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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

Showing 4 responses by dougdeacon

dougdeacon
3,338 posts
 
Thom,

Sheesh, I'm glad you didn't TITLE your thread "Hi Doug". Opening with a salutation is embarassing enough. Still, I'm glad if my speculation on p-s "goodness" helped spark an interesting thread.

Once I heard the musical clarity of effective power supplies, it became much easier to hear and identify the musical mud caused by ineffective ones. Some are just inadequate. Others are overly complex in the way they're regulated. I don't have the knowledge to explain one vs. the next but I can hear the differences. Anyone could, with a little exposure.

In addition to a starved p-s, another sonic characteristic I've heard in many preamps is a kind of general congestion or confusion of phase timing and frequencies. It sounds (to me) like the result of overly complex designs and, as you already said, too many parts. Being an electrical ignoramus I can't put it any more accurately than that.

I've heard three preamps which don't do this (or rather, which do it notably less than all the others). They come much closer to Bruce Lee, which is a pretty good analogy for my ideal too.

Hope you get some responses from people who actually know what they're talking about. It's an interesting topic.

Doug
dougdeacon
3,338 posts
 
Bob,

Thanks for your interest. I've been promising to post photos for years, so your nudge was well and truly due. Soon, soon...

I described our musical and sonic goals on our system page in this post:
http://forum.audiogon.com/cgi-bin/fr.pl?vevol&1051822874&openflup&65&4#65.
They haven't changed.

It's worth emphasizing that we are not big rock listeners. Many people find the resolution, transparency and neutrality of the sound we're seeking ill-suited to rock. We are constantly seeking ways to reduce artificially added "glue". Bloating or leading edge gentling from a component may help heavily mixed recordings sound more enjoyable, but they also make acoustic instruments and voices sound slow, congealed, larger than life and unnatural. Our favorite cartridge is a prime example. It positively refuses to add artificial overhang to any note. Natural decays are extended and reveal the sound space very clearly. Unnaturally bloated decays, which help blend the added feedback and multiple mixes of highly engineered recordings, are fairly non-existent. "AM radio" mixed recordings sound spectacularly awful in our system.

Like most tube preamps, ours can be tuned to provide more or less "glue" by rolling tubes and even (a little) with different isolation devices. Our personal choice is for the fastest, most neutral, most extended and least microphonic tubes we can find. This actually makes our preamp sound alot like Raul's on some music. They're closer than any other two preamps we've heard.

Others may prefer a different flavor of course. FWIW, we agree with Raul's longstanding contention that most tube components (and many vinyl systems generally) are tuned toward the warm and rounded. That is not our particular preference. We don't listen to sweet. We certainly don't post sweet. We don't even like sweet wine. It's pretty dry around here. If the sweetness isn't in the music we won't add any.

Doug
dougdeacon
3,338 posts
 
Nrchy,

I didn't know you owned a car. Once you've driven a Harley, what's the point?!
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
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