"For myself if we have this kind of source with these types of problems that has a VC, I can't think of it being hi-end or been designed right, better to me to change it, mod it for something that is."
RMAF 2015 award for best DAC goes to....
http://www.stereophile.com/content/rocky-mountain-international-hifi-press-awards#dUsWps4IBGMLTqEi.97
....the PS Audio DS. |
In Mr BHK's own words :-
"As obvious as it may seem, I would like to hear his take on why his preamp improves the sound in comparison to running the DS direct. I know some still prefer a preamp, I personally don't, but there is some interaction going on that no one seems to clearly understand. I know Paul had his socks knocked off in comparison to his reference preamp, but my socks are generally well attached and not subject to such easy removal. In other words call me an agnostic waiting for the right explanation to shift me into belief." -Pmotz
"Hi Pmotz.
You bring up a good point and rather timely as I have been listening to my Direct Stream DAC direct into my power amp as I take my ptototype BHK Signature preamp (1 or 3) in and out of my system to go work on it in my lab. The system without the preamp in it sounds very nice and acceptable but when the preamp is back in there is a very obvious increase in musicality, transient attack, spaciousness, and detail. I am amazed and delighted with this creation. But I must disappoint as I must be in the camp of those who cannot explain it. I just know what it does for my musical enjoyment and that, in the end, is where it is at for me." - BHK
http://www.psaudio.com/forum/bhk-power-and-pre-amp-forum/bascoms-preamp-chronicles/ |
Milpai, I have had a TVC using S&B transformers and now have an autoformer unit. As you know I am a fan of passive preamps in general and also own George's Lightspeed. They are all a bit finicky to work with but in the right system are great devices. I have been fortunate to have such a system.
However, a couple years ago I found the need for more gain in my system due to my increased use of analog vinyl and tape sources. So I turned to an active preamp for that purpose, and in my case one that is quite transparent. I still use my Lightspeed in a digital system I have set up, where it works flawlessly. |
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 |
....which still does not explain how the Aesthetix could fix the DirectStream's 'problems' and,
....that rather than tout another brand, build one of your own.
The synergy is now complete.
Cheers! J. |
"Upcoming PS Audio BHK preamp??"
Now that explains things.
Cheers George
|
Better yet, DirectStream owners can wait for the upcoming BHK preamp.
http://parttimeaudiophile.com/2015/10/05/rmaf-2015-its-always-sunny-at-ps-audio/ |
"I still wonder how this one Aesthetix preamp could fix those specific areas he's has singled out."
We can all wonder but this little gem from PM will get a lot of DirectStream owners to start adding the Calypso to their systems or replacing their current preamps with it, instead of retiring the Directstream altogether.
Why not, if it sounds as stunning as PM describes? Again, theory aside, of course.
Cheers! J. |
Like I said it's all in his careful wording if you read it again, his does not incriminate his own PS Audio DirectStream Dac as having the problem, and I very much doubt he ever will.
He says DAC's, and singles out their power supplies and jitter as the problem, and for all we know he could mean those tiny portable dacs that run on external smp wall wart power supplies.
I still wonder how this one Aesthetix preamp could fix those specific areas he's has singled out.
Cheers George
|
If the DirectStream sounds better via the Aesthetix Calypso, the design must be flawed right from the outset?
"For myself if we have this kind of source with these types of problems that has a VC, I can't think of it being hi-end or been designed right, better to me to change it, mod it for something that is."
So, should the DirectStream be redesigned? |
If you read carefully, not once did he refer the analogue power supply problem to his own PS Audio DirectStream DAC. I found that DACs with no-loss digital volume controls Cheers George |
The suggestion then is for PM to redesign his DirectStream such that it sounds better direct to power amp, without need for the Aesthetix Calypso preamp? Poor PM - just to please some dogmatic..... |
I also will stand corrected that an active preamp may help if, the source (dac/cdp) has a power-supply problem in it's analogue stage(as PM states) not by just adding colouration, or as I have mentioned it's output stage/impedance and output voltage is not up to the task. For myself if we have this kind of source with these types of problems that has a VC, I can't think of it being hi-end or been designed right, better to me to change it, mod it for something that is. How can an audiophile live with his/her source knowing the analogue power-supply stage is not doing it's job (as PM states) PM... 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.PM Cheers George |
Can we thank Almarg for finding that interesting bit of information?, yes we can. It is good to know that a preamp still has its uses. Some of you have been corrected, don't need to mention names but you are forgiven. |
"Some folks will opt for color over originality."
Not so - not PM or a whole lot of many others. It all boils down to whether there is an improvement in the listening experience.
Fully agree with Almarg :-
"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." |
Clio9,
I believe you have experienced a TVC before. I did read the review about the Bespoke TVC in Stereophile this month. If anything, I think it was a waste - giving the TVC to a reviewer who already has a biase against "passives". I got a $4k preamp home to see what I am missing against my TVC. And to my surprise, I found my TVC superior to the active preamp. I am sure you are aware that TVC will work only with a matching system. You cannot have an amp/source/speakers that are low in sensitivity.
I will sure seek out to other active preamps in future, when I get a chance, but I agree that the lesser the "electronics" in the chain, the lesser the distortion of the original music. Some folks will opt for color over originality. |
For most of us who are untrained in electronics, we just go by what has been posted previously in this thread :
"Well, it's all very simple then.
1. Start with no preamp in the chain.
2. Then add preamp.
3. If adding preamp makes the sound better, keep it.
4. If adding preamp makes the sound worse, remove it.
Preamp or no preamp brigades become superfluous very quickly here." |
Many thanks, Al, for the heads up.
When we trust our own ears as PM did, the sound truth is revealed as is.
We also understand a little bit more about the theory behind the listening experience.
Cheers! J. |
Thanks, George. 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.
Regards,
-- Al
|
I'll go along with that also Al,
1: The dac's power supply for the output stage as PM states is not up to it.
2: If the dac output buffer is not low output impedance <300ohms, as some very weak tube output dac are today some I've seen up to 3000ohms.
3: The impedance load as seen by the dac output is so severe that only something like a Krell preamp's output stage at 1ohm output impedance is able to drive it.
Cheers George
|
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. Regards, -- Al |
I am at RMAF and saw the bespoke passive preamp that George posted the link to. It is quite a piece of art, has very smooth input selection and 47 step volume control, and both balanced and RCA connections. Unfortunately cannot judge the sound because it was only on a table display. Based on the view under the hood I can say it is well manufactured with proprietary wound transformers but at the price point it sure makes me pleased I own high value passives like the Lightspeed and Slagle AVC. |
There might be more to the "impedance matching" than is obvious. A lot of amps have a DC block capacitor at their input, which attenuates low frequencies with a starting frequency that varies inversely with the driving impedance. IOW, with a high driving impedance, the blocking capacitor lets more ultra-low stuff through (which might be good or bad depending.... some amps and speakers need to keep that stuff out).
I use a series cap as a first-order highpass filter to cross to a sub, and a 'passive' box would move the crossover point all over the place. |
The correct answer is no. That should suffice for now. Even attenuated power amps with dials for gain like my McIntosh must have circuits that allows for attenuation to control volume is indeed acting just like a passive pre amp.
The correct answer is no! once again. |
That's so the missus doesn't leave fingerprints after she's stabbed you in the back. Here’s another incident A women is on trial for murdering her husband by bludgeoning him to death with his antique guitar collection Upon taking the witness stand the judge asked her ... “So first offender” ... to which she replied “No your honor , first the Gibson and then the Fender” . |
Do they throw in the preamp after buying the gloves? |
|
10-01-15: Tortilladc
Stereophile just posted a review of a GBP 9,000 ($13,619) passive preamp. [/quote]http://2.bp.blogspot.com/-GyhUlk9a9XA/VP5Csf0PiVI/AAAAAAAA2Nc/p_qnnqHizO0/s1600/the_bespoke_audio_company_preamplifier_review_matej_isak_mono_and_stereo_01_1.jpg[/url] You do get a pair of white gloves with it. Cheers George |
I've had issues with excess gain in systems over the years - but nothing remotely approaching the excess gain I'd be forking over to the maker of that $13k passive preamp should I be foolish enough to buy one. |
Stereophile just posted a review of a GBP 9,000 ($13,619) passive preamp. |
The Pass pre's that had passive or gain free attributes (?) were single ended, it seemed as though the Pass Laboratories amps worked best via their balanced inputs.
I'm not sure, but I seem to recall that the Pass Laboratories pre's were not from Nelson Pass's pen. |
PHD, some Pass labs, First watt, Threshold ect, had very low input impedance <33kohm and low gain.
So yes they would be suited better with buffered passives or active preamps. Rather than just a passive attenuator.
The ones that have >33kohm (the standard being 47kohm or more) input impedance, and 1-2v input sensitivity for full output, would suit a passive attenuator.
Cheers George
|
I was curious if anyone has successfully used a passive preamp with a Pass Lab amp and then thought it sounded far superior to one of his active preamps.
But great minds do think alike when it was stated that people will buy whatever sounds good to them. |
Knghifi,
Nice, very common sense observation. People will ultimately spent their money on what they believe sounds best to them. |
Little baby polar bear is asking his big mom polar bear same annoying question all over again:
-Mom is it true that I'm polar bear?
-Yes! you are my son just like me -- polar bear!
-Mom, Mom, seriously am I REALLY polar bear?
-Yes, but why you always keep asking?
-It's f..n freezing here mom! |
JonJon2020: No worries,...no offense taken, was only expressing a preference given my being thrown into the fray :-)
As to Nelson Pass' designs: brilliant man who is a definite asset to the audiophile community. I do not however buy the argument that not producing a passive preamp is 'business strategy' simply as stated above. If a passive preamp is superior to an active and yet may be a loss leader for a company (for a period of time presumably), and if that company makes a wealth of other gear that could potentially offset such a loss-leader product in the line up (again for a strategically chosen period of time), then belief should not be cast aside and he should produce such a product for which such a strong opinion is offered. If it is as good as it gets so to speak, word will spread, people will buy it and any potential loss will be put behind them. I agree with Knghifi's comments above. If it's a better product, people will buy it.... |
Regarding the lengthy technically oriented post which Ralph provided yesterday, I of course agree 100%. At the same time, though, I believe his post is not at all inconsistent with mine that preceded it, in which I said: If:
1)The output stage of a source component can drive whatever power amp is being used and the associated interconnect cables without compromise, or, alternatively, at least as well as whatever preamp might be inserted between those components, AND
2)The volume control in the source component, assuming it has one, is EITHER:
(a)As transparent in the range of settings that would be used in the no preamp configuration of the system as it would be if set for use with a preamp (i.e., at or near max in typical cases), OR
(b)As transparent as the volume control that is provided in whatever preamp might be introduced into the signal path,
then it seems to me that the only way inserting a preamp into the signal path can result in sound quality that is subjectively preferable would be by producing an output that is less true to the source material (i.e., less accurate) than the signal that is provided to it by the source component. And it would seem, on paper at least, that in the specific case of Rustler's PS Audio DAC both of the criteria I listed above should be met. Essentially, the output section of his DAC **is** a preamp, or so it would seem. Which means, IMO, that if he finds insertion of a preamp to result in improved sonics, chances are the sonic effects of the preamp would be compensating for an issue elsewhere. Which is not to say that there would be anything necessarily wrong with introducing a preamp as a solution, but the possibility should be considered that changing something else in the system, perhaps the power amp, might be a more optimal solution. Best regards, -- Al |
No money in them ask me, he makes 10 x the profit making actives, why add passive to the range and effect sales of the actives, it's called business strategy, and he's a very wealthy man because of it. If passive is superior, why can't you charge 20x of an active? In this stupid hobby where audiophiles pay CRAZY $ for a piece of wire, you can make it work. One example is produce one above the top of line XS. If passive is truly superior, it will sell with a BIGGER margin. YPSILON offers a passive and active PST-100. |
Unsound, you are right. I just thought it was ironic that Nelson Pass suggested that active preamps are inferior to passives yet actives are the only thing he manufactured. Maybe Georgelofi got it right when he said that there is more money to be made with active preamps. |
Rustler, I use the Aesthetix Calypso with an Esoteric K-05 and I enjoy the combination a great deal. It gives you the opportunity to tailor the sound by tube rolling.
The gain of the Calypso can be reduced by 12dB by switching two pair of jumpers in the preamp. This can be done easily by the user. Instructions are in the manual. |
Phd; The Pass Laboratories Aleph L (2 different versions?) and Pass's First Watt B1 and B2 were interesting offerings. |
|
No money in them ask me, he makes 10 x the profit making actives, why add passive to the range and effect sales of the actives, it's called business strategy, and he's a very wealthy man because of it.
Cheers George
|
"What could be better than a passive?", certainly not all the active preamps he has manufactured. I have a lot of respect for Nelson Pass and I do think his designs are simple and straight forth (minimum gain stages). However he has never marketed a passive preamp to my knowledge but does recommend them. |
Here is a quote from Nelson Pass, he is correct in every way, and I add to what he said that the only way one can better it is by going direct if the source has it's own VC.
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."
Cheers George
|
How in g**s name can a active preamp give you more REAL detail (not perceived detail because of distortions) from the source than the same well match direct source to poweramp.??
Please produce some laws of electronics in your answer and not voodoo speak. The answer to this was in my prior post. However I like to use engineering principles since you asked; we can start there... normally in any situation where we are driving a load, as a general rule of thumb the source will have about 1/10th the impedance of the load. This is a good practice to insure proper bandwidth and low distortion of the source. When you put a resistance in series with the source, the source will begin to have troubles driving the load. Now when the series element is a volume control, one might argue that the control itself becomes the source but this is not entirely accurate. The source becomes that of the volume control and the original source together, along with whatever effects are imposed by the interconnect cable between the source and the volume control. Many sources use a coupling capacitor at their output; such sources can suffer frequency response aberrations when a series resistance is imposed between the source and the load it has to drive (which in most cases will be an interconnect cable and the input of an amplifier). Generally speaking, these errors can be reduces if the source is of low output impedance and the volume control is a fairly low value, for example 10K ohms or less. The issue here is the ability of the source to drive such a load, but if that is the case the effects of the cable between the PVC and the input of the amp will be better controlled and the series resistance between the source's output coupling cap and the amplifier's input will not likely impose much of a frequency response error. When you get into higher source impedance and higher volume control values the cables play a larger role. This is partially due to capacitance. You can calculate the minus upper 3db point by the formula f=1,000,000/2xPi x C x R, where R is the source resistance in ohms, C is the capacitance to ground (that of the interconnect cable) in microfarads and f is the -3db point in cycles per second. The cable between the source and the volume control should not be ignored. While the ear cannot detect phase shift of individual frequencies, it can detect phase shift in a band of frequencies (generally as a tonality but high frequency phase shift can also affect imaging), generally phase shift effects can be heard to 1/10th the cutoff frequency, so if your -3db point is at 50KHz, there will be effects down to about 5KHz. When you put a PVC after a source, as far as the amp is concerned the output impedance of the source is increased, conversely from the perspective of the source the load impedance is decreased. This can lead to the low frequency cutoff being increased in frequency. To avoid phase shift in the audio passband, the cutoff should be about 2Hz as phase shift components (which to the ear sound like a loss of impact) can be heard to 10x the cutoff frequency. So of this moves from 2Hz to 5Hz phase shift components can have an effect at 50Hz rather than 20Hz. Thus it can be seen that while a PVC is a very simple device, if incorrectly used it can act as a simple passband filter. Keeping the phase shift components out of the audio passband is the key to success and is why they can work so well in some systems but not in others.
we are discussing about what the OP's question is, stop rambling about passives, GET A GRIP MATE.
"Is no preamp really better that a good preamp"
And I also addressed this in my prior post, which (in a nutshell) says that in some cases a passive will be better and in others an active will be better, thus both must be auditioned. I thought you would be happy that I was agreeing with you that passives can work... |
Rustler, with the Calypso I would have the concern I cited in my post dated 9-26-15, that its gain (specified as 29 dB balanced/23 dB unbalanced) may be so high that you may forced to use it with the volume control on the DAC set too low to be optimal. That issue is much less likely to occur with the Capri or Capri S2, which have gain specs of 14 dB.
Aside from that, I don't see any technical issues with either choice.
Good luck. Regards,
-- Al
|
this has all been very enlightening for me. Many thanks to all. I think I've decided to get one and see what it does for (or to) my sound. I'm thinking of a Aesthetic Calypso or a Jeff Rowland Capri 2. Any ideas regarding these two units? |
+1, Zephyr.
Sincere apologies for the unintended offense.
J. |
I'd prefer it if you wouldn't use my posts to fuel what looks to be a healthy argument brewing here as the above post (by me) is being used out of context :-)
All that aside, my comments, and I think Guido's on filter and upsampling for the Esoteric units are not meant for, and have little or nothing to do with a debate regarding preamp/no-preamp.
While it is true that the K-series Esoteric players (up until the X revision) have a volume control on their outputs, and you CAN skip use of a preamp, having heard both the P/D and K series units that offer this capability used both with and without a separate preamp, my opinion is there is no comparason in sound quality, imaging, sense of air, soundstage depth, accuracy and overall musicality when a good preamp is inserted in the chain (regardless of who makes it). In my case, I owned an Esoteric C-03 for quite a few years and now have a C-02. I've gone bare bones with my prior D-03 DAC and used no pre-amp and heard the K units used similarly; while the results are good and very pleasing, inserting the preamp back into the circuit gave me MUCH more in terms of the above criteria every single time.
This whole thread is subjective, I do realize that,...furthermore, it has everything to do with the choice of electronics, type and quality of interconnects,balanced circuitry versus single-ended, quality of power cords, grounding, etc...in use at every step in the chain. All things being equal, it is hinged on what the listener is looking to achieve, the quality of their hearing and ability to perceive differences in various sound presentations.
There is more often than not, no absolute right or wrong, better or worse, etc...that can be stamped on every possible combination in this hobby of ours. This is one of those topics :-) |
