Here is a link https://www.angelfire.com/electronic/funwithtubes/Amp-Tone-A.html to some tone control circuits that show the Baxandall circuit as +/- 20 dB ... a little less inside a feedback loop. Whether +/- 10 dB or +/- 20 my point is that tone controls lend themselves to analog solutions because with digital solutions you lose headroom and with DSP room correction headroom is all ready in short supply in the digital domain. The problem with analog solutions is you are dealing with expensive or dodgy pots and multiple op amps. Either a or digital or analog solution with "knobs" is expensive and complicated which is why most manufacturers are happy with the current fashion of no tone controls. While good for the manufacturers (save money and say it is better) I don't think it is great for the consumer.
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JBL SA750: Dirac, Class G, Roon Ready, Phono, and REAL KNOBS
- Thread starter watchnerd
- Start date
Anyone, any ideas when this is going to be out? I am looking to build a mid-range Hi-Fi system based on that or the Rotel RA-1592MKII. None of these are on the market yet 
My plan is:
JBL SA750 or Rotel RA-1592MKII
Dali Oberon 9
Pro-Ject Debut Carbon EVO
My plan is:
JBL SA750 or Rotel RA-1592MKII
Dali Oberon 9
Pro-Ject Debut Carbon EVO
Skeptischism
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They probably do indeed add a bunch more than 10-20db of distortion
I dont lament them disappearing, in any kind of calibrated system, they add much more than complication and expense. there is no reason you coudnt use an impulse response to emulate the best tone controls ever made; its common-place in the audio post production chain.
that being said, a nicely made standalone tone control might be a good seller.
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They probably do indeed add a bunch more than 10-20db of distortion
I dont lament them disappearing, in any kind of calibrated system, they add much more than complication and expense. there is no reason you coudnt use an impulse response to emulate the best tone controls ever made; its common-place in the audio post production chain.
that being said, a nicely made standalone tone control might be a good seller.
The problem with tone controls in the digital domain in a domestic setting is that they can really eat into gain headroom.... especially if you are using room/ speaker EQ. The other issue with digital filters is how do you fine tune them? It is tough to beat a knob for making real time adjustments. With all the complications and expense and the inevitable added distortion I see why manufacturers have stopped with tone controls but for me I find them very useful. My usual use case is for playing very loud or very low... bass goes up when playing low and down when playing very loud... there is no way one FR Curve is preferred for all listening levels .... Fletcher–Munson figured that out a long time ago. As far as distortion goes I can completely switch out my pre-amp from the signal chain and as you say I am sure I am adding 10 -20 db or more of distortion with the pre-amp (compared to my DAC by it's self) but I can't hear the distortion but I can hear the FR adjustments.
mononoaware
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Someone please correct if I am wrong, but Class-G performs as Class-A at low gain then switches to Class-AB after a certain point (on the volume knob).
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Well that sounds and looks interesting...
https://www.whathifi.com/us/news/jbl-sa750-is-a-modern-retro-class-g-amplifier-with-streaming
But I don't even know what Class G is.
A Class-G amplifier improves upon the efficiency of a Class-AB design by using multiple rails at different voltages to amplify the input voltage more efficiently. NAD seems to be one that used it early on (the NAD 2200 & [sister at the time] collaborating with Bjørn-Erik Edvardsen (“Erik”) (NAD designer) Proton D1200 are examples). A Class-H design goes further by using a rail of infinitely variable voltage (Benchmark ABH2)
A Class-G amplifier improves upon the efficiency of a Class-AB design by using multiple rails at different voltages to amplify the input voltage more efficiently. NAD seems to be one that used it early on (the NAD 2200 & [sister at the time] collaborating with Bjørn-Erik Edvardsen (“Erik”) (NAD designer) Proton D1200 are examples). A Class-H design goes further by using a rail of infinitely variable voltage (Benchmark ABH2)
The max I have ever seen is on both of my pair of Apt/Holman PreAmps
Check out:
https://www.kenrockwell.com/audio/apt/holman-preamplifier.htm
I also understand that AMIRM may be measuring one soon. ('soon' being relative to the backup). AMIRM does a heck of a job getting to all the things that we keep shipping to him. Maybe we can clone him so that he will have some help.
EJ3
