John Curl's Blowtorch preamplifier

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#19,221
Re: Blowtorch preamplifier

Darry said:
For years, I collect all the documentatons, informations, schematics of the best audio designers and products. I possess many of the great brands.

The Blowtorch is the only preamplifier to do the unanimity with the audiophiles of the whole world, even for the tubes fans. Also, I am very interested by this preamplifier.

The Blowtorch preamplifier is the work of CTC Builders (Curl-Thompson-Crump).
John Curl creates the electrical designs,
Carl Thompson engineers the board designs,
and Bob Crump chooses the parts.
------

Thank you Best Regards
Darry
Click to expand...

Keyword, exact phrase: John Curl
Post Results Displaying 1 to 25 of 5008

Keyword, exact phrase: Curl
diyAudio Forums > Search >Post Results
Displaying: 1 to 25 of 5849

Those are hits where 'John Curl' or 'Curl' exactly are mentined in post, or topic title.


I have indications, thinks, that some mornings, Nelson Pass,
does a search for his name within our forums.
This way he can answer posts he wants to answer
and keep an eye on his 'Pass' name and defend it, should he need to.
For Pass his name is also his trademark, which is also of some importance to him.
He has a very good name and reputation, mostly.


If you like John Curl,
you could easily do the same.
Maybe some members wait for a good and proper answer from you.
We call when a person is aksed and he reply him self for first hand information.
It is regarded as having a more valid value, than enyone answering on a man's behalf.
We call this second hand info, Nicht war? Doesnt we?


Lineup 😎 on a few occations does a search for 'lineup[tm]' / 'halojoy[tm]'
... as these are my forum trademarks
... good or bad [tm] .. is dependent on who you ask
... if you ask me, my first hand information to you is: he is not too bad
... in comparison with some 😀
 
#19,223
1audio said:
Here is the circuit diagram for the demo board in question ESS SABRE 9012 Demo board schematic

The circuit calls out 2 .1 caps to ground (my mistake, its more serious than I thought) on pg 1 U2. all of the components are really low value. the size is approx 2mmX4mm. The sample NPO's I have are easily 10X that.

And here is a picture of the board in question:
Click to expand...

And you end up using?

I am not addressing a particular application (and yes, a 0.1u NPO is as exotic as a 1uF teflon), but the general condemnation without examination (which is prejudice) of ceramics.
 
#19,227
Johnloudb said:

I agree with you, and that is like the big question that hounds everyone: What is and isn't audible?

And the only one who knows that answer is Charles Hansen who did extended listening blind testing. In which case everything including switches are audible.

http://www.diyaudio.com/forums/showthread.php?postid=1771831#post1771831

Kudos to him for doing such a test, and sharing it. Personaly, I'd like to see more of this type of testing. I'd like to try this kind of test as well, but I've got lots of stuff to do right now. It's unlikely anyone would believe the results of any test I did anyway.
Click to expand...

I think I have to check out that Charles Hansen investigation.
Subjective matters are a bit more difficult to measure than resistance or some different sorts of distortions, for example.

Sound impressions or what people can visualize in a painting, colors
are such things.

We often have rely on statistical analysis and so count result with probability factor.
100% sure = 1.0,
because from stastistical probabilty the possibility of just chance/guessing is zero.


Another member, 'Gedlee' have done one reserach, much to prove how good his spekers are.
He also suggest a special method a scale for how we experience distortion.
Gedlee is a nickname, short for Earl & Linda, who performed some investigations.

Member profile:
http://www.diyaudio.com/forums/member.php?s=&action=getinfo&userid=31488
Sound Quality
Distortion Perception
http://www.gedlee.com/distortion_perception.htm

Here are some results and plots / diagrams:
http://www.gedlee.com/results.htm

You can freely download his findings and description on the method he used, together with another researcher.

/regars lineup
 
#19,229
Probably if you say so.

Good music I know sounds good to me.
Rap music less good to me. 😀

One of Phil. Dr. Earl Geddes findings
may sound a bit funny:
Implications

The most interesting effect is that the audibility increases with signal level
Click to expand...

hmmmm ..well,
what it implies is of cause, that the audibility of (some) distortion increases with level
or something more sofisticated than first impression of the above text quote
 
#19,231
john curl said:
Please slow down on the 'crazy talk' Lineup
Click to expand...

what is crazy to you may not be craxy to all my other readers

what sound crazy from you, Mr John Curl, to my ears
may be perfectly normal to the other readers

Just dont, too often, tell me what to do or think

I have my own ways and my own think
.. and according to United Nations declaration of human rights bill
we The human beings, have absolute freedom to think and to speak our thoughts, too
... in a respectable way, of course 😉

thanks - ok, I slow down a bit, maybe you easier can catch this young fellow .. young in mind

/yours lineup

PS. You were only mentioned as 'John Curl' 6 times, so far today.
Once even in one post by me, I think
:angel: :angel:
 
#19,232
Please, everyone, I am not trying to pick on anyone, here. I am just trying to get some learned input out to anyone who might be interested.
Lineup, to me, you are not 'up to speed' with your general knowledge of audio design. Please note this. This means that I 'waste my time' getting you 'up to speed'. I don't teach at this level. I am serious about this.
 
#19,233
Johnloudb said:



And the only one who knows that answer is Charles Hansen who did extended listening blind testing. In which case everything including switches are audible.

http://www.diyaudio.com/forums/showthread.php?postid=1771831#post1771831

Kudos to him for doing such a test, and sharing it. Personaly, I'd like to see more of this type of testing. I'd like to try this kind of test as well, but I've got lots of stuff to do right now. It's unlikely anyone would believe the results of any test I did anyway.
Click to expand...

One problem I have with these tests is the editorializing, phrases like "everyone in the room" etc. show to me a bias and lack of objectivity equal to the Audio Critic mindset.
 
#19,234
When it comes to Demian, he was talking about some TINY ceramic caps on a commercial board that had a declared value of 0.1uf. THINK! Can ANY COG .1uf cap fit in that spot? NO! Therefore, it is an inferior material with LOTS of DA AND nonlinear distortion. I measured it 31 years ago, and published it! What do you want?
 
#19,235
Regardless of the type of cap such a filter in the middle of an audio chain should have some effect I would think. I moved the
"output" to one of the two I/V converters. It sounded better but not good.

I would rework the board but its a loaner and too expensive to buy just to confirm it has serious problems.

I would like Scott's input on the feedback around the differential amp. It looks to me like it has a low pass filter at a node where it could have a lot of effect combined with feedback that brings the response back to where it should be. Essentially affecting the loop gain, which is why I was interested in the effect of the low impedance.
 
#19,236
parasound hca-3500 mods done

Hello JC and the rest,

I got the HCA-3500 back in the system with the mods you recommended here and it really does sound nice. We changed out the bridges, cut out and replaced many of the caps, and upgraded several resistors. Still a bit to do on the bias switching, emitters, and wiring, but very pleased with the sound.

Many thanks to you, Phil H, and the late Bob C.

Matt
 
#19,240
Wonder what? Can it be improved? OF COURSE. Is there better, even by me? YES. You pay your money and you takes your choice:cubehead: PS I am using a stock 2500 (not for sale) in my own system. It is not as good as a MODIFIED 3500 (trust me, used one for years) but OK. NOW, if you want to modify your 2200, it will be about as good as a modified 3500.
 
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