Opinions on the role of the preamp in a modern single source system

[edorr]

If you cannot obtain a good pre-amp, then yes you are better off without one. However, a pre-amp will retain both body and soul of the music which could be loss without it.

Not arguing your point, but my observations and preference are based on expiriments with good preamps. I used a Modwright 36.5 LS/PS tubes and more recently the EMM Labs Switchman 3. In both cases I prefered the DAC direct signal path.

 

[AudioExplorations]

Not arguing your point, but my observations and preference are based on expiriments with good preamps.

Ditto

 

[Bill Hart]

Do some of the differences in perceived result depend on whether the source is digital playback? My experience, with vinyl only as a source, was that using a phono stage with sufficient gain and a volume control (tube rolled Manley Steelhead) direct to the amps did not have the body or heft or palpability that it did using the fixed outputs of that phono stage through a good line stage (a Lamm L2). Perhaps it had to do with the circuitry used to implement the volume control on the Manley. I have since changed both phono and line stages, and have enough gain to run direct from the phono stage, although no volume control if I skip the line stage without adding a passive device for that purpose.

 

[edorr]

Do some of the differences in perceived result depend on whether the source is digital playback? My experience, with vinyl only as a source, was that using a phono stage with sufficient gain and a volume control (tube rolled Manley Steelhead) direct to the amps did not have the body or heft or palpability that it did using the fixed outputs of that phono stage through a good line stage (a Lamm L2). Perhaps it had to do with the circuitry used to implement the volume control on the Manley. I have since changed both phono and line stages, and have enough gain to run direct from the phono stage, although no volume control if I skip the line stage without adding a passive device for that purpose.

Without a doubt the vast majority of observations are based on a comparison of using a volume control build into a DACs versus using that same DAC using a preamp as a volume control.

 

[AudioExplorations]

Not sure that the original audio source (digital vs. analogue) is relevant. What IS relevant however is the analogue output stage in whatever is driving the cabling and power amp input stage (whether that be in the DAC or phono stage). It needs to be of sufficiently low impedance and have sufficient current and voltage drive (akin to what is found in a high quality preamp).

 

[kach22i]

For argument's sake, let's say a "really good pre-amp" runs for $5,000, and you have no phono/turntable to contend with.

Question is; would you be better off investing that $5,000 into a better DAC (or DAS?) with it's own volume control?

Is there a big difference in sound between a $2,000 DAC and a $7,000 one?

What do you do if you have a tuner?

What do you do if you have a Reel to Reel?

For that matter, how many digital sources can the typical DAC make accommodation for?

I'm fairly ignorant of the "computer revolution", various methods of downloads and playing off your computer. However, I have to think that this will have to come into the conversation if it hasn't already.

 

[AudioExplorations]

The discussion is more of an academic nature where the assumption is a single source digital only system.

If you have multiple analogue sources there is indeed no point discussing this (although there are some DAC's that feature analogue inputs).

 

[kach22i]

The discussion is more of an academic nature where the assumption is a single source digital only system.

If you have multiple analogue sources there is indeed no point discussing this (although there are some DAC's that feature analogue inputs).

Thanks, I'll stick with the first question (slightly modified).

Question is; would you be better off investing that $5,000 preamp budget into a better DAC (or DAS?) with it's own volume control, or just leaving it in the bank?

 

[Bill Hart]

Not sure that the original audio source (digital vs. analogue) is relevant. What IS relevant however is the analogue output stage in whatever is driving the cabling and power amp input stage (whether that be in the DAC or phono stage). It needs to be of sufficiently low impedance and have sufficient current and voltage drive (akin to what is found in a high quality preamp).

Technically, you are probably right. Here's what I heard though, given the system description I gave in the earlier post: without the added line stage, but using the volume control on the Steelhead, with whatever additional circuitry that introduced, the bass was wonderful, the highs very clear, articulate, but the sound quality lacked some of the air and warmth and body that I associate with good analog playback. Now, admittedly, those are all subjective words, and I'm not one who goes by specs- so you and others may take that with the necessary grain (or pile) of salt. My thinking was, the character 'straight in' was perhaps more 'accurate' but less musical to my ears, the same complaint often leveled at the difference between analog and digital. And thus my question, since if you recognize those differences in sound exist (without agreeing with my perception as to what I prefer), perhaps using digital as a source makes the elimination of the line stage less of an issue, sonically (or actually confers a benefit since, in the vocabulary of the objectivist, it is not adding the euphonic flavoring). Please appreciate that I am phrasing this in a non-provocative, self-deprecating way, since I'm not try to do battle over analog v digital, or accuracy vs musicality, but recognizing that there is such a 'divide' in listener perception, i wondered how much the source played a part in whether a line stage was 'better' or not.

 

[edorr]

Thanks, I'll stick with the first question (slightly modified).

Question is; would you be better off investing that $5,000 preamp budget into a better DAC (or DAS?) with it's own volume control, or just leaving it in the bank?

Apparently there is no conclusive answer. In my experienve a $5,000 - $10,000 preamp subtracts from the sound quallity, while adding $5,000 to the DAC budget gives you a materially better DAC, so the answer is obvious to me. Others have different experiences.

 

[kach22i]

..... but the sound quality lacked some of the air and warmth and body that I associate with good analog playback......

This was my same experience at the lower end of the audio ladder.

 

[puroagave]

impedance mismatches aside you have to consider the input sensitivity of your amp and speakers. i have a tube integrated amp (passive volume control) w/ an input sensitivity of 670 mv which is driven directly from a DAC w/ a fixed 2v output - it has plenty of gain to drive the speakers and clip the amp. the amps in my main system have a 2v input sensitivty and speakers with an 83 db sensitivity - there exist no combination of DAC, phono or other line level source that will drive the amp properly through a passive device or that of the line source - ive tried! imo, amps with a 2v sensitivy were designed to be driven by an active llinestage. a way around it is with a speaker >95 db sensitivity and a line source with an above averge output voltage.

 

[mojave]

As I mentioned earlier, I was one of the two that voted "No (never really tried with a preamp)." I had chance the last couple of weeks to insert a Dodd Audio balanced battery powered tube preamp in my system. I listened with three different methods of volume control:

No preamp and JRiver controlling volume
Preamp at 0 gain and JRiver controlling volume
JRiver internal volume at 100% and preamp controlling volume

I listed them in order of preference. Being battery powered, the preamp added no noise to the system. However, it did add a slight thickening or "meat on the bones" as some would say. I found this to be unpleasant to listen to for very long and it obscured some of the natural decay of instruments. It could also cause some instruments to stand out more from the background. The bass also felt slightly bloated.

I had my wife listen to some songs with and without the preamp and she also preferred it without the preamp. She felt the preamp added a slight bit of harsh brightness (her words) to the music.

I tried several preamp VST plugins and found I could get very close to replicating the sound of the preamp in my system. One interesting one is the phi-L Audio TubePreamp which is the result of a bachelor's thesis called, "Real-time implementation of a tube preamplifier in order to distort discrete audio signals."

In conclusion, I'm still going to go direct to my amps from my DAC.

 

[edorr]

As I mentioned earlier, I was one of the two that voted "No (never really tried with a preamp)." I had chance the last couple of weeks to insert a Dodd Audio balanced battery powered tube preamp in my system. I listened with three different methods of volume control:

No preamp and JRiver controlling volume
Preamp at 0 gain and JRiver controlling volume
JRiver internal volume at 100% and preamp controlling volume

I listed them in order of preference. Being battery powered, the preamp added no noise to the system. However, it did add a slight thickening or "meat on the bones" as some would say. I found this to be unpleasant to listen to for very long and it obscured some of the natural decay of instruments. It could also cause some instruments to stand out more from the background. The bass also felt slightly bloated.

I had my wife listen to some songs with and without the preamp and she also preferred it without the preamp. She felt the preamp added a slight bit of harsh brightness (her words) to the music.

I tried several preamp VST plugins and found I could get very close to replicating the sound of the preamp in my system. One interesting one is the phi-L Audio TubePreamp which is the result of a bachelor's thesis called, "Real-time implementation of a tube preamplifier in order to distort discrete audio signals."

In conclusion, I'm still going to go direct to my amps from my DAC.

Thanks. I also use digital domain attenuation upstream from my DAC (not JRiver though - might give that a try sometime) with similar results. What range of attenuation (dB) did you apply?

 

[mojave]

I was around 20-25 dB of attenuation.

 

[edorr]

I was around 20-25 dB of attenuation.

That is moderate. I do about 50 dB, but even at that level, I never found any empirical confirmation of my paranoia about "loosing resolution" induced by spending too much time reading articles and opinions on audio websites. Glad I am not the only one.