John Curl's Blowtorch preamplifier part III

Status
Not open for further replies.
Hi Scott, I can confirm this. I spoke with Czar after his presentation AES San Francisco 2008: Tutorial T13

Meanwhile I don’t have any records
What? You don't do analog? only CDs and other digital media?


AND


There was a fellow DIYAudio guy here who either posted a pic
or someone else posted a pic of them with himself...Maybe it was
Ed?


I think it also had to do with a discussion about the presentation
and a solution that was proprietary etc. At some point in some

thread here in DIYAudio the solution to the problem was posted
on an attached schematic. Then I think the guy got pissed that

what was posted wat the correct solution too, and the cat was
outta the bag, therefore it was publicly disclosed through no
fault of the guy, yadda...yadda...yadda... legal mumbo jumbo, et al,
and so it could be discussed openly.


Then it was.


I still don't know which thread or with whom and the specific topic
and Sorry Dimitri i get it now, finally, I don't have any documention
or citation.


Cheers,
 
The correct solution is a Ayrton-Perry wire-wound resistor (see here Ayrton& - Wikipedia ). Mills do the best ones (great resistors for CFA feedback networks BTW - I measured the L on the 1k 10W that I use at 36nH which is about the 3x a straight copper track on a PCB).

Details here Vishay Mills - Vishay Brands - and they are available from mouser and DK.


Bonsai, can we cut to the chase?


I can't afford to make any more mistakes buying the "wrong" resistors, etc.
Would you be kind enough to let me know which series is best, please?
And if you don't want to disclose it for public consumption please feel
free to send me a PM.


Cheers,
 
I suggested a process to learn how accurate your system is. Have you tried it yet? BTW I think open tests are fine to detect differences but not for accuracy until you know from practice and experience what it ought to sound like. So, the suggested process can be used as practice also.
Yes, thank you for sharing Richard, my memory isn't that bad 🙂 No, I haven't tried it yet and as a test for accuracy, the principle seems perfect?

Perfect for "they are here" not so good necessarily for "I am there"

Wherever there is...........
 
Last edited:
Yes, thank you for sharing Richard, my memory isn't that bad 🙂 No, I haven't tried it yet and as a test for accuracy, the principle seems perfect?

Perfect for "they are here" not so good necessarily for "I am there"

Wherever there is...........

The you are here or you are there will not change. That is in the way the recording is mic'ed and your own speaker/room acoustics. That doesnt change. To sound just like the familiar voice uses the same room/acoustics.


THx-RNMarsh
 
That's what I mean, the room acoustics are still there, obviously listening nearfield makes a difference.
Close mic recording will eliminate most of the problem (on the tape).
Of course, a real voice will not excite the room resonances the same way than a speaker. But I think our brains are pretty good at eliminating-it.
The real problem I see with the RNM tip is the mike used. They can sound very different.
So, if your system sound very accurate in this comparison, it means it compensate nicely the drawbacks of the mike ;-)
 
You’ve heard of making the speakers disappear (transparency) right?

Do you think it’s possible to make the room disappear at a normal lp (8’-10’ let’s say) in a normal home setting?
For accuracy I think that would be an aim? In practice it may not be necessary depending on the speaker/room/listening position interaction and psychoacoustics (re. Linkwitz etc)
 
You’ve heard of making the speakers disappear (transparency) right?

Do you think it’s possible to make the room disappear at a normal lp (8’-10’ let’s say) in a normal home setting?

Once upon a time, there was this LEDE (live End Dead End) thing in the recording studio design.
Prof. T., can you confirm they still do this? If yes, you can do something similar in your listening room if you really want to hear what the musicians/engineers/producers heard.
 
So, if your system sound very accurate in this comparison, it means it compensate nicely the drawbacks of the mike ;-)

I use a matched pair of rode NT3 for live stereo field and/or ambience on multitrack. I find them the most accurate/well priced mic for this job.....I’m sure there’s better but I can’t afford it!

For accuracy I think that would be an aim? In practice it may not be necessary depending on the speaker/room/listening position interaction and psychoacoustics (re. Linkwitz etc)

I’m glad you didn’t say no!

Once upon a time, there was this LEDE (live End Dead End) thing in the recording studio design.
Prof. T., can you confirm they still do this? If yes, you can do something similar in your listening room if you really want to hear what the musicians/engineers/producers heard.

I’m finding geometry, active/passive phase manipulation, may be just as/more important than room treatment.
I’ll know more as I set up my new room......I’m hoping my last success wasn’t just a one off!
 
If it makes you feel better to be condescending go for it.

It might happen from time to time that my response adopts the tone of the post I'm responding to; so, if you don't like the mirror image, methinks the remedy could be quite easy......

To clarify, even subjectively, people heard a difference, to say better implies more accurate.

Isn't that just your personal definition of the term "better" in this context?
 
The distortion due to DA (Dielectric Absorption) will not show in sine wave tests. The symmetrical waveform will always average to zero in a THD instrument. IMO. Asymmetrical tests are needed and then you see the affect. A fast sample-hold instrument of transient waveforms (music) shows difference and how the differences are correlated to the sound.THx-RNMarsh
Cyril Bateman demonstrated that there is a high correlation between dielectric absorption (and voltage across the caps) and harmonic distorsion.
For exemple, he found the ceramic COG caps are among the best for low harmonic distortion. Samuel Groner confirmed how good and reliable they are :
https://www.diyaudio.com/forums/equ...omatic-distortion-analyzer-9.html#post4549551.
It seems that since Cyril's articles, COG caps are use more often used.
 
Status
Not open for further replies.