How much do I need to spend to get a preamp that sounds better than no preamp?
Hello all. I'm using an Audible Illusions L1 preamp and I think my system sounds better when I remove it from the signal path. Oppo BD105 directly to SMC Audio DNA1 Gold power amp. I have read that there is level of quality you need to hit before there will be an improvement in sound. I can't seem to find what that level is. Any ideas? Thanks in advance, Ben
I think your the one that needs to lay off the false claims about
passives with blanket statements about their ability to drive ect ect.
Every time they are bought up, your on it to protect active preamps. Here
is a person you should kneel to as he is one who makes active preamps
for a reason which I’ve outlined, yet he is man enough to tell what it
is about passives that’s the real deal. You just deny them as a whole,
just like the "detriments" of a certain autoformer.
I have math to back me up on all my claims. I have also been careful to point out that passives can work fine if one is careful in the setup.
You are protesting just a little bit too loudly... I've got nothing bad to say about Nelson- he is a brilliant designer and I often point out in my posts that he makes some of the best solid state gear out there.
Its my opinion that its a lot harder to build a solid state preamp that's going to sound right; Nelson does a pretty good job but maybe his passives are showing up some problems with his active preamps (if not, you are the expert on his quotes- you figure it out). Our customers seem to think our gear sounds better (probably why they are our customers instead of someone else's...), but we have a lot of customers that run Nelson's amps with our preamps: we have customers in common. And we are on good terms with the folks at Pass Labs.
Saying that everyone that sells active preamps is just in it for the money and somehow that someone selling passives isn't is as hypocritical as it gets.
IOW, you just attack active preamps because you want to sell more. Its not because your gear works any better! So how does that feel George?
That's the sort of crap that you lay at other's doors. The simple fact is, I have no idea what your motivation is (just as you have no idea of my motivations), I wrote that accusation so you can see how it feels. I've heard the Lightspeed and it works fine in the right circumstances. I keep trying to be reasonable with you but you keep going off like a five dollar pistol. Perhaps you can tone it down a little- I can easily demonstrate situations where an active works with less coloration than a passive, and I can demonstrate situations where a passive offers no coloration as well. Its all in the setup.
Saying that everyone that sells active preamps is just in it for the money and somehow that someone selling passives isn’t is as hypocritical as it gets.
Yes I was drawing a long bow there, yes there is a place for active preamps when, poweramps have stupid low input impedance, and if their input sensitivity is higher than 2v, eg FW F5. This is when active preamps are needed.
I’ve heard the Lightspeed and it works fine in the right circumstances.
I’m glad, and the right circumstances can be 90% of the time, if amps input is more than >33kohm and input sensitivity is less than <2v.
I’ve got nothing bad to say about Nelson- he is a brilliant designer and I often point out in my posts that he makes some of the best solid state gear out there.
"I’ve got nothing bad to say about Nelson"
And no you shouldn’t, nor should anyone else here who want to question what he’s said, if they want to then go to http://www.diyaudio.com/forums/pass-labs/ site and try to tell him there direct and see how long you last, as those technically superior like NP wouldn’t waist their time here with the BS that’s put forth on these forums .
There are a few sources that require active preamp, without while your system sounds lifeless. I had Logitech Bluetooth receiver which was one such example. Similarly connecting the headphones out from a mp3 player to a passive also sounds lifeless. I use a TVC.
Just an FYI.... Any F5 can be made to yeild 25 dB of gain very easily.
Who cares. It’s not about you and your F5. The heading of the thread is: " How much do I need to spend to get a preamp that sounds better than no preamp? I think my system sounds better when I remove it from the signal path. "
"you are such a kosst", new saying here for agitators take note everyone.
@georgehifi "Here is a person you should kneel to as he is one who makes active preamps for a reason which I’ve outlined, yet he is man enough to tell what it is about passives that’s the real deal."
Kudos to Nelson for being man enough.
Speaking of being man enough... As Ralph said you go off like a $5 pistol. I’ll add, routinely. As an example, @georgehifi , you went off half-cocked, and initiated a thread on Stereophile no longer performing measurements even though it was completely incorrect. For the longest time, the myriad (Sam Tellig, Art Dudley, Kal Rubinson, Lisa Astor, and on and on) columns never included measurements as they were subjective writings and meant to entertain and sell magazines. Sometimes, the follow-ups to the more formal reviews also do not include a new set of measurements. If you had an iota of the stones you stand up on your soapbox and claim you have, and within all the time and energy you have chasing down all the things you do, you would have issued a mea culpa. At least, THAT’S what a man does...
Regarding active versus passive preamplifiers, the world is big enough for both of them. I run direct from my digital sources, and have / had and use both active AND passive preamplifiers. All three options have their place, can provide a rewarding experience to the owner, and none is incorrect. I have respect for both you (honestly, you deserve plaudits and more for the Lightspeed) and Ralph in terms of the preamplifier solutions you put forth. But I doubt I’m the only one who feels your showing up in the innumerable threads you have to crap all over the idea of folks wanting / enjoying / needing an active preamplifier to the point of their being wrong / stupid / duped / fraudulent got old a long time ago.
Lastly, I find it beyond unfair to the point of immoral to paint folks like Ralph as someone putting profit before his dedication, belief in the knowledge / experience he’s developed over the past 45 - 50 years, craftsmanship, and overall audio landscape
Regarding active versus passive preamplifiers, the world is big enough for both of them.
Yes and I’ve always maintained that, and so does Nelson Pass But when someone of no acknowledged tech background put **** on what Nelson Pass says about passive preamp, of course I’m going to have a go at him, as should you!
BTW: are you a "fuser"? I think I may have seen you be pro fuses in posts and what "magic" they can do .
@georgehifi "BTW: are you a "fuser"? I think I may have seen you be pro fuses in posts and what "magic" they can do ."
Before we get started on that tangent, you continue to skirt responsibility for your Stereophile mistake. Again, simple question, are you man enough?
I am NOT a fuser. That said, I am NOT anti, either. And though I will take the time to answer your question, specifically, I generally stay out of the discussion, and will continue doing so.
A dozen years ago, a friend from China who sometimes visited, and as a prince of a guest, always bearing gifts, handed me a pack of what appeared as fuses with silver caps and what he claimed a superior wire inside. He stressed their benefit. I thanked him, and after he returned home from his visit, threw the pack in the drawer, and never looked at it since.
So unlike most who enter the debate, I don’t fall into either camp. Honestly, I don’t really care one way or the other. I’m not buying any fuses, nor am I begrudging anyone who does and finds happiness with them. In fact, I feel happy about their improvement. From the incessant back and forth, I think it’s clear jerks exist on both sides of the fence who never tire of arguing, insulting the other side, and posting the same statements ad infinitum. With a few exceptions, I haven’t read a post from either side in months that I found interesting or adding to the debate.
But I do hold out the ** POTENTIAL ** for fuses to improve the sound of a component.
Having worked as a material science engineer / chemist who researched and developed electronic (like conductors and resistors) materials for the household names in this industry like Vishay, Dale, CTS, Ohmite, and on and on, I know small differences in formulations, compositions, manufacture, and treatment can impart meaningful differences in the performance of an end product. For example, though there is a relatively small difference in the percentage of carbon delineating cast iron from steel, we all feel it obvious the end products differ greatly. If I still worked in that field, this whole thing would be very easy to sort out from a purely objective standpoint. I’d buy a bunch of fuses (not at $150 or more, of course), perform a slew of chemical / metallurgical analyses and electrical measurements including scanning electron micrographs, X-Ray diffraction, hot / cold (MILSPEC) thermal cycling, high voltage breakdown, high temperature accelerated aging, etc., measuring resistivity and other factors all the way and comparing them to two or three standard fuses like Bussman, LittleFuse, etc. to find out what, if any differences exist. Or, even if the materials and metallurgical treatments and hence, performance were identical. As I’ve said, I know of no high-end audio company capable of assessing the nature and objective performance of these fuses, though I do feel groups exist within companies that skirt the audiophile realm as part of their infinitely larger businesses otherwise like Samsung, Matushita, Sanyo, Sony could, even if the desire to doesn’t exist.
On the audio and guitar side of power supplies, many have heard and measured the effects of transformers, tube rectifiers, diode rectifiers / bridges, capacitors, resistors, chokes, almost all of which engender very little doubt or debate in terms of their effectiveness. I do find incredibly interesting and even passionate discussion when it comes to topics like Pi filters versus choke input power supplies, grain oriented versus amorphous transformer cores, the myriad alloys used in transformer cores, paper versus plastic transformer bobbins, directly versus indirectly heated rectifiers, the advantages of fast recovery diodes, "better" capacitors and increasing their size, how big a capacitor you can use directly after the rectifier, how many stages of filtering work best, wirewound versus metal oxide resistors, etc. Maybe that’s because so many of the folks involved in this chase spend a good amount of effort measuring, documenting, sharing, and discussing their findings, as opposed to selling something?
It did take a long time for me to get here. As a trivial example, I used to hear a lot about rolling a tube rectifier, and I dismissed all of it. Presuming they both test fine, how or why would one sound different from another? They’re not in the signal path, all they do is rectify the incoming AC. Well, trying different rectifiers made me a believer. They do sound different, and some clearly sound better than others.
However, when folks claim improvements that seem ridiculous, those people come across as just that, ridiculous. For example, an extra octave of bass response. Someone actually believes a fuse can lower the 40 or 50 Hz low-end roll-off of their system to 20 or 25 Hz??? Also, while I don’t push people on measurements, as most lack the capability, ability, and knowledge, I feel it the responsibility of manufacturers (or, are they just sellers?) to spend the time, money, and effort on documenting and making available the reasons their products can provide the sort of improvement that justifies a sale. I realize the guy who posts here 24 / 7 playing the Wizard now flat out recommends no one should provide information or explanation on a tweak they market. As in the other audio discussion forums, his opinion would never be given another thought, folks here actually engage him, and pander to his self-proclaimed guru status. No, what could have provided some meaningful benefit was when the manufacturer of the specific fuse a thread focused on showed up, and instead of actually taking part in a meaningful discussion, or shining any light on the situation, simply said keep calm, carry on, and ignore the other side.
From a distance I think I’m probably not the only one who feels curious as to what these fuses are made of, though not enough to take any action. As I said, if I had access to the equipment of my past, I would uncover that. Perhaps, few would care. I’ve watched over the past 20 years, the concept of value has evaporated from so much of this hobby. I once discovered one of the more well-known interconnect ($1400/meter) and loudspeaker cables of the past as simply a readily available CATV product costing 62 cents a foot. As it stands, I don’t know why people don’t test these fuses in their component. They could take voltage and current measurements, and someone could even look at things through a scope, throughout the power supply, comparing it with a typical fuse.
So in the end, while not a fuser, I’m not an anti-fuser. Given what I’ve experienced with material science and power supplies, I think it’s certainly possible a fuse could improve a component’s sound. In fact, I feel it is REASONABLE. But it’s not something that I think about, worry about, or much care about
@kosst_amojan,I used Signal Cable's Silver Resolution as well as Clear Day cables for the BT unit, not the ones that came with the unit. @georgehifi ,I have nothing against passives. In fact I have been using TVC for the past 9 years. You bring up Nelson Pass's statement that we have enough gain in today's sources to drive power amplifier. Yet he keeps coming with new preamps. There must be some reason for that - besides the "making money factor". I feel that audio is a personal choice and "how" a system sounds is a personal preference. With my upgraded loudspeakers, I am tempted to try a active in my system. Why? Because my new loudspeakers have better resolution. And I am hearing stuff that my old speakers never showed before. I would like to see how an active preamp works in my system.
Back to the original q - I had to pay ca 4 k dollars to get a preamp better than the direct input from my Aesthetix Io phono stage. Einstein The tube mk 2. Bought second hand. Have not looked back.
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.
OP, funny, I just posted a similar discussion on AA. I have a Parasound P5, and was thinking time to upgrade, but my system is balanced throughout, and there's not much available under under $4K. Then I came across a W4S STP E on 10 Audio and started investigating and checking the used market. Then it dawned on me that after I did two aftermarket DIYs from ebaye replacing the oem iec wire harness with a Furutek Rhodium IEC with silver wire, THEN replacing the oem power supply with a beefy toroid board @ $118.00. I connected my 105 directly to my Emerald Physics 100.2SEs and was gobsmacked, BUT I think a big part of the smacking is because all are plugged into a Core Technologies 1800, an amazing passive PLC..
you went off half-cocked, and initiated a thread on Stereophile no longer performing measurements even though it was completely incorrect.
Are you serious!!! (is this because I asked if you were a fuser.) that’s not even worth a response, but I will, as I asked a legitimate question as John Atkinson’s response shows??? And the measurements/test were not done with two reviews. I simply asked "Tests???????" https://www.stereophile.com/comment/574783#comment-574783
JA Quote: "It wasn’t possible for Larry Greenhill, who now lives in California, to ship this amplifier to New York in time for me to measure it.
Ben, Thank you for posting you inquiry. It's not a matter of money. More money won't necessarily buy you better sound. More often than not, higher cost doesn't add to the sound quality, but more to the looks of the thing.
Spending more may buy you a lot of decorative nonsense that doesn't contribute one ounce of quality to the sound. I possibly have breadboards that may sound better than many of the chrome plated, glass enclosed, polished aluminum, powder coated concoctions that are sold daily as high end audio. None of those add on decorations alter the sound in a positive way. It's just fluff.
The cake taker, prize winning gullible buyer award, for absurdity goes to the claim that replacing the POWER CORD on a turntable with a $1500.00 power cord improved the sound. BS. It definitely improved the financial position of the seller, but I have REAL SERIOUS DOUBTS that a power cord can make the highs crisper or the bass cleaner. Defies physics.
The quality of a sound is the result of supplying a acoustical experience to ones ears that is more pleasing than other experiences that the person has experienced. It may be different for each individual, however, MOST people, (possessing good hearing facility) will agree on a certain set of characteristics of an aural experience as being "quality".
It is a matter of what you buy, and how it is designed. Not the amount of polished aluminum that it is included in the illusion.
What state and city are you in? I would love to have your ears in my room for an hour if by shear dumb luck you are near me in Southern California.
That’s well put for a first time poster, I like your rationale behind most of what you said. I hope you can last in the "sometimes" cesspit of "snake oil" threads that pop up here. As there is too much "snake oil voodoo" on these pages that real designers/techs won’t endorse or go near.
And you know if those "snake oil" claims were posted on a forum where the likes of Nelson Pass, John Curl ect, ect, ect hang out like diyAudio.com the poster would get a new one ripped within the hour, and disappear in shame like many have had to do that I’ve seen.
As you probably already know, there are so many variables that are factored into each sound system that trying to nail down one preamp for your use can only be determined by testing several in your own environment. Sound is so dependent on amplification, speaker system selections and placement, room acoustics, etc. I have always purchased equipment based on reviews. I have had inexpensive preamps (under a grand) installed that sounded good and had others costing upward of several grand sound poor or not to my liking. Go figure. Part of the enjoyment in my eyes of always seeking that best sound. Good luck with your search and when you find one, keep it and enjoy it for a life time.....
@csmgolf "Clearly the answer is no, he @georgehifi is not man enough." You're right, Cris. He answered the question clearly. All he needed to say was that I was mistaken. Seems as easy as falling off a log, and yet...
Did you notice how he got so flustered he quotes me as responding with a statement I made PRIOR to his fuser question? He didn't know whether to scratch his watch or wind his butt. On the positive, he seems to have finally turned into a civilized person here instead of routinely attacking everyone in front of him. Who knows if it will last, but let's hope, as he's actually an obviously intelligent guy, and the Lightspeed Attenuator a worthwhile technology
As always, you raise an excellent and most salient point in regard to rectifiers.
As I considered what you said, I HAVE noticed the differences between types ("normal diodes" vs HexFred, 5AR4 vs 5U4 vs 5R4 vs 5Z3 vs 5Y3 vs...) far more prominent than variations within those types. I’m sure no one will say that’s noteworthy. While I have clearly observed the differences in voltage drop between them, I now realize I’ve been a bit too sloppy to not have more carefully measured the variation within a type. Thank you for providing a new rabbit to chase down!
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? By that I mean, even friends who love to tell me, "Oh, I could never have a decent system because I’m just not good enough to ever be able to hear the differences..." can easily discern changing out a Sovtek vs Shuguang vs JJ vs Mullard 5AR4
His answer is only partly true. He couldn’t even bother to wait for JA to post a response to his question, he had to immediately come here and post a click-bait thread on the subject. There was a not quite half-hearted mea culpa near the end of the thread. https://forum.audiogon.com/discussions/stereophile-no-more-bench-tests What kind of a person does that? There are plenty of designers and manufacturers that post here and do so respectfully, even when they disagree with another poster. Several even chimed in on the fuse debates. They stated their point and moved on, only replying again if they were directly questioned. Not this guy, he has multiple pages of the same reply over and over, never adding value beyond the first several posts. He apparently doesn’t realize that all members here are potential customers in an ever shrinking market. Why would you ever treat a potential customer that way? Disagree if you must, but be respectful, then leave it at that. No matter how great his product is, I would never give him a dime of my money for just that reason. I would suspect that I am not the only one. Seriously, if that is his method of marketing himself, then he is deranged. And no, I am not a fuser either. My position more closely follows what you believe, Joe.
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.
He couldn’t even bother to wait for JA to post a response to his question, he had to immediately come here and post a click-bait thread on the subject.
Really!!!!, I was asking the question, "
Looks like Stereophile may be cutting back on expenses" operative word being "may", as I’m not in the US and maybe others at Agon had some more info, if the tests going to be stricken,, as they are the most time consuming part and expensive of Stereophile and many mags are getting rid of them to save money in this diminished climate for this type of reading.
And 3 days later I did post this, your the one that needs to be questioned not me. Maybe your a "snake oiler" and just didn’t like what I said in this post. https://forum.audiogon.com/posts/1555737
no more bench testing for measurements and specs to keep the manufacturers and reviewers honest, it'll make you think twice on what to believe now, without the proof to back it up.
Your last post is classic cherry picking...and you are an expert at that. The quote above is a not a maybe statement, it is your presumption of fact. All you really had to do was wait for the answer from the source, JA is pretty good at following up questions. Hey, as long as you get the word out first, it doesn't matter if it's true or not. Kind of like the media these days. When the truth comes out, the best you can do is offer a weak, half hearted statement at a later date. I wasn't offended by your so called apology, I was bothered by your dishonesty at creating the post and your continued attempts to justify it. Your character, or should I say lack thereof, continues to shine through.
Since the topic is really about " gain ", let me say this. I have a large assortment of amplifiers, included a few pro amps, which all have input gain controls. Using these amplifiers, I have a choice, of keeping the controls on the amps at max, and using the preamp ( s ) volume controls at a lower setting, at about 9 - 10 o’clock. However I find I prefer the sound of the system with the amps controls turned down, to the point where the preamp ( s ) volume control is at about 12 - 1 o’clock. I have tried going from source to amps, and while it is clean ( possibly a little cleaner ) without the preamp, with the preamp ( s ), the drive, dynamics, well, pretty much everything, is better to me through the preamp ( s ). Enjoy ! MrD.
No you are cherry picking and must more likely have your back up over the "snake oil" voodoo'ist statement I made. As I'm a great believer in measurements, as that's how all gear is designed and made, and then listened to. And those measurements can help buyers/users choose right amps for speakers and/or right speakers for amps, instead of the many "well serving" here but wrongly saying "buy this" it sound great, but don't have any idea if it will to the job measureless wise.
I do not believe "gain" to be the main issue here. IME, the reason some hear improvements in dynamics and bass when moving from a passive to an active preamp is due to improved impedance matching through the volume control and consistent current delivery. An active buffer (with or without added gain) can make the source's job of driving an amplifier easier by allowing the source to see a high input impedance into the volume control and the amp to be fed a consistently low output impedance following the volume control. With the high'ish output of
today's
sources (i.e., CD players at 2V and
DACs at 2V to 6V) gain is probably not the main reason people hear improvements due to active circuitry.
I do not believe "gain" to be the main issue here. IME, the reason some hear improvements in dynamics and bass when moving from a passive to an active preamp is due to improved impedance matching through the volume control and consistent current delivery. An active buffer (with or without added gain) can make the source's job of driving an amplifier easier by allowing the source to see a high input impedance into the volume control and the amp to be fed a consistently low output impedance following the volume control.
Nelson Pass tends to disagree, with his Aleph L, he says when the active stage (which you would assume to be first class) is engaged on this preamp it takes a hit "his word suffer" in sound quality (3 o’clock or more) from when it’s in passive mode before 3 o’clock.
Nelson Pass: At positions below 3 o’clock, the volume control functions as a precision passive attenuator using discrete resistor ladders. Above 3 o’clock, active gain is added to the output signal in 2 decibel increments, for a maximum of 10 dB. As a result, you suffer the effects of active circuitry only when additional gain is necessary.
Is impedance matching an issue? Passive volume controls do have to make a trade-off between input impedance and output impedance. If the input impedance is high, making the input to the volume control easy for the source to drive, then the output impedance is also high, possibly creating difficulty with the input impedance of the power amplifier. And vice versa: If your amplifier prefers low source impedance, then your signal source might have to look at low impedance in the volume control.
This suggests the possibility of using a high quality buffer in conjunction with a volume control. 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.
A lot of this is system dependent....i.e., electrical values of the source upstream, amplifier downstream, and amp-speaker interface, as well as which cables are being used and how long they are. I agree there is a purity to the sound of a passive but there are more than a few of us who continue to believe something is missing when inserting a passive into our systems.
A lot of this is system dependent....i.e., electrical values of the source upstream, amplifier downstream
If we look at what the OP has there is no issue, 100ohm > 2v source and 100kohm 0.8v sensitivity poweramp. And once again this goes for 90% of matches, only high impedance tube sources can have a problem or very low input impedance amps.
Your really just not worth the effort, you live in denial kosst, and question everything Nelson Pass tells you. I’ll post it up again just in case you missed it.
Nelson Pass: "This preamplifier flows from a commitment to create the best sounding product: a simple circuit with the most natural characteristic.
Unique to this preamp, patent pending, is a volume level control which combines the best qualities of a passive attenuator and active gain circuitry: At the 3 o’clock volume control position, the Aleph L offers a direct path from input to output. The only component in the signal path is wire and switch contacts.
At positions below 3 o’clock, the volume control functions as a precision passive attenuator using discrete resistor ladders.
Above 3 o’clock, active gain is added to the output signal in 2 decibel increments, for a maximum of 10 dB. As a result, you suffer the effects of active circuitry only when additional gain is necessary."
And this as well from him just for good measure.
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."
I have had great success "bypassing" a preamp with a
Khozmo stepped attenuator using
Z-Foil TX2575 resistors inside an amp.
I ditched the volume attenuator completely in my current setup and only control the volume from the computer. I prefer to lose a few 1s and 0s from the computer volume than to add a preamp that brings so much favorable and unfavorable distortion/coloration from tubes, resistors, capacitors, regulators, diodes, interconnects, power cords, etc.
Who needs an preamp when you have a Pass XA25? (jk) This amp is amazing.
Hi again Ciro. Your XA25 (very nice poweramp btw) is 47kohm input impedance and I believe you used a 50kohm Khozmo stepped attenuator as a passive pre? You really should of used a 10kohm Khozmo passive pre, it would have been a much better better impedance match to the XA25’s 47kohm.
But your now going direct from source to XA25, even better again, so long as you don’t lower the digital domain volume control of your source below 75%, as you will start to "bit strip", 14bit resolution instead of 16bit ect ect.
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.
I suppose if I had to floor the accelerator to drive 55 mph, maybe I’d
think the life was being sucked out of my driving. Then again, maybe I
like 55. Nice and safe, good gas mileage…
Is impedance matching an issue? Passive volume controls do have to make
a trade-off between input impedance and output impedance. If the input
impedance is high, making the input to the volume control easy for the
source to drive, then the output impedance is also high, possibly
creating difficulty with the input impedance of the power amplifier. And
vice versa: If your amplifier prefers low source impedance, then your
signal source might have to look at low impedance in the volume control.
This suggests the possibility of using a high quality buffer in
conjunction with a volume control. 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.
As per usual, George omits the rest of Nelson's words **after** the quote he usually trots out. I've included more of that text above, seems to me not for the first time on this thread.
As you can see, it points out that passives can't do the best job on their own, and are helped out by the use of a buffer. I've pointed this out many times on these threads about passive vs. actives.
What Nelson does not address is that a buffer at the input of the control is useful too. However, a buffer with no gain is going to have some signal loss. Its also *very* tricky to build a circuit with only a little gain without being on the edge of linearity with many devices, tube or transistor. So if you have a no gain buffer at the input of the control and a no gain buffer at the output, you may wind up with not enough voltage to drive the amp to full output. This is why there continue to be active line stages made, despite digital sources having higher voltage outputs for over 35 years. My best surmise is that George consistently leaves out Nelson's complete remarks because they don't fit his world view.
An active preamp is an active buffer due to its gain, which largely resolves the issues of passive buffers. Lots of circuits in the world have an active buffer to better mate an input to an output stage. A stereo system is no different. I have yet to find a passive buffer/divider that does the job as well as an active buffer, mostly because of the much-lower output impedance in the latter, which prevents stage modulation. It's also very easy to witness the benefit on an oscilloscope.
SMC amps designed to work great with just volume control so no preamp is best. If you find used McCormack Micro Line Drive that offers passive and buffered active preamplification, you will forget about searching any other preamps.
@atmasphere "As per usual, George omits the rest of Nelson's words **after** the
quote he usually trots out. I've included more of that text above, seems
to me not for the first time on this thread."
Looks like @csmgolf (Cris) found the perfect description to how @georgehifi plays the game, cherry picking.
And as clearly seen, his other dirty trick is ignore questions by raising the issue of the other side being a fuser, snake-oilist, etc. Then, he can dismiss that person out of hand, on anything audio and everything else in life, forever. However, trying that with Cris and myself, George only exposed his own ploy as neither of us fall into any of those descriptions
@mrdecibel , IME, impedance matching (not matching as in "equal" but rather low to high as you move down the chain) is more important than gain. If it were not, you could simply increase the output of your source...to 4V or 6V, but that alone doesn’t seem to cut it for many listeners. Most sources (even those with sufficient voltage gain) cannot suitably handle the impedance changes that occur as the signal passes through the volume control and through the interconnects. Aball does a nice job of discussing the benefits of buffers a couple of post ago. There are trade-offs, and personal preferences, as always. Having less circuitry can sound better to some, but only if the ancillary consequences are not deal-breakers.
BTW, Steve McCormack (SMc Audio) makes one of the best sounding buffered preamps you can buy - the VRE-1C. That unit is the culmination of a career’s worth of research and trials going all the way back to his early Mod Squad/McCormack days with the Mod Squad Line Drive, TLC- 1 (Transparent Line Control), and Micro Line Drive units. You can order the VRE-1 as either a unity gain unit, or with 6dB gain through the high-end Lundahl transformers he uses. Most order the +6dB version as Steve believes the differences between the 0 and +6dB gain versions are virtually undetectable. I have tried both in my (very similar to VRE-1) unit and own a 0dB gain version. With 1.5M balanced cables to my monoblock amplifiers, I cannot hear any loss of signal, bass, dynamics, staging, or anything, compared to the +6dB version.
Regarding Steve’s McCormack amplifiers, I believe all of them originally had a 100K ohm input impedance, up to the DNA-500, which was designed with a 10K ohm input impedance. The upgraded/revised versions which have balanced inputs, all have a 10K ohm input impedance, which would generally be difficult for an unbuffered passive volume control to drive without some sort of signal abberation. My own trials with passive and autoformer preamps have mostly been into my Clayton amplifiers that have 100K input impedance, and the result has always been similar....an attractive purity but also a flatter, less dynamic, less full-sounding, somewhat bass-shy, and overall less satisfactory sound compared to what I hear through my active buffered (unity gain) preamp. BTW, I heard Steve does an outstanding job modifying/upgrading the Micro Line Drive unit so you could consider that. He also works magic on the TLC-1!
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