And to all, active preamps have volume controls as well, and most times
not as good quality as the better passives pre's usually use. Also
active pre's use many other distorting/colouring components in them.
At
least passive pre's usually only have a quality pot, which is why they
are the closest in sound to going direct (a straight piece of wire)
when used correctly.
And balanced is not needed if you only use
<3mts interconnect, and in many case better as the balance inputs and
outputs on many pieces of equipment, are opamps to make them balanced,
when their true circuit is not, so your better off using the single
ended inputs on those, again a more direct path, instead of going
through opamp etc for balanced
This entire post is false. Many active preamps employ custom multi-position switches rather than pots, built up with fancy resistors to create a volume control. MBL does this, CAT, Atma-Sphere and many others. The first 2 paragraphs thus debunked.
The '<' symbol means 'less than' but I am assuming that in the quote above George meant to use the '>' symbol.
The benefit of balanced operation is there even if the cable is only 6" long. Anyone familiar with motion control can tell you that... the rejection of noise induced in the cable does not matter how long the cable is. It relies on the Common Mode Rejection Ratio at the input of the receiver (amplifier). Most solid state amps made today are actually fully balanced and many of them have differential inputs. Some are executed with opamps, some are not. Opamps can have extremely high CMRR values, in excess of 120dB, and set up with unity gain they offer no coloration whatsoever. There are places where opamps are not a good idea, such as the input of a phono section (where the input circuit can be overloaded quite easily) but as an input to a solid state amp they can work quite well. Opamps made in the 1960s, maybe not so much. The main thing you might encounter is increased noise floor if a cheap opamp is used. But if a nice one is used the circuit will be quiet even on horns.
We've been making fully differential balanced amps and preamps since 1987 and not used any opamps for input or output, just FWIW...
George frequently quotes Nelson Pass, who is one of the top designers in high end audio today. Nelson's designs feature differential inputs without opamps for their balanced operation. His are not the only like that by any means. The last paragraph is debunked; the entire post is rubbish.
in the real world of rat race fatigue, pre-amps with their sound adjustments are just what the doctor ordered, the spectral tilt control in old quad pre-amps a case in point, some days you just need more mellow. some noisy old recordings could benefit from a true mono switch [discards the stereo difference signal and not just a mere fold-down] or groove selector to choose the quieter groove of a mono recording. a balance control for people with uncooperative listening room dimensions and poor/inflexible juxtaposition of listener and speakers within the room. EQ to improve listenability of subpar recordings and rooms acoustics. straight wire with gain is both a clear window AND a window in need of a shade at times.
@atmasphere I only meant straight wire comment as a theoretical. I've long found my active pre's superior to passives and dac direct. Bass, impact, as you mentioned, much superior with the two actives I've owned.
While I’m very much in favor of the consumer friendly policy of sticking to standards, I’m not sure that many of the benefits of balanced couldn’t still be realized if they weren’t exactly so.
I think the best way to delete the pre is to go directly from the source and avoid the additional passive volume control. In such a case, I don’t see why adhering to the balanced standard would be problematic unto itself.
Where I do see an issue with balanced, as opposed to single ended is at the amp inputs. Until amplifier manufactures adopt 2 to 2.2 Volt for RCA and 4 to 4.4 Volt for balanced input sensitivities for full power output. Many digital sources directly coupled to amps will often have to attenuate too much into many balanced amplifier inputs, and as such perhaps consequently run into a bit stripping issue. As it now stands, it might be better to sacrifice some of the advantages of balanced and use the RCA inputs. Hopefully this will change.
I think it behooves amplifier manufactures to adopt more complimentary standards for input sensitivities.
The problem is that a passive volume control isn't a bit of wire. If it were, it would not have a resistance value.
And to all, active preamps have volume controls as well, and most times not as good quality as the better passives pre's usually use. Also active pre's use many other distorting/colouring components in them.
At least passive pre's usually only have a quality pot, which is why they are the closest in sound to going direct (a straight piece of wire)
when used correctly.
And balanced is not needed if you only use <3mts interconnect, and in many case better as the balance inputs and outputs on many pieces of equipment, are opamps to make them balanced, when their true circuit is not, so your better off using the single ended inputs on those, again a more direct path, instead of going through opamp etc for balanced
It makes sense no pre would be most transparent, resolving, the straight wire concept.
Go back earlier in this thread to see what a straight wire isn't always the most neutral. The problem is that a passive volume control isn't a bit of wire. If it were, it would not have a resistance value.
Math and engineering principles are at play here- when you put a resistance in series with a source impedance which is expected to drive something to the best of its ability, its rarely a good thing. This can cause an audible and measurable loss of bass and impact. Put simply, its an example of a thing that is too simple to to its task properly.
This is not to say that you can't get it to work. To do that you have to be sure that your source has a direct coupled output and is capable of driving the load (the input of the amplifier) properly. And the interconnect cables will have to be kept short, and RCA only (balanced lines can't be executed with a passive volume control and observing the balanced line standard at the same time).
This thread goes to show you many paths to audio satisfaction. Passives, actives, no pre, resistor based, pots, transformer coupled; seems all have their adherents.
It makes sense no pre would be most transparent, resolving, the straight wire concept. But some prefer flavoring, and bit stripping can be concern. At one time or another I've tried all the above volume controls, I could see how one would prefer one over another. At present and highly likely long term, I'm keeping my present transformer coupled active pre. Adds flavor I prefer and virtually no loss of transparency, resolution. Also gives me added input for vinyl setup.
I tried my Bricasti M3 direct in place of a Lamm L1. The noise dropped and my perception of resolution increased. The first minute I thought the change was for the better. Percussive instruments were sharply augmented over vocals (like a bad mix) and the tone was worse. While I already know the Lamm is not the standard in transparency, it sounds better. I have read similar experiences from others. You have to solve for the preamp no matter what. It makes a huge difference.
Just looked overa few DAC's, that I like, None have vol pot. I have to cancel my above opinion,. Linestage are necessary as now you get more opportunities to pick which CD player/DAC you want. So yes linestage are valid and necessary.
chorus670 posts10-14-2021 11:41pmNever heard a pre that "Improved" the SQ compared to "No Pre".
~~~~~~~~~~~~~~~~~~
WEll true and not so true. My Jadis DPL , 20+ yrs old, bought last year , now have Mundorf EVO caps and Takman Rey resistors + running Tele in the AX and AU, Tele in the cd buffer out, I'd say when I put in a Tele I note a nice nuance vs a RCA, Bugle Boy AU and AX in the slot. So there must be something said for a nuance of the pre's imput. But if the Shanling, Cayin or Jadis DAC, any of the 3 hada vol pot,, I'd dump the DPL linestage. Its really not needed and adds too much gain in the circuit for my 95db sens + 91db sens dual WBers. Bottom line. Linestage/pre are not a must have, neither a should have. If you find a tube DAC /Tube player with a vol pot, go for it and sell your linestage.
I can only share my experience from what my ears have told me after experimenting on this matter. I've tried my Lumin T2 with Leedh volum control into my JC1+, I've then tried a JC2 as a pre with same source but with disabled Leedh before I went with ARC LS28 witch is where I'm at now. I can assure you that even my grandmother could tell there is a difference. I will not go into discussions if sq is coloured or not with pre but I know that I will prefer a pre any day, any week....
You have to take what’s said with a grain of salt anyone that has $$$ to be made out of something. (and no I don’t own Lightspeed Attenuator anymore) and when I did I still always said going direct was better still.
It’s said Paul backed MQA to use it, and then pulled the pin just as quickly when it lost cred.
Everything you own, every piece in the hifi chain, is designed with technical EE laws, equations and knowledge, like I said it takes both, but more so the tech side, and if it wasn’t I suggest you don’t go near it. Different if it were a painting with no math’s or EE science involved.
George, I am very aware that nothing that I say (or anybody else, on that matter) will change your views. However, as stated by many here (including the ones who thinks as you) there are diferent opinions, expirinces or tastes (called them as you like, even 'objective' or 'subjective') that will differ than yours. I would not dismiss any of those just because they are not the same as mine ( or yours in this case) perspective.
George, you may look at the description of Burmester 001 player, I believe you will read similar text as of 089.
In review in Stereophile (if that mattters) the reviewer concluded, that no matter how good the player sounded connected directly, it sounds better (for him, at least) with its preamp (011). Is the difference worth 16t usd (in Us, in that time) everyone should decide for himself. I had both pieces, together with 956 mk2 amp. Same thing with 089. Its just sounds better with Burmester preamp
I respect your technical knowlegde, but reading some of your posts I have noticed that you have few 'fixations' (in lack of better word, as english is not mine mother language)
I can understand that somebody likes one type of sound better than the other, but neither point of view should be dogmatic.
Your personal feeling when you listen without preamp, or with passive preamp is just that, a personal perspective.
For example,many times I have read your preference toward R2R dacs, but imho the Burmester 089 sound better, with 1794 BB (which is hybrid,as I understand) than the Burmester 001 whuch has 1704 BB, R2R configuration.
Just wanted to say that one should try to have open mind (and ears) and not make conclusions based on what 'should' sound better,instead of listening first. Hope that these few words do not sound as a 'lecture', as that was not my intention, but just as reminder how unpredictable this hobby might be
"Since it is equipped with high-class preamp, this player may also double as the heart of a small, but very fine high-end system."
Odd that Burmester 089 should have been great direct, as recommended by the manufacturer. As it’s output is a 60 position VC active preamp with a switchable tape input also, as these spec show with 4v low output impedance you defiantly don’t need to run a preamp into another preamp with even more gain from the second preamp. Their must be another reason, preferred additional preamp, coloration perhaps https://www.i-fidelity.net/en/test-reports/high-end/burmester-089/labreport.html Output voltage: 4.1 V Channel deviation: 0.035 dB Output resistance: 256 Ω DC output offset: < 0.5 mV
That list came from a post you made a while back. You don’t use a Metrum Acoustics Adagio dac now?
Also understandable that you preferred the active buffer as the Khozmo, and most tube pre’s would not have suited the 10kohm input impedance of the SMc monos.
George, not sure where your list of "all those preamps" came from but of those, the Khozmo (i.e., Hattor) is the only one I have owned. I do own McCormack's TLC-1 passive/buffered stage that Steve has upgraded to a much higher level that he calls
"very close to my VRE-1." When I owned that Metrum Adagio DAC with internal VC, I modified the TLC by taking the Shallco VC switch out of the circuit (replaced it by soldering two AN Tantalum silver resistors to the board) thus turning it into a unity gain buffer w/o VC. I did that because, to me, the Metrum DAC sounded noticeably better with the active buffer in the chain, even though the DAC output 4V. I have since moved to Mojo Audio's EVO B4B 21 DAC, which does not have a VC so I added the passive Khozmo unit, which provides remote VC, balance control, and a nice visual display. I have tried running my system with just the Khozmo passive unit but I much prefer the sound with the TLC active buffer also in the playback chain.
Have had Burmester 001, DCS Puccini with clock and now Burmester 089, which all can drive amps without preamp and in every case prefered the sound with preamp (Burmester 011 and Arc Ref 3)
"The clever implementation of the volume control by lowering or raising the reference voltage "in the converters" is something I have never seen before and works flawlessly." " And, its volume control is neither conventional analog nor lossy digital."
This to me means you would definitely have an I/V (current to voltage converter) stage after the R2R dac chip set, and then also an output buffer with or without gain. It’s output impedance is <100ohms SE at 2v output, which means it has an output buffer, and is a great candidate for direct to amp connection, and no problem with your SMc monos 10kohm input impedance, they only need 1v in, for full peak wattage output
So Mitch, get rid of all those preamps you have
Hattor Audio Mini Passive-Active Pre with Takman REY, XLR, and opamp active buffer ($1,550)
Benchmark LA4 ($2,599)
W4S STP-SE ( $1,999)
Schiit Freya ($850)
Tortuga Audio with CuTf caps ($4,019)
SPL Volume 2 ($499 - considered but ruled out because no remote volume)
Because you "should" blow all of them away, with what you have above, by going direct.
George, it was the Metrum Acoustics Adagio, which
changes the volume by controlling/changing the reference voltage to adjust the output voltage of the DAC.
mitch2 I have owned a DAC with a passive VC, but do not remember seeing one with an active stage.
That’s because most dac’s with VC’s do it in the digital domain, yours was a rare one to have a passive VC on it’s output inside the dac, and that would have had to have been after an active buffer anyway, as if not, then it would have had to be after the I/V (current to voltage converter stage) and that would not have been a good idea..
I am surprised manufacturers of those DACs with VC don’t provide a unity gain buffered output.
The ones that have VC’s in the digital domain, all have active output buffers, unity or with gain, as did yours, but it was before the passive VC on the output, what brand model was it??
Now if you have a DAC with multiple inputs and a volume control on it, designed to drive an amp directly, the simple fact is you have a line stage with a DAC built in. But like it always works when you integrate things like that, if you want to improve the DAC, you'll be changing the line stage too.
I have owned a DAC with a passive VC, but do not remember seeing one with an active stage. I am surprised manufacturers of those DACs with VC don’t provide a unity gain buffered output. Could be a second pair of output jacks, or maybe switched, passive/buffered. The passive crowd wouldn’t see the need, but some might be surprised with the outcome of a direct comparison.
For the vinyl guys, as many of my customers have found.
That even many stand alone phono stages these days, and there are many of them with low output impedance, and enough gain to drive the poweramp via a passive pre directly, that don’t need the extra gain of a mega dollar active preamp in the signal path, with it’s extra distortions, colorations and cost, and their systems sound better for it.
but look how much longer that has taken than anyone thought.
About 40 years so far and still counting... And now tape is back after a long hiatus. And we're already to the point where the industry doesn't want to make CDs anymore. For digital, streaming is rapidly becoming the thing; if you're into digital you might have a CD player, a streamer and a mulit-terrabyte drive with DAC... all with different output impedances.
Even if the LP dies, which I'm thinking might be about ten years (although there are still advances occurring in that field), active line stages seem to have their work cut out for them.
Now if you have a DAC with multiple inputs and a volume control on it, designed to drive an amp directly, the simple fact is you have a line stage with a DAC built in. But like it always works when you integrate things like that, if you want to improve the DAC, you'll be changing the line stage too...
Exactly . The problem today is that it adds yet another compatibility issue in an already very difficult matching problem. One more variable can just make a misstep too easy. Assembling a high end system is too challenging for many people already, adding one more level of complexity can be too much.
If you have a lot of money and are ok committing to a single product line, or you like the challenge, it can be done.
It will become much easier in the future. Especially as analog dies out as a popular pursuit… which at some point it will… but look how much longer that has taken than anyone thought.
FWIW, and at the risk of appearing wishy-washy and probably not satisfying parties at either end of this discussion, I think both those opposing ends are both right. On the one hand, for some active line stages are liking rolling down hill with one foot on the accelerator and the other foot on the brake. Yet others are grateful that the accelerator is there at all. IMHO, most with existing systems will probably benefit from an active line stage. But, for those building systems, it would probably behoove them to seek out compatible gear that can do without an additional active stage. I’ve tried both ways in the past, and had a very slight preference for an active stage. But, I have confidence that with the more current available products that my future might very well be without an active stage, and I shop accordingly.
They are not needed these days with nearly all of todays sources, except maybe with weak tube output sources.
Sheesh. It was nice when george was off. Now we have rehash this again and again. Tape is still very much with high end audio as is the LP. These media are not served by any DAC I know of. Plus there are active line stages that have better volume controls than I'm used to seeing in DACs. Line stages first started showing up in the early 1990s when the idea of an all-digital system became a thing. Rather than a relic, it seems as if they are not going away anytime soon.
If you are going to run a passive control, the best place for it is built into the power amplifier. That way the impedances involved can be far better controlled. But if you have monoblocks it gets tricky.
My front end with preamp has 30 feet of interconnect between the amps and the output of the preamp, which also drives a subwoofer amplifier. In this way I keep the front end of the system at a lower level of vibration and I can run a Distributed Bass Array. These are the sort of things you can't do with a passive control. At best, to make those work you have to run short cables- 30 feet is out of the question. If you need dual outputs, you'll instantly be in trouble, and if you want to be finally rid of that pesky standing wave in your room (causing a loss of bass at the listening chair), you'll need a distributed bass array to do it.
With all the advances in digital sources, do we still need a $5,000 pre-amp?
All we need is a switching device and maybe a Phono preamp/RIAA curve device.
Preamps are a dinosaur left over from the phono days, when sources had very low outputs and far higher output impedances. They are not needed these days with nearly all of todays sources, except maybe with weak tube output sources.
As I and many others say, in nearly all cases they are worse than going direct or using a passive, and a waste of big money for the higher end ones. https://forum.audiogon.com/posts/2262469
Not when many poweramps use opamps as their balanced inputs, and then it routes to their single ended input. In these cases by using the single ended input, you get a better sound, as there’s no opamp in the signal path then.
OK George, by this comment I have to assume that opamps are not a thing with which you are familiar. Opamps (operational amplifiers) have very high gain open loop. Their gain structure is thus defined by the feedback resistance vs the input resistance. When both values are the same the opamp has unity gain. This is a lot of feedback, and most opamps today can support that amount of feedback such that at any frequency in the audio band they will be entirely neutral.
And unity gain is how such at thing would be set up, since the amplifier in question would have no need of additional gain when using the balanced input. At any rate, if the designer did execute the opamp input in a substandard manner (and I have seen that), such a thing does not reflect on balanced operation nearly so much as it does on that designer!
Take this from someone who made their career in tube electronics, OK?
So the sound quality will be unaffected although I do concede that using an opamp solely for this purpose is a poor execution of the amplifier design; better if the amp simply has differential inputs used for either balanced or single-ended operation (and many in high end do exactly that). McCormick and Pass Labs being two examples off the top of my head...
Not when many poweramps use opamps as their balanced inputs, and then it routes to their single ended input. In these cases by using the single ended input, you get a better sound, as there’s no opamp in the signal path then.
vanson1 With all the advances in digital sources, do we still need a $5,000 pre-amp?
jasonbourne521,167 posts10-15-2021 10:31amPreamps can look real cool - like my Audio Research SP6! However a passive pot works just as well since most all DACs output 2 volts - enough to drive most all amps into clipping (1 volt needed).
Jason is correct here, a little more elaboration below.
Many amps are 1.5v or less input sensitivity for full output, and most dacs today are well over 2v output these days, so there’s no problem with being able to voltage drive. And most dacs today have very low output impedance output stages, that are equal to or better than many solid state preamps to drive any capacitive interconnects with, especially bettering most tube preamps. So it’s a furphy to say a preamps drive better than dacs can direct. And like I said if a passive pre has no voltage or impedance issues then it is the next best way.
Sure balanced has it’s place in over 3mt interconnect runs, for noise cancelation only, below that there is no need for it. As single ended is just as good, and better in many cases better, as the balanced inputs of many poweramps are just a "balanced opamp" then leading the into the real single ended input of the amp which will sound better.
I have a pal with a Mytek brooklyn bridge ( he's waiting on the Mytek Empire to arrive). His amp, speakers and connects are high end to die for gear. He played a track I know with and with out his pre-amp and directly out of the streamer. We could here no difference. YMMV
Many believe having no active preamp or linestage in the signal path is the “purest” appproach to home audio. However, the electrical parameters of the cables themselves can result in colorations. The balanced line standard Ralph often discusses provides benefits in reduction of common-mode noise and in cable drive abilities (due to noise cancellation) but must meet certain requirements, which would be difficult to meet when using components from different manufacturers, because of differences in impedance and because not all equipment that has balanced connectors is actually a differential balanced design. Some additional information for anyone who is curious.
A balanced transmission lineconsists of two conductors of the same type, each of which have equalimpedancesalong their lengths and equal impedances togroundand to other circuits.
Circuits driving balanced lines must themselves be balanced to maintain the benefits of balance. This may be achieved bytransformercoupling or by merely balancing the impedance in each conductor.
Compared tounbalanced lines, balanced lines reduce the amount of noise per distance, allowing a longer cable run to be practical. This is because electromagnetic interference will affect both signals the same way. Similarities between the two signals are automatically removed at the end of the transmission path when one signal is subtracted from the other.
Lines carrying symmetric signals (those with equal amplitudes but opposite polarities on each leg) are often incorrectly referred to as "balanced", but this is actually differential signaling. Balanced lines and differential signaling are often used together, but they are not the same thing. Differential signaling does not make a line balanced, nor does noise rejection in balanced cables require differential signaling.
need is a strong word. in my case the sound with a preamp in my system is on a higher level. soundstage, speed, life like dynamics and energy, the sound accelerates much quicker making it exciting.
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