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

Showing 13 responses by mrdecibel

A couple of things. Looking around, more and more integrated amps, and similar products, are bypassing having a preamp section altogether, taking the source and switching, only, into the amp stage. My top of the line Sony cd player, many years ago, mention in the owners manual, to go from the variable out, into the power amp. This " passive " thing is not new, and it is gaining momentum each day. About a week ago, I decided to bypass my preamp and come straight out of my fixed level dac, and specifically used a lower wattage, pro Yamaha amp, with it"s input level controls. Using my Sheffield Labs Drum Record, I so much prefer no preamp.  I am currently shopping for a passive, with multiple inputs, as the amp I would like to use is very high gain ( it was designed to be used with the source voltage driving it ). It is likely I will never use a preamp again. Enjoy ! MrD.
Well, I have been living with my Luminous Audio Axiom II for a week now. It is the top single ended unit : Walker mod, 3 in, 2 out, with remote. I can honestly say I have reached a point where I am hearing " everything " within the recordings. I can better connect with the artistry of the musicians and, the work of the recording and mastering engineers. It is an open window, unaltered, allowing me to hear it all as I believe it should be. I will report further as time goes on, but so far, I am very lucky with the synergy, and even happier with the outcome. Enjoy ! MrD.
I might be missing something, but for as long as I can remember, the dacs I have owned, the cd players I have owned, the tuners I have owned ( and some tape machines ), have all been 2 volts output, or more. I also remember early passive units from way back. So none of this is new, with maybe the buffer circuit being new. Of my hundreds of amplifiers passing through my doors, all could be driven to full output with 2 volts in ( I am not talking about the impedance here, just the output voltage ). I do understand the importance of impedance matching. Enjoy ! MrD.
@atmasphere  Why would you feel 2 volts from a source should be cut down a bit ?
Ralph, this might have been covered before, but, why do so many preamps have high amounts of output voltage ? Enjoy ! MrD.
Many amplifiers overloaded with 2 volts ? Are we talking about power amplifiers being overloaded, or preamplifier sections being overloaded ? 30 volts output ? Now I am confused. But, Enjoy ! MrD.
@tweak1 If you are finding some of the Tony Bennet recordings " wow ", listen to some Elvis Presley recordings, and realize the expert technical aspects of the recording and mixing engineers, as well as the King’s voice. Enjoy ! MrD.
Hello A’gon members. I have had my Luminous Audio Axiom, Walker Mod, 3 in, 2 out, single ended remote unit for quite a while now. Without slighting the preamp manufacturers, nor those readers who might own the preamps I have been using ( I will not name them , I will say, without a doubt, that I am much happier, without the preamps in my system. I have tried passives before, but never thought they " came of age ". Maybe it is my amp’s high gain, or my efficient speakers, but it has all come together. I suppose I am one of the few lucky ones, as I am rediscovering recordings that I thought I knew so well. Lets all just get along. Enjoy ! MrD.
If sources with 2 V output go into some kind of distortion mode ( running out of steam, if you will ), how can a preamp help the distortion ? Enjoy ! MrD.
I am really disgusted at this point, with the bickering going on here. I found Passive to be wonderful, so I know it works. I am judging this based on my 50 years of listening, and, my " current " system. Yes, there are instances when passive will not work, and we all understand this. But come on guys. Audio Research has an integrated amp that does not have a preamp ( gain stage, others too ), so, what does this tell you. If we cannot be civil, it is no longer my worth and time to be here, sharing my knowledge, and learning from others what I do not know. I have gotten this same crap with horns, cables, and some other audio related issues. It is bullshit ! Enjoy ! MrD.
I have run 3 different dacs, 4 different tuners, a Samsung cable box, and a laptop from it’s headphone jack, through the passive, all with excellent results. I have also used 4 of my power amps, again, all with excellent results. If I am listening to distortions, so be it. It betters the preamps in detail, transparency, and neutrality.  Enjoy ! MrD.
Well, it seems to me the gain issue ( voltage ) has just be proven by kosst's last post, taken from Nelson Pass himself. Take care of the impedance issue, using buffers ( 0 gain ) and the source can drive most power amps quite well. Enjoy ! MrD.
This was posted on Audio Advisors site during a review of their 5 best selling Dacs under $500. I believe I am disagreeing with them on two counts. 1st : the Dacs they yested do not put out the standart 2 volts, so to make a comment like that is not really true. 2nd : Talking about the gain controls on the two recommended Parasound amps would not give you higher output. This was in a thank you response to customers who bought and rated these Dacs they bought from AA, and I feel the person who wrote this in not very knowledgeable. " Audio Advisor05/14/18Thank you for your comments. All the DAC/Preamps on the market have limited output gain and therefore cannot drive most power amps as well as a stand-alone preamp. A great choice to mate with this Pre Box S2 Digital would be one of the Parasound amps - I’m thinking of either the Z-Amp3 or the Classic 275. These have a gain adjust on the rear panel that will give you higher output from the S2 or any other pre-level source ". Enjoy ! MrD.