John Curl's Blowtorch preamplifier part II

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This is not the way of a logical or ordered mind.

Saying 'it's ok people get me' is a cop out.

I am sure Bruno really won't lose any sleep because you poo poo his designs because I recommended them as a starter for discussion. I won't either.

I am not debating you for points. Just making comments based on experience and on tests as well. I dont even care as much as others do if I dont correct typo and misspelled words and bad grammar. To me this is just texting here.

I havent poo-poo'ed his design. I poo-poo'ed your recommendation based on your comments and expressed attitude re. excellence of work being elevated to the level of fine art.

THx-RNMarsh
 
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Joined 2012
2. Again if you are selling it's OK, but in DIY where is intellectual and technical challenge in that?

:cool: :)

And, when you go All Out..... it ends up sounding more accurate as well.

Thats just from my 50 years R&D in it and still learning. Which includes rooms, speakers et al. But some of you who like the challenge to do better, go all out in each area and see where you end up..... it actually just keeps getting better.

Just like video just keeps getting better with higher rez and other 'small' yet complex details. I cant wait to get a 4K UHD player and source material for my 4K UHD display here in my loft over looking Bangkok. Holograms are coming

Cheers,
-Richard Marsh
 
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Disabled Account
Joined 2012
Richard,

On the 0.1% thing I mentioned, it is in consideration of all the other distortion sources in the signal chain. If you change yor speakers, or the room layout and the sound changes (now that is EASY to detect), why beat yourself up of a hardly detectable level of distortion in an amp? Better to work on your speakers and secondly convince your wife to go with your acoustically optimized layout for the living room IMV.


:)

Hi Bonsai :). You know I respect your work. So lets get into this a little deeper.

If we have a recording chain of say 5 pieces of electronics to go thru for a recording and on playback we have 3 pieces.... and each produced at normal use output levels of 0.1% thd..... at times the max distortion we are listening to could be as high as 8 x 0.1% added to the original sound. To be guaranteed to never exceed 0.1% system total, we need 0.1/8. The fewest stages the signal has gone thru, I find sound better (less total distortion). At the same time it makes the just noticeable detection (JND) threshold a little lower as well.

In my particular case, I DO have speakers with no more than 0.1% in the mid range and listen in the near-field. So, for me the JND threshold would be lower. I come up with a conservative 0.05%. For others if might be less. So that is .05/8. If we need each piece of gear to have less than .006% in my example of 8 pieces of gear in a total system chain. If this were the case we would hear the Master source reproduced in our home pretty much the same as direct from the master source. When I use my headphone amp (<.001% thd) and low distortion headphones for music downloaded and Mastered for HiRes it is very close to live.


THx-RNMarsh
 
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What I found was high SNR in particular sounded more accurate even if the THD was increased.
Figure that out.

THx-RNMarsh
Hi Richard.
To be expected.
In my experimentation/experience how the circuit/system handles/reacts to signal included noise and circuit stages self noise changes the subjective experience big time.
The spectral nature and dynamic characteristic of system self noise is a large part of what separates good systems from exceptional systems.
Very interestingly this system noise behaviour can be changed at will.

For example try ferrite clip on filters in different circuit positions - to my ear the result is drive out of the room awfulness.
I have different clip on filters that render any system to entirely pleasant.
The degree of improvement varies according to the SNR quality level of the system.
THD including mild clipping becomes quite irrelevant.
This concurs with your findings.

Dan.
 
By all accounts, the simplest decent sounding amp - albeit low power - has to be JLH's 10 watter - but in the split rail version (Richard, this is less than the idle power on your amps . . . ;)

Even NP was impressed . . .

Hi Bonsai !

I wonder why nobody have tried to made that simple JLH 10 - 15 W A class amp variant but now using modern very fast complementary BJT OPS , using same simple JLH topology with only four BJT supplied from split rail PSU ?

Regards !
 
Hi Richard.
To be expected.
In my experimentation/experience how the circuit/system handles/reacts to signal included noise and circuit stages self noise changes the subjective experience big time.
The spectral nature and dynamic characteristic of system self noise is a large part of what separates good systems from exceptional systems.
Very interestingly this system noise behaviour can be changed at will.

For example try ferrite clip on filters in different circuit positions - to my ear the result is drive out of the room awfulness.
I have different clip on filters that render any system to entirely pleasant.
The degree of improvement varies according to the SNR quality level of the system.
THD including mild clipping becomes quite irrelevant.
This concurs with your findings.

Dan.

You have misunderstood what Richard wrote (it looks you've edited his post), SR (Slew Rate) not SNR (Signal Noise Ratio).
 
diyAudio Member RIP
Joined 2005
You chase guests away too with talk about amplifiers, cars, and various techno dribble, hey ?

(Happens to the worst of us. I chase them in the parking lot if they express their desire to leave, sometimes knock on the side-window of their car for a last addendum)
It used to be certain music was required to drive away guests who overstayed their welcome. But a far more effective way to at least make some space around oneself was to engage in conversations about electronics with another. I'd barely get mid-sentence sometimes in a small group before all but one would move away.
 
Disabled Account
Joined 2012
My personal philosophy is to always get the best that you can afford. I never let a lack of money prevent me from doing the best I could..... it would just take longer as I could only buy a part or parts once in while. II would rather save for a few months to get the better part. I had a car once that I spent 10 years working on it to get it to be all I wanted it to be. By then laws had changed and I couldnt get it to pass smog... 2-3 years more to clean up the exhaust. But in the end, it was a great fun machine.


THx-RNMarsh
 
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Hi Jacco !

I know that NP article , it is just one very good variation of old JLH idea/ A class amp design, which basically is SS translation of Williamson tube amp ,
My idea is different , simple singleton 10-15W A class amp without BJT phase spliter , which relay on modern very fast complementary power BJTs for OPS , here is the rough basic schematic .
(Note , there is no CT on secondary coil of main power Transf. , just virtual floating ground formed with two 680R power res.)
 

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Which has more social kudos ?

Depends who you ask.
Me, I've been raised to learn everything, and do myself what I've learned.
Took me quite some time to respect people who live by the rule that one does not have to do what one is able to do.

One or the other has its own advantages.
I received new mains on friday, last xmas they blew up every appliance in the house with 400Vac.
Friday morning at 6am, I had a chat with the mains authority employees.
Told them I financed my MSc education at Delft-U by working at A'dam city center doors for $500 a weekend night, have a DNA wrapped-sheet for severe assault and battery, and am currently in a rather foul mood.

By Jove, excellent mains quality since, flawless.
Jolly good show, and not a nickel extra spent.

But I suggested something entirely different, really.
 
Single distinguishing feature between a clown and a cynic is the level of humor.
(though it could be a horrible cnt)

Never told you Fritz Deelman en die Diepsee Duikbol is my favorite book from adolescent years ?
(500 gross was 500 net, tax deductible pc, tax deductible everything)
 

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