The future of preamps

Michael (Swampwalker) & Charles, thanks very much for the nice words.

12-14-13: Audiolabyrinth
Almarg, Can you look into this for me, the spec of 18 volts input to clip, this is the max input told to me over the phone by krell, you can do more of the math and engineering calcalating for me to find a explanation for me?, LOL!, I will never use over 10 volts to input anyway!, just currious to know my amp,, when I said that the 3.58 is the min that krell told me, they said that because all of their pre-amps put out around 6 to 8 volts for balanced operation, and this will not do nothing harmful to the krell 700cx, its the normal that I am told by krell if useing a krell pre-amp

Keith, the comments and calculations I already provided are based on a thorough look at the manual and the specs, so anything further I might add regarding the 18 volt number would be highly speculative.

A speculative guess that comes to mind, though, is that perhaps it represents how much voltage the input circuitry of the amp can tolerate without the possibility of damage when the amp is in standby mode, or is turned completely off, or both.

Regarding "their pre-amps put out around 6 to 8 volts for balanced operation," keep in mind that what any preamp puts out is dependent on the setting of the volume control, and on how much voltage is sent into the preamp by the source component, as well as on the gain of the particular preamp (preamp "gain" being the relation between its output and input voltages when the volume control is turned all the way up). So it's a bit misleading to speak of a preamp as putting out 6 to 8 volts, or any other particular number.

Also, as Ralph and I both indicated earlier, the MAXIMUM output voltage spec that is often provided for preamps should be (and usually is) much higher than the highest output voltage that the preamp would ever be called upon to put out under reasonable usage conditions.

Regards,
-- Al

@ Almarg, Hi, Thankyou very much, I have enjoyed your help, I know who to look up for all things audio now, I hope you do not mind if I ever needed some help, I may be able to ask you for it, Happy Holidays.

@ swampwalker, Hi, sorry my post did not meet your standards of puntuations, LOL!,, never knew I needed to be thorough!, It's ok, I do not care to be so thorough with posting on a thread, of course If I were writting a book to make money, I would care to do better!, You gave me a good laugh, I needed that, Happy Holidays to you.

I'd wager whether "Bit stripping" of the signal with 24-bit digital dithered volume controls isn't mostly of academic order (32-bit dittos wouldn't, in this regard, pose any in-use limitiations, at all) - that is, where it is stated it's very often based on a theoretical non-listening experience foundation. Only high sensitive speakers and high-gain combinations could tend to pose a possible sonic limitation here, and highly sensitive speakers is not what overflows the market as is.. For what it's worth my own setup includes moderately sensitive speakers (~93dB), and it sounds terrific at lower volumes with the digital volume attenuation named above.

If for whatever reason one doesn't like the final sonic outcome where digital attenuation is involved without a separate hardware preamp, the bit stripping (i.e.: truncation) is by all accounts not a factor as much, or at all as the totality of this implementation; if one has carefully tuned a setup through the use of a hardware preamp the negation of this preamp (leaving in its place a software-based digital ditto) could easily tilt the sound in a direction reflecting back negatively on the preamp as a source of more or less outspoken coloration and synergy-effect, than what is an inherent limitation of its digital stand-in solution. I'd rather rid my setup of a hardware preamp so long as the analog output stage of the source can be made to drive the poweramp suitable (which is certainly possible) - hereby doing the same as the hardware preamp, yet without an extra hardware component and set of cables.

@ Phusis, Hi, Are you useing a 32 bit source direct to amp?

another situation is that I cannot use typical tube pre-amps or sources direct to amp, or I would have to activate the coupling capacitors that are not active inside the amp to protect is from tube unstableness!

Audiolabyrinth, best I can make out, this is some form of myth that solid state people seem to transmit. Its not actually true.

In the case of our preamp, its output is direct-coupled and servo-controlled. We've had people using it with all manner of solid state amps over the last 20 years; doesn't seem to be a problem. FWIW our MP-1 was the first balanced line preamp made. It can drive the Krell just fine.

Audiolabyrinth --

Hi, no my source (direct to poweramp) is 24-bit as described in reply no. 3 from above. I would gladly convert to a 32-bit source and digital volume control if it really meant providing that extra last "ounce" of insight, clarity, resolution, organic quality or whatever to the sonic presentation (most notably perhaps at lower volumes), and it is only a matter of time when this occurs rather than "if." Until this happens there is much to treasure with a (24-bit sourced) dithered volume control a la JRiver MC19. Several who have listened to my setup have - without in any way being lead by me to this observation - noted very positively the level of clarity, information, and "ingition" at lower levels, though I believe this could be an affect of the use of a compression driver with waveguide as well. Still, had the digital volume control here used been a limiting factor at especially lower levels it remains questionable whether reports of the very opposite had flourished as they did. It is not, as you can deduce from above, that I believe 24-bit sourced dithered digital volume controls to be flawless, but they are, many things being equal, extremely capable. And when a 32-bit source is finally implemented, bit depth and any associated thought of truncation would not be my concern at all.

I often wonder if labyrinth is simply a computer generated clown here for grins and giggles.
If so, it works.

Hi all,

I find this thread so interesting, especially amongst such exalted company, that I would humbly chime in with my two cents.
I guess the proof is always in the pudding, and of course, in this hobby, listening. I have always thought that running a digital source direct to amp should give the highest level of transparency and sonic quality. With my player having a 32-bit digital volume control, even running it at sub-max volume, a truncation of bits would not degrade the sound much as there is indeed too much headroom from 32 to say, a 24 bit digital volume level.
But, I am just curious after following many forum threads that espouse the use of an analog preamp to the betterment of overall sound quality. So when I had an opportunity to audition a high-end analog preamp at home, I was flabbergasted to find how much, much more I had been missing in the past sans analog preamp.
So, whatever the math, the ears have the final say - Aye, my analog preamp is staying for good.
Cheers!
Jon.

@ Atmasphere, Hi, Thankyou so much, It's hard to find something that may work with this crazy amp I have, I never told all of you here, I have the complete owners reference and more on my amp, all the specs that Almarg stated, I have in my hand now, and alot he did not list!, Ralph, The reference says this,,Dc protective circuitry- Full powered balanced amplifiers use unobtrusive direct current {D/c} protection circuitry that strips DC from the signal without corrupting sound reproduction. Full powered Balanced amplifiers feature direct coupled circuitry from input to output. This topology eliminates all coupling capacitors from the audio signal path. coupling capacitors block damaging DC but have sonic characteristics that corrupt sound reproduction., Useing A Tube Preamplifier,The high DC output of tube preamplifiers may exceed the DC protection circuitry of full powered balanced amplifiers. Excessive DC level in a signal can damage amplifiers, speakers, or both. The coupling capacitors in full powered balanced amplifiers must be engaged when useing a tube preamplifier, the none active coupling capacitors must be inserted into the signal path before you can use the Fpb amplifier with a tube preamplifier., ok, see what I am talking about, I do have to be careful, I do not want to use the coupling caps that will degrade my performance just to use a tube pre-amp, I do know they may make some that will work without going thru this, what is your thoughts on all this info?, It's an Honor to me that you have interest in tring to resolve some issues here for me, cheers.

Jon,
Good post and you're just another example of why we have to actually listen and decide. I on general principle prefer the simpler path when it involves audio. In this regard I should strongly lean toward a direct source-amplifier approach or use a passive line stage- volume control. There's one problem however, when I listen it's undeniable that the high quality active line stages(certainly not all preamps can do this) sound better and provide more realism. They have the ability to apparently preserve more musical information, tone and nuance that's missing when these components are absent in the system. They IMO present a far more developed and "complete" sound. Leaner and thinner sound character doesn't= detail and transparency, just an inadequate ability to convey all of the audio signal intact.

Hi Jon2020, Didn't I buy a cable from you?, A Taralabs cobalt power cable, I was wondering if you are the same gentleman, I am quite happy with the sale if you are the gentleman that sold me the cable?, anyway, My assesment of running a source direct to amp is good, transparency and realism was quite spectacular!, However, I agree with you, I had a Krell 300I intergrated on a second system, I put the unit on the main system before I sold it to help finance buying the Tara zero gold, I did hear more information!, I was stunned to say the least, I am assuming this was because of the gain a pre-amp has?, thou the transparency was not matched or realism, It was quite enjoyable, now the thing is, can I possibly get both without a second morgage on the house?

Hi Charles1dad, I agree with your findings, At what cost will a pre-amp give us all of what I desire?, I know they have great pre-amps out there that can do it all! I am open to opinions, Have you tried a 32 bit resolution source componet to see if it works better?

I'm a bit confounded why it would be implicitly, and quite arrogantly assumed I'm not using my ears when stating the above; I most certainly base my findings on actual listening impressions, and there's nothing in the slightest anemic/thin/lean/unemotional or what else that robs my sonic experience from an organic, coherent, and effortless presentation through my setup without a hardware preamp. I have heard MANY setups, some of them extremely expensive (>$100,000), using hardware preamps (both solid state and tubes), and through a not insignificant number of these what has struck was: a malnourished, too soft presentation that furthermore lacked coherency and dynamic impact. I'm guessing this has less to do with the fact that hardware preamps were used here than the speakers used, and other combined factors. What I'm actually saying is also that the oftentimes prejudiced stance that 24-bit digital volume controls are marred by truncation effects is blown out of proportion, and that ACTUAL LISTENING has told me and my ears something very different. Perhaps there's much more in store for me with the addition of a hardware preamp, but until such (listening-)experience would tell me so I'm trusting my ears damn well enough to know that it sounds great without one.

I'm a bit confounded why it would be implicitly, and quite arrogantly assumed I'm not using my ears when stating the above; I most certainly base my findings on actual listening impressions

Phusis, I would guess that the reason is you have had a spat of bad luck, as your experience is one of the minority. A lot does depend on the preamp though and they are not all created equal! Some simply act as filters in the system. If you have been working with such preamps I would not doubt that you reasonably arrived at your conclusion.

Charles1dad,

It is interesting to note that personal experience does not always go in tandem with common sense and logic which would define that the shortest simplest path should be the best.

Audio design is indeed as much an art as it is a hard science.

Phusis,
I make the assumption we (or most) rely on what's heard to form an impression. As we are all different there'll be varying conclusions and choices made. My experience happened to be very similar to what Jon had written and I wanted to respond. You have your own experiences to share and certainly others can relate to you and your outcomes as well.

What I described has absolutely nothing to do with you preferences and the converse is true, they're completely independent of one another. We are just two people who happened to have different views. What I wrote about
the sound of passive-direct compared to good actives is simply what I
heard. I have no problem at all with your listening encounters/ comparisons
(how could I?), we both were expressing our opinions on an open forum. There's no rule that says we must agree with each other. You've recognized what sounds preferable to your ears and I've done the same. The ultimate result is we're happy with our individual choices.
Charles,

Jon,
I do agree that art and science are combined when designing and building audio components. The ear of the designer is a crucial ingredient. If it were exclusively hard science then one could rely only on mathematics and equations and then confirm with measurements. It obviously is much more involved than that, just listening makes that apparent. General engineering priciples can't be ignored but there's certainly a lot left to individual designer interpretation given the vast choices of different sounding components.
Charles,

Hey Phusis. I have to give you a little support here. I have been playing my nice sound systems for about 48yrs. I have also listened to quite a few other systems and pre amps. By way of back in the day(1980-1990)doing work for some high end audio stores and hanging out in them and taking stuff home listening to it quite often using the owners and employees suggestions on what would be great to try. These places are still very active businesses.

I have had some tube pre's and solid state also. I think Jon's 'Rowland' mentioned above is quite a special one and it looks like he may know that. I happen to really like almost everything Jeff Rowland produces. Anyway I personally have all ways gone back to a passive or a passive with a what I consider a high quality buffer. All very minimalist. I have found for me going this way is more musical than any active pre(I haven't heard them all). Now when I say more musical I mean it conveys more of the sounds I am familiar with. More of the sounds meaning all of it from the initial attack to the trailing harmonics and the tonal balance. So to me (I can only guess its true but I think I have a good handle on it)I find this way more true to the natural and original sound. My background with music is when growing up I had a lot of live living room musicians to listen to. Piano, guitar-electric and acoustic, banjo, tenor sax, viola, tambourine, drums, harmonica and maybe some others. And I am also a play around guitar player. And honestly I think when you are listening to reproduced music in your living room that having live music in your living room or on the patio would give one more closely a apples to apples approximation.


I think if one has an active one would probably need to do more than drop a passive in to compare. I think you really need to pick your components for a passive system to optimize it. Just like you would do with changing any component. I say that (as many here say that the pre amp has a considerable effect and change on a sound system)because I think going from a active to a passive is one of the bigger changes one would make to a system.

I think we have a lot of wonderful equipment to choose from to provide a glimpse into the music we listen to. I am grateful for the designers and producers of our fine gear. So I also appreciate the varied views because I have only mine.
Enjoy

Marqmike,
Well said,
Some will prefer active and others will choose a passive. The fact that there's a very viable market for both is all the proof we need. You're right, variety is good and there are many fine components to select from.
Charles, .

Audiolabyrinth, despite what you quoted in the manual, that idea that somehow tube preamps have DC at their output is a myth! Most tube preamps have a coupling capacitor at their output and so cannot produce DC.

I suspect that is something concocted to sell solid state preamps.

Any tube preamp manufacturer has to contend with the fact that their preamp is going to get used with a solid state amp at some point. There are many threads on this forum to that effect. Many transistor amps have direct-coupled inputs, so any designer knows that if you have DC there it will cause problems for the amp and possibly the speaker too. But fortunately its not something that is a particular concern, as coupling capacitors are very effective and will prevent DC from being a problem at the output of the preamp.

The only thing you have to be careful about (which is true of solid state preamps as well!), is to turn the preamp on first and wait for it to stabilize before turning on the amp.

Charles1dad,

It is interesting to note that personal experience does not always go in tandem with common sense and logic which would define that the shortest simplest path should be the best.

Audio design is indeed as much an art as it is a hard science.

@ Atmasphere, Thankyou, I am glad you told me that a tube pre-amp needs a coupling capacitor at the out-put to protect against DC, that was helpful info, cheers.

Audiolabyrinth, I think I need to clarify that. I think there are maybe 3-4 tube preamps with direct-coupled outputs (Berning made a hybrid called the TF-10 years ago, there was the Messenger and we make two of them. Pretty sure Krell was not talking about us... I think we would have heard about that.

Anyway, the rest of the tube preamps made have either an output coupling cap or they have an output transformer. Either way they won't be making any DC! That is actually a greater danger with a solid state preamp, although most of those have output coupling caps too.

Ahhh, yes, I 'tis remember well when, lo those many years ago, 'ol Steven Stone, reviewing still for Stereophile, told us all that passive pre's would soon take over the earth, that active pre's were not, um, "transparent" enough and that, impliedly, 'ol Ken Shindo should just then pack it up...

Jeez, can one hear an echo around here?

I know, this is hardly dispositive in an empiric sense, but I know of a guy who streams only digital into class D amps - talks a lot, doesn't listen much, cognitively chatters like a monkey - and who says that his is the most "transparent" way, it just has to be, its so, um, logical.

My response? You can't describe the color purple to a blind man...

@ Atmasphere, Hi, If your preamp M-1 is direct coupled, what do you use to safe guard from DC exsposure if I attempted to use your product with the krell 700cx?

Audiolabyrinth, it uses a servo that corrects the DC. The servo also lets you know if there is a problem it can't correct. Its simple, and very reliable.

The actual circuit does not want to make large amounts of DC in the first place so the servo only has to make small changes. We have a patent on how this is done. There are several advantages- part of the reliability comes from the fact that the circuit can't put out large amounts of DC even if it were damaged, so it does not need a protection relay or complicated housekeeping circuits to make it work. Its reliability comes directly from its simplicity.

Don't worry Phusis and others you have it right don't listen to them. When ever there is a thread that threatens the existence of preamps these three to four flat earthers always rear their heads. It's almost like they have shares the slowly decaying dinosaur the preamp.

You are correct the source (if it has volume) direct into the poweramp will give the highest transparency, highest dynamics and least colouration there is, anything added to the signal path is going to colour the sound and be less transparent.

Cheers George

George,
The constant repeating of a fallacy doesn't make it right. Over the years enough members on this site have tried your Light speed product and some found it inferior to their own active preamps. Get off your wobbly soapbox, you are the epitome of the proverbial broken record. It's clear there are satisfied fans of both passive and active components.
Cheers,
Charles,

I tried various passive preamps in the past and yes some sounded good, but the best was using a good active preamp. Your welcome anytime to come by with your passive and I know you will be leaving with your tail between your pants.

'Flat earth' usually has something to do with a lack of math coupled with ignorance. Here are the issues of what a passive has to face:

With any passive volume control the control element is a series element with the source. The more you have to turn the volume down, the greater the source/volume control impedance becomes.

Now most digital products make about 4 volts output, so you do have to knock the signal down in order to use it.

So if the source impedance is 1K, to listen to something you might have the control turned down so only 200mV is coming out of the source. With an amplifier with 25 db of gain (most amps have 30) this will result in about a watt and a half from the amp (nice for low level listening). But this might mean also that the source impedance is now well over 10 or even 50 times higher, depending on the control!

You can easily see here that the cable between the control and the amp has suddenly gotten really critical.

One way to get around this problem is to keep the value of the PVC fairly low- 10K is about the limit though, and a lot of sources will be unhappy with that, as the higher the volume setting, the more the control is in parallel with the input of the amp. If the amp also has a 10K input impedance your source might be asked to drive 5K at full volume. This could kill the bass in many systems.

This problem is solved in an active preamp because the volume control is buffered from the load of the interconnect cable and the power amplifier input by some sort of active circuit.

A passive of course has no such circuit, so now the increased output impedance of the volume control and source exacts a price upon the sound, and this will be that the capacitance of the cable is able to roll off high frequencies at a lower frequency (introducing phase shift, which messes with the soundstage presentation), and if the source has an output coupling cap, we will see a low frequency loss as well.

(Resistors and caps are often the elements of filters. To roll off highs a resistance is often followed by a cap to ground; the example of the PVC turned down above is an example. If you want to roll off bass, put a resistance in series with a coupling cap.)

Note here that *it does not matter the quality* of the control! What matters far more is the *value* of the control. This is not a quality issue so much as a math issue. Quality is something you can mess with but the math is pretty hard to get around, sort of like trying to break the laws of physics.

So when you have a passive control you have to be very careful- for example if the amplifier input impedance is high you will have greater high frequency rolloff due to the cable. If the amplifier input impedance is low (10K for example) bass will be a problem at all positions of the control except full volume.

The only real solution is to place the passive control at the input of the amp. This could be really inconvenient (especially with monoblocks), unless the setup was also remote-controlled. Otherwise the use of a passive is always going to be a compromise. Anyone who has a successful setup will probably also have had to pay special attention to the interconnect cable at the very least, unless they had a lot of good luck, good advice or both. One thing is certain, PVCs are not a universal panacea!

As I pointed out in a post above, one of the functions of a preamp is to control the interconnect cable. This is done by having a very low output impedance. When you *raise* the output impedance, as all PVCs must do, instead of controlling the cable, you exacerbate its effects due to the math involved.

Here we go again, the flat earthers rebuke.
I didn't even mention the Lightspeed Attenuator or passives. "I said if his source has volume control" it will be the most transparent, dynamic, and least coloured way of getting the sound of the CDP/DAC to the poweramps. You guys make it up as you go.

Cheers George

George,
No one is making any up, just carefully read the well written posts. It's genuine irony that you refer to those who don't happen to share your views as "flat earthers" why is that necessary? Atmosphere is responding to you with sound logic and intelligence. I can understand that you don't agree with him or others with alternative positions, but the best you have is a retort of "flat earthers"? It comes across as very weak and bereft of reasoning. You demonstrate little humility and open minded acceptance of others knowledge and their listening experiences. By the way did you noticed none of the active preamp advocates criticized Phusis? They simply shared their own perspectives which is what these forums are all about.
Cheers,

if his source has volume control" it will be the most transparent, dynamic, and least coloured way of getting the sound of the CDP/DAC to the poweramps.

Georgelofi, this is not really true, unless that source also has the ability to control the cable. If it does not a preamp may well be more transparent, more dynamic, wider bandwidth, etc. despite being an extra gain stage.

As you well know, many sources have compromised volume controls where the compromise allows for remote control. In fact this very reason is why many manufacturers do quite well selling line stages. You install the preamp, turn the volume control on the source all the way up, and use the volume control in the preamp *because it sounds better*: more bandwidth, resolution, transparency, etc.

Now a manufacturer of CDPs and the like could fix this problem but so far very few of them even recognize that its even possible to control the cable, let alone how to do it, so for the foreseeable future there will be a market for active line stages for precisely the kind of product you mentioned.

I wonder if the future of preamps might have more to do with room control.

@ atmasphere, Hi, man-o-man did I enjoy your post about passive and active preamps, I actually learned something there, LOL!, not to sound arragant, that is rare for me, I love it!, also, thankyou for taking your time to explain how your preamp protects from DC, I am interested in your products to audition one of your preamps at this point, I do need to tell you thou, I have ridden myself a long time ago of useing preamps period, I have used solid state and recently tubed source direct to amp with success since 1996!, I seen you mentioned cable control, and a roll off of the top and bottom bands of the sound, presatation etc.., I addressed this kind of problem in my opinion, by useing some of the best cables money can buy to use with source direct to amp, the presatation is extremly focused and the presatation is very large and well conceived, the most transparent, with realism of an actual musical event that I can possibly afford to buy, In regards to your product, I am hopeing preamps have changed over the years for the better, I have listened to preamps this year, I do hear more information, it's all there!, I have never heard better transparency and dynamics, with realism than a source direct to amp, and God knows I have heard alot of cost no object preamps in my time!, I am also intrigued by your preamp for the simple fact it may not allow Dc into my amp, and your preamp is direct coupled like my amp is, I believe your design and circuit will give more transparency than alot of preamps out there, I do not know when I am going to listen to your product, I do know that I am going to, I have been enjoying this thread, you make it very interesting to be able to learn of circuits etc..., we need Almarg back on this thread too, cheers and merry x-mas to all of you!

You you didn't even bother to look before making ridiculous statements of this system quote:
"this is not really true, unless that source also has the ability to control the cable."
You put a White Paper out on this Atmasphere and you'll be shot down in flames. Mathematically how is the Nuforce not going to control the interconnects to the Belles?? You flat earthers are just too much!!!

Phusis sytstem:
Nuforce dac 9 has RCA Output impedance: 0.01 Ohm. It also has Output Voltage: RCA 2.0/4.0Vrms adjustable.

Belles SA30 30w Class A:Input impedance 100kohm. Input sensitivity .74v for full rated output.

hORNS Mummy MkII speakers: 94db sensitivity

Cheers George

@ Atmasphere, Hi, If your preamp M-1 is direct coupled, what do you use to safe guard from DC exsposure if I attempted to use your product with the krell 700cx?

I've only use tube preamps (Sonic Frontier, AI, CJ, VAC ...) with all my Krells amps (KSA100s, FPB300 and FPB600) in the past and never had a problem.

Don't like Krell pre and can't remember last time own a SS pre.

this is starting to get ugly here!!! :( flame retardant suit required before entry.......

12-19-13: Georgelofi
Nuforce dac 9 has RCA Output impedance: 0.01 Ohm.

I see that in the specs at their website, and in the manual. Surely it is a typo, though?

Regards,
-- Al

Knghifi,
Did you use your Light speed preamp with the Krells? Seems like it would be a suitable match .
Charles

You put a White Paper out on this Atmasphere and you'll be shot down in flames. Mathematically how is the Nuforce not going to control the interconnects to the Belles?? You flat earthers are just too much!!!

Actually an article on this subject sounds like a good idea as the math seems to be poorly understood, apparently by even members of the industry; thanks for the suggestion.

The rule of thumb here is:

if you can hear differences between interconnect cables then the source is not controlling the cable.

This has been understood for the last 60 years. The history of balanced line operation goes back to the phone company, and its success was immediately taken up by the recording and broadcast industry and resulted in what was called 'hifi'.

Some folks here might recall a series of letters that Stereophile published back in the 90s in their letters to the editor column; these letters were written by several different audio engineers. In the letters, these engineers stated their astonishment at how audiophiles gave credence to the idea that cables make a difference in the sound.

Now anyone in high end audio understands that cables *do* make a difference, the question is, why would an audio engineer think that they didn't?? The answer is, engineers are used to working with professional audio gear, which supports the balanced line standard.

High end audio equipment for the most part does not. So its my surmise that these engineers did not think about that when they sent these letters in (basically describing the high end audio cable industry as charlatans). It was apples and oranges.

However the laws of physics have a way of hanging around and are still very much with us today. I have already described the math of why a passive control can't control a cable and why if you are going to have success with one, why you will have to put some time into auditioning cables to go with it, and often spending a lot of money on those cables, with only limited success being the result.

I will go into that in more depth in the article.

Atmasphere --

Phusis, I would guess that the reason is you have had a spat of bad luck, as your experience is one of the minority. A lot does depend on the preamp though and they are not all created equal! Some simply act as filters in the system. If you have been working with such preamps I would not doubt that you reasonably arrived at your conclusion.

Thanks for your response. I would add that not all DAC's are equally created either, and that the analog output stages here used vary (to include some that are good matches for a direct poweramp coupling) with regard to their abilities to properly drive a poweramp - something you know, of course, but a factor that needs more visibility in discussing this subject, as I see it. I'm not necessarily after simplicity per se - as in, it cannot simply overrule sonic impressions as a general principle - but I like keeping it as a mind(out-)set , even as a counterweight to conventional "wisdom" in developing a setup. Had my impressions of the DAC-direct approach, in the combinations I have tried, been less than favorable I would surely have gone back to using a hardware preamp(models from Electrocompaniet, Classé and Cary being the last ones - the latter indeed with tubes..).

Charles1dad --

Thanks for your reply. I am perfectly fine with some of us having to agree to disagree amongst a variety of taste and opinions, so this is not my dispute. I was after the subtle, back-handed notions - insofar they were directed at me, let alone that they existed at all - that I was lacking the sole experience of actually listening before forming an opinion on the related matter, a seeming prejudice against digital volume controls (speaking of actually having the experience), and that a scent of "we, the lovers of active preamps, know the sonic truth; you don't" persisted. I may have overblown the existence of all this, but truth be told there's a rather overwhelming preference for the use of an active preamp (something that can have other reasons than SQ alone), and I guess some, if not most of these haven't made extensive experiments with a DAC-direct approach; the inertia, or convention of using an active preamp is very likely a factor.

Marqmike --

Thanks for your thoughtful response. Your reference to having a history of "exposure" to live music makes for an interesting, and highly relevant backdrop with regard to "having an ear" for evaluating reproduced music, and how this relates to a more strict understanding of the term "hifi." I do not intend the walk down the absolutism-path with this (nor do I read your reply in such a way), but it is a valuable piece of information about knowing what real, live acoustic music sounds like, in a living room no less, and how this could ground some of the subjective views that "all is just as good," insofar we're actually interested in what live acoustic music sounds like, and that having the goal, or simply a natural inclination towards seeing it reproduced most faithfully has any meaning. Myself I have attended quite a lot of classical concerts, mostly symphonic scale, and more intimate jazz/club concerts as well, and through the last years has been very keen on how to recognize the signature or "pattern" of live music in optimizing my own setup - not an easy task, and one that takes some perceptive tricks to achieve, to me at least.

I think if one has an active one would probably need to do more than drop a passive in to compare. I think you really need to pick your components for a passive system to optimize it. Just like you would do with changing any component. I say that (as many here say that the pre amp has a considerable effect and change on a sound system)because I think going from a active to a passive is one of the bigger changes one would make to a system.

This is exactly one of the main points in discussing this subject. Well said.

Asa --

I know, this is hardly dispositive in an empiric sense, but I know of a guy who streams only digital into class D amps - talks a lot, doesn't listen much, cognitively chatters like a monkey - and who says that his is the most "transparent" way, it just has to be, its so, um, logical.

My response? You can't describe the color purple to a blind man...

Who're you referring to?

If you can hear differences between interconnect cables then the source is not controlling the cable.

This has been understood for the last 60 years. The history of balanced line operation goes back to the phone company, and its success was immediately taken up by the recording and broadcast industry and resulted in what was called 'hifi'.

I wish more people would get this. The 600 ohm standard eliminates cable artifacts. It is that simple. Unfortunately high end audio embraces single ended designs much more so than true balanced differential designs that support the 600 ohm standard. As a result we have cables that in some ways can act as tone controls and as a further result we have cable manufacturers who add who knows what to their cable designs to propagate this further, while taking the opportunity to charge a premium for their tone controls.

My experience with single ended designs has taught me to use very short interconnects with low capacitance to eliminate artifacts, but the sources have to be up to the task as well. Much more complicated than my balanced system that supports the 600 ohm standard, thanks to Ralph's help.

When I started this thread, I wasn't thinking about the relative merits of passive and active preamps. I was thinking more about digital sources with volume control, integrated amps, and amps with digital inputs, all as ways of eliminating the preamp box entirely. However, all the discussion on active versus passive has certainly been interesting.

I use a tube preamp going directly to a digital signal processor. So there are extra a-d and d-a conversion steps in the processor. When I remove the analogue preamp, resolution and transparency go up slightly, but the sound becomes thin and uninvolving.

I've read Atmasphere's comments in the past regarding control of interconnect cables. Although I clearly hear differences in my system made by different balanced cables, I suppose that this could be due to the inability of my front end components to adequately control the cables. It seems to me that this could be true. Mind-boggling, to think that the entire high end interconnect industry could be based on this!

Hello Phusis,
It seems you and I are actually in agreement, we both use live acoustical music as a very useful template. We both adhere to the concept of simply trusting our ears when decisions are made regarding preferred audio components. Of course we may very well reach different conclusions even if we both were listening to the same identical components/systems.
Thats perfectly fine as individual taste and a particular bias for a certain sound that is deemed right will surely vary amongst individuals. I believe both of us are confident and secure with our paths toward audio-musical satisfaction. Take care.
Charles,

In his post dated 3-22-13 in this thread Ralph provided what I consider to be both a uniquely excellent explanation and an extremely persuasive proof of his contention that a balanced interface MEETING CERTAIN DESIGN CRITERIA (which unfortunately are not met by most audiophile-oriented components) can completely eliminate interconnect cable artifacts. See also his post dated 3-28-13 in that thread, which responded to some questions I had on the issue.

Which is not to say, however, that I take an ideological position against passive preamps, or against having no preamp. As I see it, in audio there are usually multiple ways to do you know what to a feline and achieve good results, to express in a different way a point that Charles, for one, has made many times.

In my own case, fwiw, the question is moot, as I require a full function preamp. Some of the reasons for that being: I want it to be able to drive multiple outputs (both volume controlled and not volume controlled), as well as select among multiple inputs; I want to be able to mute the speakers while listening to headphones, without having to turn off the power amp; my power amp is located too far from the preamp for a passive preamp, or direct drive from many source components, to be suitable; and the output levels of some of my source components would probably be marginal without some added gain. I'd expect those kinds of practical requirements, that a goodly number of people undoubtedly still have, to be among the reasons that preamps are unlikely to go away anytime soon.

Regards,
-- Al

Did you use your Light speed preamp with the Krells? Seems like it would be a suitable match .

No Charles. The Krells were long gone before the Lightspeed.

When it comes to impedance matching, sometimes theory <> practice. ie: On paper, McIntosh C2200 is a good match but was horrible with FBP600. No bass, highs, dynamics ... just lifeless!

I did try Lightspeed with TRL Samson monos. Samson input impedance 69K, 1M ASI Liveline IC, MW Transporter so excellent match but I didn't like the sound compare to my active.

To be fair, a MP of 60's Siemens Cca or 60's Tele e88cc in my active is more expensive but overall sound quality is more important than value to me.

Atmasphere:
"The rule of thumb here is:
If you can hear differences between interconnect cables then the source is not controlling the cable."

Sorry, wrong again Atmasphere, the only time all cables will be made to sound the same/equal.
Is when the input of the poweramp is made extremely low input impedance as well, like 500ohm or less. And what's driving it (pre or source) has an output impedance extremely low like 1ohm or less so it can drive that very low input impedance of the amp.
This then will negate any differences in interconnect sound and they should then all sound the same.
The only down side is with that lower input impedance poweramp hardly any sources or preamps can drive it.

Cheers George

I'm hoping someone could figure out how to eliminate the power amp as well so I can find a different hobby.