Seldom has there been any discussions on passive preamps in the forums and although my experience with them has been limited I have found them so far to be very enjoyable and refreshingly different. They seem to fall into their own category, somewhere between solid state and tube. Finding a preamp that is satisfing has been difficult. Some active solid state preamps can be very good but they seem to inject grain to some degree in the upper registers and some tube preamps are not too far behind. So far I think they should at least be matched up with an amp that has sufficient gain which is often overlooked. Which passives are you using and with what amp? Why do you like them?
Pubul, I see your point, they do have limitations, or perhaps better put they require careful implementation, but that could be argued for just about anything. After years of experimenting I've found that a couple of stages of triode amplification and very high efficiency speakers is what floats my boat. I would venture to say that if more people heard one properly implemented they would agree. This type of system is a perfect candidate for a passive pre.
I agree completely, which is why discussions and assessments of of amps, speakers,cables, tubes etc. outside of complete system context (let alone personal taste)while useful as a guide, are no substitute for listening to something in your room with your other equipment - which is why I always say "with my amp and my speakers, this preamp....."
Passives (I am referring to TVCs) are amazing if you have the correct system matching. I am always surprised to hear wimpy and anemic associated with Passive preamps. Either I have a very good system match or people have not heard Passives with R-Core transformers.
i settled on Axiom,s passive pre.I,ve a ar l/s2 Special 2 of a kind modded piece. Great sound.Bested forte 40,rotel 1098,& the ar,also a techs super piece .Mated with the rite cables,crisp, clear sounds.very life like.Try the modded,I wish I had
I am not aware of one single amplifier manufacturer that designs a matching passive preamp to compliment their amplifiers. If you want to select components, speakers and wire around a volume control it's ok with me. I prefer the sound of an active preamp because it sounds like music.
There is at leat one fella that designs a passive preamp around his amps, Roger Modjeski if Music Reference - a "simple" resistor-based attenuator - of course it is house with an active phono stage. He is adamant about the superiority of a passive linestage, which get's my attention knowing is perfectly capable of designing any kind of premaplification he wants. I still use an active preamp with his amps though....
I remember Mr McCormack saying his amps were designed with a high input impedance so they would work well with passive and tube preamps. After talking with him several time about preamps I got the feeling he prefers the sound of passives, though he will tell you there is a difference in the way the two present the sound. Its just a matter of how you like your sound (do you prefer your coffee with creme or without). I was at that point at one time, I liked the slam or greater impact in the bass region that his active offered but I also liked the openness that the passive had. The Ultra upgrade to my TLC gave me both, at first I thought it was the buffered output but then I remembered trying that before the mod and it wasn't the same.
Phd, I have no intention on selling any of my gear I've worked to hard and sacrificed to much to get where I am with it today. Plus I like the flexibility I have with the McCormack gear in my two channel/Home theater setup.
I would like to apologize to everyone one for the bad grammar in my earlier post, I thought I read through it better. I promise no more drinking and posting. The good thing is I don't have to worry about he telephone polls jumping out in front of my words. LOL
Pubul57, I don't have any direct experience with attenuators (though have done quite a bit of research on them). I have a long tome audiophile friend who has helped me for many years suggesting and auditioning gear. We have listened to alot of music together, live and recorded, and, not only do I trust his ears, but he has guided me a great deal into trusting mine. He uses attenuators - and has had the Ayre KXR, ARC Ref 5, Lamms, etc. While he says the preamps are excellent, and urged me to audition them, he uses attenuators (he only cares about sound, not how great expensive gear looks in his racks, convenience, etc). I was considering passives as my CD player was overloading my active preamp, but when I experienced the sound of my CD player direct into the amps, I just cannot believe adding any component (+ cables, etc) into that signal chain could possibly be an improvement. My decision based solely on how incredible it curently sounds and basic electronic theory. I feel the least manipulation of an audio signal, the best. While a passive would not necessarilly manipulate (definately not amplify, which usualy always distorts)the signal, it does add cables, etc (either transformers, resistors, etc) into that signal chain (and must be compatable with the rest of the gear in the chain). My turntable/preamp and my SqueezeBox/Dac still go into my active preamp - they did not sound as good direct into my amp (actually an external crossover) so definately compatability issues there. The CD player & crossover just seem to match perfectly. I really urge everyone with a CD player (or DAC) with a volume control to try the direct connection. You may be as surprised (actually, I was floored) as I was, and stil am. If I did not have volume capabilities on my crossover, I would already have a passive in my system.
I am not aware of one single amplifier manufacturer that designs a matching passive preamp to compliment their amplifiers.
Three manufacturers were mentioned in this thread: Roger Modjeski - Music Reference, Jack Elliano - Electra Print, and Jeffrey Jackson - Experience Music.
Also, a number of manufacturers have implemented passive volume controls in their integrated amp designs. A couple that come to mind are Vinnie Rossi - Red Wine Audio and Paul Weitzel - Tube Research Labs. Ralph Karsten at Atma-Sphere offers a passive volume control upgrade for his OTL designs too.
I prefer the sound of an active preamp because it sounds like music.
Rrog, once again a dogmatic statement that fails to take into account all factors. If you want to say you've never heard a passive that sounds like music then it appears that would be true, but I guarantee you they do in the right system as many have stated in this thread. Are you saying you have golden ears and all of us, and there are many thousands, who prefer passives in their systems don't hear well?
Pubul, attenuate means to reduce or weaken so any volume control whether resistive or inductive is an attenuator. For some reason you usually see that term with stepped resistor controls and not with TVCs but they are both attenuators.
Herman, part of you thinking is that passives in the right system are superior to actives, I wonder if it might also be true that passive resistor based attentuation is superior to tranformer or autoformer passive attentuation IN THE RIGHT SYSTEM, due to the much simpler design, or is the impedance matching that comes from TVC/AVC is simply almost always better in most systems. Modjeski, who I obviously think highly of, argues for resitor based attenuation, but that flies a bit in the face of what you will hear from most Agon passive adopters. Now Roger actually has an explanation why that I can't understand:), but it does seem to be based on some knowledge of electrical engineering of which I know almost nothing.
Sure, it is close to a straight wire. But, they must also have a disadvantage. Alber Porter wend from Placette to DarTzeel, but why? What does a great active linestage do that the passive can't? The answer is straigtfoward when it is an issue of needing gain or impedance matching, but he did not seem to need either in his original set up. However, I'm interested in getting some insight into the resistor versus transformer issue, on the assumption that most all of us are in no need of gain for our sources and that our amps are sensitive with fairly high input impedance.
You all are making this appear much too complicated. I've plugged my TVC into a few friends systems and always had impressive and consistent results. I've changed amps and sources. I currently have a far from ideal load with long IC's, a 10K Zin hi-pass and parallel low-pass/bass amp. A mismatch seems to be the exception I haven't run across and I've seen some unexpected active component or amp/speaker mismatches.
I have played with a couple DIY attenuators but not as a system volume control. One was for a biamp system to control gain and the other replaced a pot in an active preamp. Probably dissuaded by the negative reviews. The TVC was a fairly cheap experiment that I didn't expect to work and, if I had believed some of the "experts", shouldn't work. There's a story but I would rather not mention names. It was a DIY project and it even worked well when I had it wired wrong. That's another story, not for A'gon.
Many of the RVC/attenuators have had a fairly low 10K Zin but, recently, there are more options for higher impedance up to 100K.
Yes, Goldpoint seems to offer a range of Zin ratings, but have no idea how that effects the Zout or what would optimal for a 100kohm load. I like the "idea" of an RVC, it just seems a lot of less complicated with less wire and iron that the transformer approach. Where is Aball when you need him?
Pubul57, you have done an excellent job of explaining the technical aspects of this subject and I as well as others have learned a great deal as a result. Given that, you now have my permission to go home and get some sleep! But I expect you to report back first thing in the morning, I don't pay time & half. In the mean time if we have any problems I will call on Herman to police this thread, as he may still may be angry.
no, no, no, no, no, no, no, no, no, no, no, no, no, no, no,
I'm not angry.
Passionate? ok
Tired of seeing people declare absolutes in a world with so many variables? ok
After so many years on these forums tired of seeing the same things debated over and over and over? ok
But I'm not angry. Amused perhaps after seeing the same preposterous statements repeated over and over (like passives are wimpy) but perhaps frustrated would be a better choice as it frustrates me that there are people like Phd who come here to learn and they get responses about passives that are so far off base that they are worthless at best and at worst scare the uninitiated away from a topology that could be the answer to their quest.
Herman, I am happy to hear that you share the same frustrations as I do but you never know when to take me seriously. I know you are not angry but still I respect you and have alot of love. Thankyou for being here to share your thoughts.
Herman, My previous statement "If you want to select components, speakers and wire around a volume control it's ok with me. I prefer the sound of an active preamp because it sounds like music".
And this is why there is a variety of equipment for sale.
I knew someone would come up with an amplifier manufacturer that makes a passive preamp. That's why I threw it out there and I'm not surprised it's Modjeski.
I did infact buy an amplifier with a passive gain control and it was the best amplifier I ever heard and still is. When Kron developed the Vaic tube he wasn't getting the results he expected, so, he went to a little amplifier builder in Italy called Mastersound to build and amp around the Vaic tube. The amplifier was named after the founder of that company, Caesar, and uses the 32V output tube. This amplifier makes all other amplifiers sound ordinary.
I also own a Manley Stingray which uses a similar design, but these amplifiers were designed this way.
Yes, many approaches to finding sound we like individually, why I will proabaly keep my Joule and Atma-sphere preamps, no matter how much I might like the Goldpoint - they will sound different, none like the real thing, but all enjoyabkle in their own right. Not only does Modjeski prefer passives, but has said the debate is really silly as he thinks the superiority of passives is clear. In sense he might be right, but obviously, many of us still prefer what actives do. Passives are so relatively cheap ($312 for my Goldpoint)that it seems to make sense to have one on hand to play with, and in case a tube or transistors blows in our actives. As for Modjeski, don't him going on power cords....
The manual for the RM-10 has a nice discourse on cable voodoo, not to mention ground loop hum.
I'm going to finish building my passive today. Sanded down, drilled all holes, and painted the chassis yesterday. Today its plugging in parts and wiring. Hopefully by tonight I'll have a new passive to try out.
Transformer based using Electra Print nickel core copper wound transformers. I was going to do balanced, but single ended for now until its fully tested (just easier to start). If all goes well I may build some more and sell a few here and there.
In a given system any active preamp of equal quality can be connected with good to excellent results.
With a passive attenuator there are many things to consider including: 1. What source will you use? 2. What speakers will you use? 3. What is the speaker impedance? 4. What is the speaker efficiency? 5. How loud do you listen? 6. How far do you sit from your speakers?
Rrog, If you want to say that the overall gain structure of the system must be considered then, yes, in some systems you do need the extra gain you can get from an active so the factors you listed which have to do with how loudly it can play do need to be considered, but that is true no matter what. It isn't something to consider only when you hope to use a passive. Having a system with so much gain that you can barely turn up the volume control is a problem just like turning it all the way up and it not being loud enough is a problem. To say your list is something to consider with a passives and not saying it is something to consider when building any system misses the point and is misleading, they are factors to consider with any preamp since either scenario (too much or too little overall gain) can be achieved with a passive or an active if the rest of the system has too much or too little gain.
Other than how loudly it can play and how much drive to the amp it takes to get there, the factors you mention have nothing to do with whether or not a passive will work well...speaker impedance? In fact you left off the most important factor; the ratios of source output impedance, passive impedance, and amp input impedance.
I don't think anyone has mentioned cable length and cable capacitance yet in this thread. Those certainly being factors that need to be kept to a minimum on the output side of a passive preamp. High output impedance into high cable capacitance (which is proportional to length, as well as varying widely among different cables) will result in upper treble rolloff, and long cables will increase the likelihood of other adverse cable effects as well.
Grant -- I'm not particularly familiar with the VRE-1, but I recall that it includes a jfet (active) buffer stage. Assuming that is in the signal path and is followed by a coupling transformer at the output, I'd expect the resulting output impedance to be much lower than in the case of a purely passive preamp. Perhaps that is why the long cable is not a problem for you?
Tvad, your VRE-1 isn't really a passive, is it? It simply has no gain, which isn't really the same thing - it certainly has buffering which, if needed, will overcome some problems presented to pure passives in the wrong system context, no?
The VRE-1 is not a true passive, it is a hybrid design with a JFET buffer stage that eliminates impedance matching issues. Great concept along the lines of the Pass B1 (JFET buffer) and the Bent Tap-X (user selectable buffer outputs).
Paul, I also heard the Pass B1 at RMAF that year we met up. I would have tried one sooner, but its not balanced and I already have too many single ended passives lying around.
I'd love to hear the VRE-1. Next time I go to one of the LA/Orange County Audio Society events I'll see if I can visit Steve before or after and listen to it.
Tvad, thanks for the invite. I'll most likely be heading out for the Brooks Berdan event May 22. Monrovia is not that far from Burbank from what I recall. I'll contact you as the date nears.
Herman, What would you rather have? A system that hardly plays above a whisper at full volume or a system that plays loud at 9 o'clock? To say the requirements for passive and active are equal can be misleading to the unsuspecting Audiogon member reading this forum.
At the end of my last statement I mentioned "and the list goes on". Meaning there are many more factors to consider, including impedances between source, passive and amp.
I don't know if you personally use a passive preamp or not, but let's do an experiment and say you do. Let's take your incredibly high efficiency speaker out of the equation and replace it with a medium to low efficiency speaker leaving everything else the same. Now what do you have?
I understand your confusion and the confusion of other inexperienced audiophiles like yourself that have not had the oppportunity to experience a wide variety of equipment over the years of being involved in this hobby and learning from the ground up so to speak.
This forum is a great place to help one another with an accumulation of experience in a helpful manor without rude or condescending behavior so we all can learn and enjoy this hobby together.
Herman doesn't sound inexperienced; not sure he was being rude either. But I do agree that a passive does take more thought to implement correctly than an active, no doubt about that IMHO.
Rrog, I'm sorry if you felt insulted but I was merely pointing out that your post had nothing that was exclusive to passive preamps. Everything you mentioned pertains to any system. I didn't point this out to insult you. I brought it up because your post didn't have anything that pertained to a debate about the pluses and minuses of passives vs. actives and it would be easy for the uninitiated who read it to falsely conclude that it did.
Again, I'm sorry if this offended you, but turning it into a pissing contest doesn't help anybody who is reading this and wants the facts. This debate will never move forward as long as you continue to latch on to some small piece of what I say and try to build a case around it. Example, you asked
What would you rather have? A system that hardly plays above a whisper at full volume or a system that plays loud at 9 o'clock?
I didn't say either one was a good choice. I said you could get either one with either a passive or an active if you didn't build the system correctly. I want neither one nor would I accept it. I've constructed my system so it plays near maximum volume with the volume all the way up. That's the way it should be.
You also stated
To say the requirements for passive and active are equal can be misleading to the unsuspecting Audiogon member reading this forum.
I never said that. In fact if you look through my posts I said that they require careful system matching, actives will work well in more situations than passives will, and that passives are not suited for all situations. How did you go from that to all requirements are equal? What I did say, and this is the whole point of my last post, is that you have to consider the same factors in regard to system gain when you talk about either one. That doesn't mean they have the same requirements. When you build a race car you need to be concerned about safety, reliability, handling, gas mileage, and many of the same factors you consider when you buy a car for commuting. Even though you consider the same factors it doesn't mean they have the same requirements.
You also stated
Let's take your incredibly high efficiency speaker out of the equation and replace it with a medium to low efficiency speaker leaving everything else the same. Now what do you have?
You once again are clouding the picture by focusing on just one facet of the equation, this time my speakers. Of course if you kept everything the same in my system and substituted low efficiency speakers it would be a problem. I could substitute a preamp that has 30 dB of gain and cause problems, I could substitute a source that had a much higher output and cause problems, and the possible ways to screw up the sound are endless. I picked a gain structure that complements high efficiency speakers because that's what I have. If I had low efficiency speakers I wouldn't build it with flea powered SET amps and low gain. Your whole premise of changing speakers is silly and has nothing to do with the debate..
Finally, as for my inexperience, I'm not sure how to answer that. It appears you consider yourself to have some experience but your incomplete answers that draw false conclusions and your use of convoluted logic would say otherwise. Why else would one bring speaker impedance into a discussion of passive vs. active preamps? Since you brought it up I'll run with it and say you are simply out of your league in this discussion. I started in this hobby in the sixties and I've put together good sounding systems using all manner of solid state as well as tube electronics including Conrad Johnson, Avantgarde, VTL, BAT, Aesthtix, Lamm, Mark Levinson, Naim, and Theta to name a few using all manner of speakers including B&W, Magnepan, Soliloquy, Wilson, Alon, Lowther, and others. I've experimented extensively with all types of room treatments and tweaks including many manfactured and DIY cables. I've built both active and passive preamps. I taught electronics in an associate degree program for 10 years, in my current system I built my woofer amps from scratch, the mid/tweet amps from kits and modified their power supplies, built the bass horns, and modified the output circuit in my DAC so it bypasses the active stages. That doesn't mean I know everything but I do understand the concepts involved in this matter. I have clearly and logically described what they are and why they matter. Since you continue to misconstrue what I say and latch onto small snippets instead of discussing the underlying concepts this discussion is pointless.
Rrog, there are quite a few people who chimed in here whose experience and opinions I trust. As with Pubul57, I can say for a fact the man has tried a number of different components and if he prefers active preamps so be it. I myself have tried a Cary SLP-98, Joule Electra LA-100MkIII, TRL Pre-1.5, Jeff Rowland Capri, all of which I have owned, and have auditioned a number of others including a very fine Herron preamp. I prefer the passives and that was whether I was using my 88db Spendor 1/2e speakers, 92db Audiokinesis Jazz Modules, or 95db Tonian Labs DL-1 speakers.
I think we've probably beat this subject into the ground. So I'll thank Phd for starting this thread, and people like Herman, Pubul57, Tvad, Almarg, and the others who offered constructive advice and opinions for contributing.
Herman, maybe you can answer this, under what circumstances would you expect a resistor based passive to perform better than an AVC or TVC. I know they address some issues of impedance matching, but they also add alot of "stuff" between the source and amp. What is your opinion. Roger Modjeski tried explaining it to me (he prefers resistors and no buffering) but I could not understand him after two minutes into his explanation.
You must have a verified phone number and physical address in order to post in the Audiogon Forums. Please return to Audiogon.com and complete this step. If you have any questions please contact Support.
