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24.250.23.59
A couple of days ago, I got my LS25MkII back from Audio Research. Apparently it was thoroughly tested and serviced, and pronounced fit. While the LS25 was out of the loop, I fed my Wadia directly into the power amp, with a startling result -- a more transparent, detailed, and clear sound, though perhaps with a somewhat reduced soundstage.
When the LS25 was re-inserted into the set up, the same old sound, with what can only be described as a veil of haze, although on the whole the sound wasn't bad, something I could live with (or so I thought). I spent a whole afternoon yesterday comparing my setup, with or without the preamp. The answer was clear: the sound is better without the pre. The difference was not very subtle. My wife who has a better ear but is no hi-fi enthusiast fully agreed.
So my preamp is on its way out. I'm not ready to spend upward of 10K looking for a state-of-the art preamp. I've tried to look into passive pres, and so far found two: StereoKnight's Silverstone Balance and a unit made by CA Audio (listed in Music Direct's website). Do any of you know anything about either? Are there other makes that you can recommend? I don't have much experience or knowledge in this area. So your help will be greatly appreciated.
Thanks all!
Follow Ups:
I'm using the Warpspeed Optocoupler. I have had TVS and resistor type passives and the Warpspeed is the best by far. Allan Flores (Blues on DIY.org) is the builder and a great guy to work with. He can custom make what you need Balanced or Unbalanced. Look him up you'll be glad you did. There is also a lot of info on Audio Circle about his preamp. Hid pricing is very resonable as well.
"Grow older not up !!!"
Jimmy Buffett
I listened exclusively to passives for 12 years, first a Reference Line (with their matching amp), then an AVC Bent. The sound was very good--clear like crystal--but I was never really satisfied. Then I bought a VAC tube preamp to go with Bryston monoblocks. I still have plenty of clarity and ultra-fine resolution but the music seems to live and breathe more. The passives now reside in the closet of neglected toys.
The move from active to passive was breathtaking. I use the Lightspeed Attenuators. Retails for $500, made in NZ. I suggest you read the long Audiogon thread about the LS. It's features may not suit your system, but it sounds great.
Try here:
Here are a couple I like.
What I used to use -
http://www.hnny.nl/archief_creek/manual/OBH-12.pdf
It's replacement -
http://www.creekaudio.com/products/obh22.php
And what I use now -
http://diyparadise.com/shop/index.php?main_page=product_info&cPath=18&products_id=113
I really like the Eva 2. Best preamp I've heard, if you don't want to drop big bucks for one.
Eva2 looks very good indeed. However, it seems to lack a balance control, or individual volume controls for the two channels. This is something I need because of the physical shape of my listening area. A pity! But thanks very much for directing me to it.
Sonic Euphoria balanced is what I have, and it's really good. Head and shoulders above Reference Line Preeminence I had before.
Easier system matching than resistor-based passives, too.
Using anti-vibration devices is a must (I use Stillpoints), and also responds well to crystals placed on top of each transformer.
... I would disqualify that one solely based on usage of Alps Blue potentiometer.
Stick with those that use quality stepped attenuator for volume control - you won't regret it.
The Jolida is passive. Volume uses an ALPS Blue Velvet, motorized with remote control. This will beat an active preamp assuming you power amp has reasonably high input impedance and I/C runs are reasonably shot.
~~~~~~~~~~~
... 99%'er
None of which have to do with the device themselves.
The problem is that the cable, the output impedance of the source, the input impedance of the amp and the impedance of the control itself all interact.
The best sound is thus when its turned up all the way. That has the least cable interaction, the best bass and the best dynamics. As you turn it down, these qualities go away fairly quickly. By reducing the value of the control you can reduce this problem somewhat.
The issue is that as you reduce the volume, it becomes part of the source impedance and *raises* it. This interacts the output coupling cap(s) of the source, effectively shrinking their value (= less bass). The increased output impedance also allows the capacitance of the cable to play a bigger role (= rolls off highs, may reduce soundstage); the higher the input impedance of the amp the worse this problem is.
TVCs are a better choice IMO/IME, but they have a different set of problems associated with bandwidth and distortion (caused by ringing of the transformer). Most of this ringing is at ultrasonic frequencies but can still affect things (manifests as additional brightness).
The best approach is actually a good line stage. I'll put it this way: A passive might sound pretty good, but a good line stage will sound even better . A good line section will control not only the volume, but also the cable itself - meaning that the cable will not longer make or break the system. If you find that you have to have the right cable to make the system sound right, then the line section is falling flat on its face.
IMO/IME this may well be the best argument for a good line section- the cable becomes immaterial and in any other situation the cable is very important!
The impedance issues you mention are not "problems" as you would like to convey. They are simply parameters or rules to consider for implementation.One thing I have found as I have ditched mega-buck active preamps is that with an AVC, if you take heed of these parameters and system gain, nothing will surpass the passive as long as you like the sound of your amp. I suspect the latter is the biggest problem of all.
Btw, it seems to me that most dacs' output are 2-2.5 and in balanced configuration double this. The more you attentuate the AVC, the more the "problems" go away.
Edits: 06/13/12
Hm. The amps work great. But I have yet to see a PVC system that really works. Not sure what you mean by AVC.
OTOH I have seen very few active line stages that work all that well too. Seems that most of the designers in high end audio have yet to recognize that the line stage should be controlling the cable (eliminating its artifact). So as a result, most of them don't.
Like I mentioned elsewhere on this thread, without hearing what a properly designed line section can do, one might well be convinced that a passive can do the job. But once you have heard a good line stage, there is no going back- that is when the realization strikes home that passives don't work.
I have owned several very high end preamps, two of which certainly took care of the cable non-problem or red herring that you speak of. Not as good as this autoformer. Not sure why you would make such an assumption without any knowledge.Second, the increase in transparency resulting from a good passive is why I say that sometimes people who don't like passives may not simply like hearing more of their amplifier. There are many other reasons as well. You have done a nice job of putting competing products on the defensive but I would merely counter that many passives avoid the pitfalls of active circuitry. You don't like to listen to cables while others don't like to listen to resistors, capacitors, switches, valves, etc....choose your poison.
Third, there is no wrong choice. One likes the sound of line stages over a passive great? Vice versa and they know how to implement it? Great. I am guessing you are a bit more dogmatic about these things.
Have a nice weekend.
Edits: 06/15/12
Not sure why you would make such an assumption without any knowledge.
Well, I do do this for a living, and have heard a lot of passives with all sorts of digital and analog gear. The performance issues I listed I have heard in all of them. When I started running the math it became obvious why. So its not without knowledge.
Audio is a funny field, even if the math agrees with the subjective experience one still has to make a case for it. You are correct about the dogma (although the whole passive thing strikes me as dogma as well); years ago when I first began developing a preamp the whole balanced-line thing was already obvious. I had played in several orchestras during high school, college and post-college. What I saw there was that when the concerts were recorded, the mic cables were often extremely long; at the local college they were usually over 100 feet as the mics hung from a 'cloud ceiling' that could be raised or lowered. So this had a big impact on me as I also knew Robert Fulton, arguably the founder of the high end cable industry. He always had very short single-ended cables...
I also run a recording studio and have refurbished a lot of studio and consumer gear over the years. The studio gear is usually designed to minimize cable problems and the consumer gear is never done that way. This comes out of old tradition (and cost) more than anything else.
I don't seen the cable thing as a red herring at all. If you install the volume control inside the amp you don't have any troubles with it- a control that robbed the system of bass as a passive does not do so if its inside the amp.
I meant knowledge about my pairing of passive to amp and knowledge about my experience with high end preamps. I like what I hear from my autoformer. I simply don't hear the downsides that you speak of and I have owned some serious preamps in the past. How many times do I have to say something similar: there is no bass being robbed in my system and yes, this passive exists outside the amp. What is there not to understand about that?I really don't have any dogma...it all depends on the equipment mix. I am not endorsing any type of preamp or linestage.
Kudos to you for making balanced gear. Wish more would do it.
Edits: 06/21/12 06/21/12
Yes, I would concede that compared to most preamps a good TVC is probably not robbing bass. I'm not sure I would say that about *all* active line stages- for example ours is direct-coupled and has response to 1Hz, which is lower than any TVC I've seen.
I should point out that TVCs are a bit different from PVCs and don't have the same issues of loss of dynamics and bass that plague the latter. The main issues I have seen with them have to do with loading, as loading on any audio transformer is paramount to prevent if from ringing (distorting) and if loaded to heavily, rolled off highs. The issue is different for each position on the volume control! Some manufacturers deal with it better than others. And some play bass better than others as they might have better bandwidth.
BTW for a preamp or TVC to play bass correctly it should have flat bandwidth to 2Hz as a minimum to prevent phase shift at 20Hz; otherwise there will be a loss of impact at that frequency. Many transformers in tube amps are only spec'ed to 10Hz, the better ones maybe 5Hz. This means that they are having problems with phase shift (impact) at frequencies up to 100Hz (in the case of a 10Hz cutoff) or 50Hz (in the case of 5Hz cutoff). If there is a rolloff in the TVC, depending on the amp used you may never know, especially if you are running SETs, as bass is one of the weak areas for many SETs (they get better if they make less power; one of the reasons why the 2A3 sounds better than the 300b and the 45 better than the 2A3).
My speakers go down to 20Hz so I am used to hearing problems in this area if they exist. Regardless I see TVCs as a better solution than PVCs...
Hi all ! I have used two passives....the Placette and the mod squad linedrive . They both sounded fairly clear , just something was missing . My Cary 05 trumps them both .
.
As a manufacturer of line stages I would expect you to argue in their favor, and all of your points are well taken, but if one knows what they are doing all of the problems you mention can be minimized or overcome.
Many (most?) audiophiles don't understand the problem. There is an impedance problem they don't understand, they have too much overall gain and have to run it with the volume control way down, they pick the wrong cables, or a combination of these. They try a passive and it is poorly implemented so they conclude they are inferior.
In simple terms a passive has some sort of attenuator and a line stage is the same thing with a buffer. If you know what you are doing you can choose components and interconnect them in a way that allows you to eliminate the buffer. If you don't then you can choose a line stage.
.
.
In order to build a proper DAC, you wind up with a lot more output than any amplifier needs. The result- you can't really do the matching that you mention, unless you have that rare DAC that only makes 2 to 2 1/2 volts...
Most DACs and digital gear makes at least 4 volts- enough to clip any amp made. CDs are usually normalized as part of the mastering process, if they don't do that, they don't sound as good as there is less resolution. So you can count on any CD being way to loud on most DACs. You simply have to be able to turn it down.
We have built line stages as an option where the direct-coupled tube output buffer is the only circuit other than the volume control (no gain). This works great with digital gear! -and easily blows the doors off of the best passive setups. I do agree though that *if* you are able to match things, you can get good results, although you will always be having to match up cables. I guess I am saying that actually doing that is really hard even if you know what you are doing. Quite literally, the digital industry is against you.
With regards to cables I have this theory, if you can hear differences between them they are both wrong. You know that the manufacturer of the better sounding cable will have a new model that sounds even better next year- or someone else will. And that's been going on now since Robert Fulton founded the cable industry 35 years ago.
That is why I have been an advocate of the balanced line system, as it has standards which, if used correctly (and most high end audio companies *don't* adhere to the standards BTW), the cable differences disappear. That is why audio engineers say that cables 'don't make a difference', they are used to that as they run pro audio gear that supports the balanced standard.
"If you know what you are doing you can choose components and interconnect them in a way that allows you to eliminate the buffer. If you don't then you can choose a line stage."
Oh that's funny, even though it's true. Usually saying that someone doesn't "know what they are doing" is an insult, but in this case it's literally true for most of us most of the time. I have NEVER seen seen anything audio specified to the point where I really know clearly what it's input and output characteristics are in and out of band. But if I have a thang that I do know that can be inserted in the path that tends to make the other ends 'don't cares', well, that has some appeal...
Somehow having a local chain of amplifiers-attenuators-amplifiers-attenuators... just doesn't seem like an optimum approach for getting the best S/N.
Regards, Rick
"IMO/IME this may well be the best argument for a good line section- the cable becomes immaterial and in any other situation the cable is very important!"
Now THAT'S a real interesting way to look at it and has a lot of merit in my book. Need to mull it a bit further. Off hand I think it would be even better to say that the output cable should be part of the preamp.
One problem I see is if you don't know the characteristic impedance of cable you can't do a good conjugate match so if the power Amp. has poor RF rejection you may be stuck and the cable will make a significant difference.
It's hard to imagine many other systems in this day and age as poorly defined and specified as our legacy gear, makes them entertaining in more ways than one!
Rick
One problem I see is if you don't know the characteristic impedance of cable you can't do a good conjugate match so if the power Amp. has poor RF rejection you may be stuck and the cable will make a significant difference.
Well you know for sure the characteristic impedance will not exceed 600 ohms. But as it turns out, what is more important in most cases is just to make sure that the cable is driven by such a low impedance that the inductance and capacitance of the cable just doesn't play a role.
So much the better if you *do* know the characteristic impedance of the cable- if your preamp can drive that load, you can simply terminate the cable at the input of the amp. I have seen that cause a $24,000 set of cables sound exactly the same as a set of $80.00 cables (both 25 feet long). IMO/IME a preamp should have this kind of drive capability- but most don't, so we have cable interactions...
"such a low impedance that the inductance and capacitance of the cable just doesn't play a role."
Hmmmm, I wonder what that would be? Apparently 100 ohms is too high if I am to ascribe my experiences to that factor and that seems to be the common Zo of the things I have, most of which are getting old and should be about ready to graduate from "old junk" into "desirable vintage".
A voltage source driving a terminated cable should be good but I went the other way and built up the outputs to 300ohms and use terminated open air lines. Kludgy but sounds good.
Why on earth would any cable cost or be worth $24,000? I guess we all have our bullshit limit...
Regards, Rick
There were a set of balanced cables, but had an external box for 'grounding'... you sure as heck don't need an external box for that on a balanced connection, but try telling that to someone who just paid the big cash.
When I bought my PASS X250 amp I was suing a BK Pro10MC preamp in passive mode. I wanted to try a tube preamp and bought a used ARC SP16 did some tube swaps, but after 3 weeks sold it and put back the B&K.
I eventually went with the matching PASS preamp, which was a step up from the B&K.
If you want to try passive on the cheap with lots of features look out for the B&K or Adcom preamp with the passive switch through
You already have been enlightened......
You are headed in the right direction looking for a transformer based passive. I use an autoformer passive and have found nothing that bests it so far. The recommendation for The Truth preamp is another valid option. I may end up going in that direction down the road.
Bottom line is that there are passive devices that offer better performance than even the best active preamps when used in an appropriate system.
Oz
Don't worry about avoiding temptation. As you grow older, it will avoid you.
- Winston Churchill
I love my silver rock transformer volume solution..
Fron their website:
" The Truth Pre Amp
It has an input impedance too high to measure, output impedance is a couple ohms, bandwidth is to 60Mhz, slew rate is a couple hundred V/microsecond.
There are no capacitors or resistors in the signal path. There is no potentiometer in the signal path.
It uses photo cells to control the volume. It does not use optocouplers.
It is an "active" device and suffers none of the "problems" that "passive volume control/pre amps" have. It can drive long (30 feet) cables with ease. "
I'm a tube guy, and never thought I'd consider something like this. Until I heard it, I mean. I had planned on building the Nelson Pass B1, as another poster mentioned. But the B1 has caps, resistors and a volume pot in the signal path. The Truth does not. Mine was $800.
I am fully behind 1973shovel on this on.
The Truth will get you as close to possible to the original signal, since there is nothing in the signal pass that could and would mess with it.
Thanks for directing me to The Truth -- rather than in the opposite direction! It seems like an interesting possibility. Other possibilities suggested by helpful posters include StereoKnight, Intact Audio, Serious Stereo, and a couple of others. I'll give my ARC pre a chance, over at least a week, but it's pretty clear I should go passive sooner or later, probably sooner than later.
Thanks again.
...Intact Audio's autoformer. It has an industrial look but sounds great. Dave Slagle winds his own autoformers and is quite well known for doing so. Make sure you amp is good to use w/ a passive.
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There are many options but without knowing what your system is, especially the output impedance of the source and input impedance of the amp, it is impossible to make good recommendations.
You might also get better results if you posted links to what you are considering and what you have instead of expecting everyone here to research your problem.
You say you don't want to spend $10K but what is your budget? Another piece of missing info.
BTW, if it sounds good direct why do you need a pre of any sort?
.
You have a good point. My signal sources are: Wadia 861SE, Sony 5400 (modded by Music Technology), Audio Research PH2, Oppo 95 and Magnum Dynalab FM-tuner. However, the last two aren't essential to my audio setup.
The power amp is an Audio Research VT100MkIII, which drives a pair of ProAc 3.5.
As for my budget, it's pretty flexible. If you have any suggestions, I would very much appreciate it.
.
I would look into Dave Slagle autoformers.
You can buy the parts to build your own or buy complete systems from Bent Audio
http://www.bentaudio.com/index2.html
or work with Jeffrey Jackson to custom build what you want
http://www.jeffreywjackson.com/Passive_Aggressive.htm
.
Thanks! That's very helpful.
If you can live with only two stereo inputs and one stereo output, I like Nelson Pass First Watt B1 buffer preamp. Not sure if he is still making them though. Enjoy the Music used to have a review of it.
to get rid of the ARC. If they replaced some parts I would give them some time to burn in. If after a couple hundred hours of music you still feel the same way, then do what you think is best. Just give it some time.
I doubt it. Hey, I could be wrong but I doubt it. Going from a tube preamp to passive as I did you could have pretty much taken his reaction as mine except I did not have any loss of sound stage. Todays modern low impedance sources have plenty of balls to drive a power amp, in my case two power amps. When I connected my DAC to my power amp its output could overdrive my powerr amp on every disc. This means that my preamp was an attenuator. An attenuator with a gain stage to boot! Many people have had this very same reaction when doing what the OP did.
ET
Certainly not cheap, but far from 10k.
........I was a vegetarian for 15 minutes... until the main course.
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