There seems to be a school of thought that between two well-designed (read no major flaws) CDP and AMP, the best PREAMP is NO PREAMP at all (let's assume that the AMP has a sort of minimalist volume control).
Is this a solid and robust statement? What would be situations where this is not true (still no major design flaws)?
My preamp is the heart of my system. I cannot imagine not having it. It creates the overall sound signature for my system that I like. I would have a sonic mess without that control over the sound.
Remember that if a CD player has a volume control, it basically has a very simple preamp built-in.
Try plugging a turntable, tuner, and other devices directly into the amplifier and let us know how it goes... The turntable even needs a separate preamp before regular the preamp.
in my opinion, regardless whether the linestage and volume control are in the CD player or preamp, the quality of these parts are key. if a dedicated preamp has a better linestage and volume control than those in the CD player, the system will most likely sound better with it.
Depends on your system...and wallet. A well designed passive volume control does very little to degrade the signal...I,ve owned the Bent Audio passive around two years ago. Great product that simply smoked all before it in my system!
That said, a system and room change caused me to need gain to reach the spl's I had in the old system/room...had to go back to an active preamp.
I found that active preamps are far and few between in matching the level of sound quality I had with the Bent Audio passive unless you spend big bucks...something I did not want to do.
After around a year, I found on the used market a tubed preamp that does replace the Bent's qualities in every way.
Had I been willing to spend $3,000 and up for a preamp I'm sure it would have been a more easy a task.
My opinion on your question: "Is this a solid and robust statement?"
Passive volume controls are better than all but the best active preamps. Passive volume controls do not work well in all systems. The best active preamps "sound passive" while only adding gain...and of course more options.
Not at all always true. It really depends on the driver stage of the source, which is often a cheap OP amp. Furthermore, volume controls on CDP are often in the digital spectrum, which means that when you lower the volume from full, you are affecting (lowering) the sampling rate of the digital signal. There are sources out there that have real analog volume control and exellent driver stages... where a good pre-amp might just get in the way of the music, but I think it is more the exception than the rule.
The appropriate preamp is system-dependent. Preamps can be viewed as a combination of a passive attenuator and a gain stage. The issues that need to be addressed are: Are output and input impedances compatible; Is there enough gain or excessive gain in the overall system; Is the built-in "preamp" output of the CDP of good quality or is it advantageous to take a direct out (bypassing the built-in if possible) and use a better quality preamp stage?
I have found that in real life passive pre's can sound very thin and bad. I'm sure it's system dependent, but if the impedances don't match well, it will sound bad.
Sogood51, your statement doesn't say very much. "Passive volume controls are better than all but the best active preamps. Passive volume controls do not work well in all systems" It is like saying French bordeaux is the best red wine out there but it is not for everyone. How is that better than all and yet it is not competetant in some system? Would it make sense to say that best active is better than all passive because it is suitable for all systems?
Actually SoGood also answers the question in favor of preamps.
You have to spend what he calls "big bucks" to improve over a well designed passive volume control.
Note first the volume control has to be well made/designded. Note also that if you have the bucks to spend a preamp is better even in his opinion.
I personally also want/need a preamp. I just don't listen only to CD's. Also a lot of CD's are poorly engineered. The good preamp will make those CDs sound better than the raw data.
French bordeaux?...hardly "essential" to the act of drinking wine.
Volume control..."essential", ever try listening to music without it?.
Let me be more clear for you:
If one only needs to control volume, a well built passive volume control (in my case...Bent Audio passive)... you will in my experience have a hard time finding an active preamp that does not degrade sound quality to a greater degree than the passive unit at under $3,000 (new). I'll mention that I paid $1,100 (new) for my Bent Audio passive.
Very good active preamps do not degrade sound quality to any large degree...no advantage to a passive here IMO. I'll use Placette Audio as an example here because they make both types of components and are well known to audiophiles.
I have listened to the Placette passive but not the active. The Placette passive almost made it into my system and was better sounding in some ways than the Bent Audio unit I went with...yes, even passives sound different.
A search will confirm that the Placette active preamp tops the passive unit in sound quality...no supprise and answers the question...NO, it's not always true that the best preamp is no preamp, although...it can be "sometimes" true up to a point.
In case you did not know, passives do not mate with all components so will not work well in all systems...the main reason I sold... after changing speakers/amp/room as mentioned above.
Agree and disagree with some of you. When I was looking at preamps I found that many of the high end preamps had just OK volume pots. When I was looking for a replacement volume pot for my preamp, I researhed what the manufacturers were using versus what was available as a "better" volume pot. It was intersting in also speaking with First Sound and what volume pots are in their preamps. So as much as this thread is about to preamp or not to preamp, you should check what volume pot is in your preamp first IMO.
Bigkidz, could you elaborate on what was interesting about First Sound's volume pots? Just curious because they're on my shortlist to audition. Thanks, Ken
I think the accurate answer is yes and no. It depends on the system, components, and match-ups. I had a Wadia 16 based system directly driving a pair of Clayton monos and Quadrature DSP-5a's which was really nice. Currently, I have a pair of Soundlab M-2's and Merlin VSM-MM's and in both cases the soundstage just doesn't seem to be anywhere near as solid and fleshed out with a direct drive vs. having a preamp in the system. Hope this helps but I really think this is purely a system dependent issue.
I have tried the following passive devices and CD players with analog volume controls;
Muse Thalia CD/DVD with all recent upgrades Resolution Audio Opus 21 CD Audio Aero Capitole MKII Sig version Audio Aero Prima MKII Placette RVC EVS Attenuators Quad CDP 99 Cary - various CJ CD player - forget the model# Gamut with active and passive stages Berning ZH270 with no pre - has volume
I so wanted to go preampless and save money. I love simplicity also. Some of the above, in fact most, sounded good even great, direct into my various tube and SS amps. In fact,I have gone preless for weeks/months at a time.
My experience in every instance, yes every one, is a good preamp improved the sound in various ways. Here are my specific examples.
1) Muse Thalia direct into Mcalister Audio tube amp and March A400s SS amp VS Bel Canto Pre6
The pre 6 gave much improved bass on both amps. Much more dynamic and firm. The highs were more detailed with improved imaging. A more balanced sound. Transparancy actually improved.
The Muse has an excellent analog volume as an FYI.
Now at first the Muse direct seemed preferabe, but after 10 days of going back and forth the above become obvious.
2) AA Capitole direct into a CJ MV60 tube amp and Mcintosh MC402 SS amp VS Aesthetix Calypso pre
Well, the direct route was very good on both counts. This is a great player - no doubt. However, when I introduced the Calypso I was astounded by the improvement. As an FYI this is a great combo! The mids and highs were more intimate and "in the room". Again, the bass firmed up and went deeper. Things simply sounded more right and alive - less smooooooothed out if you will.
3)RA Opus 21 direct into Blue Circle and JC1 monoblock SS amps and Bruce Moore Dual 70 tube amp VS CJ LS 16 pre
The CJ simply gave more meat and foundation to the music. Without it the music sounded thinner and more threadbare. Now the sound direct was very good. If I did not have the CJ on hand to compare, then I would have been very satified with the sound. Having the CJ spoiled the works!
I won't bore you with more comparisions, but will share this. The BV Audio P10 pre also improved the sound vs. the Placette RVC. Again, bigger stage, deeper bass and improved detail and LIFE to the music.I found the EVS attenuators very, very thin sounding on several amps compared to several preamps including the Tom Evans Vibe.
I have done other comparisons and never has preless been as good.The Berning ZH270 amp became fuller sounding with improved dynamics and body with a Joule LA100 MKIII preamp.
I sell gear for folks and have been blessed to have many of the finest pieces of gear in my house to "play" with. I only listen to CD's and have longed to dump a pre and save money. My experience has shown me it can't happen for me, at least with all of the combo's in my treated listening room.
A good pre just gives music more body, soul, weight and life. I am sure I will get to try other gear and look forward to be proven wrong and save money.I am open and willing :-)
Bill: thanks for sharing your experiences. My question now is why? is it because an active preamp "massages" the signal that comes out of the CDP (for example, it cleans the mids, tightens the bass) therefore making it a "better" CDP (even with top notch CDP)? or, there is something that the PRE does to the operations of the AMP itself - say it allows the amp to operate within a more efficient or "comfortable" range? I know this may sound a silly question but it would seem to me that looking at the sequence of gear in the system, a PRE improves the input signal fed to the AMP rather than magically improving the AMP. However, I often read about the PRE-AMP combo as if both were co-dependent, almost independent of the source.
Great question and I don't have the answer. I simply report my experiences as I am not a tech dude or electronics expert. Perhaps others can help. All I know is with all of the various pieces of gear and combinaions of gear my music was improved with a pre. I am sure different reasons for several of the gear match-ups. Perhaps not. Sorry as I do not know why. It just is. Ha!
Thx Sogood51 on your view. I had try few passives including the Placette and never like them just like you said about matching. The Nigra passive is nice but only if you have high output CD player like the Wadia. Too weak in most of the application. It sounded slower and less dynamic than active preamps. As far as Preamp to Amp matching, I never have any problem with good active preamps regardless of which amp I'm using. Per Dave and my view too, a good active preamp doesn't degrade signal or very little. IMHO, A perfect preamp should be less colored and yet it doesn't mean it is bright or harsh sounding. It should be transparent and very open sounding. In most cases, tube preamps tend to sound more open and less compressed than the SS preamps. However, many users complains that some tube preamps has doesn't produce lower frequency as deep as the SS preamp. The only time that active preamp would be an issue is when you need the phono stage in the active preamp. This part requires matching with the phono cartridge.
Alway gonna get better and more full sound in almost 9 out of 10 case's with a preamp.. It also adds some of the extra gain and voltage UP you need to drive deeper bass and added weight. Most of the Hi-end CD players have always gotten a bad rap in bass slam running direct, I do not have first hand on this but have heard many models with and without preamp, always go preamp, my preference is with Active and mostly Tubes, but some excellnet solid states as well, Not sure about passive, but would guess you need subwoofers in a system unless you got some super frequency speak's I never heard of or heard.
Matrix: your "theory" or "experience" should I say would then lead me to believe that even the best CDP may benefit from having its signal "transformed" via an active PREAMP to tighten up the bass and also increase gain before getting into the AMP. That makes sense to me but is somehow against some well-circulated opinions that a true "Class A" (as in Top notch) PRE is no PRE at all or Passive. Thanks
My experience mimics that of Matrix, and that includes having run both the Audio Aero Capitole and the APL 3910 direct, two very fine CD players in my book.
I think there is only one theory: The moment signal left the source it is already degrading. The active preamp helps restore some of the lost signals while the passive just let it flow through.
S23chang I think in theory and practice to our ears that could be very true. Also the fact that the meitner comment provides good proof to practice, as I would agree that should be as good as a seperate pre if not better in some case's
Thanks a lot guys, I am surprised to see that there seems to be a consensus around active PREs that easily...so, when people talk about passive PREs and how it maintain the integrity of the original signal "no more, no less", could it be that it is in fact "less" (degradation of signal)and also a little bit of audio snobbery to KISS when in reality the signal needs to be restored by some active mechanisms?
newerphile, It's just not a universally correct conclusion that passives are better.
I think one of the flaws in the "passives are universally better" school is that cables are regarded as having unity gain independent of frequency. In fact, cables (and their interactions with components) contribute to a network which can have an audible frequency dependence. One of the most important jobs of a preamp is to match the output impedance of the source plus its cable's capacitance to the input cable and input impedance of the power amplifer.
A confounding factor for resistive passives is that the effect they can have on frequency response depends on their setting. In some circumstances, higher volume settings will attenuate the highs more. If the power amp gets harsh at loud volumes this can be a "good" thing.
At an earlier stage in my system evolution I had a Tom Evans Microgroove phono amp driving a tube power amp through a resistive bridge passive attenuator and it worked fine--probably because the Microgroove had very low output impedance (hard to get the specs). However, my present tubed phonoamp absolutely requires a preamp (CJ Premiere 16 2)for uniform frequency response.
Then there is the question of overall system gain required to achieve the sound levels required. Most modern digital players are capable of producing output voltages that will saturate the power amplifer. Thus, their outputs need to be attenuated and extraneous amplification is just adding noise...or perhaps masking an undesireable artifact from the source. Still, an active preamp may be required to achieve the proper impedance matching.
In the case of vinyl-based sources with low output cartridges there may be a requirement for additional gain to be made up by the preamp as is the case in my present configuration.
It can take a pretty good (read expensive) active preamp, and a highly resolving system, to start hearing the impacts referred to above. If a system is put together appropriately a passive will do just fine.
The choice for passive versus active preamps is highly system dependent and there is no universal "always true" answer.
smokester - very interesting response. I have been researching passive preamps of late and have been getting quite confused in the process. Resistive versus transformer-based versus autoformers, where does it end. Interestingly I had a conversation with the owner of First Sound yesterday as I was interested in their passive preamp. Bottom line, he suggested I look into one of his active preamps. Go figure... (no pun intended).
Thanks. So now the ultimate question: it seems that there is a strong measurable factors rationale behind the use of the appropriate active PRE, namely impedance, gain, etc. Does this mean that it is safe to shop based on measurements that "match" the rest of my system to short-list a few PREs or is it a case of meaningless measurements and the "perfect" match is purely based on listening? Thanks, this is a great source of info for a newbie like me.
S23chang: I think it will come down to that! I looked upon the specs of my source and my amp and I see no particular problem with gain (out 2v, in 0.4v), nor impedance (out 325, in 35k). I guess I am free to listen to any preamp then, active or passive!!!!
newerphile, Yes. There are some obvious measureable things to avoid otherwise you may possibly be covering up one ill with another. However, I think the general concensus is that, once you have the right gain level and impedences matched, always trust your ears.
"I guess I am free to listen to any preamp then..."
Careful. A resistive passive can interact with interconnect cable capacitance to form a low-pass filter so one should evaluate the other components in the system.
There are other, less commercial, technical papers on passive preamps which will probably be revealed with a google search. I can't put my finger on them right now. Also, maybe try the DIY forum over at audio asylum.
Can you explain to me why you fell that 2V is not enough for passive if the amp has, for example, 0.4V input sensitivity? I trust your experience and will likely go active but that puzzles me a little. Thanks
3V is almost double the volume of 2V. It sounds more normal while 2V sounded sleepy and slow and weak. There are few CD players gives you 3V output but it all comes with $$$ price tag. Meridian Accuphase Wadia
Not sure about others since I didn't measure them.
Intuitively the answer is Yes. However, in practice in ain't necessarily so I've found. My Wadia 6i will drive the ARC VT100 direct but I can truly detect no difference if I insert the ARC Ref 2. As a purist I wanted it to be better but I can't honestly say it was. Maybe it boils down to the quality of the CD output stage? Anyway, no rules or opinions can replace YOUR ear. If you like it that way - listen to it that way.
HI, First post. It defies logic but I just installed a Krell KAV 280P pre between my power amp and tube DAC. And yes it does sound better. Better detail, better dynamics. Don't know why. Don't care.
I lived with a Sonic Euphoria passive pre between my Pass amp and my Dodson DAC. It was incredibly transparent and revealing. It showed me just how good the Dodson and Pass are. That said, I preferred the sound of my system with the Modwright preamp in the chain.
I have never heard a CDP direct to amp that I could live with.
Actually, I have been reading and hearing more and more that CDP into AMP direct is very very seldom a good idea. I think you guys have highlighted gain and impedance issues as possible cause. What would be a typical sound "default" of a direct CDP to AMP? too harsh a sound (digital glare) or, opposite, slow/fatty mid-range ? or it varies? Thanks
Newerphile, My opinion, lost dynamics and frequency extremes, could sound flat and yes make it seem more like a digital boring source. maybe not every case but in most, basically look at it this way a preamp is sorta line level amplification like an EQ would be, it will boost some of the frequencys to a fuller sounding range not because that is really its intention but because no matter what you are playing with the tiny voltage signal coming from the cd and any extra gain added to a signal that small well will sound like 10 times more effective than going from like a 50 watt amplifier to a 350 watt amplifier if that makes sense, is it pure?, is it Zero distortion?, nothing is, but the closest it sounds like emotion in the music the better in the end, this is mostly achieved by using a preamp in the chain than not from my experiance.
I've tried it in the past and it's not bad. But the preamp/buffer stage makes it a whole lot better IMHO. It never sounded slow or fat. Just slightly hard on cymbals and such. It's like having too much of a good thing that wears on you over time.
If CD playback is your only source then you'll just need to get an expensive CD player with high output + volume control. In this case, the "less" component is better off. This is different from having a passive preamp. I would go with that than having a passive preamp in between the sounce and amp. The ONLY drawback is CD player choice. You will be limited to less than a dozen of expensive players to choose from.
As far as DAC goes, it is same idea as CD player with volume control. In this case, you'll be limited with DAC that has high output plus build-in volume control.
We have the same fancy (or as they say in the car industry, "pants") CD player as TVAD, and also find that we prefer having the preamp in the chain. It allows for better separation of the instruments, a preferable 'gain floor' as a complimentary support to the amps, and it conveys a more meaningful heft and density to the music. If we run direct--and our player does have an outstanding hybrid attenuator--the soundstage collapses, and on anything other than light chamber music, vocals or soft jazz, I'm just not feeling it. We take the preamp out, and it sounds like the music is struggling to get out, losing a sense of ease and realism in the process.
Some people will choose a configuration according to sonic preferences, while others wouldn't think of adding the preamp in the interest of maintaining a purist's approach. As TVAD suggests, you'll have to decide for yourself.
I have never heard a situation, where price was not a limitation, where NO preamp or where a passive preamp was superior to a really good, system-matched linestage. I know the mantra about sufficient output and compatible input and output impedance and short cable run, etc., but even in systems that don't need any gain from source (like mine), a good active linestage simply sounds more dynamic, projects a more realistic image, and pulls the listener into the performance in a way I've not heard passive linestages do. I suspect that the putative superiority of passive units may be a superiority AT A PARTICULAR PRICE POINT, but not absolute superiority.
Now, as far as NO preamp at all, with digital sources, one would have to consider whether the volume control is digital or conventional (variable resistance). I don't know if it really is the case, but a lot of listeners claim that the truncating of low level bits to achieve digital volume reduction is not sonically desirable, so playing the source at maximum volume and attenuating with an outside volume control is superior. If the digital source has an analogue volume control, I suppose the issue is whether that volume pot is better built than that in the linestage it is hooked up to -- if it is inferior, one again might get better results by setting it at maximum and using the linestage volume control to attenuate the signal.
Well, lets see...I can think of a member here at Audiogon with a mega buck system that uses (or at least did use) a passive in his system....I don't think he's hard of hearing, and he's sure not a newbee.
If I recall he had the Placette Audio passive in his system.
I've tried two passive solutions in my system - a Bent Audio TVC with copper transformers and a built-in resistor attenuator in my Audion Silver Night. I've tried various configurations: I've used the Bent with five different amps, both tube and solid-state, and I've tried the Audion nude, with the Bent and with a couple of actives. This has been done on two different speaker systems, both of them efficient and high-res. The source is a balanced AN DAC, with quite low output impedance and sufficient, though not excessive output voltage.
The conclusions that have remained relatively consistent across most configurations are:
- The Bent was sonically problematic in all my configurations. It's very smooth, but robs enough dynamics and detail to make the sound boring.
- The tube preamps I've tried (Canary and Audion) have better dynamics than the Bent, but equivalent detail and higher noise. They tended to be more fun to listen to, but were more coloured (warmer).
- The resistor attenuator in the Audion sounds quite good nude. Putting the Bent or one of the tube preamps in front of it mucked up the sound in various ways.
- The joker in the deck is the solid state Tom Evans Vibe/Pulse. I tried it with three amps, and it produced better sound than any of the others. It even improved the sound of the Audion amp when driving its internal attenuator. Imprevements were in the areas of bass and treble extension, dynamics, detail, neutrality and transparency. The downside of course is that it is two to four times the price of any of the others. I ascribe the superiority of the Vibe to its higher output current and lower output impedance.
So, a passive can be better than a medium-high quality line stage (the case with the Audion's attenuator), or it may be worse (like the Bent). A very good preamp is likely to exceed the quality of a passive because of its current and impedance advantages.
Dovetail asked Bigkidz (in this thread, I think) what the discussion with First Sound entailed about volume pots or attenuators, etc.
While I have no way of knowing what Bigkidz and Emmanuel Go (First Sound) might have spoken about, the First Sound website says their stepped attenuators are made with Holco or Vishay resistors. I believe the upper models have the Vishays.
I have tried a passive pre-amp (First Sound, before they went to the active design) and have heard many systems with and without pre-amps. My system sounds better with the First Sound Active pre-amp than with the passive (or without a pre-amp at all). Several folks I know have tried the same experiment; they all prefer their systems with a good active pre-amp. Doesn't mean that no pre' can't be done well; I just haven't heard it.
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