I have tried passive and always return to high quality active. There is slight gains in transparency with passive, but I prefer the dynamics and size of stage to a small % gain in transparency.
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There is no right or wrong answer. Each case will be different. PErsonally I would strive to minimize the role of the pre-amp. IT is needed for source switching if more than one source and volume control only for the most part these days. Everything else can be addressed elsewhere case by case if needed.
I have several older pre-amps around that I continue to use because they are there and they work well. Were I starting from scratch today, I would probably consider building around a high quality passive pre-amp with volume control and enough inputs and outputs to suit my needs. That's pretty much it. I would expect top notch results possible with this approach for lower cost if done right.
Hello Herb, I have tried to remove a preamp from my system several times over the last 20 years or so. Either by going direct from source to amp or using a passive control unit. Basically, all I really learned from my experimentation was just how important a preamplifier can be in the overall sound of a system.
I have found that preamps can be the most difficult part of a system to get right, but when you do, it's stunning, as Alan (Arh) has also noted. At this point, I do not plan any further experiments without preamps, in fact now I believe the preamp to be the heart and soul of the system. As usual, YMMV.
It is something I want to try as well sometime.
1) I like the simplicity of the solution for the task at hand
2) I am curious how things might sound if done right
3) I like the small size and low price
For now, I have 4 decent quality pre-amps to tinker with as needed and I have seen that all have been capable performers to meet my needs. They are all a tight fit in my enclosed audio cabinet however, a minor inconvenience when it comes time to dabble mostly.
I thought, with the Aesthetix Io with volume, even upgrading to Eclipse and dual power, that I would be safe -- no need for a preamp. I was wrong. I strongly suggest you listen to a good preamp in your system before going too far down the "direct to the amps" road. At least, in my case, even with a superlative source, it did not work out.
I've tried it and didn't care for it. While I don't think you need much gain at all, no gain seemed to blunt the transients and diminsh the PRAT in my system.
I had high hopes for the Portal Pinnache when Joe first put it out, but it seemed to suffer from the same shortcomings that other passive preamps that I had tried.
Like others here, have tried using multiple high end DACs as preamps and always end up liking a preamp in the loop better. Sound is better in almost every way with a very good preamp. Surprisingly even transparency is better. I cannot explain it. I want very much to have the simplest high end system I can create that still delivers top notch sound quality. I do believe it is the future, but not there yet. I've also tried passive preamps with varying degrees of success. Prefer an active preamp to the passive also.
I always went DAC with volume, (W4S dac2, and lampizator) with the idea that simple is better. And less to buy?! Hell yes. I have since added a Shindo Aurieges L and tried other preamps. Like others stated above it surprisingly added depth, image, and weight. And i do now believe it is the heart of the system and hard to eliminate.
I have to join the chorus and say if you're dealing with a "high"
quality active preamp the sound will be superior. Initially direct or passive
may seem more transparent but over time and continued listening it's
apparent that the sound is leaner and lacking the complete sonic picture
(tone, body, emotion and information). Jaxwired hearing more transparency
with his active preamp isn't a surprise. Top notch active preamplifiers are
essential to achieve the best sound from a system IMHO. Lots of listeners
have tried to eliminate the active but eventually realized that their sound
suffered in its absence.
It may be that active preamps often sound better.
The next question would be: why?
Synergy is always a consietation. Why would a good passive mated well be any lesser than with an active pre? Easier to mate correctly perhaps due to voltage and impedance matching? If that is done right, what secret ingredient is still missing?
There is usually a reason why some things work better than others.
Of course if a sub 1k passive can compete with the best active pres as some claim, that would be a significant thing.
passives have components that can also change the sound such as pots, resistors, transformers, internal wiring. Also except for transformer type passives there impedance changes with volumn setting. As I said before the Sonic Euphoria autotransformer based passive was the best passive I ever used but it had no where near the resolving power of my Shindo. You simply have to try with your own equipment
I had a good experience some years ago in my sunroom system.
I ran a Mark Levinson 390s cd player directly into a Pass Aleph 3 amp, driving a pair of ProAc 1SCs. Supplemented at the low end with a REL subwoofer. Cardas Golden Cross interconnects and biwire speaker wire. The system sounded great.
The ML 390s had an analog volume control that preserved the detail of the music and it also had a digital input for another component that could be switched in. No preamp needed.
Another combo that worked for me was a bedroom system. My sources were a SAE 8000 fm tuner and a Sony disc player. I used a passive Promethius preamp that used a transformer for volume control, and this fed a Carver M-500t amp connected to a pair of Thiel 3.6s. Not expecting too much, I was surprised at the smoothness and dynamics of the setup. Not having an active preamp did not seem a problem.
One thing I have noticed is that most of my line level sources have more than enough voltage to play quite loudly through my amps. Most of the time, my active preamps are just attenuating the signal. Very rarely do I ever play music so loudly that I feel the preamp is actually amplifying the signal. If I lived in an apartment or someplace close to neighbors, I would never play so loudly.
Hi Herb, look at this thread, it will explain most of all you need to know. And look at what Nelson Pass has to say about passive preamps in the 7th post.
And keep an eye on this thread for results for direct in observations on the sound when he does it.
A few thoughts based on my experience, which over the last 25 years has followed a convoluted path, from integrated amp, to no preamp with no volume attenuation, to passive with buffer, to another passive with buffer, to endler resistor based volume control, to Promethius Ref 4 TVC, to Promethius Signature TVC, and finally to Coincident Statement Line Stage.
Based on my experience, one can certainly go without a preamp if one is single sourced. If the source has a digital volume control, that is good. No ability to attenuate the volume gets old pretty quickly. My path was driven by economics more than anything else. I think you can do very well in a carefully built system pretty cheaply using passive volume control, particularly transformer volume control designs. I would still prefer an excellent passive to an average active.
I don't think you can get to the ultimate level without a top notch active preamp. It is more than just volume control and source switching. You need the active pre to drive the amps. Most sources just can't do that well. There could be other issues at work, but the results in my system were undeniable. Everything--- dynamics, image, resolution, you name it. Every aspect of musical reproduction was improved by adding the Coincident CSL to my system.
It is my opinion that a top notch active preamp should be the ultimate goal in every system, money permitting. But one does have some pretty good relatively inexpensive options while on that path.
I can't see sound waves either, yet they are there. My ears tell me the difference, not my eyes. I can't explain why anymore than I can explain why a power cord can make a difference, or tubes sound better to me than solid state.
I'm sure that someone can probably come up with some techno-marketing buzz words that may help you understand why, but in the end, all the proof you should need is in the listening. Trust your own ears.
"Trust your own ears."
No doubt that is the main key, but I also find that most things that really matter in good sound can be explained at least in theory. WHether the theory is then supported by the facts during listening or not is another story.
That's how science works without in fact ever 100% proving anything. Without theory or hypotheses at a minimum, there can be no roadmap for making informed decisions. Chaos would rule. Chaos is not a very efficient mechanism for getting anywhere. :^)
Try Mytek 192 DAC-Preamp which is mostly DAC.
It's the best volume control I've ever used. It combines advantages of passive and active amplification. If your amp is sensitive, you can adjust gain to unity to have maximum transparency. You can also boost it to have better dynamics and bass control.
Prior to that I used DIY passive pre, Classe, Bryston and McCormack preamplification. In all cases I liked minimal preamplification gain figuring that minimalistic preamp is just as good as passive but better.
In my second system (the one in the vertical cabinets in my system photos), I have 6 sources:
2) Squeezebox Touch
5) VHS tape
6) cable box
The last 4 feed into an old Radio Shack/Realistic unpowered "passive" 4 source switching box gadget I have had for years. This was a $20-$30 gadget as I recall many years back.
Then the "passive" source switching device runs into tape in on an old NAD 7020 receiver that I use for pre-amp only that feeds the TAD Hibachi monoblocks that drive my smaller OHM speakers and my Stax phones.
SB Touch runs direct into the NADs aux input and phono to NAD phono input.
This works quite well. None of the sources I am feeding into the passive Realistic box are SOTA certainly, but the performance is quite suitable. I have heard these devices running directly as well in the past, and if there is a difference, it does not seem to matter much.
That makes me think a true good quality passive pre-amp with a good quality volume control might work quite well. Definitely something worth considering if needed.
Whenever Al chimes in, i just skip to the bottom of his post and try to understand his conclusion. I thought I was somewhat smart until I started coming around here, haha!
I really love my Lightspeed Attenuator. It definately removed that last layer of haze I had at the time. I think it has incredible transparency and dynamics and it was $500. I think you'd have to spend 3 to 4 times that much to even begin to make an improvement, probably at the cost of some transparency.
I admire Al's technical knowledge as well but what do you expect him to say? This is strictly an individual case by case situation. A number of people have auditioned the Lightspeed, some love it and some preferred their active preamplifier. It comes down to what you hear and choose as better. There's no technical explanation to account for the variance in choice. If Al uses/ prefers passive or active it's still his personal decision based on actually listening, not some technical theory. I find tubes better sounding than solid state in general. I don't require a theory to decide, I just listen. The same is true of those listeners who prefer transistors.
"I admire Al's technical knowledge as well but what do you expect him to say? "
A purely technical analysis/comparison as only a good EE might concoct.
Understanding the technology is always the key to making good decisions. Of course, you never know for sure how it will sound until you hear it in your situation, but I always like to go in as technically informed as possible.
My own assessment is that if the mating from a volt and impedance perspective looks good on paper, a simple high quality circuit behind it is all that is needed for optimal results. The there is the technology behind the volume control, a different and perhaps more complex story, but not Rocket science still.
Of course optimal results technically does not assure a winner soundwise in the end, given all the other things that factor into any good sound, but its a darn good place to start.
Mapman, thank you kindly for the nice words.
I haven't ever experimented with any kind of passive preamp, or with direct drive from a source component, because in my case it would pretty much be a non-starter functionally. I have five sources, having widely differing output impedances and levels; and my preamp supplies outputs to three destinations (I could readily do without one of them, the record out to my tape deck, but I definitely need outputs to my headphone amp (which I drive from a second tape out) and of course to my power amp). Also, the cable length from preamp to power amp is long enough to be something of a concern with many passives.
Regarding your question about why some people who've tried both approaches report better results with actives, even if cable lengths, cable capacitances, and impedances are all ostensibly suitable for a passive, I would speculate that one reason is that discerning listeners having resolving systems can hear effects attributable to those parameters to a degree that is somewhat greater than would be expected on the basis of conventional analysis.
A speculative and hypothetical example, to illustrate my point: If the combination of cable capacitance and the output impedance of a passive preamp (which will depend on the setting of its volume control as well as on the output impedance of the source component which drives it) results in a bandwidth of say 50 or 100 kHz, that would ostensibly seem likely to be sufficient. But perhaps in combination with bandwidth limitations elsewhere in the system the result might be phase shifts in the audible upper treble region that are sufficient to produce time domain misalignment of those frequencies relative to lower frequencies, to a degree that may be perceptible under some circumstances. In other words, more bandwidth margin may be necessary in some circumstances than is commonly recognized.
I'd imagine also that a contributing factor in some cases is along the lines of the point George has made in a number of threads, that active circuitry may be introducing colorations that are euphonic. Not that there's **necessarily** anything wrong with that, IMO.
Another reason may derive from the combination of the facts that it seems clear that not all cable effects are technically explainable or predictable, and passive preamps (or at least resistance-based passive preamps) can be expected to magnify cable effects as a consequence of their relatively high impedance levels.
The point that was made earlier about sonic degradations being introduced by the parts in a passive preamp probably also has some validity in many cases, but FWIW my own instinct is that if those parts are chosen to a high standard interface effects are likely to be more significant. Others may disagree.
And in situations where digital volume controls in source components are being used in lieu of having any preamp, presumably "bit-stripping" would be a factor in some cases.
So I think that the answer to your question of "why" is multi-faceted. And I certainly wouldn't rule out that in at least a few cases the "why" might simply be user error in configuring the application.
A lot of experienced based opinions have already been expressed in this thread, from many whose opinions I have great respect for. As you said initially, there is no single right and wrong answer, that will be optimal in all circumstances. But FWIW mine own instinct (based, as I said, on having no experience with passives) is that Brownsfan's particularly nuanced post rings especially true.
AL, thanks for that.
Yes, I suppose I'm back to my original post. Passive appears an attractive option for cost, small size, and simplicity, inc cases where those things matter, like mine, and perhaps other reasons, but you never know or sure what will work best until you try.
I'll probably stick with the various pre-amp options at my disposal already for now, in that these are working out quite well already, but I am thinking this is something I would like to give a go someday when the time is right, like if my trusty old NAD decides to finally give it up. OR maybe just something to toy with in comparison to the ARC sp16 in my main rig just for kicks, if I get a few extra bucks I don't know what to do with (ha!).
I have a passive pre in my system right now and the music sounds great: tubes on the top end, ss on the bottom, and I have no idea whether impedance matches or doesn't match.
That said, when I get my active pre (tube) back from being repaired, I'll put it back in my system, not b/c of a difference in sound but b/c I like my active pre-amp. Yes, that's audio insanity for you, but it's my own.
The point is, this an audio equipment forum for people--the vast majority of whom are males, who are either wired for it (pardon the pun) or culturally conditioned for it, or both--for people who are interested in equipment, in stuff. The more cool stuff the better. So no one should be surprised that the majority opinion falls in favor of pre-amps, and active ones at that. As others have said, let your own ears--which in this case necessarily means your own psychology--be the judge.
Hi Stewie, if you tell me the input impedance of both your tube and SS amps, and the output impedance of your source. I can let you know if your bi-amped system is passive friendly and with what value passive pot.
Stewie hi, you have no problems as far a I can see with these impedances.
Interconnect capacitance is the more important factor to you as you are bi-amped.
From the Carnary to your amps, because you are (bi-amped) and using two x interconnects per channel, I would use interconnects of 2mts or less, and of less than <50pf (picofarad) capacitance per ft. If only using 1mt lengths, then 100pf per ft is fine. This is so you will maintain proper high frequency extension.
Any decent interconect maufacturer should know this and should have it on their specs
Wow - this is good stuff.
Based on your comments I connected my VPI Classic TT thru my Fosgate Phono amp directly into my Audio Mirror mono blocks. The blocks have two RCA connectors with a toggle switch between the two. Up until now, I had no idea why the builder of these amps included two RCA connectors. The amps have a pot on the front for setting the gain I assume, so it appears I can run a source directly into the mono blocks.
It sounds wonderful for now, I just have to switch the toggle to the Fosgate source cables when I want to listen to my VPI table.
I am running my 5.5 VTL preamp into the other RCA inputs. I feed a Pathos InTheGroove phono amp and Marantz SACD player into the preamp.
The Pathos Phono is fed by a Miyajima Mono Cartridge for my second TT, a Nottingham Space Deck. I am using balanced interconnects between the Pathos and preamp with good results. I have a low level hum, but I am told that is common for the cartridge.
Anyway, if I don't add anymore source components, I believe I can live with this setup for now. I don't know if the maker of the Audio Mirrors intended his amps to be used in this fashion, but I like the sound with the direct feed. I was thinking a passive preamp would allow me to get rid of my VTL, but based on your comments I think I will hang on to it.
I think Charles1dad put it right:
"over time and continued listening it's
apparent that the sound is leaner and lacking the complete sonic picture"
My experience too, even with a a top class Aesthetix Io upgraded to Eclipse status. Very clear, but a bit washed out - my speakers sounded slow, until I got a good preamp.
I think Charles1dad put it right:
"over time and continued listening it's
apparent that the sound is leaner and lacking the complete sonic picture"
My experience too, even with the Aesthetix Io upgraded to Eclipse status. Very clear, but a bit washed out - my speakers sounded slow, until I got a good preamp.
Why? The preamp is "the heart of the system" isn't it?
Could be right Czarivey. Or the back bone, I am thinking, since I have a prolapsis now. Whatever the analogy, it is central. Listening now to the integrated Ming Da Mc-34a amp and Aurum Cantus speakers at my cottage. It can't compare to my main rig, but it does very well, at its level, and one reason is that there is no preamp problem. The preamp is integrated, well-tuned to the main amp, in one box. When we go for bigger, more specialized systems, we have to work out more of the system synergy ourselves.
From what a member has sent me O_holter, I don't think the 34A has an active preamp in it.
Both the Ming Da MC34A and MC34B are very similar and are poweramps with a 100kohm passive volume control and input switching on the input.
The B costs $100 more as it has triode switchability and uses 6L6 instead of EL34. See the circuit diagram with just the 100kohm passive pot on the input tube to the poweramp input tube.
Guys, It seems most of you favor a nice preamp in the path.
Well I made what I believe is a new discovery over the weekend, which maybe you can help me with.
Here's my situation.
I am running two turntables and their respective phono amps thru my VTL 5.5 preamp.
One is on the RCA input marked Phono, the other on an AUX input. I direct connected (i.e., by_passed the preamp) the one on the the AUX input and immediately liked the sound. I am still loving it. The direct to power amp connection just sounds more transparent and immediate to me.
1. Could I be imagining this increased transparency?
2. Could it be the AUX input is not suited for a phono amp connection and only the phono RCA connection is appropriate for phono? (The table running through this connection sounds great, albeit a mono cartridge setup.)
3. Or should I re-tube my preamp?
Hcalland, if your phono stage has enough gain by itself by comming out of aux and bypassing the preamps tube line output stage, then yes you are getting rid of an unnecessary tube gain stage and the result will be more transparency.
Todays sources (phono,cdp,dacs) all have enough gain by themselves to drive most amps to full output, why add another preamp gain stage, only to knock the gain of the source back down with the volume control and creating more noise.
Just read what Nelson Pass has to say about it here.