Adding a pre amp

[diecaster]

https://www.youtube.com/watch?v=HHl8F9amyY4

[diecaster]

I am with BHK (watch YouTube video I linked above). A quality active preamp, especially a tube preamp, makes a real positive difference. The sound is more musical and dynamic. 

[diecaster]

3 hours ago, barrows said:

This will not be the result with his set up.

 

I disagree. While the DirectStream preamp is quite good, it is no match for a quality active tube preamp. Please watch the BHK video I provided a link to.....I have a DirectStream and have tried it with and without a quality active preamp. I have a quality active preamp in front of my amp.....

[diecaster]

21 minutes ago, TubeLover said:

Not only do I agree, but I can back it up. A good friend of mine had the PS Audio Direct Stream DAC in his system for the past three years up until a couple months ago. He tried it direct to a whole series of amps, and each time, things improved dramatically when he added his PrimaLuna Dialogue Premium preamp (highly recommended, and  steal for the money) into the mix. The consistencies in sound without the DAC were sound that was lean, too much towards clinical,  and lacking texture and depth. Adding the preamp, in virtually each case improved the sonic signature of his system, adding depth, richness, a believable degree of warmth that hugely improved the midrange, and highs that extended believably and effortlessly. We spent many, many hours verifying this, as well as bringing in other audiophiles in the area to verify what we kept finding. And the findings were always consistent.

 

Now, will I say that there is no way that a DAC, with a volume control, connecting directly to amplifiers can be as good, as having a really good preamp in the system? No, but be prepared to layout out BIG dollars for that DAC. I bring this up because over the past few months, my friend has found a DAC that is actually producing better sound from his system connected to any of the three amplifiers that he owns. However, that DAC cost him well over $15k! 

 

JC

 

Thank you! BHK and Paul McGowan, the CEO of PS Audio, prefer using an active tube preamp versus using only the "purely passive output stage" with digital volume control of the DirectStream.

[diecaster]

1 hour ago, barrows said:

There is no such thing as a "direct stream preamp"...  I hate hearing this kind of statement as it suggests that one has to add something to a DAC to drive an amplifier directly.  A DAC has an output stage, which is no different from what a preamp has, an output stage (in general).

In this system case we have a DAC which has a transformer coupled output, driving an amplifier which is very easy to drive, which has a transformer coupled input.  While some have suggested that putting a preamp between an amp and DAC can result in better sound by the ability of the preamp to act as a filter for RF energy from the DAC, in this case, we already have two very effective RF filters: transformers at both the receiving and transmitting ends.

All tubes can do is add distortion and noise, you might "like" the distortion and noise, there is nothing wrong with that, but it is not accurate, or high fidelity, it is only added distortion and noise which is not part of the music recording.

 

Hate? You are arguing semantics. Of course the DirectStream does not have a preamp built in. Of course it has an output stage. Every DAC does. Heck, most preamps today are actually line stages. Should we mention that every time someone uses imprecise terms?

 

As far as what active preamps, tube-based or not, do? Yes, in in theory you are correct. Yet, to this day, active preamps are used and preferred by a huge number of audio enthusiasts. As @cjf said, this  "is the perfect example of when Theory and Reality dont line up". As a purist, I would like to believe that a passive preamp or no preamp at all would sound better than an active preamp. In my 40 years plus of experience, that has not been the case.

[diecaster]

47 minutes ago, Spacehound said:

This is SO  easy.

 

If the DAC has a volume control it's:

DAC------->POWER AMP------->SPEAKERS

Any given DAC  (with a volume control) is going have an output stage near enough the same any give preamp. Each box adds a small amount of distortion, it can never  'improve' the signal it receives.

 

So unless you HAVE have some 'analogue'  inputs  adding a preamp just distorts it some more. If you don't accept that you aren't interested in high fidelity (equals 'good sound'). Take  your fancy equipment to the local dump and go  buy a fifty dollar ghetto blaster.

 

 

Sigh. 

 

I don’t care so much about the distortion my tube preamp may add to the signal. I do care about the sound quality I hear. My tube preamp increases the pleasure I get from listening to music. You can quote all the theory you want. The proof is in the listening!

[diecaster]

If the only path to “high fidelity” were less distortion, amps with the best specs would sound the best. There is more to great sound than spec sheets. 

[diecaster]

1 hour ago, mav52 said:

After reading all of this, I'll just keep my pre-amps. 

 

My 40 years of experience never had that in doubt!

[diecaster]

1 hour ago, Ajax said:

I therefore share the position of previous posters that adding a pre amp simply adds another totally unnecessary device into the chain, creating more issues such as additional cables and more distortion for absolutely no gain (pardon the pun).

 

You certainly are allowed your opinion. But so am I. My 40 years of experience in audio tells me your position, while logically sound, falls apart in the real world.

 

Even amp designers such as BHK agree that what should be true theory is not in practice. Well designed and implemented preamps, especially tube preamps, improve the listening experience.

[diecaster]

26 minutes ago, Ajax said:

Thanks for letting me have my opinion  , however,  think the point that you and KingRex are missing is that the Benchmark DACs ARE pre amps.

 

20 minutes ago, mansr said:

So if you put a DAC and a preamp in the same box, you still need a separate preamp?

 

As someone pointed out earlier, let's not confuse a DAC output stage, even if it has an attenuator, with a preamp.

 

These attenuated output stages may or may not be active. For example, the attenuated output stage in my DAC, the PS Audio DirectStream, is passive and digital. The digital attenuator adds nor takes away anything from the analog signal put out by the DAC other than the level. This, according to theory, should be the perfect output with volume control to the amp. Yet, like other passive preamps in my experience, leave the music output lacking.

 

I have never heard a Benchmark DAC so I am unable to comment on what that output stage sounds like.

 

I have yet to find a setup where a passive preamp or a DAC passive attenuated output stage out performs an active preamp, especially a tube preamp.

[diecaster]

4 minutes ago, esldude said:

Obviously you do.  How else could it be?  Audiophile experience and all.  

 

A preamp always improves things even when it doesn't.  And if one preamp is good how can two not be better still.  I really think they should be treated like USB de-evilizers.  That people should put multiple preamps in series.  I mean if one improves sound by buffering, then why would a second one not improve it more with more buffering.  Who knows the audiophile delights that accrue to someone smart enough to series 4 high quality preamps between DAC and amp.  Heck, it may sound practically analog!!!!!!

 

Think of it, one may have incredible soundstaging, and another terrific pace, and another tremendous space and airiness.  Combine them all and you need not compromise.  You can have it all.  Each pre contributing its unique strengths in a way that can only become synergistic without end.  

 

Go ahead a mock my opinion. It is shared by many people including amp designers. If the consensus was that passive preamps were the best way to go, the market for active preamps would have died long ago. Passive preamps have a much smaller share of the preamp market than active preamps. I guess everyone that uses active preamps is just stupid.....

[diecaster]

You guys know who Nelson Pass is, don't ya?

 

Look here:

 

http://audiophilereview.com/amps/nelson-pass-interview.html

 

Specifically:

 

AR: What's your position on passive versus active preamps?

 

NP: You'd think that a minimalist switch and variable resistor in a box would be as good or better than active stages, but often it is not.

 

Some of the issues are well understood; for instance if the resistance value of the potentiometer is low, the source can have bass issues due to the output coupling capacitance and higher distortion due to greater load current.  At the other extreme, if the resistance is too high it can create distortion and high frequency issues by presenting a high source impedance to the power amp.

 

Then there are things that don't show up in the usual measurements and we simply observe that the active circuit sounds better than the passive.

 

I file these under "How About That".

[diecaster]

7 minutes ago, esldude said:

How about that any analog preamp with a volume control in fact is a buffered passive preamp. You did realize that did you not?

 

Passive preamps are the volume control in active analog preamps.  You then follow it with circuitry to make it work properly.  

 

No. A buffered passive preamp, even one with tubes, has no gain. If there is gain, it is not a "buffered passive preamp".

[diecaster]

Another quote from Nelson Pass:

 

A buffer is still an active circuit using tubes or transistors, but it has no voltage gain – it only interposes itself to make a low impedance into a high impedance, or vice versa.

[diecaster]

This place reminds me of the Left. You are welcome to any opinion you want as long as it is the same as ours. 

[diecaster]

32 minutes ago, barrows said:

Again: NONSENSE.  If this were true then stringing two preamps in series would "improve(s) sound" even more!

 

I am sorry, but that is fallacious premise. That is like saying if some salt makes a dish taste better that more salt will make it taste even better. 

 

You are, or should be, better than that. 

[diecaster]

You need to look at this part of the Nelson Pass quote more closely:

 

Then there are things that don't show up in the usual measurements and we simply observe that the active circuit sounds better than the passive.

 

I file these under "How About That".

 

BHK says something similar in the video of his thoughts on active preamps. 

 

The bottom line here is that guys with a ton more experience than you think active preamps sound better than passive/none. I am not telling you that you have to like active preamps. But crapping them makes no sense. My 40 years of experience is audio sides with Pass and BHK. 

[diecaster]

6 minutes ago, barrows said:

You are drawing the wrong conclusion from what Mr. Pass said.  He is not referring at all to DACs or going DAC direct to amplifier, he is talking about an active volume control circuit vs. a fully passive solution.

 

A DAC direct connection to an amplifier is NOT a passive solution.  The DAC has an active buffer circuit at its output, just like the active preamp Mr. Pass is referring to, so it can drive the cable and input stage of the amplifier correctly.

 

Pass is not talking about DACs at all. Part of what he says is talking about issues that are well understood. Then you have this quote:

 

Then there are things that don't show up in the usual measurements and we simply observe that the active circuit sounds better than the passive.

 

I file these under "How About That".

[diecaster]

43 minutes ago, barrows said:

...the point is, the output circuit of a DAC is the SAME as the output circuit of an active preamp.

 

Ah, so all active preamps and all DACs have exactly the same output circuit. No, I didn't think so. That's why they don't all sound the same and that's why using an active preamp can sound better than using just the DAC.

 

Oh, and no, the output circuit of a PS Audio DirectStream is NOT the same as an active preamp.....

[diecaster]

Fitzcaraldo215,

 

That is all well and good in theory. But, in practice, that's not how it works out. At least not for everyone. You go ahead and be concerned with what the signal looks like. I will care about how that signal sounds. With my 40 years of experience, I'll take a high quality active tube-based preamp over a passive preamp or a DAC with digital volume control.  

[diecaster]

36 minutes ago, Fitzcaraldo215 said:

There we have it, as it were, in a nutshell.  If some prefer the added "sounds" of the preamp added in a constant and fixed way to the original signal, I staunchly defend your right to do so. I am not concerned with what the signal looks like either.  I just prefer that it not be distorted or have noise added to it as much as possible.

 

I have also been at this for a very long time in decades myself. Count me out on tubes or analog volume controls. Been there, done that.  They  definitely add something, but not positively, in my experience.  YMMV.

 

You can certainly have the cold "accuracy" of solid state preamps and amps along with their harsh odd order harmonics and hard clipping. I'll take the gradual clipping and musical even order harmonics of tubes. Even if there is more of it.

[diecaster]

21 minutes ago, fas42 said:

 

....the tradeoff is that the "cotton wooled" version can never deliver the "big hit" of realism that pristine digital is capable of ... horses for courses ...

 

I would argue that "analog flavor" can deliver a bigger hit of realism since it often sounds more like what you would hear at real life venues. Every concert and event I have been to that uses amps/transducers (99% of them) presents more color/distortion than I will ever have in my home setup. Heck, our speakers at home have more distortion than a high quality tube preamp/amp combination will produce. Also, high quality tube preamps and amps don't necessarily give up much in detail and even harmonics sound much better than odd. 

[diecaster]

7 minutes ago, barrows said:

What you are telling me is that either your amp sounds bad, or your DACs sound bad.  And you are covering up the bad sound by adding more (euphonic in this case) distortions from your preamp.  Do you really think this is the best way to getting the best possible sound?  Would not a better approach be driving an amplifier direct with good sounding DAC, or replacing your bad sounding amp (whichever the culprit may be).

 

Always talking in absolutes you are....everyone else is wrong and you are right. Your position is the only way an active preamp could improve sound quality is if the DAC has a crappy output stage. You are being unreasonable as other industry professionals with more lofty reputations (actually, with reputations) don't agree with you.

 

 

[diecaster]

3 minutes ago, fas42 said:

 

Well, I hate real life venues like that - in particular, rock music and similar is usually terrible because it goes through PA rigs at the bottom of the food chain in terms of quality. But those sort of recordings can sound magnificent if replayed by a high SQ system ... many people would be flabbergasted by how impressive old recordings can be, when done right ...

 

I wasn't talking about huge venue events.......that's just noise.

[diecaster]

53 minutes ago, barrows said:

As an audiophile since the late 70s, I have a great deal of respect for some of the more well known figures/designers/engineers in the high end.  Such as John Curl, Nelson Pass, etc.  but I do not worship every opinion which they may have.

 

I don't worship them....and I am not asking your to worship them. Just don't discount their opinions or mine!