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?
Even with the volume turned all of the way up the CD player is loaded with 33K ohms and the Zout of your player is only 50 ohms, a ratio of about 700:1. Conventional wisdom says at least 10:1 with higher better and no benefit beyond 100:1. I think 10:1 is a bit low but you are in a very good place. I would be tempted to try a Placette or a transformer control with those ratios.
Pubul, the output voltage isn't the issue, just about any CD player has enough voltage to drive any amplifier to full volume. The problem occurs when the CD player output impedance (Zout) is too high compared to the load it sees which is a combination of the input impedance (Zin) that it sees from the passive and the amp.
Many passives have a Zin of 10K or less and this is further reduce by the Zin of the amp. At full volume they are in parallel so a 10K passive and a 10K amp would result in a 5K load for the pre. That is problematic for many CD players and phono stages no matter how much voltage they can generate with no load applied.
I can understand frequency abberations due to impedance matches, but why would a passive ever be any less dynamic?
One explanation which I suspect underlies those perceptions in many cases would be upper treble rolloff caused by the high output impedance of a passive preamp interacting with cable capacitance that is excessive in relation to that output impedance.
Upper treble rolloff would result in dull and sluggish transients, which very conceivably may create the subjective perception of reduced dynamics.
Maybe, but my CD player puts out 4volts in high setting, I would think that would drive anything without any help from a preamp. Impedance matching I get, "drive" seems to be a strawman as far as dynamics.
Pubul57, I thought this thread was closed a long time ago and here you are still carrying one.
Maybe dynamics can suffer because of what I said in my very first statement here. The source is not designed to drive anything. The source signal is designed to flow freely with it's signal boosted by the preamp.
I think of it as an amplifier driving a difficult speaker load. The sound of the amplifier is compromised opposed to the same amplifier driving a very easy load. Now it sounds better in every way.
The issue of dynamics is sometimes commented on when discussing passives, but I'm not even sure what that means. Does it mean that passives sound compressed, homogenizing the differences between soft and loud volumes in a performance? I'm not sure why that would be. I can understand frequency abberations due to impedance matches, but why would a passive ever be any less dynamic?
I have a P-L-P (pathetic little preamp) which is a 25k TDK motorized pot. At the risk of being called tin ears, or worse, my Adcom GFP-750 could switch between active and passive and the differences were virtually inaudible. Maybe becasue I listen at 60-70dB. Active a tiny bit more dynamic, passive a tiny bit clearer/ less grainy.
Ngjockey, not everyone who owns a passive is passive. I live an exciting life. After slopping the hogs I return to my listening room where I quickly fall asleep enjoying my passive preamp. My corn field don't care what kind of preamp I buy!
That is very true, for some no active beats a passive in their system. So to answer the original question, many use them becasue they are a very viable opton to SOTA sound, though some still prefer actives for their own reasons, and it not a right or wrong difference, just two approaches and choices.
I suppose that if your on a budget looking for the biggest bang for the buck than a passive could be the solution. On the other side of the coin there are some audiophiles that have enormous amount of money to spend towards this hobby and still go passive. Even a TLC-1 would require a substantial investment to get Smc's upgrades.
Chatta, that is beyond question. I've been going back forth on this a long time, I've concluded that great active linestages are better than passives, but that passives are better than many actives. But there is no doubt, that if you are on a budget, you will get exceptionally good performance from a passive for far less money than getting something comparable from an active at any where near the price point. A nice feature of the CD player is that it has a low and high output level, I can tell you with 4v output stage, there is no loss of dynamics with the passive setup (not reall a problem with 2v either).
The Clio 9 is finished and in the system breaking in. Early returns are favorable. This design requires a bit more attention to impedance matching than other TVC designs, but the benefits are very easily heard.
It is all about system building and matching between components, to the point where it come sometimes be a little misleading to even say what a particular tube sounds like absent any information of the circuit it is used in, I know the Roger Modjeksi's EL34 sound is different the CJs EL34 sound, so your left with the question, what does an EL34 sound like, and answer of course is, "it depends".
So I've been listening to the Goldpoint for a few hours, and without comparing at the this point, I would say that for $2,300 to get a Goldpoint ($312) and a Music Reference RM10MKII ($1950) you could be pretty darn happy running a pair of Merlin VSMs. For $312, the Goldpoint, in the right system is "stupidgood". As good as the Joule or Atmasphere preamps (or the CAT I used to own?)? I don't know yet, but you would be surprised how darn good a $312 preamp can sound.
To summarize some of the posts here and in addition to other aspects I have learned I didn't know before that there are two kinds of passives, resistor and transformer based. Argubly folks swear by both designs and the use of passives require more attention to the proper selection of associated gear and cabling. But once set up properly the results can produce a dynamic but superb sound.
I fell into this not knowing alot about passives but in my particular case the guess work was somewhat taken out by pairing a McCormack TLC-1 to a McCormack amp which has a high input impedance and was obviously designed to accomodate passives. Coupled with highly efficient speakers to the tune of 102db produced a very dynamic, smooth, and spacious sound. I can reach sound levels that challenges actives. It is my opinion that I have not heard a solid state active preamp that compares. The only other type of preamp that I would ever consider as an equal would be a tube preamp but I am leaning more towards the passive because I can leave it powered up all the time and is ready when I am plus it sounds damn good. I will eventually have Smc upgrade my TLC-1 and DNA Deluxe amp or possibly try other passives like the VRE-1.
I am using a DIY ALPS 10k passive to feed an Audio Research VT50 and a Powered Sub. The IC's to both amps are low capacitance. This has resulted in a very spacious lifelike and tonally neutral sound with all the dynamics I need.
It did help. I ordered a 50 kohm resistor passive from Goldpoint. I do think that 9kohm (I did have a Placette too)wa a bit problematic, but I was not A/Bing with a TVC at the time. But I did have the Placette Active (buffer, no gain)and it was signifncantly better in the bass - but that might simply have been an issue with the 9kohm Zin. Well, I'll have it to listen to soon enough. Thanks.
From a measurement standpoint resistors should beat transformers, but an awful lot of people claim they like the sound of the transformers better. My opinion is either one can sound very, very good if properly implemented and this is one of those issues where it comes down to personal preferences.
I tried a Placette in a system before I was biamping and it sucked the life out of it. I talked them into building me one that had an input impedance of 100K instead the stock 9K and it sounded wonderful. I compared it to some Slagle transformer units and to tell the truth couldn't say say which I really preferred, leaning a bit to the transformers but they were both very good. Now that I biamp I don't use a preamp as I control the volume via digital processing in Pure Vinyl software.
I know, not much help but at this point I think you need to try both and see which you prefer.
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.
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.
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.
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.
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.
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.
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.
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).
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?
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?
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.
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.
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?
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.
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.
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....
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.
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.
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.
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.
