Phono Stage upgrade to complement Dohmann Helix One Mk 2

I, for one, would welcome the opportunity to audition a top quality phono stage that does RIAA in the digital domain.  There's nothing inviolate about the precision capacitors, resistors, and/or inductors that are necessary for accurate RIAA in the analog domain. But I need to hear it.

Still wondering whether Mijo directly compared the Hyperion to the JC1.  I owned a pair of JC1s and ran them on my Sound Lab speakers before I later made a major change to the SL input circuit.  In the original configuration of the SL crossover, my Atma-sphere amps had a tough time with the very low impedance offered by the old SL crossover at midrange frequencies (2 ohms minimum at about 2kHz and only 5 ohms at around 500 Hz).  Also, the resistor in the hi pass filter sucked amplifier power at those very frequencies.  In that condition, the JC1 had no problem, but I did not care for the overall gestalt. (This goes back to Dover's statement that you choose an amplifier to suit a speaker; I totally agree.)  The JC1s were better suited to drive the old SL backplate than were my Atmas, in the midrange.  When I later modified the crossover drastically, I eliminated that impedance dip, and the Atmas sounded far better than the JC1s.  Just my personal experience. Presumably, drbond owns SLs with the later revised version of the crossover, which was implemented by Dr West in response to this same problem. I can say nothing about the sound of the Hyperions; I never even saw a pair.  But the JC1s are good but not transcendent, in my particular experiment.

@lewm  : You can listen the Devialet  audio electronics. I don't know if today still handled phono stage unit but I heard it and was really good.

Exist other manufacturers that have a digital RIAA in its design.

 

Btw, the today JC is really different to the old ones and every body knows that you are married with tubes in that specific sytem link. Nothing wrong with me.

 

R.

Specifically, I have found that I favor OTL tube amplifiers to drive full-range ESL speakers.  This category does not include conventional transformer coupled tube amplifiers.  Why add another coupling transformer where it is not needed? A further qualification is that I made my original judgements based on ESLs that were available in the 70s and 80s, to include KLH9s and Quad 57s, and a few others.  Later on in history, several speaker makers, SL included, made a decision to design crossover networks or input stages for their ESLs that made them a more favorable load for solid state amplifiers.  I have not liked such speakers as much as I liked the early high impedance ESLs, whether driven by tubes or by SS amplification.  For another example, the very first M-L ESL, the CLS, with a 16 ohm impedance, was made in heaven for the Futterman amplifiers I then owned.  I enjoyed them for several years. Then M-L messed with the input stage to lower impedance for SS amplifiers, and the resulting CLS IIs lost all the glory of the original, regardless of how you drove it. I am very happy having removed the crossover parts from my SL speakers that wasted amplifier power across a resistor and that artificially lowered input Z to favor SS amplifiers.  I am quite happy with what I have now in my PX845s, and I commend Dr West for modifying his speaker line in accordance with solving the problem they had.  I plead guilty to all of the above.  Now, will you admit that the very thought of a vacuum tube makes you have conniptions?  The JC1s plain and simple do not hold a candle to the Atma-sphere amplifiers I own for driving my current version of the 845PXs; if they were better sounding, I would have kept them.  Believe it or don't.

Enjoy the Music reviewer on the OP model:

 

"  The company claims that the speaker requires only 60 Watts to perform to its high standards, though my experience sheds some doubt on the usefulness of this figure. The Pass Labs A-250 Class A amplifier, which was otherwise a tonally wonderful match for the speaker, was unable to control the speaker's bottom end satisfactorily. In this regard, the Merrill VERITAS mono-bloc amplifiers at 400/watts a side proved far more to the speaker's liking. "

At the end really don't care about because I don't own those speakers but I listened and are very good ones.

R.

 

R.

lewm always argument something with " wrong " questions as this to myjos:

" You have heard the JC1 and the Hyperion driving the same pair of Sound Lab speakers in the same room with the same upstream gear? "

First mijos was not talking of the old JC1 but today JC1+ that's way different and maybe he never read the MF review along the measurements on the Hyperion amps where we can read:

by MF:

" 

No doubt the single tube in the Hyperion's signal path subtly greased the musical proceedings with a smooth yet transparent overlay of richness. Having become acclimated in recent years years to the sound of the darTZeel NHB-458, which is less generous in the upper bass and lower midrange (detractors of solid-state designs might describe its sound as "thin") and is faster in the transient realm (detractors might say "overly and unrealistically sharply drawn"), the gross distinctions between these two great performers were easily audible..........

But even while the contours of the new sound were still easily definable and the differences between the two amplifiers were still clear...."

 

and JA measurements comments:

 

" 

While the Hyperion's input impedance is specified as a moderately high 47k ohms, my measurements indicated a lower value at low and middle frequencies: just over 21k ohms for both the balanced and unbalanced inputs. This is still high enough not to be an issue, but at 20kHz the impedance dropped to just 3k ohms, which will be marginal with some preamplifiers, rolling off the top octave. Fortunately, this shouldn't have affected Michael Fremer's listening, given his associated equipment: His Ypsilon PST-100 preamplifier has a low output impedance, and his darTZeel preamplifier has a fairly uniform, if high, output impedance across the audioband.

Despite the Hyperion's large number of output devices, its output impedance was relatively high for a solid-state design, at 0.35 ohm. As a result, the modification of the amplifier's frequency response with our standard simulated loudspeaker reached ±0.25dB (fig.1, gray trace). Of more concern is the ultrasonic peak in the Hyperion's response, centered between 40 and 50kHz and reaching 2dB in height. The peak gave rise to a single damped cycle of oscillation with a 10kHz squarewave (fig.2) and was not affected by the load impedance, which suggests that it occurs before the output stage, perhaps at the input transformer. 

 

 However, as figs. 3–5 reveal, at our usual definition of clipping, at which the THD+noise reaches 1%, the Hyperion delivered 239W into 8 ohms (23.8dBW), 400W into 4 ohms (23dBW), and 315W into 2 ohms (19dBW). It did meet its specified power when I relaxed the definition of clipping to between 1.4% and 2% THD+N, but these are disappointing results.

 

Of more concern in these graphs is the Hyperion's linear increase in distortion with increasing power output above a few hundred milliwatts. While the THD+N percentage remains acceptably low below 10W or so, above that power, and especially at low frequencies, it reaches levels that will be audible with continuous pure tones...

When MF comments on "the immediately obvious added harmonic and textural richness," that it is what I would expect from this distortion signature. In addition, the Hyperion's intermodulation distortion was not as low as I would have liked.

Given that, it is not an amplifier that I would recommend, especially given its price. While I have found that power amplifiers tend to sound different from one another, I feel they should be engineered to be as close to neutrally balanced as possible, and not designed to produce a "tailored" sound, as the Hyperion seems to be.—

 

Obviously dover made the same that lewm in this specific matter. As I said, knowledge levels is the " name of the game ".

R.