Works both ways John...surely no one knows it all...and quite sure you get inspiration from somewhere as well...why bring stories from 1978 here....trying to frame Ortofon as a stealing company..???
What you and others have done in the past is now the foundation and platform for further developments...It's an ongoing process..target should be that we all get wiser...or at least that's what I hope it is..
What you and others have done in the past is now the foundation and platform for further developments...It's an ongoing process..target should be that we all get wiser...or at least that's what I hope it is..
The Vendetta might not be the easiest MCRIAA to make work either. Sure, my values work the JFETs used, but with other Idss values, some changes will have to be made. Not a beginner MCRIAA.
I will try to figure out how the newer Vendetta will look like schematically with your hints as a base. I will not publish anything, though.
Active+passive as you mention is what I used many years ago and a buddy of mine built a version with top notch components and PS. He still loves it but I actually stopped using active+passive and went over to passive+active or all-in-one RIAA eq. Not sure why I stopped using active+passive....must have some drawbacks....
I always use voltage regulators be it series or shunt. Right now I am getting some help from Salas to make a super low noise version of his shunt regulator.
If you only use passive elements to filter out the noise, how do you then handle AC mains variations (+-10% for ex)? Then the voltages for the amp will vary +-10%. Do you not want rocksolid voltages?
I will try to figure out how the newer Vendetta will look like schematically with your hints as a base. I will not publish anything, though.
Active+passive as you mention is what I used many years ago and a buddy of mine built a version with top notch components and PS. He still loves it but I actually stopped using active+passive and went over to passive+active or all-in-one RIAA eq. Not sure why I stopped using active+passive....must have some drawbacks....
I always use voltage regulators be it series or shunt. Right now I am getting some help from Salas to make a super low noise version of his shunt regulator.
If you only use passive elements to filter out the noise, how do you then handle AC mains variations (+-10% for ex)? Then the voltages for the amp will vary +-10%. Do you not want rocksolid voltages?
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MiiB, I regret telling 'all' about something that happened so many decades ago. It certainly was important to me then, and 'proved' to me that a patent was virtually worthless, if you are a small concern, without the resources to fight it. I also realized that it was my own 'big mouth' that gave away so much, and that I had better learn to close it more.
Now, when pressed here for schematics, perhaps you see my dilemma? IF I give you a schematic, then I am 'responsible' for it. When people who see the schematic and try to implement it, have problems, they come to me. E-mails turn into working on the individual units, myself, and the 'colleague' whining that it cost too much when I sent him the bill for my tech's time, mine being free, for the most part. I guess if I ENJOYED fixing electronics, even my own designs, I would be in 'hog heaven', but I prefer to study from books and articles, rather than putter around with a 'sick' preamp.
Unfortunately, that is MY day job, and I am working on a problem as we speak.
In any case, I was directing my 'history lesson' to Scott, who seems to forget that he was a teenager, when I made these vital discoveries, and it wasn't OBVIOUS then, as to even whether a successful MC pre-amp was even possible or at least practical.
Now, when pressed here for schematics, perhaps you see my dilemma? IF I give you a schematic, then I am 'responsible' for it. When people who see the schematic and try to implement it, have problems, they come to me. E-mails turn into working on the individual units, myself, and the 'colleague' whining that it cost too much when I sent him the bill for my tech's time, mine being free, for the most part. I guess if I ENJOYED fixing electronics, even my own designs, I would be in 'hog heaven', but I prefer to study from books and articles, rather than putter around with a 'sick' preamp.
Unfortunately, that is MY day job, and I am working on a problem as we speak.
In any case, I was directing my 'history lesson' to Scott, who seems to forget that he was a teenager, when I made these vital discoveries, and it wasn't OBVIOUS then, as to even whether a successful MC pre-amp was even possible or at least practical.
Hi,
Far from it. It will be quite some job to make it work correctly.
Same here, except I never really used mixed RIAA for what I would consider my own "designs". With Tubes I only ever use passive, with solid state the headroom penalty is usually so large that I never use passive...
Salas's shunt is quite good as such things go, but as long as you have to have some form of reasonable voltage reference you incur noise penalties.
Why would I want "rocksolid" DC voltages? What benefit do they give in sonic terms, these "perfect DC" supplies. Most circuits can handle a bit of supply voltage variation just fine, if not and your mains voltage is all over, you can get automatic voltage regulators (massive Variacs that self adjust), or build something similar into your gear...
I rarely care much about DC precsion of my supplies (it's easy if I wanted to, but don't see the point), I worry about noise and AC and transient behaviour...
Ciao T
Far from it. It will be quite some job to make it work correctly.
Same here, except I never really used mixed RIAA for what I would consider my own "designs". With Tubes I only ever use passive, with solid state the headroom penalty is usually so large that I never use passive...
Salas's shunt is quite good as such things go, but as long as you have to have some form of reasonable voltage reference you incur noise penalties.
Why would I want "rocksolid" DC voltages? What benefit do they give in sonic terms, these "perfect DC" supplies. Most circuits can handle a bit of supply voltage variation just fine, if not and your mains voltage is all over, you can get automatic voltage regulators (massive Variacs that self adjust), or build something similar into your gear...
I rarely care much about DC precsion of my supplies (it's easy if I wanted to, but don't see the point), I worry about noise and AC and transient behaviour...
Ciao T
Hi,
Tube rectifiers have no minority carriers (nor do schottkies) and the relatively high internal impedance limits the current flow and so ensures reduced steepness of the current pulse slopes.
Schottkies with suitable series resistors or even better stepped schottky rectifiers can be as good...
My DAC has Schottkies and RCRCRCRC filtering (using 4pcs Elna Silmic II 3300uF/50V cap's), at the last cap things are already very DC. Incidentally, I do use a shunt reg for the DAC, my tube output stage is unregulated though.
Ciao T
Tube rectifiers have no minority carriers (nor do schottkies) and the relatively high internal impedance limits the current flow and so ensures reduced steepness of the current pulse slopes.
Schottkies with suitable series resistors or even better stepped schottky rectifiers can be as good...
My DAC has Schottkies and RCRCRCRC filtering (using 4pcs Elna Silmic II 3300uF/50V cap's), at the last cap things are already very DC. Incidentally, I do use a shunt reg for the DAC, my tube output stage is unregulated though.
Ciao T
Ed I'm afraid you lost me on this one, though it scares me that I once got it "right". I just inherited the last two years of AudioXpress so I can catch up.
Scott it's that impressionist thing. Adding a DC bias to a shunt resistor will increase even order distortion. If you have followed what the great ears of the reviewers prefer it is usually as clean as possible except for just a bit of even order color to make the music live. (lyve not liv)
There is always some residual distortion in any circuit, I am not above masking the grungy sounding stuff a bit or even coloring to taste. If this is a compensation for what is lost in the recording process or just my bad taste, it doesn't matter.
Of course when I did a bit at MOMA they had a special extra white paint they used to make the artwork stand out more. So the technique is neither new or of limited application.
Also lets not be so picky as to what has been called impossible by the ignorant, I write virtually only tutorials and it seems some consider it controversial!
Bob, 10uh or 50uh, available today not a big point. It might be more interesting to see what was available back when JC first did his first design.
But ED it's still a balanced circuit and it can't have even order distortion. Back to a "bit" being -130dB too BTW.
Did you see Jim Williams' article on a -160dB oscillator? I can't wait to see the schematic, though I doubt it will be 100% naked Vishay and Teflon caps (but never know).
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I haven't seen the circuit, but if there is a single resistor used in the grounded shunt mode that should add the color. Yes -130db re a V or so is about right.
Matching the MOMA white paint required a special base paint that had less binders than more durable commercial paints and an under coat that just might have had a very small amount of blue!
I have seen the oscillator references. I had a bad day Friday as I was building a small oscillator as a piece of gear and all it wanted to do was amplify! (Did figure out where I was being stupid on Sunday.)
The interesting thing about such low distortion is the feedback mechanism. I found it interesting that in my resistor tests many of the resistors had more distortion than what is produced by current op-amp circuits! I read those tea leaves as monolithic ratiometric resistors are much better than last time I paid attention.
Dear Scott,
That is true only if the "balance" is perfect.
I have yet to make (or see) a single balanced circuit that does not have even HD, no matter how well we match components, even monolithic IC's do not seem immune, despite making all transistors and resistors on the same silicone...
Ciao T
That is true only if the "balance" is perfect.
I have yet to make (or see) a single balanced circuit that does not have even HD, no matter how well we match components, even monolithic IC's do not seem immune, despite making all transistors and resistors on the same silicone...
Ciao T
T,
Three guys are walking down the street. One of them says twenty-two. The others laugh. Another guys says yeah seventeen. All three laugh. An onlooker with a puzzled look on his face asks them, "Excuse me but what is it you are laughing about?." One explains they have been together so long they all know each others' jokes and stories, now they just refer to them by number. So the onlooker asks if he can try it. They agree. He says "Nineteen." No one laughs. The onlooker inquires why. One of the group looks a bit embarrassed and explains "Well it is the way you told the joke!"
You are correct there is never a perfect balance, but Scott and I have some history so at least I try to get the meaning and not be picky about the limiting case, unless of course it is funny to do so.
ES
Three guys are walking down the street. One of them says twenty-two. The others laugh. Another guys says yeah seventeen. All three laugh. An onlooker with a puzzled look on his face asks them, "Excuse me but what is it you are laughing about?." One explains they have been together so long they all know each others' jokes and stories, now they just refer to them by number. So the onlooker asks if he can try it. They agree. He says "Nineteen." No one laughs. The onlooker inquires why. One of the group looks a bit embarrassed and explains "Well it is the way you told the joke!"
You are correct there is never a perfect balance, but Scott and I have some history so at least I try to get the meaning and not be picky about the limiting case, unless of course it is funny to do so.
ES
A good bridge circuit with high quality resistors can do -180dB. Ed's example will have 2nd's so far down it doesn't really mean much.
Yes Scott,
One of our disagreements. My design goal is -160db re peak operating level. I am reasonably confident under some conditions -90 can be picked out by some critical listeners in some system combinations. How much lower I don't know.
Have you ever determined a level you are comfortable with?
ES
Let's not, Ed you are welcome to demonstrate -90dB number but ..... Here's a fun circuit. The simplest possible (I think) .4nV, 40dB or so head amp. Suitable for headshell mounting and phantom power. Cin and Rb can be traded off for low end noise/cost. .33uF and 5G Ohms works pretty well. The rest of the values need to be tweaked to split the supply and run the FET at around 5mA. MC only in this form due to input C though one might be able to work a cascode FET in there.
EDIT nope THD is only good for MC.
EDIT nope THD is only good for MC.
Attachments
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Looks like expresspcb's schematic program. (You missed a connection at Rb)
So how do you convert to jpeg?
Screenshot
I usually don't bother with the T connection, from now on I'm going to have Jan redraw all my schematics.
This was intended originally as an improvement (I hope) on the front half of the pre-amp in the Levinzon IEEE paper. With his current-in second stage it might work for MM. Just playing around.
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