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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
Thom_mackris  (Threads | Answers | This Thread)

02-24-07
  Responses (1-50 of 98)
Click title to read one, or click date to read all below it.

02-25-07   Thom, sheesh, i'm glad you didn't title your thread "h ...   Dougdeacon

02-25-07   Dear thom: imho the audio device whole design is what determ ...   Rauliruegas

02-25-07   Hi doug, do you have any pictures of your system? i think it ...   Acoustat6

02-25-07   Hi raul, indeed, holistic thinking is required - both in li ...   Thom_mackris

02-25-07   Hey doug, what kind of car should i drive??? o o .   Nrchy

02-25-07   Atmasphere recently shared some interesting thoughts on the ...   Unsound

02-25-07   Bob, thanks for your interest. i've been promising to post ...   Dougdeacon

02-25-07   Nrchy, i didn't know you owned a car. once you've driven a ...   Dougdeacon

02-25-07   Other designer's comments? well, i think you guys got it ri ...   Hagtech

02-25-07   Hi doug, thanks for the response. i am looking forward to se ...   Acoustat6

02-25-07   I have been smitten by tom evan's work for several years. hi ...   G_m_c

02-26-07   Hello, my .02 1- there are no perfect supplies or audio ampl ...   Ndoshi

02-26-07   . thom, great thread. . doug, nice acceptance speech. . nic ...   Cello

02-26-07   Thanks to you designers for posting your thoughts. good one, ...   Dan_ed

02-26-07   The idea that power supplies somehow compare to engines fall ...   Atmasphere

02-26-07   I cannot contribute to a technical discussion here, but can ...   Whart

02-27-07   Whoah, thom! look what you started here. i have to disagre ...   Hagtech

02-27-07   A line or riaa stage could be characterized as "good&qu ...   Jmaldonado

02-27-07   Jose, or anyone else, have you correlated riaa error to colo ...   Dan_ed

02-27-07   Dear dan: absolutely and josé and i already tested about, th ...   Rauliruegas

02-27-07   riaa eq deviation no more than 0.05db why? just how many c ...   Hagtech

02-27-07   Dear thom: about the line stage and specially in an analog ...   Rauliruegas

02-27-07   Dear jh: i respect your point of view and i understand it. ...   Rauliruegas

02-27-07   Hi all, it's great to get some brilliant designers involved ...   Thom_mackris

02-27-07   Ok- i have to clear up some misconceptions: the reality is ...   Atmasphere

02-27-07   Dear thom: +++++ " i too have to wonder about the neces ...   Rauliruegas

02-28-07   Thanks ralph (about balanced) ... yours is a different pers ...   Thom_mackris

02-28-07   "riaa eq deviation no more than 0.05 db... why?" ...   Jmaldonado

02-28-07   The magnitude of riaa error is not particularly useful unles ...   Jcarr

02-28-07   Interesting reading, a bit heavy on methodology but the edit ...   Ndoshi

02-28-07   Thanks ever so much for visiting this thread, jonathan. you ...   Thom_mackris

02-28-07   Hi thom, having been in the business of balanced phono produ ...   Atmasphere

02-28-07   again, your quality sound reproduction targets/priorities ar ...   Hagtech

02-28-07   Yes, the beauty of the marketplace is that we all have choic ...   Thom_mackris

02-28-07   Dear thom: fortunatelly, like jh told us, there are differen ...   Rauliruegas

02-28-07   Dear thom: +++++ " 2. will this component help me to en ...   Rauliruegas

02-28-07   Dear thom: this is the subject of your thread: +++++ " ...   Rauliruegas

03-01-07   Hi raul, yes, layout is indeed important. jim hagerman is ...   Thom_mackris

02-28-07: Jmaldonado
Jose, or anyone else, have you correlated RIAA error to colorations? As in, error of x amount or of y type leads to a z coloration.

Dan, in my experience the term "coloration" involves 2 facets:

On one hand you have a measurable deviation of flat frequency response of X dB, sustained over Y Hertz of bandwidth, which will cause an identifiable sound similar to that produced by the bands of an equalizer. ABX tests have been conducted showing that the audibility threshold is lower as the bandwidth of the deviation is increased. This simply means that we are more sensible to this error when it spans several octaves. RIAA stages are particularly vulnerable to this kind of coloration, simply because the RIAA curve is made up of 3 turnover frequencies affecting big portions of the audible band.

On the other hand, coloration is also a characteristic sound caused by a circuit's more intrinsic factors that can't readily be measured with conventional frequency-domain analysis. Nevertheless it manifests itself as a "fingerprint" in the sound (punching bass for instance). This type of coloration, at times enjoyable, will reveal itself more with the passing of time. This is mainly the reason why ABX kind of tests commonly reveal the first type of coloration, but fail with the second.

Enjoyable or not, decreasing coloration is a good thing in order to preclude our ear from extrapolating the musical signal into a predictable sound.

Jmaldonado  (Threads | Answers | This Thread)


03-01-07   Raul, give it a rest. you're making the same points over and ...   Audiofeil

03-01-07   Thom, a replay curve that deviates more from the riaa standa ...   Jcarr

03-01-07   Dear thom: with this i'm finish: +++++ " your "it ...   Rauliruegas

03-01-07   Raul:you probably mean "truer to the reference riaa de- ...   Gregm

03-01-07   Dear greg: you are right. yes, we added the 3.18us pole. yo ...   Rauliruegas

03-01-07   Thanks, jonathan. you've filled in the blanks better than i ...   Thom_mackris

03-01-07   Dear thom: imho thanks to our quest of exellence in the audi ...   Rauliruegas

03-01-07   Hi thom, i thought i ought to point somethings out. a phono ...   Atmasphere

03-01-07   "it made perfect sense to compare component colorations ...   Cardani

03-01-07   Thom: regarding playback eq deviations, a small width one m ...   Jcarr

03-01-07   Hi raul, if i may offer you a bit of friendly advice, and r ...   Thom_mackris


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