John Curl's Blowtorch preamplifier part III

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#21,701
johnego said:
Yes. I asked Bob, but you can answer too, but you must read him too to make sure that we are in tune so you can understand the points I made.
if this doesn’t look right I’m still trying to figure out the multiple quotes feature....seems out of phase!

The disconnect I suppose is more between objective vs subjective, the objectives seem to always need something to measure correctly where I seem to be drawn to the side that ‘sounds’ better (to me) yet measures imperfectly.
What do I measure? Well I measure a set of test tracks at volume at LP with a Dayton imm-6 calibrated mic, with this I’ve tuned everything ‘to the room’ as in xo,driver choice ,even down to components and cables.....the system as a whole.

Now yes it’s subjective as in ‘to my taste’ but I’m thinking imperfection might be more popular than some would like to believe....I’m getting some pretty good results. I’m finding I like the bottom bump centered around 60hz then flat to the bbc dip from 1.8k to 4K back flat out to 10k then sloping down (a lot) with this I can just about reproduce a ‘live sound’ 105db avg at lp with peaks over 110db
cleanly.
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First point is clear: in bad systems there are more trade-offs.
Second point: if the system is so bad that nothing can make you happy, at least make a good trade-off such as increasing the H2 so you can enjoy Norah Jones, a girl with a guitar, or whatever.


I’m starting to wonder if my new parasound Hint has a high H2.....it has a tubish warm quality to it, and a major concern was it seemed ‘slow’ ...so much that it’s been sent to be checked out, I’m hoping there’s something faulty but in the back of my mind I’m thinking that may just be the ‘tradeoff’ you mention.
also have a new set of low capacitance speaker wire.... I was using high cap (over 250pf/ft) cardas wire (an attempt to tame the previous Yamaha amp hot top end) in case that had anything to do with it.
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Simply by looking at the majority of designs, observing people preference etc.
This I agree with, after all it is the ‘people’ that matter
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I have access, but that's not the point. The point is, I mentioned how an amplifier with high H2 might have troubles playing orchestra with good speed/detail/separation, then you gave 'solution' which is "Get speakers with better transient response". Now I want to discuss deeply, how a speaker with better transient response can solve the issue mentioned.


Nelson Pass has a H2 harmonic generator or some such thing, might be a good experiment for me to try on my Yamaha amp to see it makes it sound like the Hint.
The speakers I’m building for the new Hint are 10”mtm (pro drivers,cd horn)
and will more than likely have a faster transient response, I base this on the fact that the new woofers (although similar) have almost half the mms of my current ones and the horn tweeter should be faster than the conventional.
So I’m thinking if the new amp comes back still a little slow that the ‘faster’ speakers in combo with the ‘faster’ wire might blend.....we’ll see in 2-3 wks
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#21,702
mmerrill99 said:
I guess you will never understand the difference between measuring audio electronics & audio perception despite the constant pointing out of this basic fact.
Some people are just not interested in absorbing/learning new information.
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You have to "turn-off" your subjective taste and preferences if you want to be objective in rating of audio reproduction quality.. Other way it is valid only for you (perception is highly subjective phenomena) at some place, in some time... , but tells close to nothing about objective properties. And audio electronics is IMO made to exactly reproduce, not to "improve" emotions via changing recorded informations according someones taste .🙄
 
#21,703
BV said:
You have to "turn-off" your subjective taste and preferences if you want to be objective in rating of audio reproduction quality.. Other way it is valid only for you (perception is highly subjective phenomena) at some place, in some time... , but tells close to nothing about objective properties. And audio electronics is IMO made to exactly reproduce, not to "improve" emotions via changing recorded informations according someones taste .🙄
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I’m not sure something built/rated objectively perfect comes across realistically at my end, the subjective end.....the end that actually matters!😀
 
#21,704
bimo said:
Dadod said about CFA. But you said VFA can not have open loop gain flat until 10kHz, which is wrong. Loop gain = (open loop gain) - (close loop gain).
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I think you misunderstand what we both say.
Make your own simulations with two amps, one CFA, one VFA, same input stage gain, same VAS, same power stage, same open loop gain, same closed loop gain.
And look at the influence of the feedback path impedance (on both) on the closed loop bandwidth.

The thing is that, in a CFA, you can, naturally set this feedback impedance low, while, in a VFA, you want, to keep the LP balanced: have-it equal to the +input impedance, IE >= 10 kOhms for a consumer product.

At 10KOhms, and 10kHz, it will introduce (in both topologies) a phase turn in the feedback signal, at the point where it is substrated to the original. IE less feedback at this frequency.

Again, CFA will behave the same, if you put a 10 kOhm as the feedback impedance, that i hope you will not do.

If you set a VFA with 600 Ohms input impedance, there will behave near equal on this point.
But, then, we will begin to look at the compressive VS expansive behavior and their influence on slew rates, that makes an other difference between the two topologies.

No need to lose more time on this, and bring a CFA VS VFA controversy back again. EOT for me.
 
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#21,705
PMA said:
I think that the only reason why some are suggesting different methods is that it doesn't bring the expected result to them.
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You may have forgotten that I made a list of few minor changes that I though would make foobarABX much more user friendly. Attempts to find source code, the original author, or someone to write a new version were unfortunately unsuccessful (I did have one volunteer programmer, but he backed out after thinking through how much work writing a new ABX would take). I wouldn't have gone to that effort if I thought the program was properly designed for good usability in the first place.

I think the only reason some people like foobar ABX is because it is the only free blind test software that has a checksum feature (which could still be cheated if someone wanted to bother with it).
 
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#21,707
PMA said:
... Sometimes a musician from Czech Philharmonic Orchestra comes to visit me, and he is able to hear the sounds or imperfections in the recording that I am not able to hear. Not surprisingly, he prefers the amplifiers with lowest distortion and highest S/N, though he was not told what he listens to. This is the opinion that is important to me. ...
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Makes perfect sense for the speaker type that you have but does not necessarily hold true for all.
 
#21,709
BV said:
I'm not sure , too. What you mean with "realistically"?? Yours subjective end ("improved reality")? It is valid only for you (not for all) and only in certain circumstances. Nothing realistic..
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I use realistically in terms of decades of ‘listening’ and ‘hearing’ , involvement in recording and mastering, live sound reinforcement of the source....live music.

After awhile you kindly get a grasp of what realistic ‘is’ when your really there.
 
#21,710
mountainman bob said:
I use realistically in terms of decades of ‘listening’ and ‘hearing’ , involvement in recording and mastering, live sound reinforcement of the source....live music.
After awhile you kindly get a grasp of what realistic ‘is’ when your really there.
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Yes, what you mean is to produce, create music (live music..), according some needs and taste. But reproduction is qute different task. And I am involved in both, for more than 30 years. So I have some idea about it..😉
 
#21,711
BV said:
You have to "turn-off" your subjective taste and preferences if you want to be objective in rating of audio reproduction quality.. Other way it is valid only for you (perception is highly subjective phenomena) at some place, in some time... , but tells close to nothing about objective properties. And audio electronics is IMO made to exactly reproduce, not to "improve" emotions via changing recorded informations according someones taste .🙄
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And herein lies the problem - both sighted listening & the types of blind listening tests we see on forums are equivalent in their level of subjectivity/objectivity - ask ScottJ - he now understands that both are just a bit of fun to be shared on fora.

To try & make a case for one being more objectively true than the other is what the real issue is & it requires an understanding of what you are measuring - auditory perception. The problem here appears to be that people don't want to understand the field of science called cognitive science & refuse to accept that testing in this field is very different to testing in physics. So people wrongly simplify such testing to the mantra "blind testing" without understanding what is involved & then proceed to try to claim one type of listening is more 'objective & true' than another.

Anyway, let's not rehash the same 'ol, same 'ol as hundreds of times before
 
#21,712
Mountainman_bob,
Regarding to your problem with the sound of your system, did you say that you design your speaker? I saw cables and crossover outside of the box. Know this: if you can't make an amplifier, you simply can't, but if you can't make a speaker, you still can! (hope you get the point).
 
#21,713
mmerrill99 said:
And herein lies the problem - both sighted listening & the types of blind listening tests we see on forums are equivalent in their level of subjectivity/objectivity - ask ScottJ - he now understands that both are just a bit of fun to be shared on fora.
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I'll ask again, why is testing such as Markw4's any different? I've also asked before why aren't all the sound of cable, op-amp rolling, sound of capacitor/resistor etc. threads on the various fora "just a bit of fun to be shared".
 
#21,714
mmerrill99 said:
.... it requires an understanding of what you are measuring - auditory perception....
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Mistake, we are measuring ability of technical tools to exactly reproduce sound ,and sound is perceived by ears only. We are talking about objective technical tools..Not about psychoacoustic abilities and imaginations and wishes of some listeners . This is quite different discipline.
 
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#21,715
scott wurcer said:
I'll ask again, why is testing such as Markw4's any different?
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Any different to sighted listening - bit of fun? IMO, it is just the same as any reported listening impression (sighted or otherwise) i.e. to be verified by one's own experience/listening.
I've also asked before why aren't all the sound of cable, op-amp rolling, sound of capacitor/resistor etc. threads on the various fora "just a bit of fun to be shared".
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They are - again to be verified (if one is bothered) by one's own experience/listening.

I'll say it again - trying to elevate simplistic forum ABX testing above the 'bit of fun' that it is, is just plain wrong but it will continue on here as I see already
 
#21,716
BV said:
Mistake, we are measuring ability of technical tools to exactly reproduce , we are talking about objective technical tools..Not about psychoacoustic abilities and imaginations and wishes of some listeners . This is quite different discipline.
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We all know that measurements don't fully characterise how something will sound - to pretend otherwise is ......mistaken.
if they did we would simply dispense with listening tests altogether & be done with it (some here probably do that mistakenly)
 
#21,719
BV said:
Mistake, we are measuring ability of technical tools to exactly reproduce sound ,and sound is perceived by ears only. We are talking about objective technical tools..Not about psychoacoustic abilities and imaginations and wishes of some listeners . This is quite different discipline.
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I think mm99 and I may be on the same page here....one or the other isn’t going to bring it home, the end sound must be considered both ways until a middle ground is found.
 
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