Bonsai,
The main reason I stopped reading Stereophile and checking out what was happening in that end of the industry was the disconnect between the technical side and the subjective side. While you could read some fairly well done bench testing the subjective reviewers would go out of there way to make something sound to them good, including special matching cables and all manner of tweaks to get a top line product, by price, to be acceptable. I would say it was painful to read some of the hoops that the reviewers would go through to find a product satisfactory. Other times their references were worse than the reviewed product and a definite bias could be seen.
The main reason I stopped reading Stereophile and checking out what was happening in that end of the industry was the disconnect between the technical side and the subjective side. While you could read some fairly well done bench testing the subjective reviewers would go out of there way to make something sound to them good, including special matching cables and all manner of tweaks to get a top line product, by price, to be acceptable. I would say it was painful to read some of the hoops that the reviewers would go through to find a product satisfactory. Other times their references were worse than the reviewed product and a definite bias could be seen.
. . . But, then there's JA's technical assessment that brings the whole thing down to earth again.
It's kind of like my wife, who I love dearly, when she goes to the makeup counter in a big downtown dept store and asks the 20 something at the counter (there's dozens of them, all touting this and that wonder potion) which is the best makeup to make her look 20 again. What comes back is a stream of psuedo bio- science babble (actually, it's absolute bs - even I can detect it). However, it makes her feel good, and she parts with her money, walking out of the store happier than she went in. So I'm also happy.
And so it is with high end audio. Some recommend, and some check the facts. Take advice from whoever makes you feel happy enough to part with your $'s!
(My wife is a very cool looking women by the way and not in any way connected to the hag I mentioned earlier
)
http://www.theaudiocritic.com/back_issues/The_Audio_Critic_23_r.pdf
Have a look at the attachment.
Anyone from the owners of an AP here to check what these transients are?
I couldn't have said it better myself..
You’ ll read the names of the gents that wrote this when you will decide to open your PM inbox.
I would like to read your comments on their work.
How could I resist to hold in my hands a jn’s CVR (and warm it up
)? I have already fallen in love with CVRs
I’ll PM you my postal address.
George
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George, you've sent me links to in excess of 600 pages..
So far, I really like what I've been reading.
The latest one you linked to is really great. Lots of little tricks and techniques I've used and pushed at work over the years.
I thought I pm'd you thanking you for the links, if not, my apologies.
How could I resist to hold in my hands a jn’s CVR (and warm it up
I have already fallen in love with CVRs
I’ll PM you my postal address.
Ok. I recently moved offices, so haven't unpacked everything. I sent scott the last one I made, it used clad perfboard.. I've a Unimat I'm refurbishing, so I'm hoping to make my next one out of .0625 thick copper using a 3 axis milling stage. That way, it'll be amenable to potting into an aluminum case so it will allow dissipation. I suspect the copper is going to break a few drill bits, I need holes about 2 mils larger than the lead diameter.
jn
My concern for this thread is to show HOW people like me evaluate and compare other peoples products, as well as my own designs, by using tests done by a 3'rd party, namely 'Stereophile'. It isn't that important what product is discussed to understand what my experience tells me to look out for when looking for potential product problems.
I just cannot get anywhere with this without being deluged with extraneous input. Sorry.
I just cannot get anywhere with this without being deluged with extraneous input. Sorry.
I missed the explanation. (TLA's are too rampant here). What is a CVR? Is it similar to one of these? Fluke A40A or Coaxial shunt resistors CSR1, CSR2 and CSR3
Yes, it’s about the latest one. We’ll have the chance to discuss a few ideas I found there.
Wow! A high tech CVR! What a treat!
Have the 3 axis machine engrave your sign on it.
Copper drilling: Yes, a pain. Lower the rpm and make the bit point angle shallow.
Demian
Current Viewing Resistor
Jn connects them in series with the return path for to measure the voltage drop across them, so ‘view’ the circuit’s current
George
My initial design from years ago and George's current builds are exactly that.
We made them using discrete resistors in parallel, with the return current in the center for my first and George's present one.
I found that two things limited me with that coaxial design. First, scaleability was pretty bad, as the diameter scaled with number of resistors. Second, the return current was in the center, which meant that the inductance would also scale. (at the time, I had not considered using a tube as the return conductor, that would have de-scaled the inductance..ah, the sins of yoot.)
At present, I make mine by interleaving half the resistors in a rectangular array through the other half of the resistors. For a .1 ohm resistor, I parallel 20 one ohm reistors, and parallel another 20 in such a way that they are spaced between the first 20.
Very easy to build once you figure out how to get 40 leads through 40 holes in two parallel plates at the same time..
jn
Ah, 350 pages... I have an hour lunch, so that'll leave me some free time to go jog..
I wish it were controlled 3 axis. Alas, it's just a stage with 3 handles, x, y, and rotation. I have to count hash marks to drill an array of holes.
I don't have the tools to change a bit point angle. But I can buy more bits..
BTW, I can only pot with a hardener which has a glass transition temp of 45C. That limits the max CVR temp to about 60C.
jn
How could I resist to hold in my hands a jn’s CVR (and warm it up
I have already fallen in love with CVRs
I’ll PM you my postal address.
George
They come with special packaging.
So then, you are shlepping the paris metro sniffing women at random??A long process of trial and error.
sigh..I've run out of dilbert postcards...
But don't forget...if you break one of them itty bitty wires, you own it.
Course, you own it anyway..
jn
JN,
Don't use a carbide drill on copper use plain steel. Also it may help to actually dull the drill a bit so it doesn't grab and break. Same goes for turning soft copper if you ever try that, mild steel and a dulled edge works best.
John,
Go ahead and tell us abut your experience in comparing products. Not sure how the subjective evaluations fall into that, but on a technical side let's hear it.
Don't use a carbide drill on copper use plain steel. Also it may help to actually dull the drill a bit so it doesn't grab and break. Same goes for turning soft copper if you ever try that, mild steel and a dulled edge works best.
John,
Go ahead and tell us abut your experience in comparing products. Not sure how the subjective evaluations fall into that, but on a technical side let's hear it.
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