Ok, dumb question. I recently was lucky enough to purchase an ARC Ref Phono 2 SE. It has Options to select RIAA, Columbia and Decca equalization curves.
I realize that most 'modern' recording use RIAA, but when I purchase reissued, remastered pressings of old classical or jazz recordings that were on Columbia or Decca, should I use the corresponding EQ curves, or is that applicable to only the original pressings?
Remastered LPs of original monos will have the RIAA curve even though the original might have used different EQ. BTW most of the alternate EQ settings (Columbia and Decca being two examples) are used for 78s and were never used for LP.
I just purchased the ARC phono stage as well. While I realize RIAA is technically correct, I've found the Columbia eq takes the edge off the bright strings on early stereo Columbia Masterworks recordings. I'm dumbfounded, but it really makes Walter and Szell much more listenable.
The problem with old records is not only RI.A.A. but in many cases also reverse/inverse phase:
"those made in the late 70's & 80's, many labels did not adopt R.I.A.A. curve in the 50's, 60's, 70's and even 80's, that was why even though I had acquired many LPs, half of them did not sound good. Yamada-san further explained to me several years ago in the tube era, big labels such as DECCA, EMI, Deustche Gramophone used their own in-house equalization curve in their recordings and all of them were in reverse/inverse phase, you can easily check this out when you play CDs with old recordings of the abovementioned labels"
Chakster, I can't agree with you on the above statement. The reason why is the labels did not choose the EQ curve. The manufacturer of the cutterhead electronics did. For example we use the Westerex 3D cutterhead and the 1700 electronics. The EQ curve is set by Westerex, not the various and many labels that used that equipment. The same is true of Neumann, who made the lathes and electronics used by many of the European labels.
If you hear differences between the labels (I know I do) its not really because of then not using the RIAA curve (every stereo LP made uses it). Its because that particular label did something to the signal prior to it ever getting to the cutter electronics. A great example is Everest, who had a special tape machine that recorded on 35 mm tape that was the same format as 35mm motion picture film. Turns out they had a bug in the EQ of the recorder that rolled off the bass at 6db/octave starting at 100Hz.
The latter sentence in your quote is simply untrue and is some sort of urban legend. If you think about it you will see why- after the inception of the stereo LP, all phono reproducers had the RIAA curve installed, with a very few preamps made that still included the older mono EQ curves. None of those older curves were used in the stereo era and by 1965 or so there were no more preamps made with the older curves. So where in the heck would the Europeans buy their preamps to play back their LPs with non-standard EQ curves?? The answer is of course that they didn't; all stereo LPs actually employed the same curves.
Does anyone know of a switchable unit which can fit, say in between a phono stage and a line amplifier, to enable switching between these curves? (I have an Aesthetix phono stage feeding an Audio Research line preamp...) Or is there an equalisation circuit that anyone knows of which can be adapted for this purpose?
Vintage, Such a device as you propose would have to operate on an already RIAA-equalized signal from the phono section. That's a whole different kettle of fish from applying an alternative equalization curve within the phono stage circuit itself. You'd be better off (less coloration, less noise, etc) just using bass and treble controls on the linestage, IMO.
Chakster, Ralph's post makes a lot of sense. But I was also wondering about the phase issues to which you refer. The very act of equalizing the signal must introduce capacitors, resistors, and, in some phono stages, inductors into the signal path. This will inevitably affect phase, whether the device or the recording is "vintage", or not.
Phase shift is removed by the act of equalizing. It was put there by the pre-emphasis network during the mastering process. So when you play it back its removed.
Vintageaxeman, The curves referred to in this thread are an urban myth, other than the RIAA curve itself. This is why you don't see switchable EQ curves on modern electronics.
Lewm, I think Chakster was referring to "Absolute Polarity". That will open up a can of worms. Some claim that it makes a difference, others claim that they can't hear any difference. I believe JGH was in the latter camp. I definitely reside in the former. That said, older LPs are all over the map when it comes to polarity. Even new releases do not always hew to the standard. Diana Krall's album "Quiet Nights" comes to mind. The new Eva Cassidy releases which are compilations from various sources has some songs recorded in positive polarity and some in inverted.
If you think about it, air is not a linear medium. One glance at the adiabatic pressure/volume curves of an ideal gas will convince one of that. This results in the asymmetric distortion of the sound wave. Common sense would suggest that inverting an asymmetric wave will change the sound. I guess the take away here is if one's system - ear/brain is sensitive to absolute polarity then it is very handy to have polarity invert on remote control.
The Rek-o-kut Re-Equalizer does what you suggest, i.e., re-equalizes an already RIAA-equalized signal to another EQ curve. It could also be used in the tape loop of a preamp. But it's intended for mono LPs & 78s and sums a stereo signal to mono.
Regarding absolute phase/polarity, on recordings which are heavily multi-mic'd and are subjected to extensive post-processing and mixing (as many and probably most recordings are in recent decades), and assuming that multiple instruments and/or voices were recorded, as I understand it the finalized mix is likely to consist of a conglomeration of randomly phased sounds from each of the performers.
In those cases, while the two polarities may or may not sound somewhat different, it seems safe to say that neither polarity can be thought of as being correct. Maintaining absolute phase/polarity would seem to be meaningful pretty much just on recordings that were engineered with "purist" mic techniques (meaning just two or three mics), and minimal post processing. Such recordings would include many of the classical releases on RCA, Decca, Mercury, etc. during the early years of stereo.
Also, it wouldn't surprise me if in some cases where listeners perceive differences between the two settings of a preamp's polarity inversion switch what they are actually hearing is changes in the sound of the preamp itself, that result from the differences in the preamp's internal circuit configuration between the two settings.
Also, it wouldn't surprise me if in some cases where listeners perceive differences between the two settings of a preamp's polarity inversion switch what they are actually hearing is changes in the sound of the preamp itself, that result from the differences in the preamp's internal circuit configuration between the two settings.
Not the case with my set-up. Polarity inversion just reverses the phono preamp's line out transformer's secondary winding.
We have had a polarity reverse switch on our preamps going back to 1989. I find that it has no effect at all unless the recording is minimally miked. Then it becomes helpful- a lot easier than reversing the speaker cables on both amps!
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