Now those responses were exactly what I hoped for. Thank you all for adding your thoughts to a question no doubt addressed many times before. It is a question I asked in earnest. There are several schools of thought going on this subject. Active, Passive or Nothing. Some contributors seem to be trying to justify the money spent on a preamp.Not ready to admit that perhaps they have only degraded their system. Many feel Nelson Pass walks on water. I am becoming a disciple myself after both reading the above quote George passed on and seeing Steven Guttenberg's interview, Part 4, in Pass's home where he said his very customized 1960's Tannoy 15 Dual concentrics reveal more about his amplifier than any other speaker he has tried. https://www.youtube.com/watch?v=msE14... I was advised to buy an Audible Illusions amp by my audio mentor Blake Hovecar. Recently I did. Retail was around $4,500. Mid-Fi I suppose. My reference point may be well below where some high brows posting here are but my mind is open to learn and this I have done, thank you all. The whole question came to me when I sent the AI back to the factory for a repair. I had a good 5 weeks of listening direct and though I am not 100% sure it sounded better but I am fairly certain it did not sound any worse. Our group met with local genius Dan D'Agostino for an evening in his new digs last April. We had an audition of his latest creation in Amplifiers. Dan made a point of telling us that if you set the volume too low on a source controlled by a preamp you will lose SQ. I believe someone mentioned this above. Thanks Again to All |
I know many love the Freya, I’m just doubting the unit would be an improvement over a $4000 preamp like my BHK pre. |
I suppose if I had to floor the accelerator to drive 55 mph, maybe I’d think the life was being sucked out of my driving. Then again, maybe I like 55. Nice and safe, good gas mileage… atmasphere Immediately following the text George quoted above from Nelson Pass is the text above. That is why one of Nelsons favorite preamps he says is the Aleph L, passive up till 3o’clock then turns active above that if you need the extra gain, but he says at sound a penalty of having active components in the signal path. (They are like unobatinium to find as no one gets rid of them.) Nelson Pass
Unique to this preamp, patent pending, is a volume level control which combines the best qualities of a passive attenuator and active gain circuitry:
At the 3 o’clock volume control position, the Aleph L offers a direct path from input to output.
The only component in the signal path is wire and switch contacts.
At positions below 3 o’clock, the volume control functions as a precision passive attenuator using discrete resistor ladders.
Above 3 o’clock, active gain is added to the output signal in 2 decibel increments, for a
maximum of 10 dB.
As a result, you suffer the effects of active circuitry only when additional gain is necessary. |
Luminous Audio makes one..... |
I think the most you can expect from a preamp is that it mitigates some limitation in the connected equipment and in all other ways is transparent.
Most of the time a preamp is there for the convenience of switching and having a single control to adjust the volume.
As @atmasphere pointed out an active preamp might act as a buffer and present better impedances than if the components were connected directly to one another. And I agree with @almarg in that a very good attenuator in a preamp allows you to leave all source equipment volume controls at max which will improve the sound.
If your equipment is well matched with top quality attenuators and you don't need the convenience then I don't think you'll get much out of a preamp. |
I suppose if I had to floor the accelerator to drive 55 mph, maybe I’d
think the life was being sucked out of my driving. Then again, maybe I
like 55. Nice and safe, good gas mileage…
Is impedance matching an issue? Passive volume controls do have to make
a trade-off between input impedance and output impedance. If the input
impedance is high, making the input to the volume control easy for the
source to drive, then the output impedance is also high, possibly
creating difficulty with the input impedance of the power amplifier. And
vice versa: If your amplifier prefers low source impedance, then your
signal source might have to look at low impedance in the volume control.
Immediately following the text George quoted above from Nelson Pass is the text above. |
almarg
Generally speaking, IMO the burden of proof should always be on adding anything to the signal path that is not an obvious necessity. This one sentence of almarg’s above and quote from Nelson Pass below, is what going direct or using a passive is all about, so long as they are impedance correct. A quote from Nelson Pass: "We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.
Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up. Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control. What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection. And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp."
One step better than this, is going direct, if the source has a volume control. If you don’t like the sound this way, then you don’t like the sound of your source. aberyclark
So who makes a passive preamp with balanced ins and outs, two outputs that are active at same time, multiple inputs for various components?
Schiit Freya +, it’s all you ask for, has remote one of the best volume controls you can get, and it’s passive, tube active or solid state active all three switchable on the fly. https://www.schiit.com/products/freya-1 Cheers George |
I do both... A tubed DAC w/ VC straight to amp OR either ss or tube DAC to DHT pre. But when it really counts to hear a new live release for the first time, it’s DAC to amp for sure...and that’s with owning a $15k pre—lol. |
In my case direct to amp was not better when I listened at low volumes. It was not even close to the quality as with a good preamp. I listen late at night when family is sleep (when I should be too). |
My experience has been with the preamp stage of the PS Audio DSD vs. an Ayre K-5xeMP, PS Audio BHK and Art Audio Conductor. Hands down, the preamps deliver a better sounding signal with a more dynamic soundstage.
Could just be the PS Audio, but there is no doubt that connecting the PS Audio to those three units was better than going amplifier direct. Other units may have better preamp stages than the PS Audio. Additionally, those are all pretty spectacular preamps so with an inferior preamp you may find their is no benefit.
The idea that preamps are obsolete is definitely something I disagree with. |
So who makes a passive preamp with balanced ins and outs, two outputs that are active at same time, multiple inputs for various components?
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Doug said it best. I will say The Truth preamp has been a revelation to me over the last three weeks. It is a zero gain, active input preamp that for the first time in my audio experience, sounds better in many ways, to many big dollar active tube and SS preamps I have owned. It has an output impedance of some 3 ohms and an input impedance in the stratosphere! No caps or resistors or volume control in the signal path.
It seems to deliver all the sonic benefits of a great passive without most of limitations of system synergy. The dynamics are there and is doesn’t suffer from the thinner sound I find with many passives. |
douglas_schroeder2,015 posts10-28-2019 11:02amDirect without preamp is better, except when it isn't. :)
Hey, I was about to say that, no fair !!! |
Direct without preamp is better, except when it isn't. :)
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Seriously, if you’ve already set your reference point so low, you are probably seeing the expense of adding a decent preamp, power cord etc. a waste of money, right?
The VC in players or DAC are purpose built. IMHO, they can never equal or replace the SQ upgrade comes from a high quality preamp not to mention the increased functionality.
Buy a cheap pre and it will degrade or yield no improvement in the SQ vs going direct. Buy a high quality preamp and you will never go back to serviceable VC in OPPO or PS Audio. |
The reason an active line section can sound better than a passive has a lot to do with interconnect cables. Passive controls have poor output impedance- usually quite high, which allows the interconnect cable to do its worst mathematically speaking- and this is audible as others on this thread have already pointed out.
If the line section has a low output impedance it can swamp the characteristics of the cable- in other words its output impedance dominates that math I mentioned. So less effect. If you've ever had to audition interconnect cables to pick the one that sounded right then you know exactly what I'm talking about.
Now this problem was identified and dealt with by the recording industry decades ago and resulted in what we know as the balanced line standard (AES48). If you equipment conforms to this standard you'll find very little difference between cables. Most high end audio products do not, but if you have one that does, interceding it between your sources and amps can easily increase transparency if you keep the connections to your sources short.
Now of course such a line section could be built into a DAC- but then you have the issue of if you ever want to improve the DAC or the line section, you have to replace both (and its often not a good idea to have a DAC and line section run off of the same power supply). DACs are notorious for going out of date; this is a very real issue.
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@jaybe thanks for the mention. This question has been discussed in a number of prior threads, of course. My perception has been that among those who have reported directly performing preamp/no preamp comparisons a significant (but not overwhelming) majority prefer having a preamp in the chain. I would expect the reasons for that to vary among many possible factors. I don’t doubt that in many cases the reason for preferring a preamp is what George referred to, namely that colorations and inaccuracies in the preamp are subjectively pleasing, and/or are complementary to those of the source component, and/or mask colorations of the source component. But I would expect other factors to be at play in many cases, depending on the specific equipment. Such as better sonics from the source component when its volume control is set at max than when it is attenuating the signal; differences in ground loop effects (which can affect low level high frequency noise and consequently “background blackness,” in addition to potentially causing hum), differences in impedance relationships; differences in sensitivity to cable effects, especially if a long run to the power amp(s) is necessary; and perhaps in some cases what Paul McGowan of PS Audio stated a few years ago in one of his blog posts: My adamant stance against inserting a preamp between a high quality DAC like DirectStream and the power amplifier should be no surprise to readers of this blog. As well, my subsequent turn around embracing the exact opposite should lift no eyebrows either. But why would inserting an extra piece of gear in the signal path sound better than a more direct approach? How could this make sense?
... For a long time I found that DACs with no-loss digital volume controls sounded better, cleaner, livelier, directly into the power amplifier. Whenever I inserted a preamplifier it sounded different–but not better. That is until I tried a different preamp. My first revelation happened with the stunning Aesthetix Calypso preamplifier. Placed between the DAC and power amplifier, music took on a life and dimensionality that took all of 10 seconds to find it was better–not just different.
... I had written earlier that it’s likely I am asking the wrong question. How could adding more to the signal path make the system sound better, not worse? It turns out the logic is correct: it cannot. So why does sometimes adding a preamp between a DAC and power amp help the system sound better?
Because it’s helping the DAC not sound worse. And that bit of logic is key to answering the question....
... Imagine we have a DAC with an identical output circuit to that of a preamplifier. How would this respond driving a power amplifier directly? Theoretically as well as a preamp and, perhaps, better because we haven’t another component in the mix. But here’s something you may not have thought about.
DACs are significantly more sensitive to power supply changes and noises than preamps. When an output stage struggles to drive a complex load, it is the power supply feeding its output stage that sees these changes. If this occurs in a preamp, it has little effect. But that same situation, when applied to a DAC, has very different results indeed. Small changes in power supplies have big impacts on sound quality–especially jitter.
So this is one reason, and there are more, some preamps can help a DAC. Generally speaking, IMO the burden of proof should always be on adding anything to the signal path that is not an obvious necessity. But while adding a preamp in the kind of situation the OP describes is not an obvious necessity, due to the variety of factors that may be involved the only way to know for sure in a specific system is to try it both ways. Regards, --Al |
I have never been able to get a passive preamp or a direct connection to sound right. It seems like the drive of a good active preamp always improves the sound of my systems. |
A high-end preamp definitely sounds better than a digital source alone straight in to the amp in my system. I’m sure someone like almarg can explain why from an electrical standpoint this is often the case. |
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Who believes that a preamp Improves sound?? Not me It adds coloration that some may like. It takes away transparency. It adds it’s own distortions on top of what you already have. Always better direct if your digital source has a volume control.
If you have one of the higher output (>50-60db of gain), phono stages then all you need is passive preamp Cheers George |
