John Curl's Blowtorch preamplifier part II

[SY]

It is a logical conclusion from forum member DF96 'circuit theory''.

In English, this is referred to as a "straw man."

 

[Steve Eddy]

In English, this is referred to as a "straw man."

You don't say!

 

[DF96]

According to your circuit theory, amps with the same specs. must sound the same.

Not according to 'my' circuit theory i.e. everyone else's circuit theory too. Circuit theory tells you how the amp meets its spec; the amp may still be inadequate if the spec is inadequate, and inadequate amps are likely to sound different from each other. In fact, 'sounding different' is a warning flag for 'inadequate'.

You must do better than throwing out random false comments. Why not address the issue? Suggest how a trivial potential divider can affect the sound, or suggest how a sighted test can be immune to all the known human effects of expectation bias, placebo effects, herd behaviour etc.

 

[wahab]

I think you will find that in the absence of NFB most valves can manage better linearity than any BJT.

Not intrinsicaly, valves have built in NFB and this trade their gain for more linearity, also supply voltages are higher, hence this is less difficult to have a linear segment of say 10V within a 200V characteristic than with a 30V such max amplitude.

Now put the transistors in the same condition/characteristiscs and not sure that valves will keep being that linear comparatively.

With NFB both are good enough for sound reproduction.

Certainly but they could compare only if using old SS designs, otherwise linearity wise there s a gap of several order of magnitude, not that it s that audible but on the measurements it is here.

 

[Coldhead]

There is no amp with "same specs"(maybee approximative) with different topologies.
This is source for diy fun.

 

[Markw4]

Suggest how a trivial potential divider can affect the sound, or suggest how a sighted test can be immune to all the known human effects of expectation bias, placebo effects, herd behaviour etc.

Here is a pretty extensive list, just in case anybody wants to get down to the particulars: https://en.wikipedia.org/wiki/List_of_cognitive_biases

The thing about the biases is that it's fairly easy to seem them operating at times in other people, but much more difficult, sometimes virtually impossible, to see them in ourselves.

"It's sometimes seems like everybody is crazy out there, except me." "And I know I don't have those crazy biases, because I would know if I did. And anyway, I am way more rational than most people."

 

[bcarso]

You don't say!

Exactly what I was about to find and post.

 

[Steve Eddy]

Exactly what I was about to find and post.

Beat ya!

se

 

[kamis]

Not according to 'my' circuit theory i.e. everyone else's circuit theory too. Circuit theory tells you how the amp meets its spec; the amp may still be inadequate if the spec is inadequate, and inadequate amps are likely to sound different from each other. In fact, 'sounding different' is a warning flag for 'inadequate'.

You must do better than throwing out random false comments. Why not address the issue? Suggest how a trivial potential divider can affect the sound, or suggest how a sighted test can be immune to all the known human effects of expectation bias, placebo effects, herd behaviour etc.

How do you compare your DIY creations?Do you believe in boutique components?

 

[31697B]

FWIW --- from PHD EE Stanford. IBM and HP resercher in linear devices and limiting factors etal --->

he said to me the most linear device was the triode tube. But tubes are too noisy for many uses.

He used FET for his audio amps.


THx-RNMarsh

 

[Kindhornman]

RNM,
Have you hooked up the JBL's yet?

 

[john curl]

Of course, the TRIODE is the most linear device. Why confuse the issue?

 

[Speedskater]

If two amps sound different but measure the same, then you are measuring the wrong things.
But this only applies to hearing not seeing.

 

[john curl]

We ARE measuring the WRONG THINGS, but that is all we have to work with.

 

[hitsware]

Unless we develop a completely new
system of measurement that depends
entirely on aural sensory input .........

 

[Coldhead]

It is possible, and introduced, for some medical needs, but, I can't imagine purist audiophile with platinum electrode threw the nerves.

Also, there is no "experienced listeners"..this experience is often useless..a lot of variables and this sensation does not last long..
Maybe "trained listeners" is a little better term.

 

[scott wurcer]

Of course, the TRIODE is the most linear device. Why confuse the issue?

I agree this does cause confusion, mV's come out of cartridges no matter what you make the pre-amp out of. Triodes have volts of linear transfer function, stating the obvious serves no immediate purpose.

 

[SY]

We ARE measuring the WRONG THINGS, but that is all we have to work with.

You may be, but don't include the rest of us in the "we."

 

[Chris Hornbeck]

One tech was caught in an accident, and knew not to inhale. He rushed to a shower, shedding his clothes on the way. He survived.

Guys (and of course it's always guys) that do hot-bluing of firearms like to work next to a swimming pool. An emergency measure for _them_, not the steel.

Much thanks, as always,
Chris

 

[scott wurcer]

Interesting.... my father was a navigator in B17's. Was the last man standing from his original group when the war ended. DFC from Dolittle etc.

After all that, Leukemia did him in.

In remembrance and honor to him, i use his initial in my signing (N).
-RNM

That's my father's jacket patch as my avatar. A really cool one. I'm sorry if your father went before his time, my father passed at 81 we all have to deal with this, there is no other possibility.