the treble the same way than when i was young. After all those years to separate instruments in my head from a musical scene, I can happens i will not even figure you are calling-me, if i listen to music at this moment. But it happened since i was lot younger.
Anyway, i don't *suffer* from my ears, thanks God, but from my eyes, as a photographer on the return. Hyperopia and presbyopia :-(
Old age is a shipwreck.
 
Last edited:
I was particularly amused by the autohagiographic interview with one of the founders of Beats in Rolling Stone (the audio journal of record) who admitted that he has hearing loss about which his kids love to tease him, yet goes on to say that he can hear what is wrong with something from a block and a half away.
Bizarrely, that does work ... when a system is not right it's easy to hear so from a completely distant perspective - many times I've been down at the other end of the house from the system playing, and thought, Nope, that's not right! Walked down to the speakers, and the problem presents itself still, just a bit more obviously.

It appears that the brain is extremely adept in judging the balance of sound from well away from a direct feed, and can pick a dud just like that ...
 
Unfortunately they do take a few heaves at the fan. For instance is there any 16/44.1 CD that has not seen some unknown SRC/downsampling? Why would some closed form upsampling improve anything?

Never said they were perfect. But they do have a great sense of humor and some good U.S. made stuff for $99. Their little Magni amp is wonderful.

se
 
Disabled Account
Joined 2012
At a simple hand waving level, continual conditioning of capacitors appears to a factor. The measuring of this is going to be difficult, but purely at a subjective level the performance, as in the reduction of audible distortion, always improves by doing this, for me. How to separate capacitor behaviour variation over time from other factors that alter? Very hard, a major exercise is setting up a decent experimental setup for "proving" it ... one thing, however, is absolutely clear to me: taking one set of measurements, at one point in time will rarely have revealing value - because all these subtle audible behaviours keep altering, over time, for all sorts of reasons. Planting a flag firmly in the ground at some point, and saying, that's it!, will only work when everything is understood ...

There is too much to put down but as the questions come, they can be handled at that time.


Winding a cap puts stress on the film. Some times it is stretched. friction between windings and slow creep of the film until stress is all gone takes time. For high quality, high stability and high reliability there is a way to relieve the internal stress somewhat quicker..... it is by annealing the cap under controlled temperature. I wont tell you the exact process of annealing - temps depend on film material, of course.... but there is a process to it. Not all cap makers do it esp if price is the major consideration rather than long and stable life. At the same time the annealing process is going on... a technique is applied to remove any remaining trapped air between windings.

To the caps which the process is applied, it becomes a hard solid block and you can saw thru it with a fine toothed metal saw and it does not shred but looks like bar stock.


.... just some more details for heavy detail oriented guys, like SY. Maybe a useless factoid to others....



THx-RNMarsh


.
 
Last edited:
Status
Not open for further replies.