How much do I need to spend to get a preamp that sounds better than no preamp?

I am feeling lucky ( punk ) ....

Lest anyone wonder, this is a humorous reference to a famous line spoken by Clint Eastwood in the 1970s film "Dirty Harry."

Congratulations, MrDecibel.  As you said, enjoy!

Regards,
-- Al 

Honashagen  5-26-2018
As I sit here listening with no preamp, it seems like common sense would tell you that if a preamp alters the sound from the source in any way it's really a processor of some type. Right? 

... Unless, that is, the presence of the preamp somehow causes the source component to behave in a more accurate manner.  And as you've read above, there are what I would consider to be plausible technical explanations for why that may be the case in some systems. 

Also, my perception has been that in past threads in which the preamp/no preamp issue has been discussed a significant majority of the reported user experiences has been that the addition of an active preamp to the path between a source component containing a DAC and a power amp has been beneficial.  I would not assume that all and perhaps even most of those experiences were the result of inaccuracies introduced by the preamp.

Subtle effects can often occur in electronic circuits and systems that have consequences which are counter-intuitive, and that are not necessarily consistent with what "common sense" may lead one to expect.

Regards,
-- Al

Anthony (Clio09), yes, it was clear to me as to whom you were attacking, but thanks for making sure.

I do think, however, that the explanation Paul McGowan stated is technically plausible, and could very well support the notion that in **some** cases inserting an active preamp between a power amp and a source component containing a DAC could result in performance that is objectively as well as subjectively better than a direct connection. And likewise with respect to my own hypothesis that I presented in conjunction with his.

Best regards,
-- Al

Trelja 5-20-2018
Difficult question, I admit, and you could maybe just chalk it up to tubes in general, and why folks compete for valued ones, but do you have any opinions on why different tube rectifiers of the same type exhibit not much difference in performance, yet such wildly different tone?

Hi Joe,

All I can offer is the very general thought that with the exception of "absolute maximum" specifications and sometimes heater voltages, most tube parameters are specified just as nominal values (either as numbers or in the form of graphs), with no specification of +/- tolerances or min/max values. As can be seen, for example, in this datasheet for a vintage GE 5AR4. Which leaves room for numerous parameters to differ significantly among tubes of a given type.

And even if the actual values of all of those parameters were known for two or more tubes of a given type that may be compared, analysis of the likely sonic consequences would probably be impractical, as well as being dependent to a significant extent on the design of the specific component the rectifier is being used in.

So what we have to go on in that regard essentially comes down to what can be inferred from empirical evidence that has accumulated over the years. With some grains of salt applied, in part because of the aforesaid component dependence.

Best regards,
-- Al

Great post, Joe (Trelja). A pleasure to read an uncommonly nuanced, balanced, and well written post about controversial audio matters.

Regarding sonic differences between rectifiers of a given type, btw, I believe that what accounts for those differences in many and very possibly most cases is simply that their voltage drops vary significantly among different makes and vintages. Resulting in corresponding differences in the DC voltages that are applied to the audio stages.

Best regards,
-- Al

Honashagen, some questions:

1)Are you using balanced or unbalanced connections between the Oppo and the Pass? I suspect balanced would be preferable, as I alluded to earlier.

2)Have you tried both the 4 db and 14 db gain settings of the Pass?

3)Are you setting the Oppo’s volume control at or near max when the Pass is being used, which I would expect to provide better results than having that control at a lower setting?

4)If you are using an unbalanced connection to inputs 1 or 2 of the Pass, is a shorting plug or jumper connected between pins 1 and 3 of the corresponding XLR connectors? (See the second from the last paragraph on page 3 of the manual).

Regards,
-- Al

Clio09 5-25-2018
Seriously, we’re quoting Paul McGowan around here now? Things have gotten a bit worse on this forum than I suspected.

Hi Anthony,

As the saying goes, don’t attack the person making the argument, attack the argument.

Regards,
-- Al

Several prior threads here have addressed the major points of contention in this thread. One of them was this one:

https://forum.audiogon.com/discussions/is-no-preamp-really-better-that-a-good-preamp?

On page 3 of that thread I quoted some insights PS Audio’s Paul McGowan provided on that subject, and added some further thoughts of my own. I think those posts are worth repeating here:

Almarg 10-4-2015
Interestingly, Paul McGowan, designer/manufacturer of the OP’s DAC, has just in the past few days been posting thoughts on the very question being discussed here in his blog at the PS Audio site. Some excerpts:

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.

Makes sense to me. So if Paul McGowan can do an about face on this issue, at least under some circumstances, I guess I can too :-) But I believe that in general the opinion I expressed in my first post in this thread still stands:

09-23-15: Almarg
The burden of proof should always be on adding anything to the signal path that is not an obvious necessity. In this specific case a preamp is not an obvious necessity, and per George’s analysis (with which I agree) the odds appear to be in favor of that burden not being met. However, as others have indicated the only way to know for sure is to try it.

Almarg 10-4-2015
... I suppose an additional possibility is that high frequency noise resulting from a ground loop condition between a DAC and a power amp could enter the DAC’s output circuit and find its way via grounds, power supplies, stray capacitances, etc. to the D/A converter device and/or its surrounding circuitry, causing an increase in jitter.

Of course, depending on the specific designs introducing a preamp between the DAC and the power amp could either resolve such a problem, introduce such a problem, or make no difference.

Almarg 10-6-2015
An excerpt from today’s blog post by Mr. McGowan on the same subject:

Our newest DAC, DirectStream, ... has zero loss at any level setting–a major achievement. So, how could a control with zero resolution be suspect? That’s a question I have been mulling on for some time now.

One piece of the puzzle seems obvious. We know that tiny changes in the way internal FPGA process are organized make significant differences in sound. Even changes to the display affect sound quality. It’s a delicate process when jitter, power supply and the tiniest of changes can be heard and must be attended to. What’s to stop us from believing that different level settings have different sound qualities–despite the fact there are no measurable resolution losses?

Were it to be found true much would be explained. For instance, we know not all preamps sound better than DACs directly into power amps. In fact, most don’t. This observation lends credibility to the explanation that it is not preamps that make DACs sound better, rather, it is preamps helping DACs not sound worse. This theory can only be true if the preamp is of sufficient quality to add less degradation than using the DAC’s volume control. That all kind of makes sense.

But, just because something makes sense, doesn’t mean it’s true. How do we make this determination to see if this theory holds water?

Regards,
-- Al

Honashagen 4-22-2018
No balanced inputs on my DNA1.

I’m not sure from this response if my suggestion came across clearly. To be sure it’s clear, I was suggesting that you consider **adding** balanced inputs to the DNA-1, either with an external Jensen transformer or via the mod Steve McCormack had offered, and perhaps still offers. I suspect that doing so would allow you to utilize better sounding outputs of the BDP-105. It would also eliminate the possibility that ground loop issues between the player and the component it is driving are affecting sonics.

A potential benefit of using the external transformer approach, rather than Steve’s mod, is that it would provide you with the flexibility of having the Audible Illusions preamp (or some other single-ended preamp) either in or out of the path, while using the balanced outputs of the player.

Regards,
-- Al

Rather than spending a lot of money for a better preamp, here’s a much less expensive possibility to consider, that could very conceivably result in a significant improvement:

I presume that all of the connections you have been using between the components you mentioned are unbalanced. Although I’m not certain, I suspect that as in the case of several other Oppo players the balanced analog outputs of the BDP-105 are driven via a signal path that is fully differential from the output of the D/A converter chips to the XLR connectors. And it has been reported in various posts here that some users of Oppo players have found the sonics of the balanced outputs to be superior to the sonics of the unbalanced outputs.

According to this review from the year 2000 Steve McCormack offered, and perhaps still offers, a mod to the DNA-1 which provides it with balanced inputs, implemented with a Jensen transformer. The cost of the mod in 2000 was indicated to be $450. And, alternatively, a Jensen transformer that could be used externally to convert balanced signal pairs for both channels to unbalanced, such as the model PI-2XR listed here (select RCA output connectors under "Pricing") can be had for ~$250.

If your DNA-1 doesn’t already have that mod you may want to consider either contacting Steve to see if it can be incorporated, or separately purchasing a Jensen transformer that would provide XLR inputs and RCA outputs.

Regards,
-- Al