What Makes a Good RIAA or Line Stage?


Hi Doug,

In a currently running thread on a certain RIAA / Line stage beginning with the letter "E", some very provocative comments were made that are of a general nature.

I fear that this conversation will be lost on the many individuals who have soured on the direction which that particular thread has taken. For the purpose of future searches of this archive, those interested in the "E" thread can click this link.

For the rest of us who are interested in some of the meta concepts involved in RIAA and Line Level circuits, I've kicked this thread off - rather than to hijack that other one. In that thread, you (Doug) mused about the differences between your Alap and Dan's Rhea/Calypso:

... the Alaap has the best power supplies I've heard in any tube preamp. This is (in my admittedly unqualified opinion) a major reason why it outplayed Dan's Rhea/Calypso, which sounded starved at dynamic peaks by comparison.

Knowing only a bit more than you, Doug, I too would bet the farm on Nick's p-s design being "better", but know here that "better" is a very open ended term. I'd love to hear Nick's comments (or Jim Hagerman's - who surfs this forum) on this topic, so I'll instigate a bit with some thoughts of my own. Perhaps we can gain some insight.

----

Power supplies are a lot like automobile engines - you have two basic categories:

1. The low revving, high torque variety, characteristic of the American muscle car and espoused by many s-s designers in the world of audio.

2. The high revving, low torque variety characteristic of double overhead cam, 4 valves per cylinder - typically espoused by the single-ended / horn crowd.

Now, just as in autos, each architecture has its own particular advantage, and we truly have a continuum from one extreme to the other..

Large, high-capacitance supplies (category 1) tend to go on forever, but when they run out of gas, it's a sorry sight. Smaller capacitance supplies (category 2) recharge more quickly - being more responsive to musical transients, but will run out of steam during extended, peak demands.

In my humble opinion, your Alap convinced Dan to get out his checkbook in part because of the balance that Nick struck between these two competing goals (an elegant balance), but also because of a design philosophy that actually took music into account.

Too many engineers lose sight of music.

Take this as one man's opinion and nothing more, but when I opened the lid on the dual mono p-s chassis of my friend's Aesthetix Io, my eyes popped out. I could scarcely believe the site of all of those 12AX7 tubes serving as voltage regulators - each one of them having their own 3-pin regulators (e.g. LM317, etc.) to run their filaments.

Please understand that my mention of the Aesthetix is anecdotal, as there are quite a few designs highly regarded designs which embody this approach. It's not my intent to single them out, but is rather a data point in the matrix of my experience.

I was fairly much an electronics design newbie at the time, and I was still piecing my reality together - specifically that design challenges become exponentially more difficult when you introduce too many variables (parts). Another thing I was in the process of learning is that you can over-filter a power supply.

Too much "muscle" in a power supply (as with people), means too little grace, speed, and flexibility.

If I had the skill that Jim Hagerman, Nick Doshi, or John Atwood have, then my design goal would be the athletic equivalent of a Bruce Lee - nimble, lightning quick and unfazed by any musical passage you could throw at it.

In contrast, many of the designs from the big boys remind me of offensive linemen in the National Football League. They do fine with heavy loads, and that's about it.

One has to wonder why someone would complicate matters to such an extent. Surely, they consider the results to be worth it, and many people whom I like and respect consider the results of designs espousing this philosophy of complexity to be an effort that achieves musical goals.

I would be the last person to dictate tastes in hi-fi - other than ask them to focus on the following two considerations:

1. Does this component give me insight into the musical intent of the performer? Does it help me make more "sense" out of things?

2. Will this component help me to enjoy EVERY SINGLE ONE of my recordings, and not just my audiophile recordings?

All other considerations are about sound effects and not music.

Cheers,
Thom @ Galibier
128x128thom_mackris
The above is true only for the standard Lipshitz method of EQ. If EQ is split across two stages (the way I do it, for example), then the switch is possible.

Quite easily in fact (with the right topology). The 3.18 us turnover point is an extension to the RIAA de-emphasis curve, whose purpose is to compensate for the practical considerations that the RIAA neglected when the standard was created. In this case, that the cutting heads at the mastering facilities were unable to pre-emphasize up to infinity, but instead they were only garanteed up to a certain frequency. The Neumann heads used this turnover point, and they have always been very popular. Many LP masters were cut with this heads.

The 3.18 us turnover causes a phono stage to stop its rolling-off of the treble at a frequency of roughly 50 kHz, which in turn causes an added sensation of "air" in the reproduction. However, this tool should be used carefully because some MC cartridges generate too much ultrasonic energy (ringing) when excited by the cliks and pops in the record.

On a scope display, the ringing looks like decaying high-frequency tones superimposed on the audio signal. Although this tone is beyond hearing, it could potentially cause trouble to the amplifier or speakers.

In my opinion, the solution is to have the option available with a switch, and leave the choice to the listener. This provided that the manufacturer actually understands that the 3.18 us is a zero in the transfer function, not a pole as some designs Raul and I have seen!
In my opinion, the solution is to have the option available with a switch, and leave the choice to the listener. This provided that the manufacturer actually understands that the 3.18 us is a zero in the transfer function, not a pole as some designs Raul and I have seen!

By this do you mean, there is the RIAA EQ curve and the transfer function is a mathematical way of expressing it. The 50kHz cutter head rolloff is not actually part of that but practically is a LP filter applied after the RIAA EQ in the recording process.

regards,

Stephen
Stephen, exactly. Having the 3.18 us zero in the phono stage simply leaves the response flat after 50 kHz (instead of keeping the roll-off up to infinity). That way it cancels the 50 kHz filter that was not part of the RIAA eq. With all things being equal, the sound would theoretically be closer to that of the master tape (or the live event in case of a direct-to-disc recording).
This thread made me re-visit the interface between the cart and the phono preamp. My thanks to Jonathan Carr for his insight on this. It has taken my preamp onto a new level.

cheers,

Stephen
Daer Thom,

After speaking with you yesterday I revisited this thread as you suggested in reference to the cartridge being or not being a balanced component. I am convinced that there is no downside to treating the source pickup as integrely balanced. I think the wiring of the tonearm from cartridge clips straight through to the phono pre line stage is the best way to exploit what potentialy can be a sound advantage in a fully balanced system.

I think that the advantages of a fully differental balanced system with first rate Phono Stage design intergrated into the Line stage to avoid signal degredation through interconnects in concert with seperate stand alone dedicated power supplies says a lot about what makes a good phono pre line amplifier.

I am so glad I did take a second look The first time I was here it left my head swimming trying to understand the logic of the technical positions presented here. I have learned no small amount since then, I understand more yet I still am content to just soak it up and keep listening to all the points of view.

Some things may feel repetitious at times but my experience is one of participents trying to achive clarity and understanding of the ideas they expound and, in this thread particularly, add detail and nuance to them in the process.

Thank you for taking the high road and encouraging the serious conversation we have enjoyed on this thread.

Now something I do have an area of expertise in is the venues of New York City. Avery Fisher Hall is best for theatre not music. Full of dead spots and more bounce then a pensy pinky. It is a failed experiment that an acoustic remodling failed to cure. The New York State Theatre and The Met are architectural monuments of beauty but not sound. Carnegie Hall has the BMT train running underneath it (besides practice its the best way to get there).

Now Town Hall is nice, it once housed the NY Philharmonic and Metropolitan Opera. It is a preferred medium sized venue. A while back I saw Elvis Costello and the Brodsky Quartet perform the Julliet Letters there. Very intimate yet a very large sound.

It is a shame that the plans to move the Met and Lincoln Center as part of a downtown arts center rebuilding the Ground Zero Battery Park area never bore fruit. IM Pei or Frank Gehry was supposed to design it.

The Opera Houses of Europe like the Concertgebouw in Amsterdam, the Gustav Mailer Hall in Viena, and La Scala Opera, these are made for Music.

In NYC give me Upstairs at Max's, CBGB's, the Fillmore East, the Lennox Lounge, The Blue Note, The Village Vanguard,The Ritz, Bonds, Irving Plaza The Cotton Club, the Bottom Line and the Apollo Theatre.

If I had to think of the place I'd like my system to sound like it would be the Electric Circus back in the sixties on Saint Marks Place. When Hendrix was recording across town at Electric Ladyland Studio he would play with everyone there. He once said if I could just get whats in my head out on stage or on the record it would be far out., but I just can't do it man.

BTW Thom did you know that on the Beatles first American tour ticket sales were poor at Red Rocks so they canceled a show, but they sold out the Hollywood Bowl twice, but I have digressed.

Thanks again

Groovey Records

Listening to
Stravinsky-The Firebird-Anatal Dorati-London Symphony Orchestra
Original Mercury Living Presence SR 90226