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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
dougdeacon
3,338 posts
 
I my case where this took me was less stages of gain overall. Figuring out what the tubes needed to be quiet was the key.
Ralph, It sounds like you and my friend Mr. Doshi are working from similar briefs, and from experience I know that's a good thing. I haven't heard your preamps but I think I'd like them.

Mothra,
It's great to see you posting here. Thom's thread has collected an impressive group of designers, plus some lucky listeners like you and me.

Your comments on cohesiveness vs. transparency nicely outlined the divide between the majority of rock listeners (I think) and a minority - like you and me - who prefer transparency to the source even for that genre. For better or worse, my ears usually won't let me enjoy a less transparent component once I've heard a more transparent one. I can't stop hearing temporal smear or overhang as an artifact, even if it blends some music or recordings into the appearance of a more seamless whole.

I recognize I'm in the minority on this, at least among rock listeners. It has occasionally gotten me into trouble with them, since we hear or respond so differently. Even Paul, whose ears are faster than mine, prefers a more cohesive sound for rock.

BTW, which B&W's do you have? I recently tried something on my N803's that I hadn't bothered trying for a couple of years - removing the tweeter screens. We've always listened without the mid/bass grilles, but when I removed the tweeter screens two years ago the sound did not improve. IIRC it sounded more shrill. That didn't make sense to me at the time, but I now understand I had HF problems (including smearing) with upstream components and wire. Removing the screens was letting me hear those more clearly.

Our upstream components are now *much* better, including Nick's preamp, amp and nearly everything else. Removing the tweeter screens now provides a large improvement. HF's are clearer and less edgy, imaging/soundstaging are much improved, just what you'd expect from removing all that diffracting wire mesh. Bass clarity has improved too, which I find weird. People report that supertweeters give a surprising boost to bass quality and removing our tweeter screens has had a similar effect. Try it if you haven't.

Sorry for the digression folks. Back to the preamp-a-thon.
Doug
mothra
110 posts
 
Thanks for the kind words, Doug. I tend to be digressive in my posts, so I don't want to mess up the threads when real designers are talking!
I have the B&W 801 matrix series 3 limited edition(which i think is just the finish and the fact they have a plaque that says "abbey road" on them). While the nautilus series smoothed out the tweeter, I find the last matrix series more brutally honest about the treble if not as flattering. I think maybe the matrix series got a little bit of a bad rep because the versions before had protection circuits as they were used in studios and it affected the sound. I thought the last series were great. they have a little lower mid-bass bloom that makes them a little more cohesive for rock and roll than say dulavy's on in the extreme, martin logans (a different animal!).

I just like hearing the details. I think if I didnt have a tube amp maybe the dunlavy's wouldn't see as much action. I also have quad's and spendors which are less precise but very musical. But one gets addicted to the details good or bad, and for me the bad stopped bother me long ago.

My choice of speakers has a lot to do with my work. If I listen to a mix I did and it stands up on the dunlavy's and the 801's then it will generally stand up on "friendier" speakers.

I work cheap and generally in very primitive environments and i often (gasp) use "color" in my recordings. But i want to know what I am doing wrong!

The doshi comments are right on. everything improved in my system and seemed to be more neutral without being to clinical.Or maybe I like clinical I just don't like harsh and thin. Who knows.
piedpiper
753 posts
 
"Since the recording likely does not sound like what you would have heard live from a seat in the audience, if you have set up your audio system to sound like what you'd hear live, it is almost certain that your audio system is modifying what's on the recording, and not in a small way, either!"

Thank you, Jcarr, for stating this so succinctly! As a fellow recording engineer, I have often rolled my eyes at the otherwise authoritative expositions touting a components ability to sound like "The Absolute Sound" of live music. Recordings themselves, often sound like anything but. The bottom line is that it is all relative, although there is some utility in aspiring to neutrality and true transparancy at each step. It can be a elusive path to aspire to, though. With that in mind, there are some recordings that do effectively aspire to natural accuracy, and can, as such, be used as a reference for dialing in a system to sound like live music, as well as exhibiting fidelity to the source, whatever it might sound like.

... and thank you all for being so willing to discuss the inner workings of these issues so candidly. I am both encouraged and discouraged to find the mystery persisting despite all our efforts. Viva la difference!
thom_at_galibier_design's avatar
thom_at_galibier_design OP
729 posts
 
Hi all,

Thanks Jonathan, Mothra, Piedpiper and others for adding some very needed focus and perspective on the variability of the recording process, microphone selection, monitoring, etc. etc.

Ultimately, as Piedpiper stated, we need a small cache of recordings we can rely on to help us map out reality and point the way to the musical truth.

I've found that this doesn't necessarily demand that we depend on unobtanium records from the golden age of recording, although this certainly helps.

You can approximate this by listening to your RECORD COLLECTION ... no small task, I realize.

Now, I don't mean listening to your entire collection, but at the same time, realize that you can effectively interpolate your results by intelligently sampling your collection ... filling in the dots if you will.

You should be reasonably familiar with a collection of recordings - ones which duplicate some well known sounds - be it a tenor, a soprano, a Strad, some drums, a Strat (played through a Tweed Deluxe amp for example).

Now, that SAME tenor will sound completely different depending on the engineer, the mastering, the mike selected, etc., but if you listen to a dozen different records, you'll be able to find a commonality amongst them that will serve you well.

Add to this, your soprano, some strings, horns, drums, and a gee-tahr, and this process of triangulating (a dirty word in politics these days, but helpful in navigating this maze) on reality will take you home.

Is this process perfect? Nope. Will it help you get the most out of your record collection? Yup.

One problem with this method is that any single change in your system will upset the apple cart. Still, if you follow this process with an open and attentive mind, it can serve you well.

Broadening your "reference" record collection will serve another purpose.

It will shift your focus away from having a "shootout mentality" and will force you to be patient. Likely (hopefully) your attention will return to what's really important - MUSICAL COMMUNICATION.

All too frequently, when we use a few "pet sounds" (sorry ... couldn't resist), we focus on those sounds instead of on music.

The digital crowd stops at this point (sound) wondering what all of this analog mania is all about. How sad for them, and indirectly for us, because being the majority, they dictate their sensibilities to the recording process - but that's a whole 'nuther topic.

Cheers,
Thom @ Galibier
doctorcilantro
59 posts
 
Digital RIAA implementation via DSP/VST:

@ 96 kHz:

two pole IIR filter:
MAXIMUM ERROR FROM 0.00 Hz TO 20000.00 Hz IS 0.0057028dB
MAXIMUM PHASE ERROR FROM 0.00 Hz TO 20000.00 Hz IS ~+/- 2.4 degrees

three pole IIR filter:
MAXIMUM ERROR FROM 0.00 Hz TO 20000.00 Hz IS 0.0000046dB
MAXIMUM PHASE ERROR FROM 0.00 Hz TO 20000.00 Hz IS ~+/- 1.6 degrees

http://www.head-fi.org/forums/f46/software-based-riaa-eq-part-2-a-311909/index2.html
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