Why negative reviews can be unethical and misleading: 10audio.com
- Thread starter Atmasphere
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Agree about the lack of magic, but "exactly as it sounds" is not a description I find useful. Is it just an excuse for joyless sound? Does it also describe the sound of an over engineered, deep nfb, vanishing distortion SS amp?
Think completely neutral and transparent with the right tubes, but not sterile or overly damped.
Fangio and Moss. Mille Miglia and Targa Florio. No less challenging or exciting.
Thank you for your kind words! Seems to me a topic for another thread?
One reason balanced connections don't seem to flatten single-ended connections in a fair fight is that there is a standard for balanced line connections that hardly anyone in high end audio observes. There are actually two- the most important being AES48 (Audio Engineering Society file 48). You would not consider using a digital cable that didn't conform to the standards for that type of connection but for some reason its OK if regular audio equipment doesn't??! The other standard is either -4dBm or +10dBm. This is the reading you would have on a VU meter while the source is driving a 600 Ohm load.
As you know most tube preamps have no prayer of driving an input resistance that low! Most but not all... in the old days driving a 600 Ohm balanced line was done with tubes with the aid of an output transformers. But there are ways to direct couple and get rid of the transformer, while supporting both AES48 and a t least -4dBm.
If you get around those problems, if your equipment supports AES48 and can do at least -4dBm then there's no looking back at single-ended connections. All those cables you auditioned so see which sounded best in your system? That all goes away- they all sound their best and just like each other. That is why 'audio engineers' often say interconnects don't have a 'sound'; they work in studios with balanced line where that statement is true.
Even if you have SETs, if you had them set up so you could use balanced connections properly you'd instantly hear the improvement. This stuff is not only easy to hear its also a breeze to measure.
And me, FWIW... I started as an audiophile before I was even out of high school. IMO if you are getting into this sport for anything other than fun, its likely for the wrong reasons; wrong reason #1 is 'to make money'.
Simpler is often better. But as Einstein points out, its possible to be too simple. Another example besides SETs is passive volume controls which are insanely sensitive to what cable you use and can change the sound of the system (other than volume) as the volume setting is changed. A buffered volume control can work a lot better.
Getting rid of the transformers gets rid of the elliptical load line problem I linked earlier.
If I can recommend the Swarm subs, they are designed to be placed directly against the wall without being boomy. They are a foot square and about 2 feet high so are fairly easy to place. I have limited space in my room as well so I understand the issue! Because my main speakers are good to 20Hz I only needed a pair of the Swarm subs (which are also good to 20Hz). I use them to break up a massive standing wave that no DSP room correction or room treatment would have a prayer of fixing. They are very effective! I have the drivers facing the wall so as to be certain they are inside the room boundary effect.
If you get something like this installed, with the bass right you'll find the mids and highs to be more relaxed due to how the ear equalizes sound in the brain. If you then do something to prevent your amps from reproducing the deep bass, you'll hear that instantly too with greater clarity and more relaxed presentation. One way to prevent the SET from reproducing bass is to simply use a lower value coupling cap somewhere in the circuit. Any technician should be able to do a modification like that. Hang on to the old coupling cap in case you sell the amp it can be re-installed.
Which manufacturers are you talking about here? I have trouble believing that ARC's, Gryphon's, Boulder's, VAC's, VTL's balanced preamplifiers and balanced amplifiers are not true differential designs.
Are you suggesting that these major (in high-end audio terms) manufacturers are not conforming to AES balanced connection and differential circuit standards?
Yes.
I didn't say they aren't true balanced designs. But that is different from supporting the standard. You can have a preamp that is entirely single-ended internally but interfaces to the world in the balanced domain. Ampex did this with their famous 351 tube electronics.
Not picking on anyone in particular here but ARC is a good example. In a number of their balanced preamps the output of pin 2 (non-inverting) makes its Voltage with respect to ground. Pin 3 (inverting output) does the same thing. AES48 pretty well calls for the output of a source to be floating. An output transformer can do that quite well since one side of its output can be tied to pin 2 of the XLR and the other side to pin 3, with no connection of the transformer to pin 1 (ground) at all. So it floats.
Put another way, the output of pin 2 should be generated with respect to pin 3 (its opposite) rather than ground and vice versa to support AES48. A sign that there is an issue here might be if there are RCA and XLR outputs present at the same time on a preamp without some sort of switch or the like to be operated depending on which output is used. Balanced and single-ended are mutually incompatible- its either one or the other and never both. It if is both, then it is by definition not supporting the standard.
One of the reasons for balanced line is to eliminate ground loops. If the equipment is ignoring ground as in the case of an output transformer, it won't matter if a ground loop exists since ground is being ignored. When the output references ground that advantage goes away and you have the same sort of intermodulation noise floor you get with single-ended connections where ground loops require a constant vigilance.
You can imagine how this might work out in a studio where there might be 25 different devices in or near the audio chain. It could take weeks to find a ground loop. So this aspect of the balanced standard is important. But its also important to eliminate colorations made by the cable itself.
As far as I know there are exactly three ways to support AES48. The first I mentioned already- by use of transformers. The second came along after the semiconductor industry got semiconductors to the point that reliable output circuits could be made that could float. That Corporation makes chips for this purpose. The third means of doing this is one we patented, which employs a Circlotron output which floats at ground potential.
Thank you, Ralph.
I don't know or understand the AES standards, so I cannot ask informed questions.
VAC preamps have a switch to select RCA or XLR outputs. Let's assume that the VAC preamp is a true differential circuit from input to output.
My uninformed question is: What's the problem with the VAC preamp regarding AES standards?
Since the common mode rejection of true balanced connections tends to cancel even order harmonics, isn't the preservation of such harmonics via single-ended connections a legitimate subjective sonic preference?
The VAC uses output transformers so it supports AES48. That switch allows the output to float (balanced) or grounds pin 3 to pin1 so is then a single-ended output.
AES48 is nicely described in this article on Rane's website.
No.
I thought we had this conversation some months back. It does not work as you described; balanced line connections do not cancel harmonics of any kind full stop. Whatever harmonics can be transmitted in a single-ended connection the balanced connection will do exactly the same but probably preserving them better.
Now an internally balanced circuit can cancel even ordered distortion harmonics but it will not cancel even ordered harmonics of the signal itself. The distinction is what distortion the circuit itself makes as opposed to the harmonics present in the signal. They are not the same!!
So re-stating my question:
Since the common mode rejection of true balanced connections cancels even order harmonic distortion, isn't the preservation of such harmonic distortion via single-ended connections a legitimate subjective sonic preference?
Since the common mode rejection of true balanced connections cancels even order harmonic distortion, isn't the preservation of such harmonic distortion via single-ended connections a legitimate subjective sonic preference?
This general theme has come in some of your posts, and to be sure, it is a head scratcher.
Namely… there is a general preference for some distortion.
As we remove distortion, the sound generally becomes quieter, but that is often not really what the majority seems to be yearning for.
(Not sure whether it is a legitimate or illegitimate subjective preference… but objectively it may be illegitimate.)
We get the objectively measured low distortion amps and a lot of people say that, “they are not musical.”
When we add in the distortion from the speaker then it gets a bit more muddled.
If we want to be able to use cables as a passive EQ device, then single ended set ups certainly can allow for that.
I think that different people are after different things.It's all legitimate. People who listen a lot to live music under imperfect conditions are used to hearing distortions which to them sound natural or musical. Playing a pristine recording may or may not sound real/musical to them. I'm still trying to reproduce the joy I had 50 years ago listening to my SL 1200 and a 38 watt Technics receiver with my very best friends. My system now is 1000x more accurate but brings me no more joy. I love it but for different reasons.
Common mode noise is a noise signal induced in both conductors of a balanced line by an external source such as the EMF from a transformer. This gets cancelled eventually as the two phases are combined, as long as the noise is equal in amplitude and phase in both conductors. Any signal carried by the two conductors in a balanced connection is already in opposite phases (split either by a transformer or a phase splitter) and will not get cancelled when the two phases are combined, but added together.
That post is a mistake on my part- not adequately editing it for omitted words and the like. In this case what I was trying to say is that if the equipment is internally balanced (especially if differential) it will be inherently lower distortion as active balanced circuits can cancel even-ordered harmonics. This results in much lower distortion and since the 3rd harmonic is treated the same as the 2nd, it is able to mask higher ordered harmonics, which decrease at a faster rate as the order of the harmonic is increased as opposed to single-ended circuits. So in addition to inherently lower distortion also inherently more musical.
But the way I wrote that is confusing and can cause one to think I was saying that about cables!
Sorry about that!
The Common Mode Rejection of a balanced line system prevents hum and buzz from getting amplified since the buzz is common to both inputs (inverted and non-inverted) so the input ignores it. That is something very different from cancelling even ordered harmonics!
Single-ended inputs lack this property so any noise impinged on the cable gets amplified.
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