Balanced, solid state amplifiers?

[Neusdoorn]

For a long time now I've wanted to go balanced, but never really sat down and looked at all the offerings.

As far as the big names go, there's the RSA Apache, HeadAmp GS-X, RudiStor NX-33, Headroom Balanced Desktop. Right off the bat, the Apache and NX-33 are knocked out of the running based on what I've read about the manufacturers here.

Also, a small thing I've noticed: While the Headroom Balanced Desktop and GS-X have tabs to release the XLRs, the other two don't. Does this mean the XLRs don't lock as they should, or is there some other mechanism to hold them in place?

As far as price goes, the GS-X is a little rich for my blood, and the Balanced Desktop can no longer be had without the DAC, which is unfortunate as it'd be totally useless to me.

I don't know much about DIY offerings, or DIY builders. I know Rockhopper has a balanced Mini^3 pre-built, but I'm not sure how that would stack up against the desktop-intended designs, such as a balanced M^3, or, if I went totally insane, a balanced Beta 22 - I know those things can cost as much as a Balanced Desktop in parts alone.

Though, after reading Dreadhead's findings, is there really much/any benefit to going balanced?

I've also wondered for some time how exactly balanced helps, other than eliminiating issues that stem from a common ground.

I mean, with my HD650, the cable inside the headphones is unchanged, so how would connecting a balanced cable change how the drivers operate, internally?

In my search, I came across Headroom's graphs, which illustrate a substantial difference between balanced and unbalanced headphones of the same model. Could it be that either Headroom or Dreadhead's methodology is incorrect?

Lastly, cables. I am not a cable believer, but it would seem the only commercial offerings are $200+ for a balanced HD650 cable. I know those Cardas Sennheiser connectors are $30 a pair and each Neutrik XLR costs $5 for the base model, but still.. That's a lot to charge in labor, I think. Are there any DIY builders who sell for less?

[n_maher]

Balanced Stock HD650 Cable.

Start saving for a GSX.

[Dreadhead]

I recommend the cable that Nate shows or for even cheaper you can modify the stock cable yourself using some neutriks.

Now for my very contradictory two cents:

As far as balanced vs single ended goes I'm now solidly in the unconvinced category. Which is a change since I was solidly in the convinced category before. With a lot of headphones and some amplifiers the balanced "tightens up the bass" but I'm pretty sure that's because of the variation of the impedance of the phones and the doubled output impedance interacting (I ran the numbers when I was running HD650s balanced out of a Benchmark DAC1 and in that case it was definately happening as the calculations showed exactly what I was hearing (I was not the one to point this out but I'll link to my mea-culpa saying that the guy was right):

Best Amp to stick between DAC1-USB and HD-650 - Page 10 - Head-Fi: Covering Headphones, Earphones and Portable Audio

On the GS-X the effect of balancing is much more subtle or non-existent because the output impedance is very low (at it should be).

Everything also sounds more open because the volume is naturally 6 dB higher and louder nearly always wins without changing anything else. If people do the volume match using a very accurate SPL meter kept in the same place or a digital/analog volume control that has steps that add up to 6 db then you can use that too. When I was doing my A/B on the beta22 vs GS-X I did it by ear with a test tone and got it within 0.5dB after going back and forth 10 times but I doubt many have that patience.

For actual advantages: as pointed out there should be common mode rejection at the headphone and a higher skew rate (which should help at higher frequencies). There are lots of other noises though that don't go away in my (ground hum).

After all this I still listen to my system in balanced because the correction I apply can require 6-10 db gains at certain frequencies which is more than doubling the power requirement at that frequency and balanced gives me the piece of mind that I'm can drive my headphones without worrying about amp based distortion. If I switch back to SE and bump the gain 6 db though I still can't tell the difference with anything as yet. I'm keeping looking though.

The GS-X is a truly wonderfully built amp and is upgradable so I view it as a worthwhile investment to spend the money on it. If I didn't have the money to spend then I would be aiming for the GS-1 I guess but in the end the GS-X just adds that level of insurance that I'm willing to pay for. I paid for it because now I don't have to look at other amps (at least if they are just amplifier and don't have any signal modification stuff in them).

[nestacio]

My first post here, I hope it's a useful one -- I went the same route after listening to my HD650s single-ended for the last 3-4 years. I picked up one of Tyll's last Balanced Home amps before the holidays and ended up returning it since I didn't need the dac either (I opted for the HR dac, and then ended up buying imho a much nicer-sounding dac, a DCC2). My current amp is a balanced beta22.

I agree with Dreadhead that the benefits of going balanced are hard to discern (esp. in light of the cost required to create a fully balanced chain from source onward); when I connected my balanced HD650s to the headroom amp, the sound was good: impactful, generally tighter bass notes, and the spacing between things improved. The nice thing about the HR balanced home was that I could A/B single ended vs. balanced from the same source just by flipping a switch. I compared a single-ended HD650/Zu Mobius against a balanced HD650/Silver Dragon and the differences were very very hard to pick out.

How different? IMHO you would probably get more benefit from finding better recorded versions of the music you like -- which are far cheaper to obtain -- than balancing your entire chain. For certain recordings I own, the balanced HD650 was amazing. However, I attribute that, in part, to the possibility that gear with balanced outputs is well-made to begin with. In addition, there is some sonic benefit to balancing the HD650s, in terms of clarity and soundstage. In my opinion, is it worth the cost of balancing? Not if the rest of your chain is lacking - in particular, your source could be limiting your soundstage in ways that a balanced headphone can't entirely correct. Plus my beta22 has a separate volume control for L/R so I increase the soundstage by slightly decreasing one channel (yeah, that's how I roll). My justification for going balanced, and staying balanced, is flexibility: you can have the best of both worlds since balanced gear can also be used single-ended. I realize that curiosity may be gnawing at you (like it did me), and I haven't really answered your original question so here goes:

With regards to choosing a balanced ss amp, I think the HD650 requires a good amp regardless of drive (balanced or single-ended) since it scales to better sources and amps. The better the amp, the better the sound - 'better' being subjective of course. You can safely assume that the balanced variations of good SS single-ended choices apply here (Gilmore Lite comes to mind, and I own a PPA that seems to demolish things every time I go back to it). That said, I don't think a balanced Mini3 will get you somewhere a single-ended Mini3 could not.

I listened to four balanced source outputs with balanced HD650s, two were dedicated amps (a HR balanced home and a beta22), and two were the attenuated balanced outs of dacs (a benchmark dac1 and a dcc2). Here is my subjective ranking:

• Beta22 > DCC2 outputs > HR balanced home (max module) > DAC1
  
  I haven't heard the single-ended versions of all these but here is an attempt to characterize the single ended flavors that I've heard:
  
  
  • PPA > Gilmore Lite (w/the PSU) I know, blasphemy > DAC1 headphone amp.
    

  So for both balanced and single-ended, the DIY designs top out, and the DAC1 comes up in the end spot. Notice that -- to my ears -- the single-ended vs. balanced ranking does not affect the quality of the amps in relation to one another -- they are positionally the same regardless of whether I was listening balanced or single-ended. If I had to make amp choices again, I would base my balanced decision on how the single-ended SS sibling (if there is one) drives the single-ended HD650.

  Of course, my SS impressions could change when my EC Balancing Act arrives in a month or so.

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[Hopstretch]

My first post here, I hope it's a useful one.

Welcome. And it certainly was to me. Thanks.

[Icarium]

Hey Neil glad to see you over here

[nestacio]

Hey Neil glad to see you over here

Thanks Dan -- I can personally credit much of the above knowledge to my finally accepting the solemn and lonely fate that I am probably willing to spend ~$(more than I want to see in print) to explore the hobby; that, and the Esoteric that started me thinking about how much better balanced drive might be. And the answer to that question, I'm afraid, may be...

...electrostats. Or rare, discontinued, dynamic headphones. Or both.

.

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[nestacio]

To add a bit more value for the OP, when I was purchasing the HR balanced home, I was told by the staff at HR that balanced OEM senn cable that Nate linked to on their site is a similar build to the stock HD650 cable so as a test, I installed my stock HD650 cable to one of my senns and listened side-by-side against my Zu Mobius aftermarket cable (my PPA has two single-ended jacks - what can I say, I like comparing things). I am not going to claim that the oem HD650 cable beat the Zu Mobius but I will say that, if you like the sound of the stock HD650 cable - and many folks do - the senn balanced cable from HR is a solid alternative to the balanced sound provided by aftermarket cables.

My personal feeling: bang-for-buck, the cable material is probably one of the last edits to your system and the same money spent, for example, on improving the starting point or end point of your chain, or on better source material, will take you much much further (which you likely already know). The value of balanced cabling imho is primarily in the way the signal is divided, and not the actual cable construction - so really, any balanced cable will give you much of the sonic benefit of balanced drive.

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[Dreadhead]

Just build it using the stock cable and build a SE to balanced adapter the same time. Remember the volume match if you A/B

[Grand Enigma]

There are people who would more than gladly reterminate a stock HD650 cable to balanced for quite a bit less then $99

[Neusdoorn]

Some really interesting stuff here.

I've never used the DAC1's headphone outputs. I got the Solo before the DAC1, so I never needed to fall back on it.

I've heard of people using attenuated line-level outputs instead of a headphone amplifier, and it's a little more fiddly than I'd like. I figure a variable resistor would prove much clunkier than a nice knob.

I wish I'd gotten into the game earlier, didn't the GS-X used to cost $1900 or similar?

So, there are proven advantages to using a balanced headphone amp, in terms of electronic properties, as you've basically got two headphone amps in one box, functioning as monoblocks.

I'm still at a loss as to how the headphones are driven when balanced. In a normal, single-ended setup with the HD650s positive is actively driven, and negative is a return wire, whereas in balanced, both positive and negative are actively driven? I'm a bit muddled because the headphone's internal cabling is still identical, so wouldn't the active driving of the negative wire be useless? Balanced headphones are weird.

There are people who would more than gladly reterminate a stock HD650 cable to balanced for quite a bit less then $99

Thanks for the pointer. On a side note, how much do the parts cost, to make a headphone cable with 2 bog-standard Neutrik XLRs and a few feet of a nice balanced cable like Belden 1800F? I know the Cardas connectors for Sennheiser headphones are pretty expensive.

[Spiug31]

Some really interesting stuff here.

I'm still at a loss as to how the headphones are driven when balanced. In a normal, single-ended setup with the HD650s positive is actively driven, and negative is a return wire, whereas in balanced, both positive and negative are actively driven?

yup

I'm a bit muddled because the headphone's internal cabling is still identical, so wouldn't the active driving of the negative wire be useless? Balanced headphones are weird.

The HD650`s have 4 wires (separate +ve and -ve wires for each cup) as standard, this is what makes retermination viable.

[Neusdoorn]

The HD650`s have 4 wires (separate +ve and -ve wires for each cup) as standard, this is what makes retermination viable.

I knew about the two pins on the Senn connectors, but I'm still confused as to how the driver responds to the balanced signal. I read somewhere that balanced headphones aren't "truly" balanced, but I know nothing other than that.

Also, since the stock cable is able to be reterminated, that means it has four separate conductors, both channels' negative wires tied to ground with stock termination?

[Dreadhead]

I knew about the two pins on the Senn connectors, but I'm still confused as to how the driver responds to the balanced signal. I read somewhere that balanced headphones aren't "truly" balanced, but I know nothing other than that.

Also, since the stock cable is able to be reterminated, that means it has four separate conductors, both channels' negative wires tied to ground with stock termination?

A balanced audio interconnect (not headphone cable) contains 3 conductors: Positive, negative (-positive, some call inverse but not the inverse) and ground. What a balanced headphone amp does is that it amplifies both the positive and negative signals and applies them to the headphones so that the effective voltage the transducer is seeing is 2x the voltage between the positive and ground. Headroom has a very good explanation (in 4 parts):

Art. I- Balanced vs. Unbalanced - HeadRoom - Right Between Your Ears

Truly balanced means that the amp has an amplifier for both the positive and negative signal for each channel (so 4 amps) some amplifiers and pro audio designs convert the balanced signal to SE amplify/modify and then convert back to balanced through a transformer or other method. This latter approach is common in tube designs where getting correct matching is very hard and it also has the added advantage of impedance matching with the phones.

[Neusdoorn]

A balanced audio interconnect (not headphone cable) contains 3 conductors: Positive, negative (-positive, some call inverse but not the inverse) and ground. What a balanced headphone amp does is that it amplifies both the positive and negative signals and applies them to the headphones so that the effective voltage the transducer is seeing is 2x the voltage between the positive and ground. Headroom has a very good explanation (in 4 parts):

Art. I- Balanced vs. Unbalanced - HeadRoom - Right Between Your Ears

Truly balanced means that the amp has an amplifier for both the positive and negative signal for each channel (so 4 amps) some amplifiers and pro audio designs convert the balanced signal to SE amplify/modify and then convert back to balanced through a transformer or other method. This latter approach is common in tube designs where getting correct matching is very hard and it also has the added advantage of impedance matching with the phones.

I'd skimmed that article in past. Reading it thoroughly helped.

To add further confusion, I've noticed a few very expensive headphone amps that have balanced I/O yet are SE internally as the builder feels it "sounds better".

Still wondering why the NX-33, Apache and B-52 have weird front XLR jacks, sans retention clips.

Observation: NX-33 and B-52 have XLRs flipped from what HeadAmp/Headroom/All-the-other-manufacturers do. Is there a function to that, or did they put their XLR jacks on upside-down pointlessly?

[n_maher]

The retention clips are wholly unnecessary, and they are upside down on Ray's gear because he uses board mount bits and that's how they fit.

[Neusdoorn]

The retention clips are wholly unnecessary, and they are upside down on Ray's gear because he uses board mount bits and that's how they fit.

How's that? Do they simply not lock on RSA gear, or is there another method to release them?

[grawk]

They just don't lock

[n_maher]

How's that? Do they simply not lock on RSA gear, or is there another method to release them?

Like Dan said, they just don't lock and don't need to. Remember, the XLR connector was invented for the professional audio market where users are concerned about cables getting kicked out during a live performance. With headphones I'd argue it's probably better to remove them.