Is no preamp the best preamp of all?


As an experiment I hooked up my OPPO BDP-95 (which has a volume control) directly to my amp. I was very pleasantly surprised to hear a significant improvement in clarity and sound quality. Typically I have the analog outputs on the OPPO running through my preamp in Analog Direct. I have heard that the circuitry within preamps can cause cross-talk in the analog signal, deteriorating the quality of the signal. So, would having no preamp (and therefore no other circuits to interfere with the signal) be better than an expensive analog or digital preamp running in Analog Direct? I am not really interested in Room Correction or DSP of any kind. I was considering purchasing a Bel Canto PRe6 (which I've read is excellent for multichannel analog), but would it be better to just have the OPPO running directly to the power amp?
cdj123
It doesn't always work this way, otherwise you'd see most everyone here doing it. Even the ones that spend over 500k for their system.
No preamp is better than bad preamp (just like spouses).
If your current system sounds better without a preamp then that's the way you should listen to it. If you find a preamp that makes your system sound better, use it.

There are plenty of people who don't use a preamp and plenty who prefer having a preamp in their system. There's no one answer for everybody.
Trebejo, your analogy or correlation is the most intriguing.
I found going direct from my DAC to my amps and using my Squeezebox volume control to be a huge improvement in frequency extension and transparency. I can even do the highpass filtering needed by my Quatros in the digital domain on the Squeezebox server, which is also a huge improvement.

I do need to figure out how to eventually integrate analog back into the system (probably with a switchbox of some kind).

I've seen several several people state that more than about 10 dB of digital attenuation is "bad". In the evening I'm typically using 20-25 dB of attenuation or more. I haven't noticed any evil effects. I tried some Rothwell inline attenuators (XLR version), but prefer the sound without them.
Be very careful not using Vandersteen's high pass filter. If the slope is wrong you can give yourself a very expensive repair of the midrange's
I had the opposite experience. Inserting an old Adcom pre I had in the garage seemed to be an improvement over the volume control of my PerfectWave DAC. I doubt there's a rule.

John
I prefer a Preamp over none.

As mentioned quality is key though.

I have conducted experiments running direct from Bel Canto dac3, PS Audio Perfect Wave system and Esoteric SA50 - in all cases prefer the preamp in the signal path (Plinius M8 used to conduct tests)

****dealer disclaimer - I sell all above besides Bel Canto********
Here is Nelson Pass's thoughts on the matter.

http://www.firstwatt.com/pdf/art_b1_man.pdf
The Vandersteen highpass filter is actually not very accurate for my amps. The closest I can get is with the dipswitches at the 100kOhm setting, which gives a drop of about -2.25dB @ 100Hz, and the slope is steeper than it should be. Disappointing for such expensive little boxes. The digital filter is very accurate, but there is the danger with software of it screwing up that's not there with a passive device. I sometimes wish I hadn't bought such fussy speakers.
There are very few great DACs and CDPs with truly exceptional volume controls and even fewer with analog volume controls. My experience in this regards is with the following digital devices, testing them direct to amps and also via preamps: Levinson 390S CDP, DCS stack, EMM Labs, Resolution Audio Opus 21 w/ GNSC mods, Audio Aero Capitol, Esoteric SA-50.

Trebejo s right, they all perform better direct than through a bad preamp. Though, with a good preamp in the system, for the most part they all performed better than direct. But a good preamp is not so easy to come by! Here are a couple of preamps that did not result in "better" performance for ALL of the players: Gamut 3Di, ARC LS16MK2, BAT 5 series (don't remember exact model), Cary SLP Series (don't remember exact model number).

I feel that with the Aesthetix Calypso (w/ upgraded tubes) and also a SF line 3, they all performed better with the preamp.

Based on your (OP) comments, it sounds like you are running through a Pre/Pro or HT Receiver, if that is the case, then I would suspect most any decent (not even great) product is going to sound better direct than going through the processor (even in direct mode).
If you like that experiment with yor Oppo BDP-95 here an even better one. Download a 192kHz 24 bit FLAC FILE ( I have done this with( Carly Simon No Secrets and others)from HD Tracks onto your computer, insert a keychain USB
(at least 4 gig) and plug it into the USB input in the back of the Oppo BDP-95, And listen to an uncompressed,
solid state(no moving parts)memory, 24 bit/192kHz playback
micro music-server.Some of thier files are only in 96kHz,
go for any music you know well in 192kHz the difference is huge. A taste of a High-Rez music server for low $.
The Flac files won't play on itunes, Windows ect. it will on the Oppo 95. Like all audio devices the USB needs break-in and may take a week on re-play to sound it's best.
Digital volume controls are the algorithmic cousins of mp3s.

In such an instance, the preamp has to be pretty contemptible if it cannot beat the digital volume control.

Don't fall for it, if a manufacturer will not name the specific algorithm used for digital volume attenuation, then you are most probably getting significant digital distortion. Don't be fooled by price, either, you can spend well over $1k and still get this sneaky problem.

I don't know what the monetary lower bound is for good preamps, but for starters, for $500 you can get a used TVC. Used Van Alstine is under $1k. A used AES is under $1k. New or used Mapletree, under $1k. Any of these should be a sonically good foundation for the rest of your future system.
I am currently running an Anthem AVM 30 to an Anthem Statement P5 to Eidolon Visions. I was going to try some Harrison Labs Attenuators (so I wouldn't destroy my speakers if I messed up) to see if they negatively affected the sound. I am running a 5.1 (with a Paradigm Sub 1) system, but I primarily use it for 2 channel listening. Would I be better off with a 2 channel analog preamp and a digital processor, a 5 channel analog preamp, going direct to the power amp with passive attenuators and crossovers, or a high end processor? Based on your recommendation, what specific brands/models would you recommend?
@Trebejo

I just don't hear it. I've done a lot of listening at various levels of digital attenuation with a wide variety of lossless files, and I don't hear any ill effects. Can you be specific about what I should listen for or give some technical details?
IME, a good tube preamp adds a nice texture that I can't live without.
I agree with jdoris, there are`nt any rules. It`s just personal trial and error for a given system. In my case I prefer a very high quality active preamp.
i really tried hard to go without a pre. in the end, my gear sounded better with one. however, many of the pre's i tried didn't sound better. without trying them out...i never would have known.
Daverz, usually the problem with digital volume controls occurs when you drop the volume below about 75-85% of full volume, heard as a loss of resolution.

To get around this problem many CD players actually have analog controls (which quite often is a chip) supplemented with digital displays.
What does 75-85% translate to in terms of dB?

I'm aware that I'm losing information when I use digital attenuation, but how does this translate into what one hears that is different that what one hears when an analog volume is lowered. Saying that one "loses resolution" is not really telling me anything as I don't know how a "loss of resolution" sounds different from just a lower volume.
Daverz, think of 2 cans with string connecting them. When the string is pulled tight and you talk into one can and listen to the other, the sound is more legible. Now take a few steps closer to the other person, the string sags. Now talk and listen again, it is more difficult to understand what the other person is saying. This is due to the loss of resolution, taken to the Nth degree, but still the same thing.
Daverz, on an analog control you will not hear much in the way of a loss of resolution. You may hear some colorations depending on the control and its position, but not a loss of resolution.
Well, let's say my analog volume is cranked up so that peaks are at 90dB above the threshold of hearing, 0 dB, on my dB meter. I can hear 90dB of signal above my threshold of hearing (for simplicity I'll ignore the high noise floor of the typical domestic listening room). Now I lower my analog volume so that peaks are at 60 dB. Details that were at 30 dB and under are now below my threshold of hearing. How is that not a "loss of resolution"?
Daverz, it does not work that way. If you turn the volume down, and assuming that 0db is your 'floor', the quietest portions will still be at or above that floor. This is true of any volume control.
I'm late to this one. They are all good before you marry them. In re to preamps, "I don't think so".
08-26-11: Daverz
I'm aware that I'm losing information when I use digital attenuation, but how does this translate into what one hears that is different that what one hears when an analog volume is lowered. Saying that one "loses resolution" is not really telling me anything as I don't know how a "loss of resolution" sounds different from just a lower volume.
Daverz

Below around 75% on a digital volume control, you start to get what's called "bit striping" this sounds like the early 1st gen 14bit Marantz cdp's, sweet smooth but a loss of air and detail/dynamics compared to the harsher sounding 16bit Sony's of the same era. The lower you go with a digital volume the more bit striping happens, 12bit 10bit and so on.

Cheers George
@Atmasphere

I don't follow. Why doesn't it work like that? I'm not trying to be obtuse, I just don't see what you're trying to get at. We agree that detail that was at 30dB before the volumen was turned down is at the very threshold of hearing afterwards, and that the detail that was between 0 and 30 dB is no longer audible, right?

@Georgelofi: Thanks for that subjective description of the effect. Do you mean "bit stripping"? Googling "bit striping" only gives me a bunch of pages on RAID. I'm aware that as you lower the digital volume you are losing some of the least significant bits.

Daverz, those least significant bits contain detail.

Now to your issue about the 30 db. Think about in terms of a magnifying glass. Without the glass you can see a small object and depending on your eyes, all the detail is there. When you use the magnifying glass (volume turned up) the detail is still there but its **size** is increased- in fact the **size** of the object is increased through the glass. But when you take the glass away the object is still there. Volume controls work the same way. In a sense, they make the sound bigger or smaller. Ideally the relationship between the smallest and largest sounds is not changed. Its just the overall size that has changed.
I'm sorry, but this analogy is even less illuminating than the last one. I'm not afraid of a bit of technical language if you want to use it.

"those least significant bits contain detail."

Of course, I never disputed that, though it is disputable how much detail can be heard at -80 or -90 dB down. What I'm am disputing is the idea that turning down an analog volume control does not also lead to a loss of information in the signal that reaches one's ears.
OK, after a bit of thought I think I see what you are trying to say with the analogy. It helps me to think of it in terms of arithmetic. If you start out with 16-bit audio you have 2**16 different peak-to-peak voltages available. If you reduce the volume by 12 dB you then only have about 2**14 available voltage steps, which is perhaps where the don't-go-below 75% maxim comes from (75% being about a 12.5 dB cut in .5 dB steps.) So don't go below 75% or you playback sounds like an old 14-bit CD player!

But most digital volume controls these days are 24-bit or 32-bit. The Squeezebox outputs 24-bit words, and shifts 16-bit audio to the most-significant bits of each word. This doesn't magically give you 24-bit resolution, but it does mean that with a 24-bit DAC you retain at least 16-bit resolution even with a quite large attenuation (theoretically 8 bits or about 48 dB; but that's nearly the full range of the volume control). Even with 24-bit files, I wouldn't worry until the attenuation was more than 24 dB (or about 4 bits) since you can't really expect to get more than about 20 bits of resolution anyway.

08-26-11: Daverz
What does 75-85% translate to in terms of dB?

I'm aware that I'm losing information when I use digital attenuation, but how does this translate into what one hears that is different that what one hears when an analog volume is lowered. Saying that one "loses resolution" is not really telling me anything as I don't know how a "loss of resolution" sounds different from just a lower volume.

it is not meaningful to just cite a figure like "75%-85% because you need more information. as a general matter, each 6dB reduction corresponds to a 1/2 reduction in power (or 3dB reduction in voltage). this means that you are losing 1 bit of resolution for each 6dB. redbook cd stores audio with 16 bits of resolution/channel (but the actual resolution, as a practical matter, is more like 14 bits). so what you need to know is how many bits of resolution is used by the audio processor in your cd player. i have a wadia 381, which operates with 21 or 22 bits of resolution. each step in the wadia digital volume control reduces the (power) output by 1 dB. so, i can reduce the digital volume to around 65% to 75% before i start to face the potential of losing significant bits of audio information.

my personal belief is that these are the considerations for deciding whether to go through a pre-amplifier or direct:

1)some people like the way that the pre-amplifier colors the sound from the cd player. such people should go through the pre-amplifier instead of going direct;

2)when i want to listen a low volume levels (like late at night), i tend to go through the preamplifier. this gives you a lot of latitude in how you manage volume: there can be drawbacks to turning the volume level too low on a pre-amplifier, so you set the volume level on the pre-amplifier to be in the range you desire and then adjust the digital volume to bring the volume the rest of the way down;

3)there are some recording (like some classical recordings) where the recording level is much lower than that of many popular recordings. in such cases, you would need to go through the pre-amplifier to get sufficient gain to achieve the volume level that you desire.
I believe the wide range of reported successes and failures of passive attenuation is based on the many variations in matching sources and amplifiers. Arthur Salvatore writes about this on his website (Link:http://www.high-endaudio.com/RC-Linestages.html#Int) and summarizes with;
In short, if you need an active line stage because your source is not up to the task of driving the amplifier(s), then...

Any good active line stage, from any era, will improve the sonics in some obvious and clear manner.

Alternatively, if your source is up to the task of driving your amp(s), then...

No active line stage, no matter how good it is, will ever equal the sonics of your direct connection (or an equivalent passive).

Regarding digital volume control, here is an interesting paper by Daniel Weiss;
http://www.weiss-highend.ch/computerplayback/Digital_Level_Control.pdf
Arthur Salvatore has updated and revised his opinion since he auditioned ans subsequently purchased the active Coincident Statemnet Linestage a few months ago. He now believes for the vast majority(with rare exception) a superior active is preferred.
Charles1dad, I do too, or at the very least I would recommend a preamp with buffering to improve impedance matching as well as to control interconnects. This is why I doubt I will give up my preamp even if I were to purchase a DAC with volume control.
I agree that many issues with passives are probably impedance issues. Inline attenuators will also reduce your effective input impedance.

It would help if more amps had adjustable sensitivity so that less attenuation was needed for the high output voltage of most DACs and CDPs (which is one reason why I got the original Neko DAC with the 1V output).
I am trying to draw conclusions from AS two statements:

"No active line stage, no matter how good it is, will ever equal the sonics of your direct connection (or an equivalent passive)."

"He now believes for the vast majority(with rare exception) a superior active is preferred."

Perhaps if you are the rare exception (me?) no active line stage can beat a passive -- the very same thing Roger Modjeski told me, though he did not think it was all that "rare" that a passive preamp would be the volume control of choice. Which does not mean I'm not going to get another active tube line stage to switch with my Lightspeed Attenuator from time to time.
There is no such thing as no preamp. A preamp is simply gain stage + volume control. Just because your DAC has a built-in gain stage and volume control, and you elect to connect it directly to your power amp, does not mean that you do not have a preamp in the circuit. You do - your preamp is built in to your DAC. If your DAC has an elaborate gain stage, then adding a preamp would quite concievably worsen the sound, because you would be adding additional circuitry.
Pubul57,
As clearly stated above, this is a recent change on his part(which has nothing to do with your own preferences).
Arthur says the CSL had a profound effect on his previous stance concerning passive/actives. YMMV.

09-05-11: Amfibius
There is no such thing as no preamp. A preamp is simply gain stage + volume control. Just because your DAC has a built-in gain stage and volume control, and you elect to connect it directly to your power amp, does not mean that you do not have a preamp in the circuit. You do - your preamp is built in to your DAC. If your DAC has an elaborate gain stage, then adding a preamp would quite concievably worsen the sound, because you would be adding additional circuitry.

you're thinking about *analog* volume control; digital volume control works differently (i'm not going to go through the detail of digital volume control here because it has been discussed many times before) and does not have the issue to which you are referring. as a clue, if you see a device that has fixed and variable outputs, then the volume control being implemented is most likely analog. with a digital volume control system, you would typically only have a single output (of course you might actually have both single ended and balanced outputs, but they would be carrying the same signal).
I read about his "conversion" a few months ago, a bit too mystical, but he sure does like just about anything Mr. Blume brings to market - must be precisely his cup of tea.
I doubt anything mystical. He wrote about what he experienced, nothing more or less.
Yup, mystical was the wrong word. I just think AS loves IB's sound, and given his views of Coincident gear over the years, it does not surprise me that he would love the line stage too - apparently the two of you must like similar things from your equipment - you gear looks like it must work beautifully together.
Pubul57,
Thank you very much for your kind comments regarding my system.
The Coincident components have worked out superbly for me.
"as a clue, if you see a device that has fixed and variable outputs, then the volume control being implemented is most likely analog."

I disagree with this statement. As a percentage of CDPs and DACs with volume control (I don't know of any that do not offer both fixed and variable output when they do offer volume control internally) very few are actually analog volume controls.

Of the several that I have owned, Wadia (two different units), Esoteric (one unit w/ volume control, 2 unit without volume control), DCS, Audio Aero, Resolution Audio and Mark Levinson. The Levinson, DCS (if I remember correctly) and the AA had analog volume controls. The Logitech Duet that I own has a digital volume control. I can only think of a small handful of digital devices that have analog volume controls vs. digital volume controls.

But back to the key point. I am quite satisfied with my Esoteric SA-50's digital volume control 90% of the time. Due to the gain of it combined with my amplifier, I have to play it at the upper end of its range. In fact, even at 100% I feel I would be happy with a little more volume in some music. My problem only comes when I am listening to music more softly. But in reality, when this is the case, I am not critically listening anyway - so it sort of becomes a mute point.

For the record, I find this to be the case with analog volume controls (whether via the digital device or a regular preamp). If I am playing music softly, it is more likely just for the enjoyment of having music playing vs. critical listening.

So perhaps, if the OP is like me in terms of the sound volume levels, his concerns may be less of a real world issue, making this point mute (pun intended) to some degree.
The DAC is the chef. The amp are the ingredients. The speakers are your stomach.

If you use a digital volume control, you are eating it take-out style, in a styrofoam container and probably reheated with the microwave.

If you use an excellent preamp, you are eating it at the restaurant with nice clean silverware and proper lighting.

If you use a lousy preamp, then the waiter is annoying and the fork has a chunk stuck to it from a previous customer.
Home cooked is live?
"Home cooked is live?"

... depends on who's cooking!
Yes, the Lightspeed works without anything in the signal path!
I have an oppo bdp 95 too, but my grant fidelity cd 427 tube cdp player is my reference. I actually tried not using a preamp as far back as the 80's with a yamaha M 80 and it sounded flat. I guess on some equipment it works better simply because of the design. I agree with some of the comments, there is NO one solution to every setup, it's all a matter of taste and preference. If there was such a thing, it would be safe to say that everyone in this hobby would be buying exactly the same products and manufacturer if they had the funds.
I liked the response that said there is no such thing as no preamp.

It sounds like one must experiment to see if a preamp improves one's sound in one's system.

Removing the cables and circuitry when not needed should help, it seems.

I've been going from a Theta cd/dvd player to 300b amps with individual volume controls. Sounds great, but what am I missing?

I do need a preamp with phono and microphones, that's clear.

It seems like convenience is another reason to have a preamp -- selecting sources, remote volume in some cases.

But I probably don't need another preamp if the output from the cd player is enough and I have volume controls in my amps.

But I am tempted to try a tube preamp and remove the volume controls on my amps.

Your thoughts?