Passive Preamps


I'm curious about passive preamps. Has anyone tried a passive preamp in their system?
mdeblanc
Please check the archives.
I prefer the agressive ones.Wait a minute,thats how I like my women!!!!
I've tried several, even use a few.
Women???
Post removed 
Unsound is right, there are many threads on this. In a nutshell, if you have an excellent front end with sufficient output v, and you don't want to enhance (or degrade) what it offers than try a passive. If you want to hear what passive will do for your system (which should be nothing or next to nothing), buy a used Placette RVC ($5-650), it only has 1 in & 1 output; but it is among the best resistor based pre's and will easily sell if you don't like it.
Yup, so far I like my Promitheus ref 4 better then any active I've had. Ludimagis makes a good point -- passive by nature doesn't add any gain so you'll need a cd player or source with enough voltage to essentially feed through to your amp.

Things you will likely notice: more transparency and air.
Things you may also notice: less body and weight.

Also make sure that the input impedance of your amp is sufficient, probably at least 50k ohms. More is better, tube amps usually pair well with impedance.

Lastly there is a buttload of info on this..search and ye shall find
Also keep in mind that with a passive preamp both the length and the capacitance per unit length of the interconnect going to the power amp should be as small as possible, because of the high output impedance which passive preamps will inevitably have.

Regards,
-- Al
The above posts are correct - it's a numbers game. But that's pretty much for comparably priced preamps, IMO. I haven't heard the passive that can compare to the really high-end actives.
I agree with Phaelon.Passives are a little to cool and the lack bloom of higher end actives
If you want bloom and realistic sound from a passive, a TVC or autoformer is the way to go. Like having your cake and.......

Shakey
The passive preamps I've tried, lack 'drive', 'dynamics', 'soundstageing'-- relative to active preamps,to such a degree that the music is, by comparison uninteresting to me. To explain...
I'll never forget the first, at the time I experienced what I considered a great preamp, the conrad johnson Premier 3. It had such terrific tonal shadings, low level resolution, adding to soundstage placement--as well as bass drive. Even the dryness/richness of the double reeded instruments on large orchestral works, came through with such a visceral sense.
Then lets come forward in time to the Gryphon L1 (I believe was the model number) circa 1991--possessing two rather heavyweight outboard power supplies, one per chanel--a true dual mono unit. That remarkable beautiful and musically superior preamp(at that time) the very best control over amps that I had ever heard. It was so remarkable, that I could pair it, with the really inexpensive $595 Adcom GFA-555 and shock audiophiles out of their chairs. It was truly remarkable piece.
The point of noticing this is that the passives were the antithisis of this kind of potential.
If I can, I'll finish by saying that, if music were a canvas, a painting, a great preamp makes the work, a Monet, full of life and shadings and wonderful vivid colors--with passives being, to me, the polar opposite, a rather mundanely done water color--washed out, lacking that snap and pop of reality and excitement.
As always, I haven't hear everything, someone may very well have had a much difference experience.
Good listening to all.
This is a great question BTW.
Larry
Can't say I agree with all that is being said here based on my experiences.

I agree with Phaelon. Passives are a little to cool and the lack bloom of higher end actives.

Well isn't that the point to some extent? Just pass the signal, no colorations. If you want bloom by all means get a nice tube preamp.

I'm using two passive preamps right now with a third on the way. One is an autoformer volume control using the Slagle-man modules jointly designed by Dave Slagle and John Chapman. The other uses opto-coupler technology and was designed by an Aussie named George Stantscheff (Lightspeed attenuator). Opto-coupler technology is not new to audiophile components. Today Dartzeel uses it and Melos used it previously. Even Nelson Pass has published a schematic for a passive preamp using this technology. On another note you can buy a pair of Atma-sphere M-60 monoblocks with a passive volume control option that Ralph Karsten offers. I'd love to try that set-up sometime.

Shakeydeal has a point as well. Kevin Carter at K&K Audio built me a passive TVC using the S&B MkI transformers which in his opinion, and I concur, exhibited a nice touch of warmth.

All of these passives deliver dynamics in spades and a very nice sound stage in my system. In the case of the Lightspeed the purity of the signal being passed is mind boggling at times (all for $500). Passive preamps have replaced very nice active preamps such as a Joule Electra LA-100 MkIII and JRDG Capri in my system. Of course my front end components and amp have a say in this too, not to mention room set-up. A passive preamp in a passive friendly system can be a thing of beauty.
Different flavors...and there is no right or wrong. Even in the same topology, there are differences in presentation.

The equipment simply must be heard to make any judgments. Reading about it only provides a sketch framework.
I think the only thing Clio09 and I can agree on is that we disagree.As Tvad stated there are no right or wrongs here.
It doesn't matter what has been written or whom uses what.
What matters is what one hears and I find actives to be more to my liking.Much more.
And yes I have a tubed preamp which is warming,and shortly will be filling my room playing a LP from JJ Johnson and Stan Getz.Happy listening to ALL
It is good to note that passives come in different flavors. I am not a technical expert in this, but a transformer volume control - TVC - I understand will generally work better and in more instances then just a resistive attenuated volume control in both impedance matching and for a fuller sound.

As I've said, with my TVC I don't lack any dynamics -- everything is as 'colorful' as it was with the few active pre's I've had, with the added benefit of more transparency and air between sounds. Bass is low and tight, highs are extended and detailed. Soundstage is better defined.

Another option is an active/passive pre in the same unit. Wyred 4 Sound, Placette and others make such pieces.
I second Tholt on the Promitheus TVCs. One more point I would like to add is that in case of TVC the amp's input sensitivity is VERY important. With a TVC, the input sensitivity of a power amp better be below 1.5V. With this n mind, there is absolutely no loss of dynamics or body or weight. The positives aspects with the addition of a TVC in your system are something to be heard and seen rather than describe in a thread.
So, system matching is very important.
10-04-09: Milpai
One more point I would like to add is that in case of TVC the amp's input sensitivity is VERY important.
Good point.

Also, the output impedance of the source component should also be low to ensure extended and defined bass. I find below 200 ohms is optimal in my system

Many tube output sources do not qualify. Something to keep in mind when considering a passive preamp.
One more point I would like to add is that in case of TVC the amp's input sensitivity is VERY important. With a TVC, the input sensitivity of a power amp better be below 1.5V.

Why is this? Is it because of the TVC volt-to-current conversion from the source? ie an amp with lower input sensitivity means it's easier to drive to full output power? apologize for the laymans terms. What would a 1.5v or higher amp input sensitivity equate to sonically?
Tholt,
no need to apologize. I was not aware of the significance of these measurements till I asked these same questions to a GURU on this forum. He has explained in detail about the TVC and the attenuation it does to the incoming volts. Send me a PM and I can send you the explanation he gave me.
PM sent
I am hamstrung by 'honor' not to mention comments by several well known designers with whom I've had this discussion. Passive, versus...
In fairness the one's who gave long dissertations, (over a few friendly glasses of adult beveridges) invariably also designed Active preamps to mate with their amplifiers.
It's funny, at the CES over the past 27 years you meet the most interesting people. Virtually all claim to have the consumer or the 'best sound' at the root of thier recommendations--or we could even ammend that to be 'most accurate' or least colored.
For all of us who actually listen, we know that, for a group interested in making the smallest 'change' possible, we seem to have a rather diverse opinion of what 'change' really is....
No one, especially me, doubts the veracity of the comments of the designers, yet I think that one quick story (and there are witnesses) about a conversation in a bar in Munich three years ago.
While discussing designing, I asked a collegue this question as clearly as possible. "During design, what point do you begin to evaluate the sonic differences in the parts, (caps, etc)?
The designer looked at me with a straight face and said, "I don't". "If I've done my job correctly I don't need to listen."
(Enter Steve Martin) "Well excuuussee meeeeee!"
Me personally, I can't imagine not making a 'sonic evaluation' along the way, during a design. Without giving a 3000 word diatribe here, let's just say that cap "X" by reputation sounds 'soft' or laid back, and cap "Y" a little brighter, and we have several of those combinations in the design. MOST designers, if not all, that I've spoken with, make SOME allowance or listening moment during this process to insure that, either 'good or evil' has been created.
This designer stood his ground.
He left shortly thereafter, and I was alone with the other 10 or 12 people, and couldn't help but ask, "Do any of you feel this way?" "Do you design without listening to the 'parts' along the way?"
The verdict that night was unanimous. "Everyone listens to the interim design."
That, could explain why everyone but the one designer is right and everyone else is wrong, or, of course, visa versa.
Now, as to the principle question, Passive versus, active.
Out of (by memory 7 designers of note) not one single designer preferred passive. Again, they all made an active, therefore had reason to prefer it. However, from a business standpoint, they had the option to make the best passive they could design, versus the best active, and all chose to build the active.
You decide.

I vote active, EVERY TIME...perfect, no, better, to my ears, yes.

Good Listening,
Larry
I use a TVC from Music First Audio and find it exquisite. Its clarity, soundstage and extremely low noise floor are quite remarkable. I recently compared it with a top notch VAC active preamp. The VAC had a bigger soundstage but also was little more colored. Dynamics and bass seemed equal to me.
My first preamp was a McCormick Micro Line Drive paired with its companion Micro series amp. The Line Drive was capable of both passive and active operation with the passive option receiving all the positive reviews. In fact, if I remember correctly, all the reviews I read were careful to stipulate that the enthusiastic recommendation pertained to the passive option only. So, being new to all this, I went passive and never gave it another thought. Nearly a year went by, and I can't recall what made me do it - probably a disappointing cd, but I switched to active. I don't doubt that I lost all the cherished nuances that the reviewers cited, but who cares - I was dancing. Larry is spot-on, and as Tvad pointed out on another thread: "Lrsky has excellent sensibilities when it comes to sound and matching, so I would give his recommendations (whatever they may be) proper consideration"
Wow. A vote by a member for another member for another member. That carries some weight. By the Kevin Bacon theory I'm now 1 against 3.
By the Kevin Bacon theory I'm now 1 against 3.
Tholt (Threads | Answers)
Tholt, not necessarily.

Lrsky votes for an active preamp. I give props to Lrsky's recommendations.

Yet, I own a passive preamp (SMc Audio VRE-1).
I've used both, to date I've come to slightly prefer active. Amongst the best passive systems I've heard were those that used the much under appreciated Reference Line pre's and amps. I would certainly consider using a passive pre in the future. However, I think the future will most likely be more about things like digital room correction, cross-overs, etc.. Passive pre's require more total system consideration and ultimately limit options more.
Out of (by memory 7 designers of note) not one single designer preferred passive.

Yes- of course they would - it a simple matter of electrical science. It is the same reason to avoid passive crossovers in speakers.

As you correctly point out - elements (caps etc.) will all add their slight signature to the sound as well as affecting the transfer function between poor impedance matched passive components and this is orders of magnitude more of a problem with passive components.

Good active circuit designs can minimize these issues by several orders of magnitude.

There is no debating these facts.

What people prefer or like to buy is entirely different. However from a perspective that seeks accurate audio reproduction there is no question that active amps are better.
However from a perspective that seeks accurate audio reproduction there is no question that active amps are better.
Shadorne (System | Reviews | Threads | Answers)
I would like to hear a debate between you and Steve McCormack on this issue.
Tholt, not necessarily.

Lrsky votes for an active preamp. I give props to Lrsky's recommendations.

Yet, I own a passive preamp (SMc Audio VRE-1).
Tvad (Threads | Answers)

My point was that Phaelon advocated your opinion, which was advocating Lrsky's opinion. It had nothing to do with what you yourself owned or even personally thought on the matter.
Tholt, my point was that you are not necessarily 1 against 3. I think Lrsky
knows what he's talking about when it comes to audio, yet I don't presently
subscribe to his general recommendation of an active preamp over a passive
preamp, and I was using my situation to explain why this is so.

I thought my post was supportive of your use of a passive, but perhaps I
misunderstood something in your string of posts.
TVAD,
I'm thinking of the 6 Blind Men and the Elephant...all different perceptions.
If I heard your particular passive with your system I may do a complete 180 in my thinking. While I've been exposed to probably more gear than most people I tend to come of as preachy--god I hate when I do that. But for me to categorically say that passives aren't as good is pretty dumb headed of me. In my experience, with the combinations I've heard, I've always prefered an active--I may need more and different comparisons to be won over.
Guys, I'm not one who believes there is a uniformly best anything for any
particular situation. There are always trade-offs to a design, and there are far
too many differences among listener preferences.

I will agree that an active preamp provides easier integration into a wider variety
of systems due to impedance matching and amplifier sensitivity, and in my
experience, not that it means a damn thing, an active preamp has usually
provided a larger "jump" factor to the music. Now, whether this
"jump" factor is faithful to the recording is another matter, but it's
not always a priority to some listeners.
Larry, I have the H2O and Fire preamp. My sound went from edgy and bright, to soft and warm, to just plain natural. These changes occurred while using the same power source. The builder ob both the Fire and the H2O as a much inferior source than I. He has never heard the full potential his gear is capable of. My findings show me his gear just gets better with every positive system change I make. The question is, how did he know which way to design the Fire preamp without knowing it's potential? He knows, because he has an intimate knowledge of all components that goes into making amps. My system is proof supreme knowledge trumps the ear when making judgement calls for excellent designers.
Tvad,

I was qualifying my comment from a 'measurements' perspective (reproducing a signal) - what sounds best with the gear each of us happen to own and our individual tastes will no doubt differ... I hope we can agree on that.
10-10-09: Shadorne
Tvad,

I was qualifying my comment from a 'measurements' perspective
(reproducing a signal) -

I understand. My comment to you had nothing to do with personal
preference.

As designer of audiophile equipment, I am fairly certain Steve McCormack
measures his components on the test bench.

A debate between you two on the topic would be entertaining.
I've used both over the years (active/passive). I haven't found an active preamp that betters a passive volume control at the lower price points....$1,000 active VS $1,000 passive.

Once you get past around $2,000 or so...I'll normally drop the passive idea as a replacement for an active preamp....the active almost always wins in my experience.

Dave

10-10-09: Tvad
Tholt, my point was that you are not necessarily 1 against 3. I think Lrsky
knows what he's talking about when it comes to audio, yet I don't presently
subscribe to his general recommendation of an active preamp over a passive
preamp, and I was using my situation to explain why this is so.

I thought my post was supportive of your use of a passive, but perhaps I
misunderstood something in your string of posts.

No worries. The real (and only) point was related to Phaelon citing you agreeing with Lrsky in a completely different thread to back up his own agreement with him here. Which struck me as funny.
Hi Dave, You just have to hear what the Fire does to enable the amps to do their best.
10-11-09: Muralman1
Hi Dave, You just have to hear what the Fire does to enable the amps to do their best.
Muralman1 (System | Threads | Answers)

If you are talking to me?....I've already had the Fire preamp in my system, and it is better than the passives I have used (Placette and Bent Audio).

And it should be at 3-4 times the price!

Dave
Sogood, How did I not know that? I reread your first post, and now realize I didn't read your second paragraph. My apologies, and good choice!!!!!
Tholt
"The real (and only) point was related to Phaelon citing you agreeing with Lrsky in a completely different thread to back up his own agreement with him here. Which struck me as funny."

Tvad is a Battleship while I'm a PT Boat. If I can access his 16 inch guns...

I'm happy that you took it in good humor.
As a designer, redesigner, inventor, yada, yada, we all face choices--and unfortunately, depending on what world you live in financially--those choices seem to revolve around price/cost of production, that is if you're trying to create a resaleable piece of audio goods, (or maybe Saturn Vehicle for that matter).
In the world of passives, I believe the 'choices' to be different than in the active product.
I can't get past that first time exprience with the Gryphon, or Premier 3 from cj. Those experiences were both what I call 'Hallmark' moments. I heard and experienced musical information that I had never heard before--not slightly, but dramatically. Were those differences 'exaggerations' of reality, or from what was actually placed into the original source? Of course, there's no way to know.
My gut, (I haven't had my 'guts ears' tested lately) tells me from a strictly musical or visceral standpoint that the excitement quotient was off the scale. So the question would be for a listener like me would be, 'does neutrality' completely colorless reproduction give me that same 'rush'? I don't think so. So maybe my internal listening mechanism, my internal reference of music tends to like the 'spectacular side of the experience.' If that's the instance I deferr to others who prefer the passive.
But the one comment that seems to mitigate the conversations here, is the one which talks about, 'up to a certain dollar amount' the passives do very well.
That may mean to me, at least, that when choices of internal parts starts to become serious, serious, expensive...therein lies the advantage of the active.
In other words, if we're not making dollar but sound choices, the active can be better. But then, the question, "Since when, when all things are equal, doesn't more money create a better product?"

Good listening.
Larry
My listening experience is that passive preamps that use a potentiometer lose dynamics, bass quality, and HF extension in most systems. But, transformer based preamps are excellent, particularly the Music First Audio preamp, which uses Stevens & Billington transformers. MFA must be contacted directly in the UK for sales to the USA, at this time, but they do offer refund for any unsatisfied buyer.
If you're a purist audiophile this is the to go.Unaltered signal and very transparent.
xonex77,
Did you experience one recently? Curious because you revived an old thread. TVCs ROCK!!

I tried out several Passives over a weekend and was very surprised
how different they were. For some reason, I thought being passive would make them sound similar, no way at all. It was two years ago, so I can not remember the brands, but the Music First Audio Baby Reference was way ahead of the other three. Very clean and neutral, with as good detail retrieval as I've heard. Yes even this expensive unit lacked the last ounce of dynamics, but what was there was still very good.

A version two of the Baby Reference is out, so the original should be a bit cheaper, if you can find one. A passive is one unit I would buy second hand. It won't last for ever, but it should be pretty indestructible.
 

never did anything for my system.
Agreed that passives are not recommended foe every system. You have to carefully put together a system so that passives can fit in. But a good passive can out gun an expensive amp in a matching system. That is my experience.
The Tortuga Audio LDR is pretty nice !
I had the Lightspeed and I liked it too, but it`s nice to have the Tortuga remote with its volume and balance control sitting right there next to me.