John Curl's Blowtorch preamplifier part IV

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Luxman have a particular pitch in the market. This quote possibly sums them up nicely
We adopted a peel coat production technique for all of the audio circuit boards, to achieve lower circuit resistance, which can have a negative effect on sound quality. Also, the smooth curves of our non-angled circuit board trace pattern ease the flow of audio signals.


So there you have it. Curved traces are the future!
 
IME the BOM on a transparent DAC should be no more than $100 or so translating into an MSRP of around $500.

Define transparent.

As I posted someone fixed the IMD hump an ESS design with maybe $2 and a little savvy.

No AKM hump to fix.

You would do your cause well to get some test equipment and do some bench engineering.

Sure. Expensive to measure some of the stuff that is audible. Like jitter noise (nondeterministic), for example. Donations gratefully accepted.
 
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I just went thru the costs for limited production. The electronic parts do not cost that much, is true. They are used in many other brands and total mfr is in the millions sometimes.

It is the chassis et al that is unique from brand to brand. And, with a limited production company, will be the major cost. If low volume milled alum, finished heat sinks et al, the cost at retail will be very high.

Then there is the distribution mark-up and retail mark-up and shipping costs.

To quote a 2$ part which is sold to many brands at high volume and imply the end product of a limited production brand should be really cheap.. it doesnt work out that way.


THx-RNMarsh
 
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I never would use Excel for anything, I tried to help someone here trying to use Excel's optimizer for IIR filters (what a nightmare).

It is becoming harder to use excel. Office 365 pushes updates every month or so, changing things, moving things, removing things. Visio, powerpoint, word, excel.. They force us to waste time re-learning how to do things again and again.

Jn
 
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I just went thru the costs for limited production. The electronic parts do not cost that much, is true. They are used in many other brands and total mfr is in the millions sometimes.

It is the chassis et al that is unique from brand to brand. And, with a limited production company, will be the major cost. If low volume milled alum, finished heat sinks et al, the cost at retail will be very high.

Then there is the distribution mark-up and retail mark-up and shipping costs.

To quote a 2$ part which is sold to many brands at high volume and imply the end product of a limited production brand should be really cheap.. it doesnt work out that way.
THx-RNMarsh

For a dac, the case doesn't need to be expensive at all. Even a custom case in small quantities is only a few tens of $$ max.
Of course you can spend crazy money if you want, but it's not necessary.
 
Further to the recent Cymbal posting, I made a 192Khz .wav file containing three frequencies, resp 22Khz, 25Khz and 30Khz, all contained in a 1Khz cosine envelope and separated by 5msec.
I then used a 20Khz Brick Wall FIR filter and subtracted the filtered from the unfiltered signal.

In the image below one can see resp. 1) the Brick Wall filtered signal, amplified by 40dB, 2) the original signal and 3) the difference between the two.

You can see that when having calculated the envelopes, that in that case Gibbs plus three 1Khz cosine signals would have been visible as a difference signal.
But apart from the addition of the Gibbs frequency, the envelopes around these 3 HF signals, do not take part in the sub 20Khz signal as you can see in the upper track.

In the 40dB amplified Brick Wall filtered signal, it's also obvious that the closer the HF signal is to the used Brick Wall frequency, the more violent the Gibbs amplitude.

This was all meant as a further explanation to my earlier posting, that when using just envelopes, a LF component within the Gibbs frequencies in the difference signal may be confusing, giving the impression that the LF part is affected by brick wall filtering, which is definitely not the case.

Hans

Difference2.jpg
 
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