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John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
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Old 17th February 2013, 05:50 AM   #35241
bcarso is offline bcarso  United States
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[QUOTE=Robert F;3373051]
Originally Posted by bcarso View Post

That is a hell of a lot cheaper than they go for here as a rule. 2010 is a decent vintage but avoid 2011 and 2012 like the plague!
This is an unusually good deal I think; even here the average price for the wine (Wild Rock, "Cupid's Arrow" ) according to some online info being about 19 US. I got a case and may even get some more if any is left. I will find out what Floyd and Sean think tomorrow, hoping that they taste it early and not after substantial additional vino. As much as both counsel double-blind testing, we are a good deal less rigorous at casual dinners
Old 17th February 2013, 06:28 AM   #35242
Esperado is offline Esperado  France
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Those American actors trying to imitate the Maurice Chevalier's accent in English are surrealistic.
Old 17th February 2013, 06:34 AM   #35243
RNMarsh is offline RNMarsh  United States
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John Curl's Blowtorch preamplifier part II
Originally Posted by fas42 View Post
Specifically in regard to supplying voltage rails to a circuit with poor intrinsic PSRR, that has other admirable properties so you proceed in using that topology. Even if there is very high current draw there are ways of making the rails exceedingly stiff, at all frequencies that count, at the points in the circuit where it matters. All already out there, and there are smart ways of doing it, that don't need to be super expensive.

yes, I know.
My Points -
1. My favorite current-mode fb amps get demerits for low PSR. They dont need to have high PSRR if the PS is done well.
2. Its most important that D-M changes on the PS be reduced with most amps especially Current-Mode amps.
3. Dual Tracking Reg supplies are yet another effective means to accomplish 1 & 2, above. And, are superiour in many aspects.


Last edited by RNMarsh; 17th February 2013 at 06:38 AM.
Old 17th February 2013, 08:06 AM   #35244
gk7 is offline gk7
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Originally Posted by fas42 View Post
... and so my system is somewhat fragile - a polite way of saying a bit of a mess ...
Originally Posted by fas42 View Post
... look at the "big picture", which is how to guarantee getting good sound every time. ...
Contradiction ?

Originally Posted by fas42 View Post
... I still have trouble shielding from interference. ...
Good sound every time ?
Old 17th February 2013, 08:58 AM   #35245
fas42 is offline fas42  Australia
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Originally Posted by gk7 View Post
Contradiction ?

Good sound every time ?
Again, this is all a learning exercise: I've assembled and fiddled with a number of weird and wonderful "devices" exploring things; getting good sound every time is the ultimate goal, and the idea of the current "beast" was seeing if bottom of the barrel electronic gear could do a good enough job. It's proven that this is indeed possible, but is not in a fit state, as is, to even be moved from its current location.

I get good sound if I eliminate interference the crude way, that is, switch off or move away all electrical gear that's causing a problem. So then I know what quality of sound I can get with a clean environment; the trick is to be able to generate that electronic peace in a totally localised way, to be able to have an electrical "riot" right next to the components with no effect on the sound. Compared to what it was like earlier on it's dramatically better at rejecting interference now, but is still susceptible. Probably going for much better shielding will do the job, but it will be very messy, and tedious to set up at the moment ...

The key is that once you know how good the sound can get you have an excellent aiming point from then on to work towards, you're not stumbling around in the fog any more unsure whether you getting better sound, or just different sound ...

Old 17th February 2013, 09:58 AM   #35246
jacco vermeulen is offline jacco vermeulen  Netherlands
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Originally Posted by Esperado View Post
They use to say "J'te kiffe trop grave"
That reads like she's giving him too much of a hard-on.

(as this thread at times)
Why does it hurt when I Pee ? (Ay Ay Ay https://www.youtube.com/watch?v=w5fLGWrHouk)
Old 17th February 2013, 10:56 AM   #35247
Max Headroom is offline Max Headroom  Australia
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Default 1/f Noise, Brownian Noise Audible Effects....

Perhaps this subject should be given it's own thread, however since there are so many high calibre participants here I pose the question...
What are the deep implications and effects of the likes of 1/f noise and Brownian noise in typical audio stages/sytems, and additionally in RF reciever stages and systems.

Old 17th February 2013, 12:17 PM   #35248
gk7 is offline gk7
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Originally Posted by fas42 View Post
... once you know how good the sound can get you have an excellent aiming point ...
I attend a classical concert once to twice a month, that´s my "reference".
There is much to be done, this is one thing I agree with you, but this includes
the "first half" of the reproduction chain, the recording. It´s not always
progress what can be observed here.
Old 17th February 2013, 03:08 PM   #35249
marce is offline marce  United Kingdom
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John Curl's Blowtorch preamplifier part II
Originally Posted by fas42
... I still have trouble shielding from interference. ...

Then here is a link to the master, good engineering practices, his book is evan better.
home page

Old 17th February 2013, 03:31 PM   #35250
john curl is online now john curl  United States
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Fas42, I also have a 'bit of a mess' for a hi fi playback system, yet I get results out of it, on occasion, that even shocks ME.
My best sound reference on a regular basis is FM radio. Every saturday and sunday, 'A Praire Home Companion' comes over the local National Public Radio' for two solid hours of the best FM programming possible, both technically and actually for appreciation of the audio arts. This week had an Opera Singer, some lovely folk groups, with a mean fiddle (not really violin, but fiddle) and this show usually has some really high quality natural singers, who remind us of what it possible vocally. Human female voice is my best clue to 'natural sound' that I know of. Of course, the show is digitally taped, stored and transmitted thousands of miles, but IT STILL SOUNDS REALLY GOOD! It shows what CAN be possible, rather than what people can get away with.
When it comes on, I turn on my main system with with the WATT's and a subwoofer, Parasound amp, a BLOWTORCH preamp, sourced by a modified SONY FM tuner.
Do I listen all the time this way? No, I am happy with a pair of computer speaker-amps and a portable SONY FM radio. Why not? News and discussion don't need hi fi, and it saves electricity, and disturbs the neighbors less in early mornings and late evenings.
Could I do better? YES. But the cost/hassle ratio is just too much for me at this time. If I were 30 years younger, I would upgrade in a minute, I have the extra cash, but who do I need to impress?
Just last week, a pair of WATT3's with Puppy woofers were made available to me at a discounted price, but I decided not to go for it.
15 years ago, I would have just about 'killed' for this combination that I found the most musical of the WATT series, as heard at the house of a colleague of mine, back then. Now, it would be just slightly better (to me) but then I am getting old.
The Sony F1 tuner had to be modified to sound OK, but IF I can get it together, I want to get my Marantz 10 tuner back in operation. IT SOUNDS WONDERFUL (when working), and I hope to replace the filter caps to get it back in operation. Just haven't gotten around to it. BUT it is a better sounding tuner than the even modified Sony, that runs rings around an unmodified one. In time I hope also to replace my aging Parasound power amp with something better, as well. I have heard better in my system.
Yet with all this, I have spent most of my time listening to an old Sony Walkman with some cheap headphones, and really enjoying a new format rock FM station that I recently found. Yes, rock and roll often is not always best friends with really good hi fi, and as some have described it here, is often made with lots of 'second rate' equipment and compromised signal paths, YET the essence gets through with a pair of cheap headphones, because it was made to do that, and that is the major audience for it. It is like another listening experience, with 'forgiveness' being useful, and stereo being absolutely necessary. Fascinating!
"Condemnation without Examination is Prejudice"

Last edited by john curl; 17th February 2013 at 03:56 PM.

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