[minimus]

A few more suggestions: if the amp is not going to be fully balanced, make sure to offer a 1/4" headphone jack.  XLR jacks are not necessary unless the amp is truly balanced.  In any case, most people do not have balanced headphone cables lying around.  Also, adding too many features -- like speaker outs, DAC, remote -- may drive up the cost for features that most won't use.  I have owned headphone amps that can double as preamps and low power integrateds and never use them for that purpose.  Avoid making an amp that seems to be a potential "jack of all trades, master of none".  Finally, Woo is in need of some competition in the $1200-$2500 range.  Above that price, though, and the potential market thins out a lot and you will start competing with Eddie Current, which seems to operate on low margins and is well regarded.

Oh, one last request, create an amp that has some tube warmth.  Singlepower sold a lot of amps before it imploded.  Users loved them for a combination of midrange warmth and great dynamics.  The remaining amp makers seem to adhere too closely to the straight wire with gain manifesto of amp design.

[FullRangeMan]

Most headphones came stock with the unbalanced banana but the best sound quality are with the balanced aftermarket cable.
So both are necessary IMO, I just do a web reseach and came to the result I prefer the single XLR 4 pin connector (over the dual 3 pin).

So I prefer a phones amp with 6,3mm stereo banana jack and XLR 4 pins for best sound.

[Srajan Ebaen]

Here's a concrete example of a headphone/preamp/DAC that's really well done and in the $1.200 slot: http://www.aprilmusic.com/eng/main/sub02_03_07.html
Of course it's made in South Korea so we all realize a pricing advantage but let's look at the design. It's the right size, as a preamp it has remote control and numerical display and as a headphone amp it has a very effective bypassable all-analog bass EQ and drives anything out there. As a DAC it's limited to 16/48 USB because a dedicated DAC in their mini line is forthcoming. It's not a tube piece so it doesn't have to worry about where and how to put the glow bugs. Volume control of course is analog and tracks real well into standard loads (haven't tried it with IEMs as I personally find the notion of portable hi-eff in-ear phones and stationary 'monster power' amps ridiculous. For IEMs people use portable amps... but others could feel differently. Then inter-channel tracking from the very get go of whatever pot you choose becomes truly vital. I would not even consider stepped pots in 1dB increments. Too coarse. Even my 14000 euro Nagra Jazz tube preamp uses a continuous-type pot and there's plenty of good ones out there to where clunky steppers (which often produce switching transients to boot, particularly nasty with IEMs) shouldn't even apply.  But that's just me.

I would agree that a DAC/headphone box is rarely used as a 'serious' preamp i.e. in the big system. But I would say chances are good it ends up on a desktop mated to a basic stereo amp if it's got USB, S/PDIF (say for an iPod dock) and Toslink (for various other portable sources).  Now remote and numerical display aren't necessary. I'd not worry about driving speakers at all but if you do, one all-in-one box to emulate would be Wyred4Sound's mINT.  That's what I use on the desktop and in sequence of quality I'd say it's #1 = amp, #2 = headphone output and #3 = DAC.  I'd rather see a dedicated tube hybrid headphone amp that can also be a super tube preamp on the desktop. Just to throw a few more things into your thinking pot 

[minimus]

Sorry to derail the thread a bit...but Srajan, I use JH16s with a Headphones Lounge silver IEM cable with two home amps -- an Eddie Current Super 7 and an ECP Audio L-2.  The sound quality beats my LCD-2s rev 2s with ALO cable by a country mile.  They are so good, I sold my HD800s.  I only keep the LCD-2s around as a backup should something ever go wrong with the JH16s. Give the JH16s a try with a "monster power" amp (but preferably low noise and low gain) and you are in for a treat.  As a longtime member of Head-Fi and Head-Case, I know of a few veteran hobbyists who sold everything but their JH16s and a good dynamic home amp.

Fullrangeman, I own a half dozen aftermarket cables.  Unless the amp itself is balanced, a balanced headphone cable sounds no different than a single-ended cable. Trust me, I have a single-ended and a balanced headphone cable for my LCD-2s, both from Q Cables, and they sound identical when used with my Super 7, which is not balanced.

Now back to design features Dan might care about: I don't know of too many who would use a headphone amp as a computer monitor stand.  I have a dedicated rack from Mapleshade Audio that holds my amps, DAC, and transport.  No way I want a monitor propped on top of my $2500 L-2.  I don't think many would feel comfortable resting a monitor on one of Dan's works of audio art either.


 

[Srajan Ebaen]

On the monitor stand issue, see here:



I'm talking as a guy with a speaker & headphone system on the work desk. As you can see, to keep things reasonably tidy there's simply no room unless certain electronics double as monitor stand. And mine isn't a small desk but properly grown-up version  If the speakers weren't there, it'd be a different song. But if we're talking headphone amp with a second purpose as a desktop preamp... now it can easily become an issue where to put things. Hence my suggestion to style such a component in a way that putting something on top doesn't cause overheating and in fact is nice and flat and strong to begin with. Of course my purpose for contributing here isn't to get into arguments. It's simply to throw ideas and feedback into Dan's bag so he has a full list of things to consider, weigh and then ultimately decide on for his new project.

Interesting on the IEMs. I simply dislike the wear of things in my ears. On the go it's convenient and natural but for long-term listening at home I'm old-school and prefer on-ear cans 

[DaveBSC]

I'm talking as a guy with a speaker & headphone system on the work desk. As you can see, to keep things reasonably tidy there's simply no room unless certain electronics double as monitor stand. And mine isn't a small desk but properly grown-up version  If the speakers weren't there, it'd be a different song. But if we're talking headphone amp with a second purpose as a desktop preamp... now it can easily become an issue where to put things. Hence my suggestion to style such a component in a way that putting something on top doesn't cause overheating and in fact is nice and flat and strong to begin with. Of course my purpose for contributing here isn't to get into arguments. It's simply to throw ideas and feedback into Dan's bag so he has a full list of things to consider, weigh and then ultimately decide on for his new project.

Get a bigger desk    I have Event Opals on my desk on TerraStone platforms. The DAC is on a stand under my desk, and I use a passive pre for volume which is on little Symposium pads. The last thing I would want to do with a high-end DAC or HPA is plonk a monitor on top of it.

My advice would be to create basically a tube driven version of the Headamp GS-X. The feature set of the GS-X is just about perfect.

[modwright]

Thank you all for the input!

Minimus, I AM planning on a hybrid design as I DO prefer some warmth, ALONG with the drive and dynamics of SS power.

At this point, I am thinking of a tube gain stage with differential SS output stage, direct-coupled with no output transformer or coupling caps at the headphone connection.

We shall see how this works out.

Price-wise, I DO hear you guys and I am also looking at what is being sold.  There are A LOT of products in the $500 and less range.  I don't intend to fish in that pond, but I do agree that if the price is too high, then it is rarified air.

Take care,

Dan W.

[ajzepp]

...and the headphone/headamp world becomes even MORE interesting   

I was really excited when Paul G (Tube Audio Design) gave in to my naggings and began developing his first headamp (he was working on it at the time of his passing), and I love that another prominent AC'er is working on one now, as well.

Good luck, Dan...we're all looking forward to seeing what you come up with!

[modwright]

Thank you.  I did not know Paul G. and am sorry to hear of his passing.
 
We have lost too many good people in this industry over the past few short years it seems.

I am not going anywhere as far as I know….

I have some great tube/hybrid and SS ideas that I am pursuing.  Hybrid design will be first, but I am also looking at taking some of our standard amp technology and simply revising it to suit the needs of a headphone design.  Design principles are NOT that much different, except for total power and impedances.  More on this later.

Alan Kimmel and I are noodling over a hybrid concept right now!

Thanks,

Dan

[funkmonkey]

Glad to hear you are giving this a shot! 
A semi-portable desktop unit is the sweet spot for me.  Less than $1K sounds about right...  $5-750 might get my dollars.
Glowing tubes on top and a little MW blue glow under chassis, bleeding up through the glass... and a big fat and heavy volume knob. 
Can't wait to see what you come up with, Dan.
Cheers

[modwright]

Hi, I expect that it will not be semi-portable and WILL be more than $1K.  Sorry but without having the product built in Asia, we just CANNOT offer products at those prices.  I am not really sure about having our products made overseas, despite the great savings, because I am always uncertain of build quality and reliability.

Thanks,

Dan

[dminches]

I think there is a pretty good demand in the $1500 - $3000 price range depending on the features, specs, etc.

[Alleye]

Dan - I can say that I appreciate the made in the USA approach. It was one of the "pros" of picking up the 100SE and LS100.

I guess from my perspective If the price is nearing/exceeding the $3,000 range, I'd probably just invest that money into my larger system. If it's closer to the $1,000-$2,000 range, I'd be more interested/willing to increase/duplicate my music reproduction "tools".

Hope that helps and thanks again for reaching out and listening.

[dlach]

Dan - Don't think I saw this among the previous replies...but a potential advantage of including a DAC in the amp would be to support DSD playback and computer listening without a bunch of extraneous wires and other components.  This month's Absolute Sound predicts the number of DSD downloads to increase in the near future.

I do my headphone listening late at night (so as not to disturb anyone) with high resolution flac files on my Windows 7 laptop along with a few DSD downloads.  I bit the bullet a few months ago and bought a Benchmark DAC2 HGC, one of the few (but growing) number of DACs that supports DSD playback, because I intend for my DSD collection to grow.  I use J River Media Center 18 for playback software...an excellent product.  Media Center 18 is their first release to support DSD playback.

There's a definite "house" sound to the Benchmark DACn product line...hyper accurate...vivid...somewhat sterile...a little bright sounding perhaps.  The DAC2 is a definite improvement over the previous models, and DSD playback is superb.  Would love to hear DSD playback on phones with some tube warmth and bloom.  I alternate between Sennheiser 650's, AKG 702's, and Grado 225i.  I'm not much of a fan of in-ear stuff...guess I was born too late.

I realize incorporating a DAC will increase cost, but there are a growing number of computer headphone audiophiles out there, relegated to late night phones listening, by family and circumstance.  And DSD is "the next big thing" in computer audio playback.  DSD support would help you differentiate your product from the rest of the pack.

Regards,
Denny

[modwright]

Hi guys and thanks!  I have a circuit right now that is hybrid, with discrete bufferd output, capable of driving virtually any load and I am determining how much power it needs, so that the supply can be designed properly.  I am going to build it as a standalone headphone buffer first and then plug any/all of our tube preamps or tube sources into it, to determine how this works.

I will then settle on a tube gain stage and build a complete amp.

I may offer the straight headphone amp FIRST, without DAC, as this will be cheaper of course.  I do THEN plan on offering a DAC/Headphone amp. DSD would be a must at that point of course.

Right now, I am finishing our current Elyse DAC design, our PH 150 standalone high-end phono design and the headphone amp is still in schematic stages.

Your input has been INCREDIBLY HELPFUL!

Thanks,

Dan

[funkmonkey]

I am going to build it as a standalone headphone buffer first and then plug any/all of our tube preamps or tube sources into it, to determine how this works.

This is interesting to me...  any chance this version would be available to the public as a low cost option for those of us that already have one of your Pre-amps?  I've wished for a headphone out on my 36.5 ever since I got it.

[modwright]

Hi, interesting point!  I will see how it works out and go from there!  Ultimately, i do want to offer several different designs at different price points with different options.  The top model will ultimately have all possible output connections and will suit the most demanding loads.  I expect this design will have different outputs for different loads.  I want this to have tubes and SS tech and would also expect to add DAC to it ultimately.

There is also a market for a more mainstream amp that works well for most regular headphones, down to 32 ohm Grados, but perhaps not the more modern TOUGH high power loads.

Regarding a zero gain design, a headphone amp REALLY doesn't need gain for most headphones, it just needs to match impedance and amplify current.  This is exactly what the buffer only design would do.

More on this once I get a circuit bread boarded and evaluated. We already have a schematic concept, I just need to determine the necessary voltage rails and see how it sounds.

Thanks!

Dan

[modwright]

It is Saturday night and I am Not working...OK so I am posting here, but ultimately I am chilling on the couch.

I have a glass of good bourbon in my hand, headphones plugged into my iPad, listening to Pandora.  Headphones are Philips noise Canceling OE types (now don't be hatin') that I use when I travel.

Pretty mainstream, non-audiophile gear, but I have to say that this a great music escape and I am starting to see the appeal.  I am going to invest in some Audeze, HiFi Man or similar modern headphones that are more state of the art for design purposes.

The point is, as our lives become crazier and more 'integrated', headphone listening makes a lot of sense.  I am hearing that the new breed of headphones can TRULY compete with the best speakers out there.

An exciting new audio frontier indeed!

Thank you all for the input as I embark on this new design journey.

Happy Holidays!

Dan W.

[Alleye]

Doing roughly the same tonight - So I'll raise a glass to you and wish a Happy Holidays to you and yours!

Thanks for helping me enjoy a quiet Saturday night!

[modwright]

Right on!

It is a beautiful time of the year and we all should take time to relax, clear our head of work and other stressors and be sure to spend quality time with our family, loved ones and significant others.

Happy Holidays!

Dan