John Curl's Blowtorch preamplifier part II

[Max Headroom]

ok - thanks.

My pleasure.

Talking about Zobels', a few years ago I had about 3 or 4 meters of speaker cable coiled up and looked at the waveforms at the speaker end (B&W 703's). ~ 10 kHz square waves were ringing like hell on the speaker end.

Yeah, it would be interesting to take a look across the individual driver terminals with a balanced probe.

I've been meaning to make up a switch box with adjustable R and C for damping at the speaker end - something I'll pick up in the next few months hopefully

A local magazine came up with this design a while back.
The resistor thumbwheel switches are Decimal, with same value resistors across each 1 through 9 switch position.
The capacitor thumbwheel switches are BCD, with 1uf, 2uf, 4uf, 8uf (scale accordingly) connected from common wire to each of 1, 2, 4, 8 BCD switch inputs.
You get the idea, if not PM me.

Dan.

 

[jan.didden]

One more then.

Isn´t that one of the basic logical falacies - to conclude from a specific mechanism to the general?

In isolation, yes.In the greater scheme of things it is another nail to the coffin, so to speak. Amassing observations to strengthen the theory as more and more comes in. That's how science works.

Btw, following the same route of reasoning you have to conclude that the "gorilla" is indeed invisible (up to ~49% didn´t recognize it; inattentional blindness and inattentional deafness).

Um yes, not sure what your point is?

Obviously true....

Furthermore, if you couldn´t remember auditory events via long term storage any practical relevance is per se extremely questionable.

Again, not sure what your point is. Are you saying that because memory deteriorates with time, it becomes more and more unreliable? In that case I agree; witness the often incomplete and totally contradictory statements of 'witnesses' at crime events, accidents etc. Sentencing man to a harsh punishment based on 'eye witnesses' is at best a rigged Monte Carlo game!

Secondly, as you can´t most often present audio sources at the same time, you have to rely on memory in controlled listening tests. Which memory model would like to follow?
The more traditional one, where auditory memory (in the strictest sense) just last for a few hundred milliseconds - a few seconds?
Or the more modern one where items will be transferred to the socalled working memory, which means memory content can be processed (especially compared to content from long term storage)?

The former was the basis for Precoda/Meng´s proposal to restrict the length of music sample in tests to ~5s to (hopefully) ensure that participants could not use their categorical memory for evaluation but had to use the specific auditory memory. (they obviously didn´t know of any publication that examined the relationship between the degree of a difference and transfer process to long term storage either)

Yes, good points. Memory is not digital - its not a 'now you have it, now it's gone' type of thing. The closer you can to simultaneous (and you can't get there completely) the better you will be able to compare.

Jan

 

[vacuphile]

Now the reason why I posted this is because I suspect the low price was not just because of the stain but what caused it!

So would anyone else use or even keep such a rug?

A flexible casket on the floor beats a dead animal and people do that too.

 

[Jakob2]

You are most definitely on the top of such list.
You have much to say about audio systems and yet you do not have a system that has any chance of being 'in the race'.
Stick with pcb layout and give audio a miss.

Dan.

Please, can we refrain from this sort of argument?

The system that we used for the first listening tests (as the capacitor test as described before) wasn´t extraordinary, consisting of a record player, a diy mc headamp an intermediate stage with volume control and a transistorized single ended class A amp driving a small budget diy loudspeaker (two way pseudo-transmissionline, ~300 deutschmark a pair).

I´d never claim that we were able to reveal all sonic differences between the two capacitors but obviously we were able to perceive a difference. I suppose mainly because we were used to listen to music with this system.

 

[vacuphile]

IIRC we're still waiting for various bits of evidence from Max on such as his different sounding files?
And isn't this "DIY Audio" not "Fashion Audio" at heart -- ie about doing it yourself....? Rather than a race ('in the race' - whatever that means) to an unspecified point?

Yes, absolutely, the list goes back a long time.

 

[Bonsai]

I read somewhere (maybe it was on this site) that one of the issues with mixing nowadays is that the mastering engineers tend to play the music too loud and as a result often dial the bass down. If you listen to most speakers, when you dial the volume down, the bass drops off as well. This is more a function of how human hearing works than the actual speaker I surmise. I have many CD's that are fantastically well mixed (try Dianna Krall, Yo-yo Ma, Ry Cooder, Ryan Adams to quote a few examples). Then there are others that have me wondering where the bass went - they are just sub par. There are a few producers that know how to produce a really good recording, and probably reign in errant mixing engineers - we need more of them around and perhaps we would spend our time listening and not tweaking as much.

 

[Bonsai]

My pleasure.


Yeah, it would be interesting to take a look across the individual driver terminals with a balanced probe.


View attachment 564956
A local magazine came up with this design a while back.
The resistor thumbwheel switches are Decimal, with same value resistors across each 1 through 9 switch position.
The capacitor thumbwheel switches are BCD, with 1uf, 2uf, 4uf, 8uf (scale accordingly) connected from common wire to each of 1, 2, 4, 8 BCD switch inputs.
You get the idea, if not PM me.

Dan.

That's a 'decade' test box. I am thinking more along the lines 3.3, 5.6, 10, 15 Ohms and then series cap 0.02, 0.05, 0.1. Resistors maybe rated at 3 W since I don't expect much energy up at HF.

IIRC the ringing was at about 75 or 100 kHz.

 

[Max Headroom]

IIRC we're still waiting for various bits of evidence from Max on such as his different sounding files?

I'm getting back to that, suffice to say I have taken things to another level, ie experimenting with Wifi streaming and getting very interesting subjective results.

And isn't this "DIY Audio" not "Fashion Audio" at heart -- ie about doing it yourself....? Rather than a race ('in the race' - whatever that means) to an unspecified point?

I see this community as a meeting place of minds and experiences, with notable/sensible/useful inputs from a great many....(JC, Ed Simon, RNM, Scott W, 1Audio, Marce, Bonsai, NP, Bear and others, e&oe 😱 )
As is the course with public meeting, there is a great deal of 'noise' from those who are not at the levels of experience and knowledge of the above mentioned.....PITA really, but to be expected.

Different ingredients, different recipes is good fun and learning experience for the amateur.
Yes, this is a DIY community, BUT there are those here who are at the cutting edge.....I include myself in this, but my direction is uniquely different to the 'norm'.
Reinventing the wheel is by far the best fun that one could ever have.

Dan.

 

[Max Headroom]

That's a 'decade' test box. I am thinking more along the lines 3.3, 5.6, 10, 15 Ohms and then series cap 0.02, 0.05, 0.1. Resistors maybe rated at 3 W since I don't expect much energy up at HF.

IIRC the ringing was at about 75 or 100 kHz.

You could put an MIT like label on it and charge the earth for it....endless tweaking for the ocd audiophile 😉.
More seriously I suggested such decade type switching for readily homing in on electrically correct values for the particular application example....after that you can mistune and take comparative listenings.
The thumbwheel switch displayed values are a useful bonus.

Dan.

 

[gpauk]

I see this community as a meeting place of minds and experiences, with notable/sensible/useful inputs from a great many....(JC, Ed Simon, RNM, Scott W, 1Audio, Marce, Bonsai, NP, Bear and others, e&oe 😱 )
As is the course with public meeting, there is a great deal of 'noise' from those who are not at the levels of experience and knowledge of the above mentioned.....PITA really, but to be expected.

Different ingredients, different recipes is good fun and learning experience for the amateur.
Yes, this is a DIY community, BUT there are those here who are at the cutting edge.....I include myself in this, but my direction is uniquely different to the 'norm'.
Reinventing the wheel is by far the best fun that one could ever have.
Dan.

That's fine as long as subjective -- "I love the way this sounds, it's good for me" isn't mixed with "therefore it's better, and good for everyone".

 

[Max Headroom]

....I don't do PCB layout.

Ok then, just give audio a miss.

Dan.

 

[billshurv]

says the man who is convinced he can control noise? Sorry advice from you is worthless.

 

[Jim the Oldbie]

...As is the course with public meeting, there is a great deal of 'noise' from those who are not at the levels of experience and knowledge of the above mentioned.....PITA really, but to be expected.

Gee. Thanks a lot for letting the other 99% of us dirtbags know where we stand in your estimation. We do apologize for being such a collective pain in your ***.

- Jim

 

[Max Headroom]

I read somewhere (maybe it was on this site) that one of the issues with mixing nowadays is that the mastering engineers tend to play the music too loud and as a result often dial the bass down. If you listen to most speakers, when you dial the volume down, the bass drops off as well. This is more a function of how human hearing works than the actual speaker I surmise. I have many CD's that are fantastically well mixed (try Dianna Krall, Yo-yo Ma, Ry Cooder, Ryan Adams to quote a few examples). Then there are others that have me wondering where the bass went - they are just sub par. There are a few producers that know how to produce a really good recording, and probably reign in errant mixing engineers - we need more of them around and perhaps we would spend our time listening and not tweaking as much.

Yes, acoustic mixdown mastering level is mission critical, Bob Katz has much to say about calibrated mastering SPL.

You are correct in your observations, ie a mixdown monitored at overly high SPL will sound 'right' when played back at that same/similar SPL level, BUT will sound 'bass light' when played back at lower SPL.
The converse is also true, ie a mixdown monitored at low SPL will sound 'bass heavy' when played back at higher SPL.

Fortunately there is a crossover point where all is good.... iirc Bob Katz specifies 84dBA SPL.
A mixdown monitored/balanced at around this SPL will sound 'right' when played back at pretty much any SPL....at late night low levels the sound does not 'fall apart', and when cranked to max still sounds balanced....and more fun.

This is the secret sauce of the iconic/successful, singles and albums that we have all grown up with.

Dan.

 

[Max Headroom]

Gee. Thanks a lot for letting the other 99% of us dirtbags know where we stand in your estimation. We do apologize for being such a collective pain in your ***.

- Jim

By 'noise' in this context, I refer to the sniping and useless comments, QED.

Dan.

 

[DF96]

Talking about Zobels', a few years ago I had about 3 or 4 meters of speaker cable coiled up and looked at the waveforms at the speaker end (B&W 703's). ~ 10 kHz square waves were ringing like hell on the speaker end.

So what?

IIRC the ringing was at about 75 or 100 kHz.

With a 10kHz square wave it would have to be 70, 90 or 110kHz. Bats might hear it.

As is the course with public meeting, there is a great deal of 'noise' from those who are not at the levels of experience and knowledge of the above mentioned.....PITA really, but to be expected.

Much of the noise on this forum comes from people, including some of those commercially involved in audio, who seem to need to have basic electrical theory and the relevant mathematics explained to them over and over again. This can be tiresome, but we always hope that one day light will dawn. The occasional success, usually with genuine newbies, spurs us on.

That's fine as long as subjective -- "I love the way this sounds, it's good for me" isn't mixed with "therefore it's better, and good for everyone".

Sadly, that particular confusion seems to occur almost every day.

The other common confusion, especially in this thread, is "As your system costs less than $5k, you are not qualified to teach me about Kirchoff/Fourier/Nyquist".

 

[Jakob2]

<snip>
Nothing about your test seems remotely robust, both in prior plausibility and in execution. Let me rephrase and see if I missed anything: there's a claim about swapping between two industrial capacitors of reputable quality (one polypropylene and the other polystyrene), and of (hopefully) similar capacitance and parasitics on a single amplifier (thus relying on long term memory) having (expected) differences?

Let´s see, you missed only two things (it was polyester and not polysterene compared to polypropylene and the tolerance was not "hopefully" but measured) so i think you did not that bad...... 😎

The time span between two trials was roughly 70 - 90s (fixed 60s for the capacitor work to exclude any clues from different time spans) and the remaining for starting the music. So as stated before, it depends on the memory model you want to believe in, but in no model (afaik) is this considered to be a matter of long term storage. The information is considered to be hold in short term storage or in working memory.

So you doubt the robustness, but could not present some data to back up your claim.
A citation for the claimed inability of memory to store information for longer time spans wrt to multidimensional perception events would surely help.

"Prior probability" is a nice line of thinking. Do you remember that i posted the old aphorism "......for the nonbeliever is no confirmation ever good enough" ?
If you set in a bayesian framework the prior probability to zero no experimental result could ever change your belief......

Sheesh, that reads like a fishing expedition for results.

Again, I want to emphasize, whatever anyone wants to do is all well and good, but, for goodness sake if you're going to do an experiment to determine X from Y for whatever reason, don't do garbage tests.

Remember the list of selfimmunization "arguments" i´ve posted some time before. You´ve worked your way through it quite well, but real arguments and data are lacking.

Last time you presented a false assertion and the document that you´ve cited confirmed exact the opposite, but even that you were unable to admit.
How could we progress if even in this no consens is possible?

 

[jacco vermeulen]

As it stands now, I am able to dictate the signature sound of any system, instantly and consistently across replay systems of any type/size/quality.

Frank Lives (another day)

 

[marce]

You have me confused with someone else. I don't do PCB layout. If you are going to try and belittle someone a teensy bit of research works wonders, otherwise you come across a little foolish.

I think he may be thinking of me here as I am a lowly PCB designer, so should stick to that and not audio maybe... Though I do seem to do an awful lot of high end analogue layouts... where everything does matter.
😀

What I do find interesting is that JC said one difference between a and b grade is layout... that worries me, I would never do a sub standard layout, I cant see the point, maybe I am missing something.

 

[Max Headroom]

......The occasional success, usually with genuine newbies, spurs us on.

Apologies, I omitted you from my list, I did say e&oe 😱 .....I do note what you have to say.

Dan.