[Hirsch]

This is not a small amp. I'm not understating this. It's in two Maesto ZR style cases, but each case is bigger than the Maestro. This is needed, because it's actually two complete SDS amplifiers. This gives it a lot of versatility. You can use it as a two-input fully balanced headphone amp or preamp. Or, you can use each side of it as a single-ended headphone amp or preamp. In that configuration, two people can listen to two different sources, with two different headphones, each one with a separate SDS quality amp.

If you're going to use this monster single-ended, though, you might as well simply get an SDS or Maestro ZR. This amp is for when you want to listen to balanced headphones. The real question is "are balanced headphones worth it"?

On first listen, the answer is an unqualified "yes". Starting off with the HD-650 and balanced Silver Dragon cable, the HD-650 had a power I've never heard from it before. The size of the stage is absolutely huge. There's a three-dimensionality that I simply haven't heard from the HD-650 before. Further, the noise floor is simply absent. The silence between the notes, that "blackness" that separates the instruments, is profound. The level of detail is greater than I had thought the HD-650 was capable of. Hearing this, I already knew that this was a special amp. However, I didn't buy this amp for the HD-650.

The next headphone up was the Qualia 010 with Black Dragon balanced cable. Here is where the SDS-XLR is truly in its element. The Qualia is simply far more capable of detail than the HD-650, and the SDS-XLR is one of the most detail-oriented amps I've ever heard. The transparency is incredible...and the amp was able to translate this to the Qualia. If you've heard the Qualia, you have probably heard a hollowness in the mids, or a cavernous sound. The single-ended SDS had eliminated that, I thought. However, I had never really heard the Qualia until I heard it balanced. Anybody think the Qualia is bass-light? Guess again. Think the mids aren't rich? Guess again. The Qualia's biggest problem is that it requires a monster of an amp to control it. The SDS-XLR is just the amp for the job. Most of the Qualia quirks that have been attributed to everything from position (still critical) to design flaws are the amp losing control over the headphone, IMO. That's where this amp steps in. It takes control of the headphone, and simply makes it play the music. The staging of the Qualia may be the best of any headphone I've heard, and this amp lets it shine. Image is precise. Bass is deep and has strong impact. Vocals are to die for. Nothing in the music is hidden. (The downside of this is that you're going to need a good source). Dynamic range is excellent, as is the ability to have quiet sounds co-exist with loud ones.

After listening to the Qualia, the HD-650 sounds sluggish in comparison, and it takes some time to get used to it again. Here is where the signature sounds of the headphones become apparent. I need to listen to the HD-650 first with this amp, if I'm going to use it. It's not as easy to listen to the Sennheiser after hearing the Qualia. There's a sense of loss of detail that's hard to shake off. I'm still reeling from new amp bliss but I'll go on record as stating that the SDS-XLR/Qualia 010 combination may be one of the best headphone setups possible. I don't really want to listen to the Qualia single-ended again. I had thought I had a pretty good sound out of the headphone, but I was wrong. Now that I've heard the Qualia balanced, it's as though it were a newer and better headphone. Much better.

More on this as I get used to it, and figure out the tube set I want. Right now I'm using black glass National Unions in front of Sylvania black base 6SN7W's. Good combo, but it's a starting point, not the end.

Time to sign off and listen.

 

[kartik]

I wonder what the PS-1s would sound out of this monster!

 

[gpalmer]

My prediction is that Hirsch will be answering that question in the very near future.

Can't wait to hear this beast Hirsch, I've been holding off on getting into the Singlepower amps till the balanced one was out, now might just be that time!

Please keep us informed (and my spot by the new amp nice and warm!!)

 

[mikeg]

Hirsch - How well does the SDS/R10 combo match up to the Qualia/SDS-XLR combo? What source are you using? Any idea how well the Qualia/SDS-XLR combo compares to the performance of the Orpheus? You are the pioneer who guides our headphone dreams.

 

[Jon L]

I have a quick technical question. Headphones like HD650 has 2 wires per side, correct? Balanced amps like SDS XLR has a 3-pin XLR connector per side, right?

So how are the 2 wires from headphone connected to 3-pins of XLR? Is one pin of XLR not connected?

 

[daycart1]

Amazing! Does the dual architecture make tube matching the channels difficult?

 

[EdipisReks]

Quote:

Originally Posted by Jon L I have a quick technical question. Headphones like HD650 has 2 wires per side, correct? Balanced amps like SDS XLR has a 3-pin XLR connector per side, right? So how are the 2 wires from headphone connected to 3-pins of XLR? Is one pin of XLR not connected?

i was actually wondering the same thing.

 

[Hirsch]

If I understand the technology correctly, the ground pin is not connected. Both leads are active, with one a positive and the other a negative signal (as opposed to a signal lead and a ground return).

Channel matching is not all that hard. However, you do need double the tubes. The single-ended SDS needs one driver and a matched pair of tubes for outputs. The SDS-XLR needs a matched pair of drivers, and a matched quad of outputs. Actually, I heard an imbalance on the first tubes I used. On looking, I noticed that one of the 6SN7W's I put in had a slightly different architecture, with a raised lower mica, while the other three had micas below the top of the plastic base. I replaced the oddball tube with one that matched the others physically, and all was well.

 

[gpalmer]

Quote:

Originally Posted by Hirsch If I understand the technology correctly, the ground pin is not connected. Both leads are active, with one a positive and the other a negative signal (as opposed to a signal lead and a ground return).

That is the basic idea, one of the odd things is that the different manufacturers connect the wires differently. (Caution Hirsch, I have single-ended converters on the balanced headhones and the ones for the Grado's and the Sennheiser's are not wired the same so please keep track of which is which)

 

[Glod]

Congratulations! It is a very fine piece of music reproduction equipment you have got there. I guess the ultimate statement in non-portable head phone equipment has been found

You gave a good description also of the sound signature. From that it is easy to imagine what it sounds like.

But, is it already burned in? My modest MPX3 needed a minimum of 100hrs, but this colossus...

And then perhaps it has Black Gates here and there too?

 

[Rob N]

Hirsch,are you using tall or short 6SN7w's?

Also what component options did you go for?

 

[tom hankins]

Quote:

Originally Posted by daycart1 Amazing! Does the dual architecture make tube matching the channels difficult?

The amp has no problems using unmatched tube sets. I have tried mixing up tubes in both the power and gain positions that test all over the place and cant hear any difference as compared to using matched sets. All of these tubes were of course the same kind. (1 pr. input and 2 pr. different output)

Hirsch, glad you are enjoying the amp so much. Hoipe you end up recabling one of the R10's for the amp also.

Have you switched it over to the Meridian or Wadia yet?

 

[kartik]

Quote:

Originally Posted by Glod Congratulations! I guess the ultimate statement in non-portable head phone equipment has been found

Non Portable?!???!
Now what would make you think thus? Portability is all in the mind.

Seriously though, it would interesting to watch this beast face off against the balanced gilmores, dynahis and the Blockhead.

 

[tom hankins]

Quote:

Originally Posted by kartik Non Portable?!???! Now what would make you think thus? Portability is all in the mind. Seriously though, it would interesting to watch this beast face off against the balanced gilmores, dynahis and the Blockhead.

We need ayt999 to add in on the differences between the Gilmore, SDS-XLR, and the Blockhead balanced amps. As far as I know he is the only one who owns all three.

 

[Hirsch]

Quote:

Originally Posted by mikeg Hirsch - How well does the SDS/R10 combo match up to the Qualia/SDS-XLR combo? What source are you using? Any idea how well the Qualia/SDS-XLR combo compares to the performance of the Orpheus? You are the pioneer who guides our headphone dreams.

Initial source after putting it together was the Creek CD53. I'm going to move it to the Meridian today (more accurately, I'm going to move the G08 to the amp. You don't move this amp unless you have to

)

The SDS/R10 is a very different sound. I strongly prefer the R10 to the Qualia, all other things being equal. However, in going to the R10/SDS last night, I noticed that it simply couldn't keep up with the low-level detail presented by the Qualia/SDS-XLR. Another thing that I noticed is that for the first time ever, the stage presented by the R10 felt small. I'm seriously thinking about putting balanced connectors on an R10.

I haven't heard the Orpheus enough to make any meaningful comparisons, except for the low end. The bass presentation of the SDS-XLR/Qualia is the best I've heard out of any headphone.

Rob, I'm using the short-bottle 6SN7W's. I've only got one pair of the tall bottles, but about a dozen pairs of the smaller ones. I've got a pair of the metal base ones on the single-ended SDS, and have decided to leave that tube set there, which may not leave me with a quad of identical metal base tubes to try as outputs. I've got the single-ended SDS sounding the way I want it to, and don't want to change it again.

This amp has the "stock" parts, and would be considered the base model, I think. I need to listen over the long-term before deciding if any upgrades would be worth it. Possibly not. This amp is clean and transparent, which is exactly what I want.