Have Passive Preamps Finally Come of Age?


Back in the late 90s (eons ago) I tried a variety of passive preamps (PPs). The most musical was an autoformer, but back then my system was not balanced. For the last decade I have been using active preamps, both tube and solid state, but finding a quality balanced preamp under $4K is damn near impossible. Enter the Parasound P5 (2.1), which in addition to having balanced I/Os, it has a separate bass management circuit (MSRP $1095), and I was hoping it would provide better control over the built in class D plates incorporated into my 2 SVS powered subs, whose volume controls are STUPIDLY sensitive: when barely cracked from zero they overwhelm. Alas, no bueno. 

Recently i watched a PS Audio YT video that was emphatic about NOT connecting powered subs with interconnects; instead he recommends speaker cables piggybacked off the main systems amp/s. I had a spare set of DIY flat copper cables, and was shocked how much better they sounded, but doing so did not change the  volume control problem and unfortunately this id not bypass the SVS amps whose class D chips are now ancient. Thinking there could be an impedance problem led me to revisit PPs.

I sold my P5 and was using the XLR outs from my Oppo 105 (upgraded power supply and IEC/wiring to the power supply) direct to my Emerald Physics 100.2SEs (class D). The noise floor dropped tremendously, allowing me a much better view into the music. My Core Power Technologies 1800 PLC had more than a little to do with this, but...  

Days of PP research later, I came across LDRs, which seem like the ultimate PP option, but XLR versions are ~ $2K and up, with the Tortuga coming in at $2700, seems like a true SOTA bargain, just not in my current budget. Scouring the' for sale' sites I came across a Hattor XLR (MSRP $995) which was in my price range. Hattor's www had links to 2 reviews both were extremely positive: one used it in combination with a class D amp. Bingo! I snapped it up.

It arrived late yesterday, although Hattor's www pictures look awesome, they do not compare to seeing and touching it. The metal carrying case was an indication of the designer's dedication. This is an etremely well made piece of kit, but how does it sound? Alas it came with no manual and Hattor's site does not have a PDF. How hard can it be to hook up? Well, after a couple scary minutes, I discovered that it would not light up until I connected the 105. 

Stone cold, the first thing that shocked me was a further reduction in noise floor and an incredibly wide and deep sound stage, but as can be expected, it was dry. Fingers crossed, in about a half hour I began to be rewarded with texture as well. Tis only got better as the night wore on

I hope somebody chimes in with their Tortuga experience, or any other high quality PP information.that goes under the reporting radar. 
tweak1
a marriage made in heaven

After waiting at home all freakin day  for my Audio Alchemy DPA-1 stereo amp (had to sign), it showed up after 8pm. It only has ~ 100 hours, so a lot more break in awaits, BUT...

OMGosh, after about an hour for my entire system to warm up (sold my EP 100.2SEs about 3 weeks ago) I am hearing a much more complete musical experience. Think early digital (Perfect Sound Forever) and today's high resolution digital

Glimpses of being transported to the venue

My Emerald Physics KCIIs never sounded so good, but they are FS as I await their replacements

Im a very happy camper
tweak1 OP



Tweak1 It may sound good, but I don’t want to burst your bubble, you should have asked, if your still using your Hattor passive, you didn’t heed what I said about your EP 100.2 amp being only 19kohm input impedance, and not the best match for your Hattor passive.

Now you bought the AA DPA-1 without looking at it’s input impedance, as it’s even lower and more difficult to drive than the EP was, at 17.0 kohm xlr and 10.7 kohms rca, this I hate to tell you it's a worse match for the Hattor than your EP was.

You said you were looking at the Nord Two Stereo amp, and I said this was better than the EP, should have stayed with that.

You have two options to get the best with what you have.
1:Send your Hattor back and get them to install the optional OPA2134 output buffer in into it, this will allow it then to drive the very low input impedance of the AA or the EP if you still have it.
2: Send the AA back and get a poweramp that has got higher input impedance 33kohm or higher.

Cheers George
(This is a corrected post regarding my passive unit’s name.)

I have a number of active preamps and one passive unit. My favorite?

A passive unit called “The Liquid Pre”, by Teo Audio.

Unbuffered and not powered by electricity.
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It will also pass clean 1080p component video or coaxial 24/192 digital & DSD.

It might also pass a couple of amps of current at ~12vdc. All with the volume wide open, of course. High current DC and high MHz AC capable, all in the same box.

Let me rephrase that a bit. (deleted my above prior post) Wrote it too fast and slightly incomplete. Some capacity for AC, as in HF alternating current. More like ’RF capable’, would be the better analogy. Lowe current, low voltage, but Radio Frequency. Similar in bit bandwidth, as well. Very high bit bandwidth, essentially.