John Curl's Blowtorch preamplifier part III

Status
Not open for further replies.
Jump to Latest
#30,262
mountainman bob said:
...
What’s the best (reasonably priced) DMM.......there seems to be no lack of choices! I suppose my analog meter is probably 30yrs old it’s about time to upgrade.
...
Click to expand...

I recently ordered this one for about $14 on sale, advertised as 9999 count. The actual item I received is a 5999 count; I complained, and they reimbursed $5 in "points". No more complain 🙂. Accuracy is about 0.01% in DCV, checked against a AD584K voltage reference.
 
#30,266
mountainman bob said:
...
I would think something decent that would last me ‘till death do us part’ could be had for under $100?

(Estimate 20 more yrs!)
Click to expand...

You'd be surprised how tough these el cheapo's can be. The one pictured has been with me for field use for well over 30 years, so beating your criterium by at least 10 years 🙂!
 

Attachments

  • IMG_20191106_155815.jpg
    IMG_20191106_155815.jpg
    533.2 KB · Views: 211
#30,267
Max Headroom said:
My searches indicate that typical large through hole CM Chokes such as the ones I am using are powdered iron not ferrite.
Click to expand...

I detect an unusual trace of rationality here; by its nature, powdered iron cores have low lower permeability and higher saturation compared to ferrites. Which could mean that your bad experience with ferrites was due to improper use, leading to saturation.

As usual, bad engineering can have a sound impact, there was never a doubt about.
 
#30,268
#30,270
syn08 said:
I detect an unusual trace of rationality here; by its nature, powdered iron cores have low lower permeability and higher saturation compared to ferrites. Which could mean that your bad experience with ferrites was due to improper use, leading to saturation.
Click to expand...
BS, my objections with ferrites is with standard clamp-on split core ferrite filters as applied to standard power cables etc.



As usual, bad engineering can have a sound impact, there was never a doubt about.
Click to expand...
This is not my engineering.


Dan.
 
#30,271
Mark Johnson said:
I am thrilled, THRILLED, with my recently purchased Hakko FR-301 (amazon sales link). Add a cheap overseas hot air station and you've got the complete package.
Click to expand...
That’s actually the one I was looking at.......I figure if I’m gonna do this I might as well do it right!

Zung said:
You'd be surprised how tough these el cheapo's can be. The one pictured has been with me for field use for well over 30 years, so beating your criterium by at least 10 years 🙂!
Click to expand...

lol......yah, I’m sure there’s exceptions to the rule, but it’s usually bit me in the rear end everytime I try to save money with budget tools......as in I usually end up buying a better one anyway. I’m fairly certain my entrance into this aspect of the hobby is not just a whim......it seems like something my arthritic *** could do into old age!
 
#30,272
Max Headroom said:
BS, my objections with ferrites is with standard clamp-on split core ferrite filters as applied to standard power cables etc.

This is not my engineering.
Click to expand...

I see you got energized in the last couple of days, due to the rather slow feedback from the members in the rational group. Which are probably bored to death of your nonsense and lack of elementary understanding of what's happening inside those cases and your passion for inventing your own private physics.

These reactions (or lack, thereof) should not be considered, by any means, a license to perpetrate your usual pataphysics nonsense and promoting your Goop and so-called "knowledge" or "experience". You are still the same sad character that is desperately trying to push your crap down the throat of whoever is willing/happens to listen to your stories.

Indeed, not your engineering. Engineering is something you are totally parallel with.
 
#30,278
PMA said:
... what is the issue that he specifically dislikes in sound of the AD797 chip. I recall he has several time mentioned this chip is good for measuring purposes, but he does not like it much for audio. ...
Click to expand...
A refresher. 🙂
john curl said:
... The AD797 can't properly drive its own feedback loop. jcx
Click to expand...
john curl said:
Well, congratulations Scott, for the AD797. I think that this is a great measuring IC, especially with normal loading...
Click to expand...
john curl said:
The AD797 sounds OK, I tried it in my Parasound JC-3, before finding a cheaper alternative, that sounded just as good.
However, for a line amp I would use the AD825, because it has a jfet input, and this is important, because I would use a 50K pot in front of it, and it has a much greater OPEN LOOP BANDWIDTH. Yes, it would have somewhat more harmonic or IM distortion, so what? It might have less PIM than the AD797. That is a fairly safe bet.
Click to expand...
john curl said:
We changed the input IC to the LME49990 because it sounded just as good (just different) from the AD797 and it was much cheaper to buy.
Click to expand...
 
#30,280
Max Headroom said:
...
I use solder 99.3%Tin/0.7%Copper as it is a common alloy and I reckon it sounds good, the Parasound should be lead free from factory I expect, make sure to keep all traces of lead totally outside of that box is a primary advice. 😉.

Dan.
Click to expand...

Does anyone know if the Sn62/Pb36/Ag02 from American Iron and Metal Inc. (AIM) is any good?
I've been using the same from Multicore for ages, but nowadays, it seems only Farnell carries them.
 
Status
Not open for further replies.
Top Bottom