John,
Sure.
The standard of the RECORDING INDUSTRY ASSOCIATION of AMERICA standard, which several RIAA Members of significant commercial impact in the market simply ignored for much of the 50 Years. So it is a standard only in the mind of those who like to have an easy way out.
In the actual reality it is not a standard at all.
Actually, standards other than RIAA existed worldwide (especially CCIR in Europe). EQ Cards certainly for Neumann Lathes where available.
East Germany had several DMM Lathes (and subcontracted a lot of cutting for west german companies in the 1980's) which had EQ cassettes that where interchanged between RIAA and CCIR in the 80's depending which market the issue was intended for (unless someone forgot to switch the cards when they should have, so some west german pressings have CCIR instead of RIAA and some east german pressings have RIAA instead of CCIR as a result).
Decca in the UK had a long tradition of either scratch buidling their gear or substantially modifying commercial stuff. Many US "Audiophile" Labels replaced the electronics of the Lathe's wholesale, I know some commercial labels other than Decca also did varying levels of modifications.
The PH-77 specifies and meets it's spec of less than +/- 0.5dB deviation from the RIAA EQ 20Hz to 20KHz and less than +/-0.25dB 100Hz-10KHz. This curve can be readily switched to without problems.
Do you have any problems with a RIAA Response that is +/-0.5dB? I don't.
If you check how many Phono Stages reviewed in Stereophile have more deviation than that you may understand why I feel that this spec is sufficient.
Phono Preamp Reviews | Stereophile.com
What you seem to object to is that I deliberately designed the shape of the deviation to be something I wanted, to give certain overall result when implemented in a Phono Stage. So instead of aiming for absolutely flat with the less than +/-0.1dB guaranteed deviation that I COULD have implemented in the design, using the same components, I choose to introduce a deliberate "trend" (still a very minimal one).
Yet your Vendetta as measured by Stereophile also does not offer a truely flat response but a similar tilt (no, I am not copying you), the tilt is less pronounced than the one in the PH-77 but both "trend the same way".
Maybe you also object to the fact that I deliberately adjusted the distortion spectrum of the Phono for a certain ratio between even and odd harmonics instead of simply going for the lowest THD?
In the end you design your gear according a set of goals you have, I design according to mine.
Mine included a specification that had a RIAA EQ (and other EQ) deviation of less than +/-0.5dB.
You may opine that this is not flat enough, I may opine that it is more than flat enough, there is no simple conclusion to that.
The customer will decide if he prefers to buy a Phono Stage specified as +/- 0.1dB RIAA EQ Error or +/- 0.5dB or if he perfers to listen to it and decide what he likes the sound of better or even if he likes a different manufacturers Phono that has more 3dB deviation from a flat RIAA response (trust me, there are plenty).
So did you, right?
No, I have no interrest in "HiFi". HiFi does not sound like music, it sounds like HiFi.
To me all is "fair game" as long as the results justify it.
John, let us be clear again, we are talking about a frequency response deviation of less than +/-0.5dB.
That is 0.7dB more deviation than the sample of the Vendetta Stereophile measured.
But it is also 0.5dB less than one other manufacturers phono, 1dB less than two other manufacturers phonos, 2dB less than a fourth manufacturers phono and 3dB less than a fifth manufacturers phono (all measured by Stereophile).
Now Speakers & Room produce response deviations of > 20dB for a "flat". Speaker response. Now "flat" Speakers do not exist, even ones that do 50Hz-10KHz +/-3dB in room with a lot of averaging are rare. So even the worst "offenders" WRT to RIAA Response will see their effect mostly swamped by speakers and room.
Please retain some sense of perspective.
Ciao T
Sure.
The standard of the RECORDING INDUSTRY ASSOCIATION of AMERICA standard, which several RIAA Members of significant commercial impact in the market simply ignored for much of the 50 Years. So it is a standard only in the mind of those who like to have an easy way out.
In the actual reality it is not a standard at all.
Actually, standards other than RIAA existed worldwide (especially CCIR in Europe). EQ Cards certainly for Neumann Lathes where available.
East Germany had several DMM Lathes (and subcontracted a lot of cutting for west german companies in the 1980's) which had EQ cassettes that where interchanged between RIAA and CCIR in the 80's depending which market the issue was intended for (unless someone forgot to switch the cards when they should have, so some west german pressings have CCIR instead of RIAA and some east german pressings have RIAA instead of CCIR as a result).
Decca in the UK had a long tradition of either scratch buidling their gear or substantially modifying commercial stuff. Many US "Audiophile" Labels replaced the electronics of the Lathe's wholesale, I know some commercial labels other than Decca also did varying levels of modifications.
The PH-77 specifies and meets it's spec of less than +/- 0.5dB deviation from the RIAA EQ 20Hz to 20KHz and less than +/-0.25dB 100Hz-10KHz. This curve can be readily switched to without problems.
Do you have any problems with a RIAA Response that is +/-0.5dB? I don't.
If you check how many Phono Stages reviewed in Stereophile have more deviation than that you may understand why I feel that this spec is sufficient.
Phono Preamp Reviews | Stereophile.com
What you seem to object to is that I deliberately designed the shape of the deviation to be something I wanted, to give certain overall result when implemented in a Phono Stage. So instead of aiming for absolutely flat with the less than +/-0.1dB guaranteed deviation that I COULD have implemented in the design, using the same components, I choose to introduce a deliberate "trend" (still a very minimal one).
Yet your Vendetta as measured by Stereophile also does not offer a truely flat response but a similar tilt (no, I am not copying you), the tilt is less pronounced than the one in the PH-77 but both "trend the same way".
Maybe you also object to the fact that I deliberately adjusted the distortion spectrum of the Phono for a certain ratio between even and odd harmonics instead of simply going for the lowest THD?
In the end you design your gear according a set of goals you have, I design according to mine.
Mine included a specification that had a RIAA EQ (and other EQ) deviation of less than +/-0.5dB.
You may opine that this is not flat enough, I may opine that it is more than flat enough, there is no simple conclusion to that.
The customer will decide if he prefers to buy a Phono Stage specified as +/- 0.1dB RIAA EQ Error or +/- 0.5dB or if he perfers to listen to it and decide what he likes the sound of better or even if he likes a different manufacturers Phono that has more 3dB deviation from a flat RIAA response (trust me, there are plenty).
So did you, right?
No, I have no interrest in "HiFi". HiFi does not sound like music, it sounds like HiFi.
To me all is "fair game" as long as the results justify it.
John, let us be clear again, we are talking about a frequency response deviation of less than +/-0.5dB.
That is 0.7dB more deviation than the sample of the Vendetta Stereophile measured.
But it is also 0.5dB less than one other manufacturers phono, 1dB less than two other manufacturers phonos, 2dB less than a fourth manufacturers phono and 3dB less than a fifth manufacturers phono (all measured by Stereophile).
Now Speakers & Room produce response deviations of > 20dB for a "flat". Speaker response. Now "flat" Speakers do not exist, even ones that do 50Hz-10KHz +/-3dB in room with a lot of averaging are rare. So even the worst "offenders" WRT to RIAA Response will see their effect mostly swamped by speakers and room.
Please retain some sense of perspective.
Ciao T
John,
Low frequency is "flat" at 20Hz, only the region around 40Hz is boosted gently, so no loss of LF. Yes, 10Hz is 3dB down, arm resonances are usually around 8Hz, ideally I should have had a steeper filter there, but that does not sound good.
If you know how records are cut you know than anything at real low end is filtered with a steep filter (you actually cannot cut it, mechanically) plus, it's Mono anyway.
Perhaps my fault is that I know how records are and where cut and within reason adjust my designs to complement this, even it that means they vary somewhat from any given theoretical ideal or standard.
Ciao T
Low frequency is "flat" at 20Hz, only the region around 40Hz is boosted gently, so no loss of LF. Yes, 10Hz is 3dB down, arm resonances are usually around 8Hz, ideally I should have had a steeper filter there, but that does not sound good.
If you know how records are cut you know than anything at real low end is filtered with a steep filter (you actually cannot cut it, mechanically) plus, it's Mono anyway.
Perhaps my fault is that I know how records are and where cut and within reason adjust my designs to complement this, even it that means they vary somewhat from any given theoretical ideal or standard.
Ciao T
Hi,
The information derives largely from exactly the same inaccurate article (in 1955 Audio IIRC) and is hence at least in part wrong. For a more accurate view:
Manual of analogue audio restoration techniques by Peter Copeland
Ciao T
The information derives largely from exactly the same inaccurate article (in 1955 Audio IIRC) and is hence at least in part wrong. For a more accurate view:
Manual of analogue audio restoration techniques by Peter Copeland
Ciao T
A sad story- long ago I somehow acquired a Fisher preamp, model lost to history. It had a beautiful gold colored front panel. The only thing I really remember is that it had a knob for various different phono equalization settings, riaa and others. One quick wipe with some alcohol on a cloth, and all the markings were completely gone. It made me so sick to look at it, I either cannibalized it or tossed it. A lesson in restoration learned the hard way.
Thank you ThorstenL for the links. Helpful as always.
No ThorstenL.
Sy is in principle against opinions presented as facts (luck of sufficiently supporting data).
And when he senses that the other person has the potential, he is purposely persuading to get this extra juice out for the benefit of all.
Otherwise he is an ordinary DWYL person
YouTube - Blind Faith Do What You Like
I don’t think that I am way off if I say that both of you do feel an ease with the lyrics of this song (different paths may be)
YouTube - Porgy & Bess - It Ain't Necessarily So
Regards
George
Hi,
No worries, glad to help.
This is not the impression I am getting, so perchance we part company here on Sy.
I do tend to quote this song myself. Here a recent example:
State of the Union - Asynchronous USB DAC - Caveat Emptor - Thorsten - DIY HiFi Forum
Some other songs in that as well...
Ciao T
No worries, glad to help.
This is not the impression I am getting, so perchance we part company here on Sy.
I do tend to quote this song myself. Here a recent example:
State of the Union - Asynchronous USB DAC - Caveat Emptor - Thorsten - DIY HiFi Forum
Some other songs in that as well...
Ciao T
when looking into this there seems to be so many different curves with different time constants...one vital information I am missing when reading the papers on this, is just how common they are...
In my time of playing vinyl and my collection of vinyl is manly Rock-pop from Beatles and onwards is clearly, but with a steady growing number of classical recordings...also older..I would like the option of hearing the records as intended...
In practical terms I was considering to make 3 to 4 different curves..that then could be switched in and out.. Question is where to start and where to end.. what is the most commonly used of the alternative curves...(apart from the Riaa)..
In my time of playing vinyl and my collection of vinyl is manly Rock-pop from Beatles and onwards is clearly, but with a steady growing number of classical recordings...also older..I would like the option of hearing the records as intended...
In practical terms I was considering to make 3 to 4 different curves..that then could be switched in and out.. Question is where to start and where to end.. what is the most commonly used of the alternative curves...(apart from the Riaa)..
Hi,
You may find reading in the PH-77 FAQ somewhat useful:
Abbingdon Music Research - Information - Frequently Asked Questions
Note that the commonly cited Decca curve is not what was used by Decca in the Stereo LP days (neither did they use RIAA). I'm unaware of any formal documentation for the Decca/DG/Teldec curve (and I'm not telling).
I guess you can work it back from the curves published in Stereophile.
Ciao T
You may find reading in the PH-77 FAQ somewhat useful:
Abbingdon Music Research - Information - Frequently Asked Questions
Note that the commonly cited Decca curve is not what was used by Decca in the Stereo LP days (neither did they use RIAA). I'm unaware of any formal documentation for the Decca/DG/Teldec curve (and I'm not telling).
I guess you can work it back from the curves published in Stereophile.
Ciao T
haha... No giveme..ies...hehe
I'll look closer at the curves...At first glance it seems like the major difference is in the 50-500 Hz shelf...were some of the curves have other time constants..and also the forth constant...which I don't really see as a good idea...or maybe one could put it in and then put a cap over it so the circuit starts rolling off at 100 KHz or so...
Guess the major types are the Riaa, the Decca, the CCir and maybe the DMM/Riaa
Thinking about switching them in/out with a Low Ron Jfet..As my experience with relays an other mechanical switches in the Signal path is rather poor...
I'll look closer at the curves...At first glance it seems like the major difference is in the 50-500 Hz shelf...were some of the curves have other time constants..and also the forth constant...which I don't really see as a good idea...or maybe one could put it in and then put a cap over it so the circuit starts rolling off at 100 KHz or so...
Guess the major types are the Riaa, the Decca, the CCir and maybe the DMM/Riaa
Thinking about switching them in/out with a Low Ron Jfet..As my experience with relays an other mechanical switches in the Signal path is rather poor...
Hi,
Then don't implement it.
The AMR PH-77 allows you select between having it or not. I usually sounds MUCH better with it, good idea or not.
If you think relays are poor, try Fet's for something REALLY bad.
You can try mercury wetted reed relays, get them before the ROHS police does.
Ciao T
Then don't implement it.
The AMR PH-77 allows you select between having it or not. I usually sounds MUCH better with it, good idea or not.
If you think relays are poor, try Fet's for something REALLY bad.
You can try mercury wetted reed relays, get them before the ROHS police does.
Ciao T
Over all switching is a bitch....weather it's inputs, volume controls or like here different attenuation curves..
Have done some comparison on volume controls...and for sure not all relays are good..but as you state.. they may be the lesser bad thing of all the bad things...
Jfet's were just an idea...
Have done some comparison on volume controls...and for sure not all relays are good..but as you state.. they may be the lesser bad thing of all the bad things...
Jfet's were just an idea...
Two relevant products from Hagerman Technology LLC
http://www.hagtech.com/pdf/bugpro.pdf
http://www.hagtech.com/pdf/archiverman.pdf
And some info http://www.hagtech.com/equalization.html
Regards
George
http://www.hagtech.com/pdf/bugpro.pdf
http://www.hagtech.com/pdf/archiverman.pdf
And some info http://www.hagtech.com/equalization.html
Regards
George
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Thanks The Hagerman page posts some additional time constants(frequencies)...and a tool to calculate a two stage voltage riaa as well....
My Riaa has current output to the Riaa circuit that complicates things a bit....I start simming with values from an active feedback shunt...type circuit. and use the Laplace transform Anti Riaa to verify the component values
Still contemplating weather it actually worth having the extra curves implemented...Thinking that the loss in inserting a switch will prevent optimal performance for 95% of my record collection..
My Riaa has current output to the Riaa circuit that complicates things a bit....I start simming with values from an active feedback shunt...type circuit. and use the Laplace transform Anti Riaa to verify the component values
Still contemplating weather it actually worth having the extra curves implemented...Thinking that the loss in inserting a switch will prevent optimal performance for 95% of my record collection..
Hi,
Well, given that 95% of your LP's are post mid 1980's and/or recent reissues, just leave the extra curves out and concentrate on +/-0.1dB or better RIAA.
In my Collection only maybe 5% of LP's are like that though, so I'll take the switches, thank you very much.
BTW, one trick with the switches is to look at the current flowing. If there is no current then there can be no distortion from imperfect contact. If the impedance (source) to which the switch connects is very low, then any capacitive effects will likely be swamped.
Based on that it should be obvious that it matters how switches (any switches) are used, for example, the same switch sitting connected to ground will behave different than the same switch floating.
Equally, a switch that must pass (relatively) a lot of current will behave different than one that passes virtually non. There are so many complex issues in this that need considering.
Ciao T
Well, given that 95% of your LP's are post mid 1980's and/or recent reissues, just leave the extra curves out and concentrate on +/-0.1dB or better RIAA.
In my Collection only maybe 5% of LP's are like that though, so I'll take the switches, thank you very much.
BTW, one trick with the switches is to look at the current flowing. If there is no current then there can be no distortion from imperfect contact. If the impedance (source) to which the switch connects is very low, then any capacitive effects will likely be swamped.
Based on that it should be obvious that it matters how switches (any switches) are used, for example, the same switch sitting connected to ground will behave different than the same switch floating.
Equally, a switch that must pass (relatively) a lot of current will behave different than one that passes virtually non. There are so many complex issues in this that need considering.
Ciao T
For real heresy, why not digital equalization? Now .00005dB is no problem. The Pure Vinyl folks did an AES white paper pointing out that the usual arguement against is not as strong as it seems. Certainly a base equalization with digital tweaking further removes the arguement against digital.
I noticed you quoted "The Beast" a follower?
I noticed you quoted "The Beast" a follower?
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Hi,
The precision of playback EQ for LP and Tape as such was never a particulary difficult problem, since the invention of the HP Pocket calculator.
And they did so by comparing a theoretical 24 Bit recording of a unequalised LP followed by digital EQ to a theoretical 16 Bit recording of a pre-equalised LP.
Actually, I would say given the deplorable state of AD converters it is probably worthwhile to record and store, for archiving, either fully unequalised or at least only partially equalised LP Signals and then doing the EQ in analogue hardware following the D2A.
This way the lack of real resolution at high frequencies due to cheap 12 Bit equivelent or less hardware coupled to aggressive noiseshaping is mitigated against (as it is by increasing the sample rate, assuming the AD converter has a constant rate of oversampling, which many do not), similar to the original CD "pre-emphasis".
Not really.
In order to do this we need all the analogue circuitry of a good phono stage, then a true reference grade AD Converter a PC or DSP and a true reference grade DA Converter just to do what a handfull of decent capacitors, resistors and relays do no worse.
Now if the systems in use accept directly digital signals (e.g. Lyndorf) this situation is somewhat adjusted, but in a system that is mainly analogue, a digital EQ has no justification.
BTW, I used to use a RIAA EQ'ed Phono AND a digital EQ for compensating deviations from RIAA during cutting, speaker/room EQ and additionally for re-equalisation where I felt the need. I no longer use this.
I quote Scientology and Frater Perdurabo (after all, Ron was a follower), Einstein, Ghandi, the Bible, the AlQur'an and Rumi, the Bhagavad Gītā, Jonathan Swift, Lewis Carol, Groucho Marx, Charles Mordechai, Bakunin, Trotsky, from the rosicrucian manifestos and Saint Martin plus many others.
And I am not doing it to demonstrate my erudition, but merely because at times the quotes just seem a perfect fit.
Ciao T
The precision of playback EQ for LP and Tape as such was never a particulary difficult problem, since the invention of the HP Pocket calculator.
And they did so by comparing a theoretical 24 Bit recording of a unequalised LP followed by digital EQ to a theoretical 16 Bit recording of a pre-equalised LP.
Actually, I would say given the deplorable state of AD converters it is probably worthwhile to record and store, for archiving, either fully unequalised or at least only partially equalised LP Signals and then doing the EQ in analogue hardware following the D2A.
This way the lack of real resolution at high frequencies due to cheap 12 Bit equivelent or less hardware coupled to aggressive noiseshaping is mitigated against (as it is by increasing the sample rate, assuming the AD converter has a constant rate of oversampling, which many do not), similar to the original CD "pre-emphasis".
Not really.
In order to do this we need all the analogue circuitry of a good phono stage, then a true reference grade AD Converter a PC or DSP and a true reference grade DA Converter just to do what a handfull of decent capacitors, resistors and relays do no worse.
Now if the systems in use accept directly digital signals (e.g. Lyndorf) this situation is somewhat adjusted, but in a system that is mainly analogue, a digital EQ has no justification.
BTW, I used to use a RIAA EQ'ed Phono AND a digital EQ for compensating deviations from RIAA during cutting, speaker/room EQ and additionally for re-equalisation where I felt the need. I no longer use this.
I quote Scientology and Frater Perdurabo (after all, Ron was a follower), Einstein, Ghandi, the Bible, the AlQur'an and Rumi, the Bhagavad Gītā, Jonathan Swift, Lewis Carol, Groucho Marx, Charles Mordechai, Bakunin, Trotsky, from the rosicrucian manifestos and Saint Martin plus many others.
And I am not doing it to demonstrate my erudition, but merely because at times the quotes just seem a perfect fit.
Ciao T
Thorsten, just to finish up. I can't find ANY vinyl records that I now own that don't use RIAA or very close to it, equalization, including one mono record of Joan Baez (Vanguard) and Harry Belefonte, both recorded in the late 1950's.
However, I can understand your position as well.
Still, IF you cannot guarantee RIAA accuracy to better than +/- .25dB, you are falling into criticism, because YOUR design cannot be accurately be compared to other phono designs. That is a fact. Now, whether your EQ sounds better or worse, is not as important to the objective critics. They don't care about absolute accuracy, just relative accuracy for A-B comparison, but this is where they can lay criticism on your design, and indirectly to the rest of hi end audio.
It is best to have SOME setting that is as accurate to the RIAA as possible, to avoid this.
Overall, your design looks pretty good, and a worthy contender against my newer designs. Digital EQ? Pointless.
However, I can understand your position as well.
Still, IF you cannot guarantee RIAA accuracy to better than +/- .25dB, you are falling into criticism, because YOUR design cannot be accurately be compared to other phono designs. That is a fact. Now, whether your EQ sounds better or worse, is not as important to the objective critics. They don't care about absolute accuracy, just relative accuracy for A-B comparison, but this is where they can lay criticism on your design, and indirectly to the rest of hi end audio.
It is best to have SOME setting that is as accurate to the RIAA as possible, to avoid this.
Overall, your design looks pretty good, and a worthy contender against my newer designs. Digital EQ? Pointless.
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