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
If a power amp has an input sensitivity of say 1v input to make it reach full wattage output (eg: clipping) There is no need for the preceding stage (whether it be a preamp or direct from the source) to put out any more than say 2v so long as it's clean.
Having the ability to put out 30v instead of the 2v, and said to sound better because of it!, is a total furphy by the one who said it.
George's confirmation of his earlier comments leaves no doubt that he's clueless on this topic! Any competent engineer knows this.

Any linear circuit has distortion that increases with output. If the circuit only has to do 2 volts but can make much more, its distortion can thus be kept extremely low- to the point that its difficult to measure.

This is why many active preamps have such low distortion, because they are operated well below their limits. This is just good engineering.


I have no doubt that Ralph is just in protection mode for his product. 

Any source that has been designed to give out 2v has been done so to be done to do so in it's most linear state, you would be a fool to do otherwise, unlike what Ralph will have you believe.
  
To use all this 2v, is better than shunting it to ground with the preamps volume control, and then having to make back up again with the gain stage of the active preamp which also will increase the noise factor by the gain amount of that gain stage.

Nelson Pass: on active preamps.
" We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.
Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up."

So get rid of that output gain stage (you end up with a passive) and utilise all of what the source can give out, instead of throwing away half of it so the preamps output gain stage can make it back up.

Cheers George
Yet every single Pass pre-amp has at least about 10dB of gain... It's like he doesn't even take his own advice!
 I really don't think atmosphere is in protection mode for his products, he doesn't fly that way. In fact if anything I think George is consistently pushing these passive threads for that exact reason. 
I actually push direct to amp more because it’s the best, if they have a volume control, if you bother to do your homework, which you clearly don’t.
The only time passives are mentioned is as the next best option is if the source has no volume, but hey you believe what you want.

Cheers George