Easiest ways to add headphone output to a tube system

seanrr

Well-Known Member
I have been trying to figure out an easy (and inexpensive) way to add headphone capabilities to my tube system. I have a nice tube amp and nice tube preamp, and they are fed by a DAC from my computer. I am interested in adding a headphone out - is there a way to add headphone out somewhere post-tube stages in this configuration? I figure it would need to come from the preamp out somehow. What is a way that would take advantage of the tube sound? Sorry if this is an elementary question or a stupid one to which there is not an easy answer.
 
I've got an old DIY K12G tube amp and I made a little box out of Radioshack parts for driving my headphones (AKG K701) off of the amp's speaker outputs. Here's the thread over at DIY Audio Projects that I used as a reference http://diyaudioprojects.com/Forum/viewtopic.php?f=9&t=2763

What kind of headphones are you planning to use? Low impedance headphones will have a bit of a hum to them when plugged into the speaker outputs of a tube amp. It's just the hum that comes through from the transformers. Higher impedance headphones, 300ohm or 600ohm, are supposed to cover up the hum.
 
Actually, I am open to the headphones used since this is for future planning. It is just that I am having somebody build an amp for me, and I am thinking I could use headphones in the future with it. He said he could probably put a headphone set up in the amp for an extra $150, but I am already spending a lot on the amp - thus, I was trying to see if there is a cheap work around down the line that would give me similar results, and I can buy headphones per what works best at that point - probably not for a year or two after my wallet has recovered.
 
I would plan on just using an external headphone amp. You can get one that's acceptable quality for less than $150, and then further down the road, if you decide you're more serious about headphone listening, you can upgrade to a nicer headphone amp without having to do anything to your tube pre and amp. If your preamp has 2 sets of outputs (very easy to do) it'll make connecting any headphone amp very easy.
 
Depending on how much you use your headphones, I concur that a dedicated headphone amp is the best way to go. You can then shop for one that can drive the correct impedance for your chosen cans and leave it alone if anything else changes in your system. Headphone amps should be set-and-forget IMO.
 
I actually went the Stax way - it is possible to pick up a Stax adapter plus headphones (for the older lower end model - SR-30 plus SRD-4) for quite a bit less than a headphone amp, plus it allows me to take advantage of a nice single ended amp when listening to headphones. In fact, I am picking up two sets for less than it costs for even a used headphone amp - so, I can use them both at work and home. They are the old Stax with the passive adapter that connects to my amps' binding posts. This seems to be a decent solution as long as I am listening to the headphones just once in awhile.
 
Woo Audio makes the WEE - a set of transformers specifically made to convert a speaker amp to STAX headphone out. It has connectors for speakers in and speakers out, with the headphone output on the front, along with a switch to go between them.
 
Woo Audio makes the WEE - a set of transformers specifically made to convert a speaker amp to STAX headphone out. It has connectors for speakers in and speakers out, with the headphone output on the front, along with a switch to go between them.

That is cool - I guess the SRD-4 that Stax made is a poor man's version of that... It is also just for the entry level Stax, which are not made anymore - they are fixed bias.
 
Correct, the SRD-4 will only work with the electret Stax models, like the SR-30 and SR-40. The SRD-4 is not an energizer, just an adapter to feed the amp output into the electret earspeakers (which have a 'permanent charge' to them, not any sort of externally-induced bias like the true electrostatic models).

Anyway, another option is to build something along the lines of this, which is similar to what has been mentioned in this thread already:

http://audiokarma.org/forums/showthread.php?t=401313

I'm planning to build one so that I'll be able to run my AKG K240 Sextetts from my Dynaco ST-35. Like the Stax adapter, it'll have a switch to allow me to toggle between speakers and the headphones.
-Adam
 
Your tube power amp's speaker taps are the key to any sort of headphone listening if you don't want to spring for a dedicated headphone amp. It's the only place where the output impedance of the preamp or amp is down low enough to talk to regular headphones or your Stax transformer box.

For dynamic/orthodynamic 'phones, get some power resistors (not wirewound types; they're inductive) and an inline headphone jack and wire up that adapter stoutblock linked to. Won't cost very much at all, assuming you can solder. If not, see if anyone on eBay is still selling the old Pioneer JB-21 headphone adapter, which is basically the same thing. 1/4" headphone jack, though.
Pioneer JB-21 headphone box.jpg Pioneer JB-21 box-a.jpg

Oh, and my standard nitpick on what constitutes a "true" electrostatic headphone: Electret-type headphones also are "true" electrostatics. They don't have a choice.
 
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