John Curl's Blowtorch preamplifier part III

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simon7000

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billshurv said:
But I tend to listen to music. Masking is there. Is it not valid to ponder if, with real music a buffer with 0.5% low order THD is in fact transparent?


Aside (and honest question). For concert halls where reinforcement is added what is the additional THD that the sound system adds. I know that at covent garden it really messes up the imaging from the cheap sets, but cant say I can hear its amplified.
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The point was that music being multi-spectral masks many defects. How much depends on the program material. If you ever try adjusting a power amplifiers output stage bias using a low level signal you just might be surprised by how little distortion you can hear. Totally buried in use with music.

A decent concert hall system at 10 dB remaining of headroom should be under 1% 2nd harmonic. But it should be a delayed signal so even if 10 dB louder from the loudspeakers but 15 mS behind probably will be masked by the direct sound field even though it is not as loud.

Now messing up the imaging is an issue with how many channels of microphones, matrices and ampliers channels is the critical issue. To do it properly in a concert hall will run about $500,000.
 
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gpapag

gpapag

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Markw4 said:
Can't say specifically.
Its just that if Morinix said he heard something in the tube processed sound that wasn't in the straight wire, I would not necessarily jump to the conclusion that the listener's imagination is the only or most likely possible cause.
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Thank you Mark
My objection was due to the exaggeration used and the inconsistency shown.
Some 0.5THD in the buffer manages to ‘suck the mids out’ while an x10 THD higher and more IMD in the vinyl, doesn’t.


It could possible there was some real audible perceptual effect that some listeners might notice. I have seen something like that before from a small-ish nonlinearity, is all. I don't see a reason to make assumptions about what it was in this case either way. If we really want to know which we might have to do some more work to find out. Do we really care all that much?
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I don’t.
I do watch with interest, remaining silent as long as egos and personal agentas don’t grow that strong to ruin what I consider diy intentions.


john curl said:
Well said Markw4,I essentially said the same thing, 40 years ago about ABX testing.
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You mean what Mark said about ABX testing in this post?
John Curl's Blowtorch preamplifier part III

George
 
billshurv

billshurv

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simon7000 said:
A decent concert hall system at 10 dB remaining of headroom should be under 1% 2nd harmonic. But it should be a delayed signal so even if 10 dB louder from the loudspeakers but 15 mS behind probably will be masked by the direct sound field even though it is not as loud.

Now messing up the imaging is an issue with how many channels of microphones, matrices and ampliers channels is the critical issue. To do it properly in a concert hall will run about $500,000.
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Thank you. In my case the messed image is because I like the cheap seats in the gods with a direct LOS into the orchestra pit. When doing that the line array points at the top of my head!


simon7000 said:
Bad judgement, hormones, opportunity and boredom with the wife! Generally not a good idea and can become expensive and painful.
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Yes, yes and yes. Been there done that.


scott wurcer said:
Ed could we keep this to the average home system that folks here listen to?
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Sorry Scott entirely my fault.
 
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Jakob2

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@billshurv,

billshurv said:
<snip>
Ah, now this is where I could accuse you of twisting words, but I will accept I was terse in my initial post and put it open to interpretation. These are not controlled listening tests. As mentioned the nearest we get to a control is the Foobar ABX plugin which group 1s don't like if they can't game it.<snip>
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Thanks for providing such a detailed post with answers. Today i´m a bit in a hurry so will at this moment only the segment cited above. (more later on)

A Foobar ABX test _is_ a _controlled_ listening test (what else could it be), it is just not a sufficiently controlled (or well planned/executed) test itself.
It seems that at this hidden point the controversial difference emerged.
 
john curl

john curl

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Ticknpop, the size of a power amplifier is mostly controlled by MARKETING. Bigger and better is usually their direction, sometimes to the price of reducing performance at listening levels. However, I have to make something larger than my largest Parasound, to make something more expensive, appear worth the money. I have chosen 500W into 8 ohms, 1000 into 4 ohms. This is because I should have more than twice the heatsink area available than I do with a typical 400W amp. The heatsink available should be the actual determining factor, rather than marketing, but that is a tough fight.
 
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