Thursday, June 14, 2012

Review: Quicksilver full function preamplifier


Introduction
Quicksilver has been around for quite some time, but their products are often overlooked for the more flashy Conrad-Johnson, Audio Research, or whatnot.  However, much like VTL, Quicksilver instead concentrates on simple but solid tube circuitry, robust old-school construction, and moderate - at least for audiophile gear - prices.  The full function preamplifier in question is the earliest incarnation of the product having first hit the street in 1988.  Price back then was a princely $1995, making it roughly in the same price range as the famed Audio Research SP-8 or the slightly later Conrad-Johnson PV11.

I bought mine from a seller on Audiogon.  Shipping was prompt and I received a very heavy duty preamplifier that doesn't quite have the same ooze of quality that ARC or McIntosh has, but certainly is no slouch in fit 'n' finish.  Cracking open the top plate grills, you will see that the power supply and signal path are separated by a thick steel wall.  Very nice.  Component quality is also good though hardly esoteric.


Circuit and Controls
A quick look over the tube complement and circuitry:  Some of this is based on guesswork since no schematic could be found.  The power supply uses a large power transformer, a pair of 6X4s which are still widely available NOS, a small choke and a number of large Mallory capacitors to provide the DC smoothing, along with some regulation for what I assume are the tube filaments.  The line stage uses one 12AX7, one 12AU7, and one 12FQ7.  Since the reported output impedance is so low, I'm assuming the 12FQ7 is being used as a cathode-follower with some negative feedback wrapped around the entire circuit.  The last bit is the phono stage which only uses a single 12AX7 and a 12FQ7 with some sort of green LED biasing.  Coupling capacitor quality is in the meh range, but hardly out of place for the era.  The big 2uF capacitors on the output stage are some REL Polyesters (ughh).  The smaller signal caps are branded Quicksilver though also look to be REL made.

Front controls are fairly standard though a little dated: No remote here!  Lighted power, AC rear receptacle switch, and a mute button make up the left hand of the faceplate.  The right side has a tape monitor switches, a reduced (20dB) gain switch, a selector switch, and a stereo/mono/etc switch.  Volume control is dual mono with one stepped Blue Alps per channel.  These actually work better than expected - with the numbered volume steps it's very easy to match levels between channels.

Rear panel is the usual assortment of nice gold-plated RCA jacks and a grounding post for the phono stage.  Power cord is captive.  Fuse Holder holds a 1A unit.  AC receptacles are a nice throwback to the days when the user would power up his amp and sources with one flick of the on button.


The Sound
Okay, enough introductions - how does it sound?  Well, since this is an older unit, the stock tubes are long gone.  For the purposes of this review I used some really nice NOS tubes from my stash, so results will vary to a certain degree depending on what is plugged into the sockets.  In my case I used early 1960s short plate Mullard 12AX7s, a late 1940s black-plate RCA 12AU7, and 1960s-era side-getter RCA 12FQ7s.  Rectifier tubes were Tungsol 6X4s.  Some generic tube damping rings came with the unit, so I kept those in place.

It's been my experience that ultra-regulated, current-sourced, current-sinked, and whatnot circuits are very detailed, but also suffer from sounding slightly unnatural.  Note that tube regulators are usually better than solid-state, while shunt suffers from less sterile sound than series.  My own DIY experiments with a simple linestage showed that pulling regulation out of the circuit actually improved overall musicality and enjoyment.  Sure, some of the last bits of inner-detail are missing, but the music usually sounds more relaxed with a looser power supply.  This type of sound was very evident with the Quicksilver preamplifier which just uses chokes and caps to provide a clean source of DC.

Compared to my old Threshold FET-10/HL linestage and Audio Sector Phono Stage, the Quicksilver (with Cinemag step-up transformers) has a relaxed presentation that draws you into the deep soundstage.  It's almost like unclenching your teeth after a roller-coaster ride, or taking a good solid gulp of your favorite adult beverage: the muscles relax and you sit back with enjoyment, washed away by the sonic swirl of the music.  A good stereo should be a psychedelic experience - an unregulated and legal high - that lets you forget the troubles of the world.  With the Quicksilver preamplifier, I feel as if my entire audio experience has been improved.


Listening Notes:
I used my turntable exclusively for this review, but the linstage by itself is no slouch either.  The Audio Sector phono stage combined with the Quicksilver was a pleasant surprise, but the Cinemag and native phono section got the nod in sound quality.

The Who - Tommy (W. German Polydor):  The Quicksilver has very excellent detail and speed, keeping up with Keith Moon's manic drumming without breaking a sweat.  Small individual instruments - like a small bell - maintained their place in the soundstage while still being audible in the wash of thundering bass and guitars.  Depth was deeeeep, making my room seem bigger than reality.

The Beatles - Rubber Soul (Japanese Parlophone): This particular cut of this famed album has been described as bright and bass heavy compared to the original British pressings, but to my ears it sounds like it was eq'd flat.  With the Quicksilver, treble is extended and detailed with out any forwardness or grit.  There is lots of nice detail with John's wonderful voice cutting through the primitive stereo mix.  It's harder to get closer to the Beatles than this.

Tom Waits - Closing Time (80s Asylum): Perhaps I'm a sentimental slob, but I love this album.  However, the Quicksilver revealed the limitations of this later pressing.  Some detail, compared to some better versions, was missing, as if the music was hiding behind a thin gauze.  Tom Waits voice, however, was still wonderful, leading to some near tears while listening to the bittersweet song Martha.

Record after record revealed a preamplifier - and stereo system - that was very analog sounding.  Perhaps somewhat lacking in some of the hyperdetailed / transparency of more modern pieces, the Quicksilver was still no slouch.  When it came to musical enjoyment, I give it an extremely high ranking since it never sounds bleached out or unnatural, even with less-than-perfect recorded music.  If you want a preamplifier that speaks to the mind instead of the heart, you may want to look elsewhere.  I've gone down that road with my foray into solid-state gear, but I'll take naturalness over artificial effects any day of the week.


Overall:
Soundstaging:  Deep and Wide, imaging goes beyond the boundaries of the speakers and even the walls of my listening room.

Treble: Airy and extended, but also pure and detailed.  Compared to the darker Threshold/Audio Sector, it seems there is even more overall treble, but yet it never is harsh or unfaithful to the record.  A strange effect and not at all what I expected from tubes and a step-up transformer.

Midrange: Glorious, but not overly slow or "tubey" in the classic sense.  The Quicksilver certainly doesn't sound like a soggy Dynaco PAS.

Bass: The 12FQ7 output tubes can swing some current while delivering a low output impedance.  This translated into control.  I certainly didn't miss the solid-state drive of my last preamplifier combination.

Speed: (or PRAT) Good tube gear isn't supposed to be sloggy 'n' slow.  The Quicksilver preamplifier and Yaqin amplifier combination certainly doesn't sound like an aged tube integrated or a Dynaco 70 in need of a rebuild.  Instead, the music transients started and stopped on a dime with no overhang.  With the UREI loudspeakers, this led to a very dynamic, exciting, but yet unfatiguing sound.

Detail: As mentioned above, the Quicksilver is no king at wringing out the very last drop of detail from the music.  No, it isn't flat or uninvolving, but the very last bits of information are perhaps less apparent than some other units I've heard.  Some of this may be due to the large Polyster output capacitors.  An upgrade is due for some of the parts - notably some new polypropolene capacitors - so it will be interesting to see what effect this has on the sound.  But really, I'm not complaining because I'll take all of the positive attributes over hearing the squeaky chair of the violinist in the third row.of the orchestra pit.


Conclusion
For a going used price of $850-$1000, the Quicksilver full function preamplifier is highly recommended.  It's extremely well-made and is very natural sounding.  Errors - and I mean minor - are ones of omission with a high scale of musicality.  The simple circuitry will minimize future troubles since there are less "moving parts" once you get rid of the solid-state and regulation support circuitry often found in modern tube preamplifiers.  I expect to increase the audio grade of this unit with some coupling and electrolytic capacitor replacement, so stay tuned!


Main System:
VPI HW19 Mark III with SDS Power Supply
aluminum rebodied Denon DL-103R
Rega RB300 with Cardas wiring
Cinemag CMQEE-3440A in custom aluminum box
Cardas Cross 1M interconnects
Quicksilver preamplifier with (real) Mullard 12AX7s, RCA 12FQ7s, and a RCA 12AU7
Cardas Quadlink 5C 1M interconnects
Yaqin MC-10T amplifier with black-plate RCA 12AT7s and (real) Mullard XF2 EL34s
Cardas Hexlink 2M speaker cables
UREI 813A speakers
VTI BL503 equipment rack

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