John Curl's Blowtorch preamplifier part II

[Soundminded]

Originally Posted by john curl

As far as protecting your ears from potential damage, I also suppose that you put earplugs in your ears when near a construction site, and have NEVER used firearms or been in the military. These are causes of potential hearing damage also, perhaps more than an exposure of the GD on a fine day.

That is correct. I have ALWAYS taken extreme precaution to protect my hearing and sight. I've used form fitting earplugs of the type I got from my first employer's medical department whenever I was exposed to loud noise such as the NYC subway or in areas where there was heavy construction (my first job was in an enormous steel mill where among other things they manufactured pipe and nails, both very noisy operations.) I wear glasses that darken automatically as light increases in intensity and I don't squint directly into the sun either. I've never been to a live rock concert nor do I use firearms. I've also been lucky that I have not suffered any injuries or diseases which could have impaired them. My last hearing test about 3 years ago showed excellent response out to the limit of the test, 10 khz. And I also learned you can become very sensitive to sound under certain circumstances. During the test, not only did I become aware of the sound of my own breath, I even became aware of the sound of my own beating heart, something I'd never heard before without a stethoscope.

I've also learned that hearing can become quickly adaptable. That is why making critical adjustments for each recording is an iterative process. It isn't finished until I come back after some hours or days and it still sounds the way I remember it the last time I thought I had it right.

[Steve Eddy]

Originally Posted by john curl

Finally, we have a 'lifetime' warranty that has cost me many thousands of dollars to honor, due to import-export fees, shipping, and erratic owners, one of whom blew up 2 of our power amps and both channels of the CTC Blowtorch due to a mod to a tuner by someone else.

Why on earth would you provide free repair service, including paying for shipping and import-export fees, for failures due to someone else's carelessness and/or stupidity?

You should have been making thousands of dollars off that.

Oh, yeh! WHAT A PROFITABLE UNDERTAKING!

It could have been if you hadn't come up with such a suicidal warranty agreement. Who wrote it? One of your competitors?

se

[wakibaki]

Originally Posted by Soundminded

That is correct. I have ALWAYS taken extreme precaution to protect my hearing and sight. I've used form fitting earplugs of the type I got from my first employer's medical department whenever I was exposed to loud noise such as the NYC subway or in areas where there was heavy construction (my first job was in an enormous steel mill where among other things they manufactured pipe and nails, both very noisy operations.) I wear glasses that darken automatically as light increases in intensity and I don't squint directly into the sun either. I've never been to a live rock concert nor do I use firearms. I've also been lucky that I have not suffered any injuries or diseases which could have impaired them. My last hearing test about 3 years ago showed excellent response out to the limit of the test, 10 khz. And I also learned you can become very sensitive to sound under certain circumstances. During the test, not only did I become aware of the sound of my own breath, I even became aware of the sound of my own beating heart, something I'd never heard before without a stethoscope.

I've also learned that hearing can become quickly adaptable. That is why making critical adjustments for each recording is an iterative process. It isn't finished until I come back after some hours or days and it still sounds the way I remember it the last time I thought I had it right.

Good plan. Best to avoid contact with the opposite sex, too, they are a hotbed of disease.

w

[scott wurcer]

Originally Posted by Soundminded

That is why making critical adjustments for each recording is an iterative process. It isn't finished until I come back after some hours or days and it still sounds the way I remember it the last time I thought I had it right.

I still find it interesting that you think your style of listening might have commercial potential.

[john curl]

We made them good, so we have had few returns.

[john curl]

Personally, Soundminded, while I do not criticize your choices of what to listen to, and how loud, I would rather not bother, and I passed the audiometry test too!

[jacco vermeulen]

Originally Posted by wakibaki

Best to avoid contact with the ...

Mr Weedy-B,

'cough', you do realise that still leaves 2 options.

(of which i gathered neither is a safe bet)

[Steve Eddy]

Originally Posted by hhoyt

Good question; the two mechanisms I am aware of are: conducted RF on shields which is demodulated in input stages, and modulation of DC operating points by ground potential lift inducing currents in chassis and PCB traces.

Yeah, but in both of those instances, I don't see that a signal is required. The noise should be there with or without signal.

I appreciate the info! Budgets being what they are at non-NPR college stations, we need all the help we can get!

No problem.

Tom and David (the company's VP) are good people. And if you ever call, it will be either Tom or David who will answer the phone.

se

[Steve Eddy]

Originally Posted by john curl

We made them good, so we have had few returns.

Huh?

If you had few returns, how could those few returns have cost you "many thousands of dollars" as you stated previously?

If I'm not mistaken, you never made more than a dozen or two, yes?

se

[simon7000]

Originally Posted by Steve Eddy

Yeah, but in both of those instances, I don't see that a signal is required. The noise should be there with or without signal.

se

Depends. When your ground gets down and dirty all sorts of nasties happen. You can define them as you want, but here is the picture of the same amp different ground schemes, (One of a series so it is not variation of parameters)