John Curl's Blowtorch preamplifier

[jan.didden]

I was refering to uses of Diffmaker that have a speaker in the path. I can't see how there would be much use for equalization in a good D/A -> A/D chain.

Hmm. Bill?? 😡 😉

Jan Didden

 

[andy_c]

I was refering to uses of Diffmaker that have a speaker in the path. I can't see how there would be much use for equalization in a good D/A -> A/D chain.

Oh, okay. But I don't think you'd want to test caps that way though. The kind of situation I was thinking of was comparing two coupling caps whose values differed by, say, 10 percent via high-pass filters whose outputs go straight into the sound card inputs. Seems like such linear differences could swamp out any differences due to nonlinearity. I'm aware you could tweak the resistors to get an analog null, but I thought the EQ was supposed to do the equivalent thing in the digital domain.

 

[Johnloudb]

Do I dare ask why so many high end preamps omit tone controlls. A small tweak of the treble and bass control can make many bright recording much more tolerable, and listenable. Maybe caps have a small affect on sound but the biggest differences are going to be between this or that recording.

 

[scott wurcer]

Is it stationarity or time invariance ?

JPV

Sorry being sloppy, I meant time invariant.

 

[Edmond Stuart]

Do I dare ask why so many high end preamps omit tone controlls. A small tweak of the treble and bass control can make many bright recording much more tolerable, and listenable. ..............

 

[jan.didden]

Do I dare ask why so many high end preamps omit tone controlls. A small tweak of the treble and bass control can make many bright recording much more tolerable, and listenable. Maybe caps have a small affect on sound but the biggest differences are going to be between this or that recording.

But..., but...., I was told that anything in the signal path kills the sound. You saying that aint so?? 😉

Jan Didden

 

[Bob Cordell]

syn08, normally the difference between "linear" and "nonlinear" is closely related to the alteration of the spectral content of a signal.

So, if the original signal is altered, by for example a change in frequency response, but no new spectral content is created during this alteration, than it is called a "linear distortion".

Otherwise, if new spectral content is created during a process, than it is called "nonlinear distortion".

Well stated Jakob2. You are EXACTLY right.

Cheers,
Bob

 

[Bob Cordell]

Re: decoupling caps

Hmm...when decoupling has to be effective in the (tens or hundreds of) megahertz range (power MOSFETs!), I wouldn't rely on polystyrene or other winded caps. I think that MLCs and other stacked capacitors are more appropriate.

Here some interesting links about caps:
http://www.cliftonlaboratories.com/capacitor_voltage_change.htm
http://www.cliftonlaboratories.com/bypassing.htm
http://sound.westhost.com/articles/capacitors.htm#7.0

Regards,
Edmond.

Good point, Edmond. In our telecom work with 10GHz and 40GHz electrical baseband signals, coupling and bypass capacitors have to be carefully selected. We actually use a small surface-mount 0402 in-line with the transmission line so that it effectively looks like part of the transmission line so that the effect of its inductance is minimized.

Yesterday I was working with frequencies like 192.733 THz - in the DWDM optical spectrum, of course.

Cheers,
Bob

 

[Edmond Stuart]

Re: Re: decoupling caps

Good point, Edmond. In our telecom work with 10GHz and 40GHz electrical baseband signals, coupling and bypass capacitors have to be carefully selected. We actually use a small surface-mount 0402 in-line with the transmission line so that it effectively looks like part of the transmission line so that the effect of its inductance is minimized.

Yesterday I was working with frequencies like 192.733 THz - in the DWDM optical spectrum, of course.

Cheers,
Bob

Thx, Bob

BTW, how to decouple a 192.733 THz signal? 😉

Cheers,
Edmond.

 

[john curl]

Here is an important task that you 'objectives' can do for the rest of us. You simply build a MICRO-EQ network that we can use to make a Levinson sound exactly like a Krell, or an Ayre, or a CTC or whatever. Go for it. Please! Do the audio community some service!

 

[metalman]

This thread moves too fast to properly keep up!

It would be quite helpful if you (and others who lean towards measurements) could restrict yourself/ves to one simple response when presented with something new:
"I have not tried (fill in the blank). I have no opinion."
Short, sweet, to the point, and most important, intellectually honest.
If you do try something, might I suggest one of the two following possibilities:
--"I have tried it, and I heard (fill in the blank, be it good or bad)."
--"I have tried it and was not able to hear any difference." ....

First, I 100% agree with everything you said.

But (Flame wars on .... ) to complete both sides of the equation a little more needs to be added.

--"I have tried it, and I heard (fill in the blank, be it good or bad). This neither proves nor disproves its existence.

Not pointing a finger at anyone in particular, and very much making a generalized statement from a view of 10,000 ft or so, but for every genuine Golden Ear out there, there are 10 who have creative hearing, and unfortunately there is no possible way to determine whose reports are credible.

Basically what I am saying is that for subjective analysis, both null and positive results can be erroneous, as both can also be correct. So if we are going to place guidleines on what one side can say, let's be fair and make the other side adhere to the same restrictions.

For the record, I am definintely not a "Golden Eared One", I have heard things my measurments couldn't explain, and though I do not believe it to be so, it is entirely possible that I have creative hearing.

Terry

 

[john curl]

Metalman, maybe you just heard a difference that you are not YET able to measure. That's OK. Happens all the time.

 

[metalman]

Actually, the stuff that bothers me far more is the stuff I CAN measure, seems like it SHOULD be audible, but I CAN'T hear!!!

 

[bappe]

It´s funny. So many times i have been able to verify with my instrments what i´ve just heard, but VERY seldom the other way around. it´s also funny how i spend less and less time measuring and more and more listening to music.

/Anders

 

[PMA]

Mostly the wrong, unimportant parameters are measured.

 

[Bratislav]

Here is an important task that you 'objectives' can do for the rest of us. You simply build a MICRO-EQ network that we can use to make a Levinson sound exactly like a Krell, or an Ayre, or a CTC or whatever. Go for it. Please! Do the audio community some service!

Are you saying you can actually tell the difference (blind of course) ? Or is it only when you see the units in question you can "hear" the differences as well ?

It is really tiring to hear all this nonsense about 'superiority of hearing'.

It has been proven infinite number of times that human senses (including hearing!) can not be relied upon as they can be easily fooled. Even pros (read about Joyce Hato scandal where neither today's top conducturs nor performers whose work was stolen recognized the performances as their own).

All the examples given by Grey (redbook CD, driver phase alignment, triode vs SS etc.) can EASILY be measured with confidence level infinitely more reliable than listening alone.
Perhaps we don't know (yet) how to interpret all of the measurements. But if things cannot be measured with modern equipment, you can be quite sure they can't be heard. Golden ears or not.

BTW, noone took the time to explain to me how come those early Krells reached cult A status among the golden eared, despite having the worst possible capacitors in them (tantalums)? Superior hearing, what was that again ?

 

[SY]

Here is an important task that you 'objectives' can do for the rest of us. You simply build a MICRO-EQ network that we can use to make a Levinson sound exactly like a Krell, or an Ayre, or a CTC or whatever. Go for it. Please! Do the audio community some service!

That's an easy task as long as you're willing to just judge by listening and not peek. And no clipping, of course.

 

[john curl]

Just a true A-B, behind a screen. Not ABX. However, the SAME micro-EQ could be used for ABX tests as well, but there, we don't expect as much difference as just pure blind A-B, so an A-B would be a more sensitive test in this situation.

 

[john curl]

Easy, SY says!

 

[bappe]

People tend to listen to music very differently, some can communicate directly with the feelings of the musician, some can not(or will not). Any reproduction equipment that can take me anywhere near the performer has merits in my book. An old Dynaco st-120, properly biased and with a not to difficult load does a very good job compared to say, a Krell. It will fall short if the music (or the load) is to complex and it does not do very well when measured traditionally. I do trust my instruments during the design and build phase, i just don't use them to evaluate THE END RESULT. Also please remember that most of our listening experience is created in our brains and our equipment is only stimulating it to fill in the rest so what is needed to to stimulate mine might not be what is right for someone else.

/Anders

Be Nice!