John Curl's Blowtorch preamplifier part II

[Telstar]

Originally Posted by Esperado

I don't know. My actual preamp and power amplifier have 1000V/µs of slew rate, and low IM distortion. I can reasonably suppose they do not produce too much of TIM ?
Really, i cannot explain why i do not like any (good) tweeter. May-be more a question of acoustical coherency due to filters.
Anyway, most of us are too old, here, to can experiment in a useful way: we need young girls to talk about HF limits.

I font really have an idea. It could be phase shifts in the vocal range (but if you add a tweeter above 15k it shouldn't have any), or its not the speakers but the dac. Did u try with analog?

Btw I'm 35 and I can hear up to 19k.

[fas42]

Originally Posted by Telstar

Btw I'm 35 and I can hear up to 19k.

I'm lucky enough, or kept well enough away from sound nasties so that I can still pick up 18kHz. It's borderline, have to focus a bit for it to register, but it's there. I make sure that when I sense the telltale signs that the ears have had enough, to back off ...

Perhaps one reason why I'm still so fussy ...

Frank

[elektroj]

Originally Posted by Esperado

And i will add a ADC to deal with my analog sources.

Do you mind to tell us which ADC specifically it will be?

[qusp]

Originally Posted by BV

Sorry, but this is IMO very "suboptimal" solution.

you really have to do better than that. tell us your secret....

[john curl]

Don't give away more than you are comfortable with, BV. '-)

[Esperado]

Originally Posted by elektroj

Do you mind to tell us which ADC specifically it will be?

AKM 5394 ?

[qusp]

Originally Posted by john curl

Don't give away more than you are comfortable with, BV. '-)

then dont say anything at all if you arent prepared to share a more 'optimal' solution

[BV]

Esperado, qusp
Citation from oldier Wolfson white paper , claryfying my word "suboptimal"

Drawback of digital volume control is that the signal-to-noise ratio (SNR) worsens at low volumes. This is due to the quantisation error, which is inherent in any digital system and may result in audible noise. Its magnitude depends on the resolution of the digital audio data and/or the DAC. High-end audio systems are designed such that any noise is negligible compared to the magnitude of the audio signal, and therefore inaudible. However, when volume control is performed in the digital domain, the digital audio signal’s amplitude may be decreased by several orders of magnitude while quantisation noise remains constant, resulting in a lower SNR

Always will be regulation in digital domain acompanied with relative increasing of quantizations errors and partially loosing of informations. You can manipulate 16 bit data with 32 bit resolution, but if you need e.g. 20dB attenution, lower valid data from original information get lost. That is why I prefer regulation in analogue domain, with fixed resistors ,at lowest acceptable impedance, and relay network. This solution offers best linearity and lowest own noise.
Whole pdf is in attachment, I can not find it currently on webspace.

[fas42]

People have this bizarre notion that somehow analogue S/N is always "magic", but digital S/N is bad, really bad. Well, I have yet to be offended by "poor" digital S/N, but my ears have been savaged by vile, offensive analogue S/N far, far too many times ...

Frank

[PMA]

In case that some like it masked, then please go on with volume bit reduction and/or high noise analog stages. The details would be lost and the ear may be pleased