Music First Audio Baby Reference passive preamplifier

In April 1987, Anthony H. Cordesman had mixed feelings about the Mod Squad Passive Line Drive System Control Center. (Read his review here.) Introduced in 1984, the Line Drive offered volume and balance controls, five line-level inputs, and switching and monitoring for two tape decks. You didn't plug it into the wall; it provided no gain. Was it even a proper preamp? (footnote 1)

AHC demurred. "I'm not sure that I'm ready to advise anyone to take the risk of not buying a unit with a top-quality phono stage, no matter how well CD or DAT perform," he concluded, between commenting on Middle East wars.

Many audiophiles were not eager to abandon analog. Back in the 1970s and through the 1980s, well-heeled audiophiles lusted for the likes of an Audio Research SP10, Mark Levinson No.26/25 combination, or Klyne Audio Arts SK5 full-function preamp. What's a line stage? You mean Aux?

Cheapskates like me bought an Advent 300 receiver for $300 ($200 on sale). It had a fine moving-magnet phono stage designed by Tomlinson Holman. It also had a fabulous-sounding but frustrating FM tuner (it dealt poorly with strong stations on adjacent frequencies), and an even more irritating 15Wpc power-amp section (mine blew up while trying to drive large Advent speakers). It was cheap, after all. (Advent's founder, Henry Kloss, told me that he expected buyers of Advent 300s to use its preamp outputs to drive a pair of powered Advent speakers.)

On the West Coast, things were happening. In 1974, in Santa Maria, California, Paul McGowan and Stan Warren set up the initially eponymous PS Audio. Their first product was a standalone phono stage—probably the first good one ever marketed. Soon the company was known for its preamps: plain looks and pimped (!) phono sections. Almost four decades later, in 2012, the same Paul McGowan wants to help you get rid of your preamp.

After CDs came along, in 1983, PS Audio began offering preamps that could be used actively or passively—that is, with or without line-stage gain. Other manufacturers took up the idea, including Supraphon and B&K Components.

Can you get by without an active line stage? The question that had vexed AHC in 1987 bothered John Atkinson in 1994, when he reviewed the McCormack Line Drive TLC-1. [Harrumph. Snort.] It's as if the audio establishment—manufacturers, journalists, dealers, audiophiles themselves—feel they must cling to having an active line stage.

A CD player or DAC with a 2V output (more or less standard) should be able to drive most power amps directly, right? Well, sometimes. For comparison, a moving-magnet phono cartridge might have an output of around 4 millivolts; a moving-coil might have an output as low as 0.5mV.

Going passive can and does work for some people. The advice goes this way: Keep your interconnects short. Be sure your power amp can produce full power on 2V. Your speakers need to be reasonably sensitive. It would help, too, if you don't like to listen very loud.

When everything comes together, the results can be stunning. When they don't, the highs sound rolled off, the dynamics squashed. You might not be able to crank up the volume to party levels.

JA has told me that he's not sure passive preamps should be called preamplifiers; it's an oxymoron. Does the preamp itself have to amplify?

Better if it doesn't, is where I come down.

Those who produce active preamps are quick to explain that there's more to the game than gain, or having enough signal voltage. You "need" a buffer between line-level sources—a CD player or FM tuner or DAT (!)—and the power amplifier.

An active line source—ie, a proper preamp—drives your power amp with a low output impedance and plenty of voltage gain. Your power amp doesn't "see" your source components; it sees your preamp.

There are several potential problems.

For starters, those 2V from your CD player or DAC might overwhelm your line-stage input by way too much and cause distortion. In the mid-1980s, several electronics designers told me so and suggested in-line attenuators. All the ones I tried spoiled the sound, to some degree.

Active preamps add parts, including switches, more wire, and a power supply.

Paul McGowan points to the problem
Paul McGowan has been back at the helm of PS Audio since 1998. (Should the company be renamed P Audio, now that Stan Warren has been so long absent?) While McGowan no longer makes preamps, he does produce a fine phono stage, the GCPH ($1000). It has a volume control, so you can use it straight into your power amp—if phono is your sole source.

PS Audio also makes a digital processor, the Perfect Wave DAC ($3995), which can run straight into your power amp without an intervening line stage. No problem when all sources are digital—but why didn't McGowan include analog inputs? Those who own both a GCPH phono stage and a Perfect Wave DAC are faced with what McGowan calls . . .

"THE PREAMP CONUNDRUM." On PS Audio's online forum, PS Tracks, McGowan wrote that a customer was "upset" because he liked his GCPH phono stage less when he inserted a preamp between it and his power amp. McGowan referred to "the cumulative degradation . . . where each piece in the [signal] chain adds a bit of flavor not natural to the source—but preamps may be the worst of the lot."

Of course, it's easier to make the preamp the fall guy when you no longer make them (though I, too, dislike preamps). McGowan again: "The vast majority of sources you connect to a preamp have enough output to drive your power amplifier directly[;] in fact, many have more than enough. Preamps reduce that volume level of the source only to re-amplify it back up to match what the amp wants. This process can only cause harm to the purity of the signal."

Can I pimp that last sentence? "This process can only cause harm to the purity of the signal."

McGowan suggests that manufacturers offer "power amps with multiple inputs and a volume control. " Yes. And how about DACs with analog inputs? There are some. But isn't what McGowan describes an integrated amplifier?

One poster at PS Tracks observed that integrated amplifiers tend to be less costly, and thus more compromised, than separate preamps and power amps. Who can blame manufacturers for pushing separates when, past a certain price point, "the market" in North America arbitrarily demands separates?

One prominent US high-end manufacturer did precisely what McGowan suggested: built a little more gain into a highly successful stereo power amp, and added a source selector and a volume switch but not a separate line stage. The Conrad-Johnson CAV50 integrated amplifier was superb. (See my review in October 1998, Vol.21 No.10.) Sadly, C-J no longer makes integrateds.

So who's to blame for the plague of unnecessary preamps? Not the British. Not Europeans. There are manufacturers who emphasize integrated amplifiers over separates. They include Giovanni Sacchetti, of Italy, who makes the Unison Research Simply Italy ($2500); and Dr. Richard Bewes, of the UK, who produces the solid-stage LFD Mk.IV LE ($3695).

As Sr. Sacchetti explained to me a few years ago at his fabbrica, near Treviso, you do need a separate line stage when you offer massive monoblock amplifiers. Otherwise, Unison favors integrateds, as do many European and Asian customers. Smaller living spaces, less stuff. No need to dis-integrate your amp?

Air Tight, a Japanese maker of tube electronics, offers their ATM-1 and ATM-2 power amplifiers (in production since 1988) with what they describe as a "CD direct input enabling unimpaired digital reproduction."

Normal people don't need such solutions because they avoid the problems of hi-fi in the first place.

Benchmark's DAC1 HDR ($1895) offers an excellent onboard DAC, a line stage, and headphone amplifier. It even includes a pair of RCA analog inputs and remote control—a great convenience in a headphone amp.

If you already own a DAC you like, you can choose among a number of headphone amps, many of them tubed, that can double as an active line stage. But these usually limit you to just one pair of analog inputs, and you may have so much gain for your power amp that you have to turn the volume almost all the way down. Or use an in-line attenuator.

What if an active line stage actually enhances the sound?
Enhance? You want to enhance? Add "flavor"? An active preamp is supposed to add nothing to the signal sent it by your source components. That, of course, is impossible, because every part—every switch and connector, every wee wiggle of wire—is yet another ingredient. Worst of all is that additional power supply. AC power = pollution. Ask Paul McGowan.

Back to square one and the Battle of Hastings
For the past 20 or so years I did not knowingly own a line-stage preamp. Then I discovered, in my basement, a pristine Musical Fidelity X-PRE line stage with X-PSU power supply from 1999. A fine active line stage—tubed, too—it has few parts. No display. No remote. I shall treasure it.

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Footnote 1: The Mod Squad, cofounded by Steve McCormack and Joyce Fleming, began as Music by the Sea, a store in Leucadia, California. Mod Squad invented Tiptoes, the first pointy feet to put under amplifiers, turntables, loudspeakers, and other gear. The company name was [ahem] modified to McCormack Audio Corporation of Virginia, now owned by Conrad-Johnson.
Source : stereophile[dot]com