And I will add something here in favour of the electronics designers from Japan. When we had discussions with them about the designs which we especially made for them for use in their I.C.'s, they showed their excellent knowledge and design skills concerning electronics circuit designing and electronics theory.
So, for me it it hard to accept that they designed "cheap cludge" that time back in the late 60's and early 70's of the past century. Perhaps those designs may make a somewhat old fashioned impression when looking at these circuits now but, to speak of for instance a "MESS with Power Amp frequency response and stability." is a little bit too harsh. You have to realize that in those days all calculations had to be done by hand (that is also the way I started to do in the early days as a designer). Especially calculations concerning the stability of an amplifier were a real "pain in the neck" those days.
So, for me it it hard to accept that they designed "cheap cludge" that time back in the late 60's and early 70's of the past century. Perhaps those designs may make a somewhat old fashioned impression when looking at these circuits now but, to speak of for instance a "MESS with Power Amp frequency response and stability." is a little bit too harsh. You have to realize that in those days all calculations had to be done by hand (that is also the way I started to do in the early days as a designer). Especially calculations concerning the stability of an amplifier were a real "pain in the neck" those days.
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I hink it was mostly a marketing "audiophile "choice along with the more linear newly launched CD players to scrap those types of tone controls as purists started to claim at some point that they need no tone control, although all the amps i have seen with this type of tonestack have the ability to completely bypass it,
@Joe Alders:
"And that is just the way I am doing it now in my latest headphone amplifier design.
"
Unlike RJM i am using the true LH0002 military version for my switched buffer... The first buffer is the original Class AA buffer, the second is LH0002 when i untie the input of lh002 from the output.The first voltage gain op-amp is njm2043 , the second is LM6172 as two in parallel can drive 50 ohms cans without output series resistors.With two LH0002 in parallel in circuit you can drive any dynamic headphones on the planet.
https://www.diyaudio.com/forums/ana...hones-amplifier-equalization.html#post6324926
"And that is just the way I am doing it now in my latest headphone amplifier design.
"Unlike RJM i am using the true LH0002 military version for my switched buffer... The first buffer is the original Class AA buffer, the second is LH0002 when i untie the input of lh002 from the output.The first voltage gain op-amp is njm2043 , the second is LM6172 as two in parallel can drive 50 ohms cans without output series resistors.With two LH0002 in parallel in circuit you can drive any dynamic headphones on the planet.
https://www.diyaudio.com/forums/ana...hones-amplifier-equalization.html#post6324926
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Hello, it's true but with minor modifications, you can design a baxandall tone control without frequency shift according the wiper position. I maybe saw this in the following documents:
- Small Signal Audio Design, 2nd Edition, 2014, By Douglas Self
- Audio-Radio Handbook (National Semiconductor 1980)
Bonus : TL082 Application - Amplifiers forum - Amplifiers - TI E2E support forums -> There is a TINA-TI (free) simulation file.
Well I did say 'nearly all', and what I was commenting on was the claim that 'they use it in the NFB of amplifier (mostly)' rather than in the preamp. One swallow does not a summer make.ejp: I guess you never came across any Kenwood amps (KA-1000) for instance, or the like, which used those types of "feedback" tone controls.
They ARE out there.
original bax circuit (in the 1952's article) was in the NFB of valve but a passive version exists (this is the james tone stack tab in the TSC software). The passive version shall use Log potentiometers. Linear are better for active version.Did you read Baxandall's paper. He's all about the NFB.
Clearly most folks here do not want to think in terms of math.
You can always use CCW pots(counter clockwise log) pots with caps and resistors with a 10 to 1 ratio to get a flat position with a gain of 20db ie 10x. Crown did this in the IC150 preamp. I also did it in the 70's when tape decks and tuners put out 0.250 Volts or so. CCW pots are harder to find.
Not again please. The James control predates the Baxanlall by several years and is not a version of it in any way shape or form, nor the converse. They are completely different beasts. The need for log vs linear pots is evidence enough on its own.