Im connecting two speaker in series for rear speaker 2*4ohm. this will give 8 ohm.But I have poor quality speaker cable.when measure near the amp the total resistance together with rear speaker and cable is around 20 ohm.Sud I change my cable.
Unfortunately this URL is death.Try here.
Thank you for this URL.No changes necessary, AFAIK. The tone circuit output needs to see a high impedance. The 1M seen in the LM1875 datasheet app should be enough, or another op amp stage.
How far can it help? That can be hotly contested. I'm convinced tone controls can help SQ. And I follow the rule that if tone controls need to be turned way up, something else is wrong with the system. I have maybe +4dB on the treble and +1 for bass (I'm sure I have eardrum scar tissue from a bout with meningitis. Tinitus also. Hence the treble boost.). And they stay there. If a particularly worse recording gets played, I'm almost always reaching for the volume knob. That's rare though.
If you don't think tone controls are just for sissies, you might want to have a look at this thread: A usable tone control
I am looking for comercial available high quality preamplifiers and integrated amplifiers include such a tone control unit.
Which brands are here a good choice?
Last edited:
Similar topic - other thread:
http://www.diyaudio.com/forums/solid-state/21307-looking-very-good-tone-control-schem.html
http://www.diyaudio.com/forums/solid-state/21307-looking-very-good-tone-control-schem.html
I was interested in making a tone control for my amplifier project. The Baxandall filter looked attractive for its ease and passiveness. I just analyzed the phase response of the Baxandall tone control with source impedance of 500 ohms. There is noticeable phase shifts in the high and low frequencies at various pot settings. Did I do something wrong or is this inherent in this design?
excuse me my bad english - the correct term is of course "most ultimate" and not "Ultimatest"Ultimatest (R) Integrated Power Amp.
Nice one!
Many thanks to the moderators for changing the headline for topic (for better finding at a later time).
Last edited:
an alternative toncontrol solution to Baxandall's approach:
http://www.diyaudio.com/forums/solid-state/44834-quad-44-preamp.html#post3355215
For a special application I want to create on half of Baxandall's approach - those half for treble boost. Therefore I have found follow proposal:
Treble boost - found under fig. 4 by
http://www.angelfire.com/electronic/funwithtubes/Amp-Tone.html#Amp-Tone-Primitive-4-back
and attachment here.
Theory of operation (quotation from mentioned URL):
On the left is an input terminal which connects to the grid of a triode, 12AX7.
The grid goes to ground through a 470 k ohm resistor.
The cathode goes to ground through a 1.8 k ohm resistor.
The plate goes to B plus two through a 100 k ohm resistor.
The plate also connects to one end of a 0.1 microfarad capacitor.
The other end goes to the top of a 500 k ohm pot.
The bottom end goes to a point labeled output.
The output point goes through a 47 k ohm resistor to ground.
The wiper of the pot goes through a 330 pf capacitor to the top of the pot.
This one gives about 14 dB of boost.
Oddly enough it requires a linear pot rather than the audio taper of the other circuits.
Also as shown the pot will work backward unless it is reverse wired.
The capacitor can be connected from the wiper to the output terminal without any change in performance.
That makes the pot work forward.
I will reduce resistors and enhance capacitors by factor 100, because the previous driver stage can deliver 1A output current. Instead the potentiometer I will use an ELNA rotary switch. Additional rotary switch I will use for variation the lower cut-off frequency (determining of the frequency, from those I want to get treble boost).
Maybe someone has an idea of what one can take also into account like the variation of the degree of slope etc.
Thank you for advices.
http://www.diyaudio.com/forums/solid-state/44834-quad-44-preamp.html#post3355215
For a special application I want to create on half of Baxandall's approach - those half for treble boost. Therefore I have found follow proposal:
Treble boost - found under fig. 4 by
http://www.angelfire.com/electronic/funwithtubes/Amp-Tone.html#Amp-Tone-Primitive-4-back
and attachment here.
Theory of operation (quotation from mentioned URL):
On the left is an input terminal which connects to the grid of a triode, 12AX7.
The grid goes to ground through a 470 k ohm resistor.
The cathode goes to ground through a 1.8 k ohm resistor.
The plate goes to B plus two through a 100 k ohm resistor.
The plate also connects to one end of a 0.1 microfarad capacitor.
The other end goes to the top of a 500 k ohm pot.
The bottom end goes to a point labeled output.
The output point goes through a 47 k ohm resistor to ground.
The wiper of the pot goes through a 330 pf capacitor to the top of the pot.
This one gives about 14 dB of boost.
Oddly enough it requires a linear pot rather than the audio taper of the other circuits.
Also as shown the pot will work backward unless it is reverse wired.
The capacitor can be connected from the wiper to the output terminal without any change in performance.
That makes the pot work forward.
I will reduce resistors and enhance capacitors by factor 100, because the previous driver stage can deliver 1A output current. Instead the potentiometer I will use an ELNA rotary switch. Additional rotary switch I will use for variation the lower cut-off frequency (determining of the frequency, from those I want to get treble boost).
Maybe someone has an idea of what one can take also into account like the variation of the degree of slope etc.
Thank you for advices.
Attachments
Last edited:
I suppose even within the best Baxandall design there will be some 'inaccurate' phase and frequency behaviour
what else is to be expected from a filter ?
I plan to use it as integrated part of active xo 😀
what else is to be expected from a filter ?
I plan to use it as integrated part of active xo 😀
I suppose even within the best Baxandall design there will be some 'inaccurate' phase and frequency behaviour
what else is to be expected from a filter ?
I plan to use it as integrated part of active xo 😀
This I know. But most important to know is the fact, that audible effects rises up by the phase and frequency behaviour of the whole audio system for the reproduction and the whole recording system (created at a previous step).
This means, all exist kinds of tone control/equalizer topologies provides not in all cases disadvantages by listening tests.
I try to help with my treble boost a guy, which had losses the high-frequency hearing in a for me unknown kind.
Last edited:
what you say now sounds more like using medicine with sideeffects, and adding further medice for it
or live with small side effects if the medicine is a needed cure
is that what we usually call 'compensating for errors' ?
or am I reading you wrong ?
or live with small side effects if the medicine is a needed cure
is that what we usually call 'compensating for errors' ?
or am I reading you wrong ?
what you say now sounds more like using medicine with sideeffects, and adding further medice for it
or live with small side effects if the medicine is a needed cure
is that what we usually call 'compensating for errors' ?
or am I reading you wrong ?
My english is in general not the best and particularly concerning hearing aid stuff very very bad.
I don't understand also this:
"medicine with sideeffects"
The aim is indeed to compensate the unwanted owner's ear/brain low pass function - according the graph from user's consultant.
Successes in this matter I doubt very much - but I want to test it nevertheless.
frequency response from all tone control positions of Luxman's L550
Who can upload the graphs/curvatures of any test review from this amp device?
Thank you very much
Who can upload the graphs/curvatures of any test review from this amp device?
Thank you very much
Mr Douglas Self say here : Douglas Self Site
"Tone-controls cause an audible deterioration even when set to the flat position."
-This is usually blamed on "phase-shift". At the time of writing, tone controls on a preamp badly damage its chances of street (or rather sitting-room) credibility, for no good reason. Tone-controls set to 'flat' cannot possibly contribute any extra phase-shift and must be inaudible.
According to my observations over the years only the following causes for this undesired effect (i.e. the sound deterioration) come into question:My view is that they are absolutely indispensable for correcting room acoustics, loudspeaker shortcomings, or tonal balance of the source material, and that a lot of people are suffering sub-optimal sound as a result of this fashion. It is now commonplace for audio critics to suggest that frequency-response inadequacies should be corrected by changing loudspeakers. This is an extraordinarily expensive way of avoiding tone-controls.-
And I agree with him 100% !
Actually I have idea to experiment and implement this Luxman`Duo Beta
` tone control circuit on the one of mine older conventional designed DIY PP tube power stereo Amp, simply returning GNFB loop from OPT outputs via tone control circuitry to the input tube differential gain stage ,in the same manner as Luxman did on the countless number of SS integrated commercial Amps .
Best Regards
1) with extra gain stage for bass-treble unit:
- additional sound signature due integrated or discrete operational amp stages
2) without extra gain stage for bass-treble unit (i. e. network for bass-treble unit in the NFB loop of power amplifier):
- not unity-gain stable and thus sometimes unwanted superimposed RF oscillation
Independent of this ordinary cheap parts concerning high impedance bass/treble potentiometer and small sized polyester capacitors makes sound character muddy, which is often clearly noticeable when the tone defeat switch is pressed. Effects by phase shift are inaudible because slope is max. 6db/oct. - so I think (minimum phase character).
Only the use of a low-impedance NFB network for the tone control unit with ELMA 04 rotary switches and high-quality KP capacitors in combination with a unity-gain stable power amplifier avoids the audible disadvantages of tone control.
P.S.: in post #1 I have updatet some URL's
Last edited:
What find annoying is that very few baxandall active designs considered to have at least a small overall gain for the op amps then they complain of phase shift, poor psrr, cmrr unless they use very expensive op-amps...Way too many active Baxandalls wired for unity gain...
If you're into discretes you'll hardly find anything better than this:
http://www.hifi-classic.net/review/realistic-sta-2250-262.html
If you're into discretes you'll hardly find anything better than this:
http://www.hifi-classic.net/review/realistic-sta-2250-262.html
Attachments
Last edited:
The Quad 33 is one such, although executed with discrete components. Gain of 5 around the Baxandall stage.
But I take exception to the title of this thread, which contains two internal contradictions. There is no such thing as a passive Baxandall tone control, and the so-called 'James-Baxandall' topology is a fiction.
But I take exception to the title of this thread, which contains two internal contradictions. There is no such thing as a passive Baxandall tone control, and the so-called 'James-Baxandall' topology is a fiction.
the terms "active" and "passive" often define different meanings.The Quad 33 is one such, although executed with discrete components. Gain of 5 around the Baxandall stage.
But I take exception to the title of this thread, which contains two internal contradictions. There is no such thing as a passive Baxandall tone control, and the so-called 'James-Baxandall' topology is a fiction.
An active speaker box e. g. can mean that the power amp is integrated in the speaker enclosure.
But for me an active speaker means
1) the filter stage is located in front of the power amplifier stage and
2) the filter components are arranged as a positive feedback (Sallen-Key) or negative feedback (MFB) network around an operational amplifier stage.
Even in cases, where this unit operates as outdoor unit.
But maybe I am wrong even on this.
In case of this Baxandall tone control network for me "passive mode" means, this network operates between two linear gain stages and "active mode" means, the network operates in the NFB network of a gain stage - sometimes even the gain stage is the power amp itself (like Luxman L550).
What is from your view the right naming of topology for tone control unit as mentioned here ?
https://audiohertz-com.translate.go...tr_sl=en&_x_tr_tl=de&_x_tr_hl=de&_x_tr_pto=sc
'Active' means there is a necessary active gain element. 'Passive' means there isn't. Active is different from passive, but neither of them individually can mean different things.the terms "active" and "passive" often define different meanings.
See above. QED. I don't know what else it could mean, but I'm open to suggestion.An active speaker box e. g. can mean that the power amp is integrated in the speaker enclosure.
No. That would be a passive speaker using an active crossover before the amplifier. It doesn't have to use PF or a Sallen-Key topology to satisfy that criterion. The speaker itself is two stages away from being active.But for me an active speaker means
1) the filter stage is located in front of the power amplifier stage and
2) the filter components are arranged as a positive feedback (Sallen-Key) or negative feedback (MFB) network around an operational amplifier stage.
Sure. That makes the Baxandall stage active, and the James network passive, and the so-called 'James-Baxandall topology' a meaningless fiction. It comes from one term paper by an undergraduate in South America that should have been taken down years ago.In case of this Baxandall tone control network for me "passive mode" means, this network operates between two linear gain stages and "active mode" means, the network operates in the NFB network of a gain stage - sometimes even the gain stage is the power amp itself (like Luxman L550).
He is talking about the Baxandall, active, tone control. No mystery.What is from your view the right naming of topology for tone control unit as mentioned here ?
https://audiohertz-com.translate.go...tr_sl=en&_x_tr_tl=de&_x_tr_hl=de&_x_tr_pto=sc
Interesting. Completely new to me. Until now I assumed that Peter James Baxandall was the inventor of this kind of tone control. Has this already been discussed in detail here?'Active' means there is a necessary active gain element. 'Passive' means there isn't. Active is different from passive, but neither of them individually can mean different things.
See above. QED. I don't know what else it could mean, but I'm open to suggestion.
No. That would be a passive speaker using an active crossover before the amplifier. It doesn't have to use PF or a Sallen-Key topology to satisfy that criterion. The speaker itself is two stages away from being active.
Sure. That makes the Baxandall stage active, and the James network passive, and the so-called 'James-Baxandall topology' a meaningless fiction. It comes from one term paper by an undergraduate in South America that should have been taken down years ago.
He is talking about the Baxandall, active, tone control. No mystery.
Independent of this, the words for "active" and "passive" are almost identical in German and English, but colloquially in both languages - partly depending on the context - sometimes different.
In English for me is a loudspeaker with integrated power amp a so called "Powered Box" - independent of the used kind of crossover network.
- Home
- Source & Line
- Analog Line Level
- Ultimatest Passive Tone Control Network based on James-Baxandall's topology wanted