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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
georgehifi's avatar
georgehifi
4,966 posts
 
Most good interconnects are 100pf per foot or less your citing of 300pf for a mt, is for a reasonable low capacitance interconnect and all my figures above in my last post are correct, and I have always stated so from the first Lightspeed built, and to use good quality interconnects that are 100pF per foot or less.
What you stated is a total falsehood and misleading.
With a 3 foot high quality cable (which would have 300pf) in such cases you would have a roll-off that is very real world.

Apparently you had either clone or a faulty one or just BS’ing, and if your going to start on my product then you’ll receive the same.

As for impedance matching, I have also always stated from the first one built that an output to input (Lightspeed to amp) impedance ratio should be 1:10 or higher, and have never said that it or any other 10kohm passive would be happy into a 10kohm amp input impedance.
And that sources should have a low output impedance <500 ohms, not like most tubes sources have, very few like the Herron phono stage are fine.

As I still believe these falsehoods are of someone in product protection mode, and to be honest I don’t blame you, threads like these cheap passives are a killer for $$$K preamp sales, and OTL’s can only drive so much, unless aided by Zero band-aids, of which I’m also anti.
atmasphere's avatar
atmasphere
7,068 posts
 
Hmm. George, I'm not worried about it- I simply acknowledged that you were correct yet you're still going off. If anyone seems in damage control mode, its you right now. Just calm down.

You'd have to imagine that I'm well aware of what our amps can and can't do; our amps don't use feedback, so speaker choice is important. But the flip side of that has consistently been that if the speaker requires the amp to have feedback, it also has no chance of sounding like real music (I can outline exactly why easily enough). So I just vet each sale to make sure the customer is going to have a success. Works pretty well- that's why we're one of the older manufacturers in high end audio- 42 years in about 10 days. 

I don't remember which customer lent us the Lightspeed, but we had it for a week. As passives go, it was one of the better ones we checked out. If you are on a budget and have only high level sources, its not a bad way to go. IOW like any passive it can do well but not state of the art; plain and simple. That's why I'm not worried; passives are just a little too simple to do everything correctly (the better your system gets, the easier this is to hear). Cable control and buffering the source to prevent distortion are two example of why and I can name more.

Now that's not an insult, its just a statement of fact. State of the art nearly always costs more and that shouldn't bother you.

BTW, your comment about headroom in preamplifier and source design is still false and no amount of remonstration on your part will change that. I chose not to continue that bit but you insist on attacks. Just calm down and it will be OK.

georgehifi's avatar
georgehifi
4,966 posts
 
I don’t remember which customer lent us the Lightspeed
You attack my product and you tell me to keep calm, conveniently not remembering who it was.

With a 3 foot high quality cable (which would have 300pf) in such cases you would have a roll-off that is very real world.
Then you present this BS, and then try to back peddle after I’ve shown the truth with the math.

Clearly it’s you in damage control, after all this is a Passive Preamp thread and all you present is negatives.
Stick to the active preamp threads and stop putting **** on passives at every opportunity.
celander's avatar
Ag insider logo xs@2x
celander
1,036 posts
 
This back and forth is hilarious.

Let us distill it to its simplest form.
1. atmosphere considers George’s Lightspeed unit to be a fine passive preamp device, albeit limited in its design (1 input and 1 output) and clearly not as good as what atmosphere has auditioned by way of active preamp devices (hint, hint: atmosphere’s own company’s devices.)

2. George feels butt-hurt because atmosphere views his Lightspeed passive preamp as being inferior to atmosphere’s active preamps.

3. The causal observer of this banter would conclude that:
(a) atmosphere is entitled to opine about comparisons between his company’s active preamps and George’s Lightspeed passive preamp, because the forum thread is entitled, “Have passive preamps finally come of age?” Atmosphere concludes that the answer to that question is “No,” at least with respect to the Lightspeed passive preamp.
(b) George is entitled to take the opposite view of atmosphere’s opinion, notwithstanding his disappointment in atmosphere’s conclusion.
mitch2
1,911 posts
 
@celander 
This back and forth is hilarious.
I mostly agree.  For example, what does "finally come of age" mean? 

The Hattor is simply a resistor based passive volume control, not unlike Goldpoint, Placette, and others that have come before, and not really unlike what is in Ralph's preamps except that those also provide buffering and gain. 

George wants us to believe the Lightspeed is "compatible" with most impedance and gain situations - and that may be true.  However, just because something is "compatible" doesn't mean it is the best-sounding option. 

What's missing is that this is really about what one hears in their own system.  If a listener likes the sound of a certain type of passive in their system, then that's what matters.  If they want to compare their passive with an active circuit, then they can simply connect a buffer to the passive and decide which sounds better.  There are many on this site who enjoy the sound of their passive volume controls and many others who prefer their active preamps or buffers.  There are other options such as DACs by Empirical Audio and Metrum Acoustics that adjust volume by changing the reference voltage, which does not negatively affect the signal like DACs that throw away bits of information to reduce the volume level.  This is really easy, try several options and stick with what you like best.
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