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 |
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
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Phd, yes the "less is more" is they way to go if you have a well sorted system.
But if there is a problem area that needs to be fixed, then by adding the right preamp that can tame or accentuate that problem area, then yes by adding the preamp that has those colourations in that area then it can be a pseudo fix.
Good luck on finding the right preamp, as they all sound different, in different areas.
Audio enthusiasts, reviewers, and even manufactures have allways said as far as I can remember, "the prefect preamp" should sound "like a straight wire with gain" which funnily enough is the direct in approach with no preamp.
But I'm of the school that looks at the problem area and changing to or modding the component that causing it, not by adding another one into the signal path chain to gloss it over.
Cheers George
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Some power amps need the drive to sound their best. Phd, Please give the OP some preamp examples that would better the drive that his PS Audio dac gives direct into his amps? And his PS Audio Dac is not a passive volume control on it's output!! Cheers George |
[quote]However I'm advocate for using a preamp.
Some power amps need the drive to sound their best.[/quote]
I didn't ask you to recommend a preamp to the OP,
I asked you to name preamps that would drive better than the output of his PS Audio dac could do, after your statements above.
Cheers George
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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
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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 |
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
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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 |
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
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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
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09-28-15: Almarg
Not to disagree with two of my favorite and most respected A'gon colleagues (Ralph & Jon), but if: I too Al have respect for Ralph, and have praised his OTL amps many times in these forums and others when partnered with the "right speaker". But I'm at a loss also in this thread, makes me think there is something else at play. Cheers George |
Yes Al, same, same, colourations, distortions, inaccuracy.
I use the word colourations when I'm being kind, after that when pi**'ed I'll start to use the proper term "distortions".
Cheers George |
Ralph??? 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"
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We (audiophiles) all try to get the very best possible sound that blows us away, then it's a shame that some of us have to compromise it because we need to change sources and are not up to just to unplug and change them.
This why I have a dedicated system with the least compromises in my hifi room, and another one in a TV room for all the other stuff/crap like surround sound, tuner, internet streaming ect.
Oh and I suppose your may have read this post about the K-01 which is Delta Sigma vs his older Reimyo R2R Ladder Multibit dac, which all the very best are starting to use again because this way of conversion it is said to give a better presentation of real music, the owner also missed the warmth of his Reimyo when he changed to the K-01
[url]http://forum.audiogon.com/cgi-bin/fr.pl?ddgtl&1358613368&&&/Unsatisfied-with-Esoteric-K-01:-Alternat[/url]
So that's two of you with the same beef about the K-01, wouldn't it be better to fix the problem rather than just putting a very expensive band-aid on it, and causing maybe other problems.
Cheers George |
"finding a preamp that warms things up a bit to neutral, is just what I need to fix this problem."
You have hi-end components, and I think that's going to cost big time and a lot of A/Bing preamps just to warm the sound over and maybe loose transparency and detail in the process.
Better off trying to warm it up in other ways that are cheaper, like changing any silver cable/s for OFC Copper ones or change and sell the component that has the "cool" sound to a warmer sounding one. Your pocket will thank you.
Cheers George
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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.
Cheers George
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Of course Jon2020, and I've said exactly that, if he likes what a preamp adds (and that's a colouration) because something else is not quite right that's ok.
What erks me is when the preamp brigade use blanket statements that preamps are better than direct period, without even knowing if the user needs that colouration or not in his or her system.
And then also saying it drives the poweramp/interconnect better which in this case it cannot, as he has a perfect impedance, voltage and gain match going direct.
Cheers George
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No freezing, just that warm feeling of not having to empty your pockets on an added active preamp that not needed under these conditions, and probably going forward with the sound instead of backward in the process.
Cheers George
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09-26-15: Clio09
If you do not need the gain, the source variable output section can control the interconnect, and you like the sound then you should stop there. Correct Clio, Once again, please anyone who wants to put their head on the chopping block. Using and quoting the laws of electronics (not just voodoo speak) what is not matched with the OP's PS Audio Dac 100ohm 2.8v output running direct into the Spectron's 50kohm 26db of gain input. Cheers George |
09-26-15: Rustler
I guess my final question, then, is what kinds of specs should I look for in a preamp if I want to add one at some point? Ah!! now that's another ball game, if you want to colour the sound in some way instead what you get going direct, this will be a bit of a merry go round, as all preamps have different sound signatures, and no one here could give you the right answer to which to get unless they are you. Cheers George |
Yes Bdp24 that goes for everything active or passive from the source output to the poweramp input.
If impedances matching is not correct (Ohms Laws) and the current is compromised (Kirchoffs' Laws).
No amount of voodoo speak will solve the problem. This is why I asked Phd to name preamps that can drive better than the output of the OP's PS Audio Dac.
BTW: I don't know how passive came into this conversation, maybe it was just a bit of baiting?? The OP question was just "Is no preamp really better that a good preamp?"
Rustler: Almarg and I have both told you have a great match to go direct, and adding an active pre is going to do nothing but colour the sound and put a hole in your pocket.
Cheers George
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Driving the inter-connect cable---what a concept!Maybe another reason why the sound of any given cable is so system-dependent---it's interacting with the volume control in the pre-amp of every system it's put in. This is either tongue in cheek, or your so wrong. Just in case it was not tongue in cheek. The volume pot in a preamp has nothing to do with the interconnect cable, as there is and active buffer between them, totally isolating the pot from the interconnects Cheers George |
Hi Rustler.
Your PS Dac has from it's single ended output has 100ohms output impedance at 2.8v from it's "Resolution perfect volume and balance controls"
Your Spectron amp has 50kohm input impedance at 26db of gain.
These are a perfect match for each other to go direct with, and will give you the best transparent/dynamic sound you can get.
By putting a preamp into the mix you are just throwing money away to colour the sound with.
Cheers George
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Rustler hi,
Please list your models of source and poweramp so we can let you know if you have a good impedance match to give you the best (most transparent/dynamic) sound.
Cheers George
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"Upcoming PS Audio BHK preamp??"
Now that explains things.
Cheers George
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