Balancing a vinyl rig

[grawk]

[philodox]

Because your criteria for balanced is only half the story. Yes, tying the negative signal to the other terminal is part of it, but they must both be relative to ground, and since most dynamic driver speakers and headphones don't have a ground, it can't be done. Only electrostatics can be truly balanced.

Remember, it's just a potential difference, if you float the ground, then you've lost the stable reference for the common noise on the line.

I'm not saying it's bad -- faux-balanced is still an improvement over completely single-ended, but to call it balanced is not entirely correct. I realize I'm being pedantic, but that's not the same as being wrong.

You're either talking over my head or through your ass. Can we get KG in here to clarify or something?

[Dusty Chalk]

You're either talking over my head or through your ass.

I doubt it's that black and white -- I will fully allow that I may be wrong on details or word usage here and there, but I'm pretty sure of myself on the overall concept ("common mode rejection", to be explicit [and to give you something to google, in case KG does not answer your query]).

Can we get KG in here to clarify or something?

I already said that I wouldn't -- you're welcome to ask him.

[kevin gilmore]

OK, a phono cart is a 2 wire source. It does not know whether it is balanced or not,

and does not care. What does make a big difference in this case due to the very low

output voltages is how much noise and hum is added to the signal due to the cables

and connectors. A 2 wire rca connector and standard coax references one side of

the cart to ground, and does so thru the cable shield. Way better, an i know this for

a fact is to use 3 wire coax, connect the 2 inside wires to the cart, then if you have

to, at the rca end, connect one of the wires and the shield together. Way better, but

still an unbalanced signal. Even better is to actually have a balanced input front end

which in general requires twice as many parts, but can if done right get an additional

noise level 3 to 6 db lower than a non balanced front end. Ray's piece of shit phono

preamp does this. At the output ray uses a drv134 to convert the unbalanced signal

to balanced. In fact this really does absolutely nothing. The 5 wire connect is clearly

desirable, but really only usable with a true balanced phono section.

Now balanced output is a similar yet completely different animal and for a different

reason. Take a 200 watt rms amplifier into 8 ohms. Bridge the thing. Given enough

heatsink and power supply you instantly have an 800 watt rms amplifier into 8 ohms.

Plus you get absolutely matched rise and fall times. In fact you can take 2 lousy

amplifiers (as in quasi complementary) and put them together this way and get something

that sounds really excellent, as in the crown macro reference monsters.

The reason krell et all do the balanced (as in bridged) output is because of the lack

of quality pnp output transistors past about 135 volts. Its the only way to get huge

amounts of power and retain the rest of the characteristics everyone desires.

[philodox]

Wow, thanks for the detailed info Kevin.

What is your take on balanced headphones being faux-balanced?

Because your criteria for balanced is only half the story. Yes, tying the negative signal to the other terminal is part of it, but they must both be relative to ground, and since most dynamic driver speakers and headphones don't have a ground, it can't be done. Only electrostatics can be truly balanced.

Remember, it's just a potential difference, if you float the ground, then you've lost the stable reference for the common noise on the line.

I'm not saying it's bad -- faux-balanced is still an improvement over completely single-ended, but to call it balanced is not entirely correct. I realize I'm being pedantic, but that's not the same as being wrong.

[kevin gilmore]

see you are mixing up words that mean nothing.

unbalanced headphones are the same as balanced headphones with

a common ground.

The load (in this case the headphones) cannot possibly know how it

is being driven. But if it is being driven from a balanced (really bridged source with

no ground) then it has to be 4 wire.

[Dusty Chalk]

The load (in this case the headphones) cannot possibly know how it is being driven.

So from the headphone's perspective, "balanced" means nothing. One of the drivers from a pair of headphones doesn't "know" if it's being driven by a bridged amp, or one single-ended one.

I will admit, "faux-balanced" is not an accepted term, but I don't think "balanced headphones" is anything other than "mixing up words that mean nothing", either. I mean, turning that middle sentence in your post around, this one:

unbalanced headphones are the same as balanced headphones with a common ground.

you're saying that balanced headphones are the same as unbalanced headphones with separate grounds (what I would prefer to call returns). That's not truly balanced. That's the headphone equivalent of "dual monoblock" design, whatever the correct terminology for that is.

[spritzer]

A headphone driver (dynamic) is simply a coil of wire so it doesn't care if you feed it SE or bridged. What it does like is more power so the should be some benefit.

[Smeggy]

A headphone driver (dynamic) is simply a coil of wire so it doesn't care if you feed it SE or bridged. What it does like is more power so the should be some benefit.

Surely if it were that simple, using speaker taps instead of a headphone jack would do the trick. I've run plenty of phones from speaker amps over the years with no problems just to bypass the added circuitry and crappy connectors.

[luvdunhill]

I don't really get your argument Dusty. Say that DC offset is zeroed between the + output and - output and then zeroed to ground. This is what I'm referring to as a floating ground. There isn't a "ground" connected to the the load per say, but this is definitely balanced drive, or "true" balanced as you say.

Also, most balanced cables do not connect the "ground" on each end, as this can create a ground loop. This happened to swt61 at our DFW meet, as someone didn't know how this should worked and just connected all three wires straight through the cable. The ground on the input side is usually connected to the shield.

[Dusty Chalk]

Also, most balanced cables do not connect the "ground" on each end, as this can create a ground loop.

Well, then they're not balanced cables. "Floating" the ground is just a fancy way of saying I "disconnected" the ground. I'm not saying that you shouldn't do it in the circumstances that mandate it -- absolutely you should. But most roadies would keep their truly balanced cables separate from the ones that had the ground disconnected, use the balanced ones first, wait for the ground loop, find it, then replace the balanced cable with the floated one.

I'll address your first paragraph later, I need to get some more work done before I go home. To be honest, I was kind of hoping that KG would explain that part better. I'm not sure I can, but I'll try and give it a go later.

I mean, think about it this way -- you don't call them balanced speakers when you drive them with separate + and - connectors, do you? They're just speakers. The whole thing about using three connectors was a design decision made early on with headphones, because headphones were so much easier to drive, they just used a common ground and single-ended topology to drive the two drivers. You don't need to go balanced just to go to the four-connector topology -- you could very easily have dual-monoblock, single-ended amplifiers driving the left and right drivers. Would you say they were balanced then? I would say no, but what I'm getting from you guys is that you'd still say the headphones were balanced, but that the amp is not. I don't get that.

[Pars]

The ever popular Rane app note on balanced connections:

http://rane.com/note110.html

I think that a "balanced" cable with the ground disconnected at one end is still balanced, just not the best way to do it from a noise perspective. From the signal's perspective, ground is irrelevant.

[spritzer]

Surely if it were that simple, using speaker taps instead of a headphone jack would do the trick. I've run plenty of phones from speaker amps over the years with no problems just to bypass the added circuitry and crappy connectors.

More current brings more control over the driver but the problem with speaker amps is the excessive gain and that they are designed for a 2-16ohm load, not 300. Noise is an issue unless you use resistors to lessen the load.

[Smeggy]

Well gain can certainly be a problem but I've never had much trouble with noise. Provided the phones aren't too sensitive I found the advantages outweigh the deficits.

[spritzer]

I wonder sometimes how many of those saying that the "balanced amps" are the second coming have heard phones driven by a good, powerful SE amp?

[Dusty Chalk]

I've heard tkam's (now someone else's) SP Dragon. And it is quite good, nee, superb.

[philodox]

Well, then they're not balanced cables. "Floating" the ground is just a fancy way of saying I "disconnected" the ground. I'm not saying that you shouldn't do it in the circumstances that mandate it -- absolutely you should. But most roadies would keep their truly balanced cables separate from the ones that had the ground disconnected, use the balanced ones first, wait for the ground loop, find it, then replace the balanced cable with the floated one.

XLR cables are supposed to have the ground only connected at one end. Having them connected at both ends does not make them true balanced, it makes them poorly designed.

I mean, think about it this way -- you don't call them balanced speakers when you drive them with separate + and - connectors, do you? They're just speakers. The whole thing about using three connectors was a design decision made early on with headphones, because headphones were so much easier to drive, they just used a common ground and single-ended topology to drive the two drivers. You don't need to go balanced just to go to the four-connector topology -- you could very easily have dual-monoblock, single-ended amplifiers driving the left and right drivers. Would you say they were balanced then? I would say no, but what I'm getting from you guys is that you'd still say the headphones were balanced, but that the amp is not. I don't get that.

People call headphones that have been recabled to accept + and - for each driver "balanced headphones". Get over it. No, you don't call speakers balanced speakers, because there is no recabling needed. If the drivers are being driven by a 4 channel amplifier, the system is effectively balanced as far as I and everyone but you use the term. There is no difference between speakers or headphones in this regard.

BTW. A dual monoblock is the same as one stereo amplifier... so no, that is not balanced. To go balanced with monoblocks you would need 4 of them.

Like you said before, you are being pedantic. The language we use in this hobby is basically created by us, so you can't go around telling everyone they are saying things wrong. That is Reks' job! [though at least he sticks to the English language proper]

[n_maher]

XLR cables are supposed to have the ground only connected at one end. Having them connected at both ends does not make them true balanced, it makes them poorly designed.

There's a fair bit of conflicting information with regards to that, Jay. I used to think that the one-end only ground connection was correct (based on what I'd read) but I've recently had a few folks experience problems using cables built like that. Further research has determined that it is actually very much application dependent. Not trying to stir the pot, just provide more information.

[philodox]

There's a fair bit of conflicting information with regards to that, Jay. I used to think that the one-end only ground connection was correct (based on what I'd read) but I've recently had a few folks experience problems using cables built like that. Further research has determined that it is actually very much application dependent. Not trying to stir the pot, just provide more information.

Good to know.

I have no problem being corrected when I'm wrong.

I've always been told that one side being connected was the way to go, but I suppose it really does depend on the two devices you are connecting and how their grounding is setup.

[luvdunhill]

There's a fair bit of conflicting information with regards to that, Jay. I used to think that the one-end only ground connection was correct (based on what I'd read) but I've recently had a few folks experience problems using cables built like that.

can you give an example?

[thrice]

can you give an example?

He sent me a pair of XLR cables set up with the ground connected at one end only. I was using this on my balanced Beta22 and experiencing some hum...that's when I checked the connections. The Beta22 in balanced mode references the + and - signals to ground, so it needs to be connected. (from the source to the amp that is.)

[grawk]

He sent me a pair of XLR cables set up with the ground connected at one end only. I was using this on my balanced Beta22 and experiencing some hum...that's when I checked the connections. The Beta22 in balanced mode references the + and - signals to ground, so it needs to be connected. (from the source to the amp that is.)

So the beta you built doesn't reference it's own ground?

[Dusty Chalk]

XLR cables are supposed to have the ground only connected at one end. Having them connected at both ends does not make them true balanced, it makes them poorly designed.

I take it you didn't read the Rane page that Pars posted a link to. Here it is again. Note: I did read it, including the part right after "the last best right way to do it" which says that it is not frequently practised, but it does very clearly state earlier under "the absolute best right way to do it" that equipment should be grounded on both sides, and that that is the most correct way. It is this sense of "correctness" that they espouse that I've been trying to differentiate as "true" vs. "faux".

-10 reading comprehension points for you, and you miss a down for being snippy about it.

FURTHER, if you scroll down towards the end, to where it says "Floating, Pseudo, and Quasi-Balancing", you'll see that they very explicitly define exactly what I was talking about, when I used my made-up term of faux-balancing. So I AM NOT ALONE in making this differentiation. NYAH*

BTW. A dual monoblock is the same as one stereo amplifier... so no, that is not balanced. To go balanced with monoblocks you would need 4 of them.

(sputters) Exactly!!!1! That's why I don't want to call it "balanced"!!!1!

You are correct that I should not have used "dual monoblock", but...I was grasping -- there is no term for going from 3 connectors to 4 connectors. All I know is that it's not "balanced". It's basically "stereo with separate returns". I don't even like "pseudo-balanced", since it is by no means a requirement -- you can still be single-ended stereo with 4 connectors.

Like you said before, you are being pedantic. The language we use in this hobby is basically created by us, so you can't go around telling everyone they are saying things wrong. That is Reks' job! [though at least he sticks to the English language proper]

Well, there's two things going on here. One was the one that you latched on to, that I referred to "balanced" headphones as not really balanced, but you seem to have forgotten about why I mentioned that. I mentioned it because it confuses us, and is insufficient definition for "balanced" in other contexts, such as the phono cartridge as was originally asked at the beginning of this thread. I stand by that point, especially after this discussion. I do appreciate KG bringing us back to that, since that was the original purpose of this thread. And he also brought up a very good point in that even though a cartridge can have a 5th connection for that ground reference which I seem to so cravenly require, it is not necessarily a good thing, since it is not a piece of gear with a power supply. The Rane page mentions how the reference ground if used correctly can be a very powerful shield against hum and RF noise, especially in signals which are about to be amplified (and this is crucial with phono, since it is about to be preamplified). So I have no idea if one really wants to use that 5th connection in a phono cartridge, unless one is sure that it is implemented correctly in the cartridge, as a chassis ground (I.E. the cartridge shell). I think.

So, I think you owe me an apology for (a) accusing me of quite possibly talking out of my ass, and ( for trying to bully me into succumbing to your point of view. NYAH*

*NYAH == fuck you, the horse you rode in on, the herd it came from, and your mama.

[Dusty Chalk]

Pop quiz: K1000, stock cable, driven out of a single-ended stereo speaker amp -- balanced, or no?

[grawk]

Pop quiz: K1000, stock cable, driven out of a single-ended stereo speaker amp -- balanced, or no?

Not balanced.