Scott,
Fred wrote about it in the article with the schematic, APARENTLY it is not causing problems in practice. Others have build this and it seems to work fine and quite reliably so...
Ciao T
Fred wrote about it in the article with the schematic, APARENTLY it is not causing problems in practice. Others have build this and it seems to work fine and quite reliably so...
Ciao T
Hi,
It is a choice indeed.
However, respectfully disagreeing with John, I do feel that there is much that can be gained using a decent EQ and using it well... Way back when... I wrote a review of a Pro Audio digital EQ and this includes examples of how I used the EQ...
Behringer Ultracurve Pro 8024 Digital Equaliser by Thorsten Loesch
The classic Baxandall Tone controls are rather limited, compared to a real EQ. So full "re-mastering" of recordings, especially where the midrange is messed up is not possible.
But they do serve well for a "pinch less treble" or a "soupcon more bass" or "unboom this Rap track"... They should not be set up for +/-20dB boost though, I would +/-6dB at 100Hz/10KHz are more usable...
The effect of the tilt control is easily simulated using a Baxandall Bass/Treble (bass up/treble down or reverse), but having the ability for example to simultaneously cut bass and treble (modern Rap and Pop often needs that) puts the Baxandal ahead of a single tilt...
John, as I am personally "Pro-EQ" (as in pro-choice) I have spend considerable time looking at ways in which Tone Controls and EQ may be made less complex and more high performance. Much interesting material is found in older Japanese gear.
I think this is a very interesting topic, but not one that should be pursued in this thread. So I would suggest that anyone wishing to seriously discuss "High End Tone Controls" moves into a new thread (maybe the Mod's could move the discussion here to make a start?) and I'm happy to drop in some of the stuff I found over the years.
I would however say that only one of your counter arguments is valid and that is that of cost. To get to the same quality for tone controls as for the rest of a chain they need to be made of same quality level componentry, which is not cheap, but does not have to be ruinously expensive either...
And if one will not use an EQ or Tone Control, there is no point paying for one.
Yes, being "pro-choice" (not in the sense of family planning, but generally) I often note that it is always to have something (Equaliser, Headache pills, Body Armour, Gun) and not needing to use it, compared with needing to use it and not having it. And just having it does not oblige it to use it...
With PC playback becoming more common and analogue sources rapidly going the way of the Dodo and the 12 year old Virgin the problem has largely moved into the software domain and I think I personally will focus my efforts in that domain, especially on the Usability and Player integration side, as decent software EQ's have existed for a long time...
Ciao T
It is a choice indeed.
However, respectfully disagreeing with John, I do feel that there is much that can be gained using a decent EQ and using it well... Way back when... I wrote a review of a Pro Audio digital EQ and this includes examples of how I used the EQ...
Behringer Ultracurve Pro 8024 Digital Equaliser by Thorsten Loesch
The classic Baxandall Tone controls are rather limited, compared to a real EQ. So full "re-mastering" of recordings, especially where the midrange is messed up is not possible.
But they do serve well for a "pinch less treble" or a "soupcon more bass" or "unboom this Rap track"... They should not be set up for +/-20dB boost though, I would +/-6dB at 100Hz/10KHz are more usable...
The effect of the tilt control is easily simulated using a Baxandall Bass/Treble (bass up/treble down or reverse), but having the ability for example to simultaneously cut bass and treble (modern Rap and Pop often needs that) puts the Baxandal ahead of a single tilt...
John, as I am personally "Pro-EQ" (as in pro-choice) I have spend considerable time looking at ways in which Tone Controls and EQ may be made less complex and more high performance. Much interesting material is found in older Japanese gear.
I think this is a very interesting topic, but not one that should be pursued in this thread. So I would suggest that anyone wishing to seriously discuss "High End Tone Controls" moves into a new thread (maybe the Mod's could move the discussion here to make a start?) and I'm happy to drop in some of the stuff I found over the years.
I would however say that only one of your counter arguments is valid and that is that of cost. To get to the same quality for tone controls as for the rest of a chain they need to be made of same quality level componentry, which is not cheap, but does not have to be ruinously expensive either...
And if one will not use an EQ or Tone Control, there is no point paying for one.
Yes, being "pro-choice" (not in the sense of family planning, but generally) I often note that it is always to have something (Equaliser, Headache pills, Body Armour, Gun) and not needing to use it, compared with needing to use it and not having it. And just having it does not oblige it to use it...
With PC playback becoming more common and analogue sources rapidly going the way of the Dodo and the 12 year old Virgin the problem has largely moved into the software domain and I think I personally will focus my efforts in that domain, especially on the Usability and Player integration side, as decent software EQ's have existed for a long time...
Ciao T
Once, 25 years ago, I built an all fet preamp with a set of Baxandall tone controls. My associates, including Saul Marantz, himself, decided that we would limit the peak high frequency output to 10dB, rather than 20 dB, as was usual.
I made it, measured it, and delivered it to New York, where the rest of the company was. I get a call, AND they accused me of not giving them a full 10dB high frequency peak. I asked, 'Did you measure it? They said NO, but they were sure that 10dB boost would be much more obvious. Well, that's life. You never know.
I made it, measured it, and delivered it to New York, where the rest of the company was. I get a call, AND they accused me of not giving them a full 10dB high frequency peak. I asked, 'Did you measure it? They said NO, but they were sure that 10dB boost would be much more obvious. Well, that's life. You never know.
25V breakdown is not great for a discrete, maybe the process was improved and it's not reflected in the DS.
Fred knows what he is doing.
I tested a few J74's a few weeks ago that were good to around 60V.
Obviously I am not suggesting working up to this but it gives indication of
the ratings conservative nature.
cheers
T
About eight years ago I measured all of the Toshiba JFETs that we use, six in all. I only measured one random sample of each type. The actual breakdown voltage ranged from 1.4 to 1.8 times the voltage rated on the datasheet.
The J74 I measured at 42 volts, which is 1.7 times the datasheet rating. If push came to shove and the only way to create a circuit was to over-volt a Toshiba JFET, I might use one of these parts at 1.2 times the rated voltage. Normally I never use semiconductors at more than 0.8 times their rated voltage, although there are a couple of parts that we use at their rated voltage.
If your sample measured at 2.4 times the rated voltage, I would say that you got an oddball or else you are measuring them differently than I or Toshiba do.
Transients and hearing
This sounds very interesting...
I completely agree with you. Transient is the most important part. Music is made of transients. Ear is continuously immersed in lot of transients that sorround it in the real life.
Every musical note of every musical instrument is completely defined by 4 time parameters: Attack, Decay, Sustain and Release.
Measure how the audio reproduction chain affects these parameters, expecially Attack, and you will be on the right track to correlate what is heard.
Measure how much the Attack is "distorted": you will discover that it's orders of magnitude more than any THD, IMD, etc.: ear is very sensitive in time resolution. Many and many time more than in frequency.
This sounds very interesting...
I completely agree with you. Transient is the most important part. Music is made of transients. Ear is continuously immersed in lot of transients that sorround it in the real life.
Every musical note of every musical instrument is completely defined by 4 time parameters: Attack, Decay, Sustain and Release.
Measure how the audio reproduction chain affects these parameters, expecially Attack, and you will be on the right track to correlate what is heard.
Measure how much the Attack is "distorted": you will discover that it's orders of magnitude more than any THD, IMD, etc.: ear is very sensitive in time resolution. Many and many time more than in frequency.
You make a good point, Ivigone. Many advanced studies of musical reproduction, including high fidelity reproduction denote that we do not take 'transient performance' seriously enough.
What this implies is that single or two tone tests do not give adequate information to completely define musical quality in audio reproduction.
What this implies is that single or two tone tests do not give adequate information to completely define musical quality in audio reproduction.
In the confines of a digital system music can be used as the test signal and the difference extracted :
Distortion Isolation in the Time Domain
Distortion Isolation in the Time Domain
When you take in consideration every single note, each one has a transient: it's this transient, the duration and the time interval between two of them that makes any given sequence of notes a very different musical piece.
Well, I'm a simple diyer, I'm not a professional or professionally involved in the audio business, so the test I developed is quite rudimental, but effective for my needs.
The story started more than 20 years ago when a friend of mine, who had a wonderfully musical system, asked me to design a power amp to replace the one in his system with a more powerful one, but with the same musicality. My friend built up his system like many audio maniac: he loved electrostatic loudspeakers and started by exchanging many hi-end pre and power amp up to his complete satisfaction. His musical taste was very well educated, so the results he got from his system was of very high level, one of the best I ever heard.
I had a reference to start, but the task was very difficult: I spent more than 6 years during which I built many prototipes and made many mistakes before to understand why that power amp sounded marvellously in his system (I repeat: in his system. In real life the absolute doesn't exist).
The light started to glow-up after reading H.F. Olson book: Music Phisic and Engineering. Attack, Decay, Sustain and Release concepts entered in my brain.
I started to think about a test to verify the transient performance of an amp. First of all I needed a test signal with some features that can be used to check the transient performances of the device. I ended up with a shaped pulse, only one pulse, with all of the harmonics well inside the audio band. Years before I built Bill Waslo Imp, presented on Audio Amateur, for testing loudspeakers and, by the chance, this instruments had the signal for my job.
By using only one pulse for the test (I didn't want periodic signal, but a single transient signal, like a musical note), I needed a mean to display that signal: a Tek 5115 storage scope was elected for the task.
End of the story: when I was able to replicate the same pulse from my amp like the reference amp, the two amps sounded exactly the same!!
That was the starting of a new trip that has never ended.
John, I wondered why this happen. I have an engineering background, so I was biased by my studies when I faced with the why of differences between musical reproduction devices.
It takes me a long before I was able to open my mind and to try to run on new roads. Have you ever asked you why we are able to immediately (usually less than 2 seconds) identify if the music that we hear while walking on a street, is reproduced or live?
Try to ask "WHY?" 5 times and you will got the real truth.
Single or two (or even more) tone tests don't give much informations: the musical note of an instrument is very rich of harmonics and the ear is not able to separate the added one in a musical piece. It's able to separate them only with steady pure signals, not with music. So, according to me, these tests are not really useful to understand the performances of an audio device.
Joachim, what is the difference between the yellow and the blue tracks?
This is two channels of a sound card. One channel is shifted in frequency and you can see the crosstalk. This is only for illustration. I have shown on my MPP thread how i measure dynamic distortion. Problem is that for example a stage made with an AD797 and with not too much gain does not show any kind of serious distortion, no matter what signal i throw at it and still some people prefer the sound of simple discrete circuitry for example with tubes that show all kinds of sins when you put in an artificially generated signal of what ever complexity. Something else is going on with perception that we may not fully understand. If you have found a transient signal that if reproduced exactly by two different amps and makes them sound exact alike i would nominate you for the Nobel Price.
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