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
Thom, a replay curve that deviates more from the RIAA standard can sound better on select recordings, but it will almost certainly also sound worse on other recordings, compared to a replay curve that deviates less. My experience is that a flat RIAA curve is likely to allow you to enjoy more of your LP collection, not less. If 0.1dB or better is possible, go for it, as I think that on the whole, you will be ahead. The one categorical exception is when an LP contains sampling noise (sometimes CRT monitor noise). There are albums by Kraftwerk and Lorie Anderson that have this which I find painful. Everything sounds find until the sampler kicks in, and then I look for a wad of cotton, or wish that I'd designed an RIAA playback network that shelved down the top end (grin).

As an aside, the other possible solution for an RIAA playback curve would be to implement an EQ trim control, like with the FM Acoustics designs, or maybe a Cello/Viola Pallette. I've listened to and played with both, and yes, I can see their point.

I also find that a theoretically "better" solution - better power supply, better regulators, better amplification circuitry etc. will nearly always improve the sound of nearly every LP that you own. I don't find that "more accurate" means that you become more picky about the LPs that you can find enjoyable. Yes, you may become more aware of recording, EQ or mastering issues, but the music and performance comes through even more strongly, more than enough to overwhelm trivial concerns about the recording. The better my designs become, the more I appreciate a greater number of musicians.

I do find, however, that when it comes to component selection, you have to use your ears and subjective taste, in addition to your head. I've picked components that on paper should have been the cat's meow, but in listening turned out to be a pig's kiss instead. The designer cannot know each minute particular of every component that he chooses, and as they say, the devil is often in the details. So unlike the case with overall topology or circuitry or layout, with components I find it necessary to have a "range of candidates" on hand and go with whatever sounds the best - in the context of the circuit being tested. Engaging in this is more like cooking or choosing clothes than it is intellectual design, and is the phase where the more artistic types can strut their stuff, and pull level with or even ahead of other designers who may be their intellectual superiors. That's the fun part about audio (designing it as well as using it) - there is a place for the sensibilities as well as the intellect.

regards, jonathan carr
Dear Thom: With this I'm finish:

+++++ " Your "it has to be perfect" mantra is really tiring me out " +++++, that's what I posted: we are different in this subject but I can asure you that we have more in common than differences about sound/music reproduction.

+++++ " I'm sorry, Raul but as good as the Essential is, it is as colored as many of the other fine RIAA/line stages I rank in the top tier (and the Essential is a fine piece). " +++++

Absolutely, I never speak that it is not only that we try to leave those distortions/bad colorations at minimum, that's all.

+++++ " Please get over it and realize that no one can be all things to all people " +++++

Absolutely, I don't think in other way: I agree.

+++++ " Regarding Audio Puritans, " +++++

No. I'm not: I'm only trying to be better.

+++++ " a very lean and modern sound. " +++++

No, it is not ( I don't know what means " modern sound " ): the sound perception depends on the whole system and my point of view about is that our design is very high revealing of what happen in all the audio chain because that design does not hide almost anything out there, of course that the Essential is part of that audio chain and puts its " grain of salt " about.

The diffrences is how you, other people and I perceive the sound reproduction in an audio system and how be related against the live event or at least near to the recording.

Our attitude/philosophy in the electronic audio design is: truer to the recording and you can't blaim me for that, it is only a way to think that is a little different from yours and other people but there are other people that think in the same way that us: our design goes for that people and we will wait that the other people could change ( a little ) in the future, no our design is not for all in the same manner that horns speakers are not for every one.

Thom, thanks to our differences we have some fun and we can learn a lot about those differences, don't you think?

Regards and enjoy the music.
Raul.
Raul:
Our attitude/philosophy in the electronic audio design is: truer to the recording and you can't blaim me for that
You probably mean "truer to the reference riaa de-emphasis curve". Whihc, hopefully, means closer to the recording. After all, the phono equaliser only equalises whatever is picked up by the TT setup and transfered through the wire & connectors...:)

BTW, Raul, do you have an added pole at 3,18us as well as 75us?
Dear Greg: You are right.

yes, we added the 3.18us pole. You can choose it with an internal " switch ".

Regards and enjoy the music.
Raul.
Thanks, Jonathan.

You've filled in the blanks better than I could hope to do, so I won't elaborate (too much). I completely agree with you that there is a difference between hearing flaws in a recording and being annoyed by them. A very good friend of mine runs a Lyra Olympos cartridge which exhibits exactly these positive attributes.

Perhaps a good mechanical analogy to what we're discussing lies in tonearms. A world-class tonearm can allow the turntable and cartridge to better do its thing by more effectively dissipating resonances. In being less resonant (perhaps a better term is "appropriately or artfully resonant"?), you can hear more of the music in the groves while at the same time ticks and pops fade to black much more quickly and become less annoying ... more of the good stuff and less of the bad.

The conversation about RIAA tolerances as well as the frequency width that you and Jose have been exploring is a provocative one. I think that all of us agree (at least no one has corrected me on this point yet), that getting low RIAA deviations is not so much a design constraint as it is one of labor and parts cost (component matching) to achieve the correct turnover points.

The meaningful threshold beyond which RIAA deviation becomes "specs-manship" and nothing more is what Jim and I were calling into question. I can't say for certain where this response threshold is, but your comments about the ear's higher sensitivity to electronic colorations over mechanical ones (speaker, room interaction, etc.) makes much sense, but still doesn't tell me whether .05% is just enough or if it is excessive overkill.

On a related issue, I'm curious about any psychoacoustic effects as far as the width of a frequency response deviation is concerned. I suspect we have several different thresholds along a continuum.

What I mean is that a very small width deviation might go unnoticed, whereas a slightly wider deviation (but still a spike) might be perceived as an anomaly, and a slightly wider band deviation may well be masked, or blended in. As Jose commented, these wider band colorations may well take some long term listening in order to be recognized and become potentially bothersome.

Some of the Lamm electronics exhibit such a wide band coloration which is quickly recognizable in completely different system contexts. While the gear is highly resolving, the colorations are very noticeable. I would never criticize someone for loving a Lamm, BTW, otherwise I'd have to own up to being an Audio Puritan (grin).

I have no insight into psychoacoustic experiments on this subject, and if someone does, I'd be interested in learning about it.

As Jim Hagerman (I think it was Jim) commented, we have to start from a technically correct baseline if we have any hope of coming up with a design that inspires us. I think everyone is in agreement that excellent technical performance is a necessary but NOT SUFFICIENT condition for greatness.

The good news (for me) is that when I get lost in a design change, my astute, musically trained wife drops by and immediately tells me whether we have music or merely hi-fi. Many of us are lucky to have perhaps the finest measuring tool known to man ... a smart, sensible wife who understands the goal of hi-fi.

And yes Raul, Jose's brilliant effort is one of those very fine, top-tier components which achieves greatness. I have difficulty simplifying my English to help you with many of the subtleties in my writing.

I try to be clear ...

It made perfect sense to compare component colorations to those of concert halls. The language has been in our hi-fi vocabulary for some 30 years. I look at the term modern in a component to be analogous to the frequency bias of many modern concert halls like Avery Fischer. As an aside, I've heard that Portland has a fairly new concert hall that resembles many of the fine halls of the past with more of a mid-bass and lower midrange center of gravity.

Unquestionably, the Essential is Avery Fischer Hall, and I've received quite a few private e-mails to back me up on this. Is Avery Fischer a bad hall? Absolutely not. Do some people prefer the hall in Rochester, NY (can't remember its name). Certainly.

Back to our regularly scheduled programming ...

Cheers,
Thom @ Galibier