What Makes a Good RIAA or Line Stage?

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

Dear Thom: IMHO thanks to our quest of exellence in the audio performance this thread exist. That quest on exellence bring us here.

I know exactly what you like to hear unfortunately you don't know the same about me.

You are a very well respected TT designer and I wonder what is your quest through your great TT design?

IMHO, I think that we have to look for " evolution " and this is what we are trying to do through our designs.
We always think that there are " out there " a better future for all of us and a better way to make " things ", we are on the quest of it.

I know that we have " to fight " not only against limitations in electronic parts, technology limitations but more important than that limitations in the way people think: this is our challenge, 90% or more of the Essential 3150 ( presentations ) were on tube lover audio systems, not an easy task I can tell you.

We try to be " open mind ", many people ask me why don't tubes?, my answer ( till today ) was always the same: we use all kind of technology that could help us to achieve in the best/better way our sound music reproduction targets and unfortunately the tubes can't help us, not yet: maybe in the future?, maybe: who knows?

Btw, my " hat off " to all non comercial mind tube designers because it is a great really great challenge to achieve " decent goals " in the Phonolinepreamp design with that technology: congratulations!!°

Thom, I know that you are the " boss " in this thread but I'm only trying to help to all of us with a little different point of view, at least from yours.

Regards and enjoy the music.
Raul.

Hi Thom, I thought I ought to point somethings out. A phono section needs to be really accurate. Many seem that way, but are not as they add something in trying to be 'detailed'.

I have found that high overload is a good thing. So our MC section overloads at about 250mV so that even a high output moving magnet can't overload it; at overload the output is making over 120V peak to peak.

What happens is that less than perfect recordings can thus still be enjoyed. IOW bad sounding LPs should be utterly playable on the best of systems without a lot of fatigue while the best sounding LPs transport you to the music.

In practice this works and yet our RIAA accuracy is within 0.05%. We extended the curve all the way to 100KHz and the low frequency cuts off at about 1.5Hz, so tone arm resonance defines the lower cutoff. In order to pull this off the power supply has to be very very stiff, and I think I mentioned before that we created a proprietary regulation setup just for this purpose (our regulators are quieter than the 'Super Reg' for example).

Differential amplification comes into play here as differential amplifiers have a 'cross mode rejection ratio' which is an ability to reject noise in the power supply. This is further enhanced by using two-stage constant current sources that are also designed to reject power supply noise.

Overall this gets you is a phono section that is unperturbed by poor recordings. It does seem if a phono section has issues, that often bad recordings will reveal that more than good ones!