MPP

Wise words. I certainly enyoy what i am doing here, so i go back to the bussiness of designing and try to ingnore issues like that. I think there are enough people that still like good sound athough we are all getting older.
One of the biggest positive surprises i had in Taiwan some years ago. Many young people
(men and women) came to a big High End Show and lots of them wanted to listen to classical music, especially from the classical German period ( Mozart, Beethoven etc.).
I asked them why and they said that they regard classical music as part of their education ! I started to understand why so much High End gear is sold in the far east.
 
You are doing the right thing!

To me the mass market music business was well explained when an American record promoter about ten years ago told me that the age group at which most pop music was targeted was the 10-14 year old kids. A flashy personal stereo they may get for a birthday but a multi thousand euro/pound/dollar system is so far away from their reality that this very large recorded sound group of buyers makes absolutely no difference to or impact on the higher end Audio market. As long as their personal player is loud enough they simply don't care. As they age most will loose interest and only a few will convert to become critical listeners.

Another group of end users comprises of the rock fan....now often old men and women!!! Give them a pair of big old JBLs and a Citation 1 &11 outfit (preferably fitted with dirty tubes) and they will feel they are 20 again!! The music they listen to at gigs etc. is, generally, heard from a stacked wall of speakers: dynamics and volume are important: location of sound - other than in L or R terms - unimportant. The signals which feed the speakers is - often deliberately so - in our terms very distorted.

But those who truly listen to music - especially played on non-amplified instruments - will always warm to a decent sound system.

Salas is right-on-the-ball regarding 'statement' buying; there has been a gradual return to high sound quality equipment produced by smaller companies. (I suspect that the big-boy-makers will have to change their tune to stop their market share slumping). I also like the Greek who said that because he liked his audio so much and that it was so expensive he drove a very old car! The music lover existed before the explosion in rock and then pop music interest. Walker and Leak in the UK were at it before this time which I suppose was in the 50s. I saw Rock Around the Clock when I was thirteen. I saw Song to Remember when only nine! I still listen to Lizst.

The smaller maker/designer usually relies heavily on proper listening tests and, in some cases, more so than on the results printed out by test equipment. The other end is well (?) catered for by the Asian import market!

Keep doing what you are doing the same way as you are doing it - your methods and priorities are right on! Good luck.:)
 
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The smaller maker/designer usually relies heavily on proper listening tests and, in some cases, more so than on the results printed out by test equipment. The other end is well (?) catered for by the Asian import market!

Yes, and don't forget to extend your vocabulary and perhaps prosody. It's much cheaper than a decent analyzer and could be ultimately much more lucrative, M. Fremer could witness this.
 
Thank goodness for that! I understand; for the record I have to say that I am not a total subjectivist. I certainly do not subscribe to the "neat" snakeoil camp, however I do believe that some magical qualities exist in some playback items which neither you or any of the other scientists and EEs can discern from measurement. Some can discern such sound quality with their ears - Joachim is one and JC appears to be another. I suspect that only those who truly experience music as having soul can hear in this way. Of course the strict measurement approach practitioner may well be unaware of some element in the make-up of audio reproduced sound so can therefore not be expected to measure its qualities. Likewise such reasons may equally well be the result of an extremely small constituent part of design or materials or a combination of such which is simply not measurable even with the best of todays knowledge and instruments....but the ear can sometimes get it more right!
 
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iko

Ex-Moderator
Joined 2008
Big words, small ideas, that's a market too. Another market: impeccable measurements. The continuous implication that many designers are after great profits at any cost is ludicrous, IMHO. Sure, people need to feed their families, but I find it highly unlikely that only a handful of people in this world have integrity.

Sometimes I wonder, can this be the acme (suckers for big words rejoice) of egotism? A complete inability to understand what personal taste is?

Addendum: that being said, I am also against false advertisement, purposeful deceit, and cheating, as I'm sure it does happen with some audio companies.
 
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I sometimes believe what people have to say...it does not in my experience pay to be too cynical. Their awareness of the differences of which I have posted (and extended by edit function) makes them OK in my opinion. That you on your own admission do not place much value on your listening ability tells me several things, but which are true is the real question.

Incidently Nelson Pass is another to add to the list and for the same reasons - these guys actually take trouble to explain their stance and two of them simply do not pontificate.
 
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I am a fool to love you. Billy Holliday

First a quote from an aplication note of Analog Devices concerning intrumentation amps:

"is single-ended with respect to a reference terminal.
Most commonly, the impedances of the two input
terminals are balanced and have high values, typically
109 , or greater. The input bias currents should also
be low, typically 1 nA to 50 nA. As with op amps, output
impedance is very low, nominally only a few milliohms,
at low frequencies.
In contrast, if a standard op amp amplifier circuit were
used in this application, it would simply amplify both the
signal voltage and any dc, noise, or other common-mode
voltages. As a result, the signal would remain buried under
the dc offset and noise. Because of this, even the best
op amps are far less effective in extracting weak signals."

Intrumentation amps intrigued me for a long time.
In my commercial stages i use both the transimpedance and the transresistance version. One of the lowest noise Inamps is the INA163 with 1.0nV/qHz. Considering the feesback resistor it is hard to get any better then 1.2nV/qHz. To circumvent this i use massive paralleling. For example 8 AD797 in the Spiral Groove Phono Stage for a result of 0.5nV/qHz balanced for example. This is good for series production because no sorting and no servo is needed.
In DIY we can efford to use a discreet input. Hfe and Ube matching is time consuming but why not if we do it in our spare time. i looked at posibilities of input biasing and see two major posibilities. One is the classical shunt feedback version that lends itself to an unbalanced input and one is the "direct bias" version that could be a good candidate for balanced operation. The input pair can be cascoded for better PSU rejection but may require some dominant pole compensation. See my 3 concept circuits with default values that do not represent the "real" values. I see no reason why to go to unbalanced immediately after the input stage so fully balnced RIAAs in various disguises are a posibility. I will alaborate on that later.
 

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  • Intrumentation Headamp Balanced Cascode.TSC - TINA.pdf
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Errata. there was a rooting mistake in the cascode version so here comes the real thing.

Further work on the DC coupled Fet MPP:
I studied the instability problem further and also took advice from Jürgen Ultee to give the servo less "authority" as D.Self likes to call it. The situation was the following: the servo supllied ca.1V into 470 Ohm for DC of under 1mV at the output. I changed that for 3.5V into 1.8kOhm. The low level moovement of the cones at insane volume now is minimal. At "normal" level, that means 100dB peaks in my case ( around 25 W), anything more hurts my ears, the naket eye can not detect anything. Surprisingly the sound got better still. I am now totally happy and can imagine that some people prefer the result over the Low Z versions because it is very smooth and human. It definetely sounds like music. I can hear no loss of detail any more still it does not have the dramatic slamm of the Low Z versions. I did not find the time to try the 1kOhm Caddock in comparison to the 3Kohm YAM2. That is on the argenda tomorrow.
 

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Hi Joachim

The balanced version to work correctly as an instrumentation amplifier, you should leave out R12. You only need R11, R15, R13, R5 around OP3.

Isn't R14 a bit large? Is there any reason for this?

Probably you should choose some suitable opamps because most of them are not happy to drive loads as low as 1k or lower (distortion?). Feedback resistors should be considered as part of the output load.

chrissugar

(my first post at diyaudio) :)
 
Hi Chrissuger ! I got a bit confused and have drrawn the resistor after the lower inverterstage double. Sorry! The first version of the cascode should work after removing that resistor in principle. I posted after a long day of work and was a bit tired. When you read my text carefully i put in only default values, so i made all resistors 1kOhm and all caps 1uF and so on. So this circuits are only concepts and i am still working on the "real" values. Sorry again for any confusion. I will first build the balanced, uncascoded version and i have also put more thought into the cascoded version that will eventually include a constant current source. When i have the circuit ready i will post it.
On another issue i have again followed advice from Scott Wurzer to make the input stage of the High Z Fet Headamp trimable. When the cascode transistors are selected for Hfe and Ube using the trimmers can reduce second harmonic and DC offset the same time and not much selecting of the input devices are necerarry.
I think this is very convenient. Thanks for that advice.
 

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