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_at_galibier_design
Hi Ralph, Jonathan, Raul ...

Back to our regularly scheduled programming. This is good stuff ! I need to take it in small chunks.

This concept of immunity from input overload is a critical one. Listen up to these wise folks folks.

If you're scratching your head and wondering if you screwed up your tonearm setup (or if your cartridge is unable to track a passage), try borrowing another RIAA stage ... hopefully one which is known to be both immune to input overload as well has having a lightning fast slew rate (the ability to respond quickly to transients without overshoot).

If you're not practiced at listening for this, you may well assume you have a mechanical issue to resolve (cartridge or tonearm setup) when the real problem may be with your electronics. Don't beat yourselves up about your setup skills until you validate what you're really hearing.

Cheers,
Thom @ Galibier
A quick note on riaa fm practical experience only. The necessities: Overload margin, stabilised power, fully corrected and stabilised curve, channel identicity. The last two are more than just difficult -- they're horrendously painstaking, boring (think of "trimming" to get the "right" R -- and once you get there, you realise that your next pole is off...), and expensive: anyone ever try to really "match" components? -- and I don't mean those that do this for a living... Goodness! Trying to match the 1st stage loading before riaa was a trial... let alone further up.

This is only fm a small experience trying to make my own phono as, the ones I could afford were miserable and the ones I wanted were out of reach financially.:)
Dear Jcarr: +++++ " Many instruments have very different tonal balances depending on the angle and distance that you listen to them from, and you need to physically put your ears where the microphones are to verify whether what you think you should be getting is really what is inscribed on the LP or not (and don't forget that mikes have different frequency responses from our ears). I am fortunate enough to have friends who are recording engineers and have allowed me to sit by the microphones (sometimes on a ladder!), tap into the mike feed, go back to a normal seat in the audience, listen to the analog tape master on the same day, and then a few days later, listen to the lacquer masters. Very, very educational. I encourage you to search out opportunities to experience this. " +++++

This statement/experience is of paramount importance to understand the statement " truer to the recording ".

A week ago ( during my visit to San Diego ) Norm, Tim and I were talking exactly what you posted: that what we have to " hear " is what the micro's " take " and not want to hear what we perceive at our seat in the hall: that's too different, a lot different.
This is an e-mail that I send to those people following on that subject:

+++++ " De: Raúl Iruegas [mailto:silviajulieta@prodigy.net.mx]
Enviado el: Martes, 20 de Febrero de 2007 12:10 a.m.
Para: 'ctm_cra@yahoo.com'
CC: 'timryanbmw@yahoo.com'
Asunto: Essential 3150.
Importancia: Alta

Dear Norm: Our “ hot “ conversation last night was really “ teaching “ for all of us ( I think ).

I would like to share with you some additional thoughts about:

For many years I asked why the sound of my system was more transparent, better soundstage, tonal balance, etc, etc than the sound that I heard at the music hall, after some time suddenly I “ find “ that the recording microphones have a very different “ seat “ position than mine, it is not only that the microphones are nearest to the source ( instruments and instrument “ room “ area ) but in more “ clean “ environment: Tim, you and me normally seated at 6-8 rows ( 20-25 meter ) where the sound that we perceived against the one that goes through the microphones are truly different ( not only by the distance subject ) for the dispersion ( reflections, diffusion, hall time delay, etc, etc, ) through the absorbing/diffusion of the “ hall environment that includes all the people that surround our seat place.

Now, the sound engineer on the recording process always try to choose the best microphone for its quality reproduction that include ( between other subjects ) very wide frequency response ( this depends on what kind of music they would to recording ) and the lesser frequency range deviation from flat: this means ACCURACY. With out this accuracy the sound recording will be more colored and normally the sound engineer does not want to have a “ colored “ sound session. This same sound engineer choose the best monitor speaker he can get and the main subject a bout is a “ whole “ accurate characteristic monitor speaker, not a colored one ( I hope ).

So, the recording must be an accurate one to the live event.

What is the “ critical mission “ that any ( decent ) phono cartridge has? ( TT/tonearm ), well to try to reproduce what is on the recording in the better accurate manner, with the less distortion/noise/colorations.
This signal that comes from the phono cartridge has to pass through the Phonolinepreamp and this audio device has the “ absolute mission “ to reproduce in an accurate way ( yes I know that other subjects about, but please forgot for the moment ) exactly what the cartridge get from the recording that was made through the microphones that were in a different position that our hall seat that is the way that you like to hear in your home.

Norm, I want that you think in deep about not thinking who is right here but using common sense and trying to help the true music reproduction. It is not a fact that what you like or what Tim and I like but what is the “ true “ or near the truer.

This “ truer to the recording “ accuracy approach does not means : analytical, cold, polite, lean, etc, etc sound reproduction, that I´m sure the Essential 3150 does not have, it must be accurate and “ pleasant “ and this is what we have to look when any one heard the Essential 3150. I´m not saying that the Essential 3150 already achieve that goal in a perfect manner but it is very near to that target.

In my humble opinion all the music lovers must support that kind of audio devices design approach because in that manner all of us could help to the music and most important could help to growing up faster the quality reproduction on the high-end audio device performers: any.

Anyway, we really had a great time during my visit.

Kind regards.
Raul. " +++++

Regards and enjoy the music.
Raul.
Raul, this is a different thread. I have just read your same post in your Essential thread. Why do we need two Essential threads. Please give us a break.
Thom attempted to start a new thread exploring some very interesting ideas regarding phono stages in general. Several designers have responded and have made this a great thread for some of us to learn new things about design philosophy. Please, please give it a rest.