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Woo WES XLR Input or RCA inputs?

post #1 of 18
Thread Starter 

I ordered a Woo WES (stock) and an SR-007 recently after having heard them (in the maxed configuration) at a meet, but I only have relatively cheap sources (a xonar essence soundcard and a USB 'ODAC' from JDS Labs - but neither have balanced outputs) at home. The sources sound great to me with my previous headphones, but I've never owned anything with balanced inputs before, nor anything as high-end.

 

If you connect via RCA to the Woo WES you have to use "phase splitter" tubes, apparently. Jack told me that they're included with the WES. I'm completely confused by what that means, though...

 

Could anyone offer some insight as to what that entails exactly, and offer me any suggestions as to whether the difference in sound quality would be significant between connecting via the balanced xlr inputs vs the RCA inputs? My understanding of "balanced" was just that there was less noise along the lines, but I can't get a clear explanation.

 

I'm contemplating adding a $1-$2k usb dac with balanced xlr outputs to the mix, but I'm trying to get some idea as to whether or not it would really pay off.

 

Thanks!

post #2 of 18

Assuming you are serious about this question; would you really buy over $10K  in esoteric audio equipment and pair it with anything less than it's full potential? I suspect you have had no replies because no one can take this question seriously. Of course you would need a high quality source/dac to take advantage of such glorious equipment. I am not enjoying a balanced setup but with your equipment I would not consider anything less. There are several good dacs out there for your price range and even one very good one for less (Yulong Sabre D18). When you really get all this together I think we would all love some pictures.

 

There are many threads on headfi that speak about the advantages of balanced systems. Do a little searching. There is much more to it than just "less noise". 

post #3 of 18
Thread Starter 

Well, no, I am serious. I can understand that the amp and of course the headphone comprise a major portion of sound quality improvements in an overall system, but I'm not at all convinced that all the very expensive DACs are necessarily significantly better than all the less expensive DACs.

 

My question was more about what is involved in converting the RCA signal through a phase splitter and any impacts that in itself would have on sound quality rather than the question of whether far more expensive DACs themselves would have a huge impact on sound quality. I think it could be argued that they would have *some* impact on sound quality, but I think that for the same amount of money I could likely get much more value by tube upgrades, for instance... assuming there aren't some inherent disadvantages in connecting to the amp with RCA in and of itself.

 

I've read quite a few posts and articles about balanced systems as a whole, but they all mostly focus on the amp and headphones rather than the DAC and cabling, so I'm just looking for a little guidance here. I may just end up flipping a coin, but I thought someone might have some experience with the source aspect of balanced systems. Thanks for the Yulong recommendation, btw.

 

Anyway, if I end up ordering a balanced-output dac as well then I'll definitely post my impressions back here regarding what kind of a difference I can tell between sources.

post #4 of 18

There different opinions on the merits of balnaced v single ended, and there are too may variables to confidently predict how any particular combination will fare.

 

I don't know the WES, but if it has rca sockets and you get a decent sound, then stop worrying - it's got an extra "phase splitter" section to marry the two together, so there may be some minor loss in SQ, but there are other variables that could have a bigger impact:

 

IMO, a superior DAC will give a bigger improvement irrespective of whether it has a balanced output or not. Even if you don't believe that, at this price range, you owe it to yourself to find out (on a trial basis). Obviously, if both source and amp are balanced, it's a no brainer that the connecton should be balanced as well.

 

Futhermore, once you have the DAC sorted, IMO, getting superior cables, a top power conditioner, attention to vibration control, etc could have a greater affect than whether the connection is balanced or not. Even if you don't believe that, at this price range, you owe it to yourself to find out (on a trial basis). 

 

In short, stop worrying, because if you're the worrying type, there are plenty of other things to worry about smile.gif

post #5 of 18

I suggest starting with this, if you haven't already: http://www.headphone.com/learning-center/balanced-drive-faq.php

 

The ideal way to form an all-balanced system is with: (1) balanced source component, (2) balanced amp, and (3) balanced headphones. There are caveats on each item though:

 

Balanced source component: These can be identified through their XLR outputs, which is standard for all balanced sources. However, not all sources with XLR outputs are necesarily "truly balanced". In order for a source to be balanced, it has to have what's called a "dual-differential DAC configuration", which essentially means there needs to be at least one, stereo physical DAC (chip) in each channel. Some DACs are mono-channel, which means that each channel will need 2 of that DAC, for a total of 4 in the source component - at least. Adding more DACs per channel lowers noise and offers other technical improvements, but manufacturers rarely do that, as it drives up cost.

 

A source with a dual-differential DAC config is where the entire system starts. If you don't have a source that meets this basic criteria, the whole headphone system will NOT be truly balanced. All of the sonic benefits from balanced operation won't be heard if this criteria isn't met.

 

I'd personally recommend not bothering with any balanced sources that cost less than $1K, because the inherent idea of balanced implies that it's two logical DACs, not just one, so it should be twice the price for twice the parts than a usual unbalanced source. In other words, a $1K balanced DAC probably won't sound any better than a $500 unbalanced DAC. To go a bit farther, I wouldn't personally waste any time & money on a balanced DAC that was less than $1.5K (excepting something made by Schiit Audio, maybe). And on a system for the SR-007, I'd increase that minimum to $3K, as the SR-007 is extremely revealing of the source component, much more than other headphones.

 

Balanced headphone amp: Some amps aren't truly balanced, and others are. An amp that's truly balanced can also be called a "dual mono" amp. Most traditional balanced amps are built this way and it's the ideal way to build a balanced amp, without clutter.

 

The amps that aren't truly balanced contain "phase inverters", aka "phase splitters", which can generate balanced output from only RCA input. The Woo WES sounds like it's one of these amps, from your description, when used via RCA input, anyway. (The amp would operate in solely balanced mode when using its XLR inputs, however.)

 

There are also other amps that generate balanced output through other means, without having XLR balanced inputs. While some of them do it legitimately, none of them will provide the sonic benefit that can be had through a balanced source.

 

Balanced headphones: Not all headphones necessarily support being able to be re-cabled for balanced drive. A certain number of wires have to be in the cable for it to work.

 

Also, not all headphones necessarily benefit from balanced operation either, and the most success will usually be realized on high-impedance/low-sensitivity or low-impedance/low-sensitivity headphones. I blanket recommend avoiding attempting to re-cable low-impedance/high-sensitivity headphones for balanced - every headphone I've heard of this type never benefitted sonically.

 

Note: this section doesn't apply for electrostatic headphones, as electrostatic amps are inherently balanced.

 

Balanced equipment: As I've gone through my own share of balanced sources, amps, & headphones, I'd flatly recommend against it in general. If you want to do it right, you have to be prepared to spend a lot of money, and potentially time. It takes a lot of effort to get a balanced system all in sync.

 

To achieve satisfaction faster and cheaper, it's easier to just stick with unbalanced equipment. I've found "balanced" to be vastly overrated and if I could go back in time, I'd choose the path of unbalanced gear instead.


Edited by Asr - 7/22/12 at 12:43am
post #6 of 18

The WES is a fully balanced amp or rather a quad single ended amp.  Unlike most electrostatic amps the WES doesn't have enough gain to phase split on its own so the single ended inputs have to be fed through an external phase splitter.  Using the high gain to do the phase splitting does produce some side effects but the phase splitter found in the WES is far worse and should be avoided. 

 

There is also a flipside to this and that's how things are setup in the source.  Some have XLR's but aren't really balanced or that balanced signal is derived from the single ended output and phase split with some crude opamp circuits.  Neither is good. 

post #7 of 18
Thread Starter 
Quote:
Originally Posted by Asr View Post

Balanced equipment: As I've gone through my own share of balanced sources, amps, & headphones, I'd flatly recommend against it in general. If you want to do it right, you have to be prepared to spend a lot of money, and potentially time. It takes a lot of effort to get a balanced system all in sync.

 

To achieve satisfaction faster and cheaper, it's easier to just stick with unbalanced equipment. I've found "balanced" to be vastly overrated and if I could go back in time, I'd choose the path of unbalanced gear instead.

 

Thanks for all that information! I had no idea DACs could contain more than one core DAC chip, but what you're saying makes sense. It sounds like it probably wouldn't normally be worth the extra expense, though I do have a nice balanced amp and pair of headphones on the way... I was considering ordering a Benchmark DAC1 PRE since they offer an unconditional 30-day trial period, and it's a balanced DAC. On the other hand, it doesn't advertise anything about having differential sets of DAC chips, and its specs don't seem to demonstrate much difference between the balanced and unbalanced outputs...

 

Quote:
Originally Posted by spritzer View Post

The WES is a fully balanced amp or rather a quad single ended amp.  Unlike most electrostatic amps the WES doesn't have enough gain to phase split on its own so the single ended inputs have to be fed through an external phase splitter.  Using the high gain to do the phase splitting does produce some side effects but the phase splitter found in the WES is far worse and should be avoided. 

 

There is also a flipside to this and that's how things are setup in the source.  Some have XLR's but aren't really balanced or that balanced signal is derived from the single ended output and phase split with some crude opamp circuits.  Neither is good. 

 

Thanks. It sounds like I should avoid the RCA inputs, then. I guess the question now is just what DAC I should consider...

 

Quote:
Originally Posted by TheAttorney View Post

IMO, a superior DAC will give a bigger improvement irrespective of whether it has a balanced output or not. Even if you don't believe that, at this price range, you owe it to yourself to find out (on a trial basis). Obviously, if both source and amp are balanced, it's a no brainer that the connecton should be balanced as well.

 

 

That's what I liked about the idea of being to demo the Benchmark DAC1 PRE for 30 days, but now I'm wondering if something like the Calyx 24/192 wouldn't be a better choice? It has multiple sets of DAC chips, though it does seem to be a bit more than I wanted to pay at $2200 or so, and I wouldn't be able to trial it (I can't even find anyplace online in the US to order it from)... And the DAC1 does seem to have some nice features.... Are there other DACs I should be thinking about? Woo Audio has one of their own, but I couldn't find too many details or reviews/feedback about it...

 

Ah, decisions decisions :)

post #8 of 18
Thread Starter 

Also, I'm going to want to connect some 3.5mm sources for the sake of comparison. Should I use a 3.5mm->RCA and then connect to the amp with the RCA cables? Or should I just use a 3.5mm->dual XLR cable? (like this one: http://www.amazon.com/HOSA-STEREO-3-5mm-TWO-XLR/dp/B000068OEP/ref=sr_1_6?ie=UTF8&qid=1343007173&sr=8-6&keywords=3.5mm+balanced)

 

Seems like the latter would skip the phase splitter, which would make the input to the amp unbalanced when it would expect it to be balanced, right?

post #9 of 18

There's a Calyx 24/192 on the For Sale (FS) "Source Components" forum for $1600 (and it comes with the PSU).  I can vouch for the seller.  He's good people. (http://www.head-fi.org/t/618225/calyx-24-192-psu-8-months-old-shipping-included)

 

If you're not going to use the preamplifier output functionality, you can get a Benchmark DAC1 USB over a DAC1 Pre/HDR and save yourself some money.  I'd also check AudiogoN and keep an eye on the FS forums, as you can get good deals on Benchmark stuff that way.  Alternatively, you can pick up a Lavry DA11.  These are incredibly rare on AudiogoN and the FS forums because the DA11 is a phenomenal DAC.  It can be purchased directly off the Lavry Engineering website.

 

Which 3.5mm sources do you plan on connecting?  If you're referring to something like an iPod, I'd get a dock, like a Pure i-20 or a Wadia 170i, and feed digital output to your high-end DAC.

post #10 of 18
Thread Starter 
Quote:
Originally Posted by sridhar3 View Post

There's a Calyx 24/192 on the For Sale (FS) "Source Components" forum for $1600 (and it comes with the PSU).  I can vouch for the seller.  He's good people. (http://www.head-fi.org/t/618225/calyx-24-192-psu-8-months-old-shipping-included)

 

If you're not going to use the preamplifier output functionality, you can get a Benchmark DAC1 USB over a DAC1 Pre/HDR and save yourself some money.  I'd also check AudiogoN and keep an eye on the FS forums, as you can get good deals on Benchmark stuff that way.  Alternatively, you can pick up a Lavry DA11.  These are incredibly rare on AudiogoN and the FS forums because the DA11 is a phenomenal DAC.  It can be purchased directly off the Lavry Engineering website.

 

Which 3.5mm sources do you plan on connecting?  If you're referring to something like an iPod, I'd get a dock, like a Pure i-20 or a Wadia 170i, and feed digital output to your high-end DAC.

 

The used Calyx looks promising, and it's nice to hear that you can vouch for the seller... I might go for that. Thanks for the suggestion! At least I would be assured then that I'm not possibly missing out by having not gotten a better DAC (within reason).

 

Regarding the 3.5mm sources, I just want to try connecting a variety of different sources, for the sake of comparisons. I've got a cheap DAC that only has a 3.5mm output, and an assortment of media players, etc. In particular I want to try connecting the cheap DAC... it's an ODAC, and there was such hoopla made about how pristine it's supposed to be that I ordered one. The specs are certainly worse on that than the calyx/DAC1, of course, but I'm just curious if I'll actually notice a significant difference. Maybe I'll even have someone swap between them for me with my back turned to get rid of expectation bias, lol. I'm sure I'll end up drinking the kool-aid, but I want to at least put up a fight!

 

I emailed Jack regarding how to connect 3.5mm sources and he said I should use a 3.5mm->RCA converter.

post #11 of 18

Quote:

 

Originally Posted by badhabit View Post

Regarding the 3.5mm sources, I just want to try connecting a variety of different sources, for the sake of comparisons. I've got a cheap DAC that only has a 3.5mm output, and an assortment of media players, etc. In particular I want to try connecting the cheap DAC... it's an ODAC, and there was such hoopla made about how pristine it's supposed to be that I ordered one. The specs are certainly worse on that than the calyx/DAC1, of course, but I'm just curious if I'll actually notice a significant difference. Maybe I'll even have someone swap between them for me with my back turned to get rid of expectation bias, lol. I'm sure I'll end up drinking the kool-aid, but I want to at least put up a fight!

 

I emailed Jack regarding how to connect 3.5mm sources and he said I should use a 3.5mm->RCA converter.

 

Something like these will be what you want for the ODAC:

http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10218&cs_id=1021804&p_id=665&seq=1&format=2

http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10218&cs_id=1021815&p_id=5599&seq=1&format=2

You'd go straight into the RCA inputs of the amp.  That's probably your best bet.

 

I understand the utility/importance of measurements, but don't drive yourself crazy over stuff like THD 0.01% vs. 0.001%.  If you want the best-measuring piece of equipment on the market, get a Benchmark.  But make note that you can't hold a spec sheet up to your ear and hear what a given piece of equipment sounds like.  You should pick what sounds best to you.  You're the one who's going to have to live with it.

post #12 of 18
Thread Starter 

Something that may be of interest to others -

 

It doesn't seem to advertise it, and http://www.soundstage.com/revequip/benchmark_dac1.htm indicated that it wasn't differentially balanced, but I emailed Benchmark asking if the DAC1s are differentially balanced, and John Siau replied that they are and went into great detail as to the balanced output design, confirming that a dual differential DAC is used, amongst other things (the placement of the differential amp very early in the signal path, etc).

post #13 of 18
Quote:
Originally Posted by badhabit View Post

Something that may be of interest to others -

 

It doesn't seem to advertise it, and http://www.soundstage.com/revequip/benchmark_dac1.htm indicated that it wasn't differentially balanced, but I emailed Benchmark asking if the DAC1s are differentially balanced, and John Siau replied that they are and went into great detail as to the balanced output design, confirming that a dual differential DAC is used, amongst other things (the placement of the differential amp very early in the signal path, etc).

 

I have a DAC1 USB.  It's a damn good DAC.  A lot of people on Head-Fi kept commenting that it's sterile and cold and lifeless, so I thought I'd get my own to see if any of that was actually true.  I completely disagree with those assessments.  I'm listening to it at this very moment, and I think it's a phenomenal piece of equipment.

post #14 of 18
Thread Starter 

Well, I've got all my equipment in. The DAC1 arrived first. I compared its headphone output to the O2+ODAC, and I honestly could tell almost zero difference between them. At that point I was anticipating returning the DAC1.

 

Then my WES and Stax arrived. With that, the balanced XLR inputs sounded much better than the RCA inputs. I don't know if that's a function of a problem with the phase splitter like spritzer mentioned or a genuine improvement in the balanced input as opposed to the single ended input... there is a bit of detectable hum with the volume knob up to 12 o'clock on the WES when switched to the RCA input - even when the RCA cable isn't actually plugged into anything, so I'm thinking it's the former.

 

Anyway, I just thought I'd post back with my conclusions in the end. Thanks for the assistance!

post #15 of 18

badhabit, your comments bother me.  I too have the Woo WES and Stax SR-009.

 

First, you already observed that the RCA inputs on the WES are a joke.  Not worth even talking about due to all the noise they generate.  Woo should not even be promoting this feature on the WES, it's that bad.

 

Second, you should not be connecting a 3.5mm output into the WES.  The sound quality degradation would make it pointless.  Put it this way - your Woo WES and Stax SR-009 are like the engine and body of a Ferrari Italia.  Now, for tires, you are using no name Walmart brand.  Yeah, the car runs and it's still fast, but the handling is so far below what it should be, you'd be better off with a Toyota FR-S and its stock tires.

 

So if you're going to use a DAC or source with a 3.5mm output, you might as well get a $1K amp instead of a $5K amp, because EVERY ITEM IN THE CHAIN needs to be in the same caliber, or your entire system will sound like the weakest link.

 

The CHAIN consists of: A/C receptacle (or even further back to the panel) -> A/C cord -> power regenerator/conditioner -> source -> cable -> DAC -> cable -> Woo WES -> Stax SR-009

 

I tried to rationalize and wonder if a top-end DAC will really be necessary; but after much studying the answer is yes.  Especially with the WES and SR-009 which is the most revealing rig you can buy.  So if the source is not top-tier or the recording sucks, or the DAC is just so-so, you will hear the impact on the sound quality much more than with a lower priced rig.

 

So seriously, think about spending $5K on A/C/cables, $5K on source/DAC to go with your $10K WES and SR-009 combo. At a minimum!  This is a ratio that I've heard used before (i.e., 1/3 on source, 1/3 on amps, 1/3 on output)

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