[Vka]

I was thinking that my SCD-1 has balanced inputs in addition to analog inputs. The problem is my DCT-1 only accepts analog instead of balanced. I have heard of Headroom's blockhead that accepts balanced signals. Anyhow, I was curious to know if the Cary 300SEI have balanced input/output and how would it affect the sound. Moreover, how does balanced sound improve over analog sound? If it does, does that mean the Blockhead is the most superior headphone amp because of its advanced design?
Hmmmm....

 

[DanG]

From what I've read on Audio Asylum, it seems that balanced interconnection does not necessarily improve sound (although some think that it does), but rather is less susceptible to EMI and RFI.

 

[headster]

Hey Vka! I see you finally acquired the SCD-1. Man isn't it a beautiful unit eh? Not to mention all those shiny metal used in the construction weights a ton. That's the only thing I hate of high-end suff. It seems that as you climb up the ladder, the toys seem to get heavy and heavier.

Balanced connections are not popular with headphone system. I believe this is due to the fact that many amps are not made with balanced inputs (even your mighty DCT-1 unit). Hence, not much response to your question. You probably remember I once owned the 777ES Sacd Player (essentially the same to the SCD-1, but without balanced inputs). I replaced it with the Electrocompaniet EMC-1 unit. Using the balanced outputs of EMC-1, I get some extra headroom on my tube amp. Where I recall using unbalanced inputs on the Sacd Player and the unit I have now, my maximum listening volume top off around 5 1/2 no more than 6 depending on the quality of the recording. Using balanced via the EMC-1 unit, my maximum listening volume is around 5 (of course, 10 is the max on the volume pot). I suspect the voltage of the balanced ouputs are far greater than unbalanced ones. Check the spec on your unit to see if this square with my findings.

As far as the music is concern, I have to agree with DanG. While I don't claim to hear any differences between the two, balanced configuration is definitely quieter. When you get a chance to listen to the balanced ouputs of your SCD-1 unit, pay close attention to the noise floor (this is where you'll hear the biggest differences). A quiet noise floor allow you to hear the fine detail otherwise mask over.

I've talked via e-mail with one of the fellow who I believe is a die-hard enthusiast in this hobby. When I inquire the same query, this is what he has to say:

"I got into the stereo arena about 1.5 years ago and upon starting I checked out the difference between RCA and XLR ends. At the time, I discovered that balanced was a quieter method of transferring a signal between two points. This is a fact and not conjecture. Since then, a number of amplifier manufactures have gone to only balanced inputs (i.e. Pass, Mark Levinson, etc.). Transparent will be the first to tell you that the Transparent Reference XL balanced is almost 6db quieter than the RCA ended interconnect. I feel that more and more you will see balanced take over the high-end market, especially here in America. The Europeans, however, just do not want to switch.

Regarding your friends saying balanced is no different than RCA I would propose the following: first is that they have not gone to balanced throughout their system and/or have a "weak link" somewhere along the way (i.e. an RCA connection or something of less quality within the system); second is that the system they have is not of high enough quality to reflect the difference (i.e higher quality the system the more of a difference it makes). If you will notice on audiogon.com you will see how many of the high end RCAs are being sold. I would propose that this is being done because those with the high-end systems are going to balanced.

Finally, I would suggest that you contact Pass Labs or Transparent Audio and have one of their technicians describe why balanced is the way to go. Not trying to be "snippy," just trying to inform."

 

[Dusty Chalk]

Well, the thing about balanced is, it doesn't work well on headphones, because headphones are effectively speakers, and they only need two connections (these are dynamics, now, electrostatics are a different story).

At least, that's true between the amp and the headphones, what you do before then is up to you.

I saw the ad from Headroom in this month's Stereophile, and I have to admit, I am intrigued.

Crosstalk should also be less (equivalent to EMI and RFI from the other channel), so your separation should be better, leading to a wider and more accurate soundstage...inasmuch as headphones give you a soundstage...

 

[KR...]

Quote:

Using the balanced outputs of EMC-1, I get some extra headroom on my tube amp. Where I recall using unbalanced inputs on the Sacd Player and the unit I have now, my maximum listening volume top off around 5 1/2 no more than 6 depending on the quality of the recording. Using balanced via the EMC-1 unit, my maximum listening volume is around 5 (of course, 10 is the max on the volume pot). I suspect the voltage of the balanced ouputs are far greater than unbalanced ones.

Which cables were these? And were the Balanced and Unbalanced cables the exact same brand & model number and size with the ONLY difference being the connectors?

 

[kwkarth]

I debated as to whether or not to jump in here, but in the interest of helping everyone to understand what a balanced line is as opposed to an unbalanced line, I will attempt to explain.

Let me wander around for a while and see where this goes… In a balanced circuit, two wires carry the signal and have a ground/shield wrapped around them. Neither signal wire is grounded. Thus you can imagine the ground as a zero reference and the two signal lines being plus and minus respectively in a balanced differential arrangement. Balanced circuits operate on the principle that any interference picked up will be present more or less equally on both signal wires and since one is positive and the other negative, will cancel or null out at the amplifier which will have a balanced input. Simultaneously, the actual signal passes unaffected.

So, the concept was developed and is used in the interest of noise rejection. This is principally important at microphone signal levels and over long lengths of cable runs, both conditions which are common in recording studios and similar venues. At short cable lengths and at line levels, this is really not that important. When you as a hi-fier mix balanced and unbalanced equipment in a system you run into the following issues;
Let's say you have a balanced output on your pre-amp and you want to drive an unbalanced input on a power amp… By design, the preamp splits the signal energy 50-50 about the center reference You have three wires: ( +, ground, and - ) and you have to somehow plug this in to an unbalanced input, two wires: (+ and ground) A couple different ways can be used depending upon the circumstances. You can connect the balanced line, plus and minus wires into the primary winding of an appropriate transformer and the ground to the chassis. We then ground the - phase of the output winding of the transformer which becomes the ground line of the unbalanced signal and the hot phase of the output winding, the + signal wire. The alternate method uses a center tapped transformer primary with the ground of the balanced line hooked to the center tap of the primary and left as a floating ground. The two output wires of the output winding become the unbalanced signal and can be phased as needed. The third method of conversion more commonly used today is to run the balanced line into a unity gain differential op-amp, using a single ended output as your unbalanced out. Obviously, the undesirable aspect of this is that you're either putting a transformer or an active component in the signal path. Either case, not entirely desirable. The alternative is to simply take the minus signal wire and tie it to ground to form an unbalanced line. This is undesirable because you've just lost half of your dynamic range and compromised your signal to noise ratio, The situation as you can see is similarly bad when you are feeding an unbalanced signal into a balanced input. You either need to use a transformer or a differential amp (zero gain) stage to create your balanced signal or give away half of your potential dynamic range by shorting minus to ground. So in a home system I recommend sticking to one scheme or the other and don't mix your metaphors.

Happy listening!!

 

[Dusty Chalk]

Yeah, but...all that has to do with pre-amplification, at the end of it all, the amplifier has to take the signal (a differential, basically, of two voltages) and amplify it, and drive a driver to move...how is that done in Headroom's new balanced amp (and by how, don't explain amplification to me, I mean, how, specifically, is that done differently in a way that makes sense with dynamic headphones)? (Squeezes head) I just don't understand...

 

[kwkarth]

Hi Dusty,
I've never had a chance to look the Headroom amp over, but as I mentioned, in the end you still end up with two wires carying a signal. Most headphones have three wires in their cable coming from the three circuit plug on the end. Tip, Ring, and Sleeve. The tip is left hot, the ring is right hot, and the sleeve is common ground for both channels. In the Cary, the Blockhead, and virtually every other amp on the plannet, the final output is always a standard two wire output to the driver, whether it be a speaker or headphone. The Blockhead I believe is wired differentially so that what used to be the left and right channels of a single amp are used as differential halves for a single channel instead so at the final output what would otherwise have been the hot left and hot right now become hot and cold of one individual channel. So an entire amp is dedicated to each stereo channel. The advantage here is that you have twice the theoretical dynamic range capability of a single amp. Something debatably unnecessarry in a headphone amp, but one could argue that this way for a given signal, the amps are only working half a hard as they otherwise would be and therefore perhaps would remain more linear and exhibit lower distortions under large signal conditions. Nice stuff if you've got the bucks!