John Curl's Blowtorch preamplifier part II

[PMA]

Too many fakes of Cannons now. At 50 cents/pc.

[scott wurcer]

Originally Posted by simon7000

For chuckles try:

http://www.analog.com/static/importe...als/MT-042.pdf
http://www.analog.com/static/importe...als/MT-043.pdf

Test or bait?

Maybe you prefer these:

http://www.ti.com/lit/an/snoa475c/snoa475c.pdf
http://www.intersil.com/content/dam/...an55/an551.pdf

Intersil fig. 1 standard Teradyne/GR/Tek/etc. test loop ancient history.

[Esperado]

Originally Posted by PMA

Too many fakes of Cannons now. At 50 cents/pc.

So, it is just a LOOK' decision, because of the existence of fakes, it looks cheaper ?

Manufacturers order their parts to the manufacturers, so they are not in concern with fakes. I found the Canon flexible isolator better, for heavy professional use, while Neutrik cords plugs are easier to weld and more resistant to lateral pulls.

[PMA]

I am afraid that audio manufacturers are trying to decrease input costs as much as possible. Regardless quality or genuine parts. Even for higher price products.

[simon7000]

Originally Posted by jneutron

So what your saying is...power cords make a difference even in a stadium.

jn

Then there was the first time I used amplifiers with switching power supplies. I changed all the IEC cords to shielded ones. With 100+ amplifiers it made a difference. They were 14 gauge. Which under code would work for amplifiers rated to 3000 watts. Of course none of the amplifiers were that large or even loaded to below 8 ohms.

The next consultant in had all the power cords changed to thicker ones. Of course. They ended up with imported thicker cords still 14 gauge just way more plastic.

[Waly]

Originally Posted by PMA

Christophe, after new listening tests of the buffered AD797 I find this opamp very, or I would say extremely transparent, with great resolution of highs and details, and tight solid bass.

What would be a good reason for any op amp DC coupled gain stage to NOT have a "tight bass", or is this poetry?

[Esperado]

Originally Posted by PMA

I am afraid that audio manufacturers are trying to decrease input costs as much as possible..

Wile they can waste a lot of money, in the same time, with stupid things like motorized lateral rear mirrors in your car, driver side, witch add nothing and cost a lot each time you have to replace one !

[gpapag]

Originally Posted by Max Headroom

So you were hearing changes according to the polarity of only the mid driver then ?....if so, then there is nothing to be embarrassed about. Not noting the missing highs is another matter .
Dan.

Dan, no. The polarity of the mid was fixed. I was only changing the tweeter’s polarity.
The important point in this story is that because I was physically doing the action of switching the polarity (thus I was “certain” that an acoustical different effect will take place) I was genuinely fooled by my senses/brain that I was perceiving acoustic differences.
I had unwillingly turned this test into a blind test, on which of course I failed.
My hearing acuity (very degraded) is irrelevant. Were it relevant, I should have decided that I did not hear any difference.

Ed wrote on a relevant case with a professional involved. John Curl's Blowtorch preamplifier part II
This sent me back some 30 years ago when a singer was testing different mikes in a venue for to choose the best one for her.
It was me that brought the mikes there and I was asked to adjust the controls.
“Give me highs”, “give me lows”, “give me presence” she was not satisfied with the results, all this for half an hour.
After a while, on each call from her, I was just pretending that I was moving the controls with a high precision, so she could see that. I was doing no actual adjustment. She started to like the results.
She ended with one mike and asked me to mark the final settings on the console.
She was fooled by her senses as I was -confirmed- fooled 30 years later (and unconfirmed all these years and beyond).

Originally Posted by Max Headroom

Enough A/B comparisons and even very fine effects are reliably discernable.

See the storie of the three fools above.
You have –for your own sake- to prove this reliability to you.

Originally Posted by Max Headroom

Typical clean sand has no permanently magnetisable iron content, however sandbags can be a good mechanical damping method.

That’s why I proposed it, suggesting to look for mechanical issues, before loosing your time with investigations on magnetics. Compare the results of the sandbag with the results of the brick.

Originally Posted by Max Headroom

In the observational cases I have described, I am sincerely asking for physics explanations from the theory adept fellows collected here....oh well....
Dan.

It follows from your hypothesis that you have to check first if the brick has any relative permeability different from the value of 1. Are you willing to do that?

George

[Esperado]

Originally Posted by Waly

What would be a good reason for any op amp DC coupled gain stage to NOT have a "tight bass", or is this poetry?

Limited slew-rate, witch gives the basses attacks to sound 'soft'. A kick drum can have a very fast attack edge, at high level, and we perceive-it as 'bass'.

[morinix]

Originally Posted by Esperado

Limited slew-rate, witch gives the basses attacks to sound 'soft'. A kick drum can have a very fast attack edge, at high level, and we perceive-it as 'bass'.

When I started dropping in high slew rate op-amps to modify a preamp or reverb the bass was the first thing I noticed.