John Curl's Blowtorch preamplifier part II

[fas42]

Sounds familiar ...

What drives me nuts is getting the right focal length for seeing the damn thing I'm trying to work out. I don't "do glasses" so I have an assortment of cheap, plastic spec's to provide the right power for the occasion. The right power is often just not quite right enough, and then in the heat of the moment I step on the last one I was using, that I took off a moment before ...

Frank

[RNMarsh]

Originally Posted by jneutron

I would assume that the actual distance would be dependent on the impedance of the circuit as well. High impedance circuits will have lower magnetic fields, whereas low z one will have higher..

jn

yes, of course. The circuitry was 50K-100K in and low Z out configuration. Note that at the time, the measurment resolution wasnt what it is today. I dont recall all the gory details -- just the summary conclusion..... routing wires against the chassis was (is?) popular. Keep from lashing wires against a steel chassis bottom etc and keep a distance of an inch or more and you are good. Or, just use aluminium. -Thx RNMarsh

[bcarso]

Originally Posted by fas42

Sounds familiar ...

What drives me nuts is getting the right focal length for seeing the damn thing I'm trying to work out. I don't "do glasses" so I have an assortment of cheap, plastic spec's to provide the right power for the occasion. The right power is often just not quite right enough, and then in the heat of the moment I step on the last one I was using, that I took off a moment before ...

Frank

I'm using one of those visor-type magnifiers lately. The one I got has a built-in lamp and three levels of magnification. It's not bad, and leaves both hands free. As long as things don't get a whole lot smaller I can do sloppy breadboarding with SM parts.

[Max Headroom]

Originally Posted by john curl

Max, I think your question on the sonic differences between steel and aluminum is valid, but I don't have any evidence to prove it directly, except my experience.....I try to suggest to others what I have found over decades of designing audio products....Now, I just specify aluminum, because it sounds better in listening comparisons.

John - thanks
Nelson, Richard, others - thanks, all good info.

Dan.

A wise man learns by the mistakes of others, a fool by his own - Latin Proverb.
11 Wise Lessons - Essential Wisdom for Life | Personal Development

[fas42]

What bothers me is that "standard" texts for amplifier, etc, design don't mention this at all - can't see anything in Duncan or Cordell. So, only insiders know of these important "tricks", and the divide remains, between a very small number of people who can get everything right, and those that can't ...

Frank

[fas42]

Originally Posted by bcarso

I'm using one of those visor-type magnifiers lately. The one I got has a built-in lamp and three levels of magnification. It's not bad, and leaves both hands free. As long as things don't get a whole lot smaller I can do sloppy breadboarding with SM parts.

Thanks, I have been thinking about one of these ...

Frank

[morinix]

Originally Posted by bcarso

I'm using one of those visor-type magnifiers lately. The one I got has a built-in lamp and three levels of magnification. It's not bad, and leaves both hands free. As long as things don't get a whole lot smaller I can do sloppy breadboarding with SM parts.

0805 or 0603 or even 0402?

[Esperado]

Originally Posted by bcarso

I'm using one of those visor-type magnifiers lately.

Those ones ?
http://www.materielmedical.fr/I-Gran...airage.net.jpg

[Max Headroom]

Originally Posted by fas42

What bothers me is that "standard" texts for amplifier, etc, design don't mention this at all - can't see anything in Duncan or Cordell. So, only insiders know of these important "tricks", and the divide remains, between a very small number of people who can get everything right, and those that can't ...

Frank

I have noted sonic changes by shifting internal cables well away from chassis steel.
Eons ago there was a tweak called the VPI brick - a timber box enclosing I believe transformer laminations. There are varying views of optimal placement and sonic effects.
I have placed a standard clay house brick on top of my cd player in the past and the added mass altered the sound. Rotating the brick 180* further altered the sound

Dan.

[Max Headroom]

Originally Posted by fas42

Sounds familiar ...

What drives me nuts is getting the right focal length for seeing the damn thing I'm trying to work out. I don't "do glasses" so I have an assortment of cheap, plastic spec's to provide the right power for the occasion. The right power is often just not quite right enough, and then in the heat of the moment I step on the last one I was using, that I took off a moment before ...

Frank

Haha. I have a library of those two-dollar shp specs also....works for me !.

Dan.