How do I hook uo headphones to my system?

I have a Pass Int-150, which has neither a tape loop nor a headphone jack, so I can't (easily or conveniently) used an outboard headphone amp or plugs the headphone directly into my amp. Yes, I know I could use an outboard amp and directly plug in whatever source I am using into the headphone amp, but I really don't want to go that route.

The other thing I thought of is slightly nuts- my CD player has a digital out; my tuner has balanced and unbalanced outs and my phono stage has balanced and unbalanced outs.

I could run my CD player into a dac and then run the DAC's output, the unused tuner output, and the unused phono output to an headphone amp which also has the capability to switch among input sources or to a preamp that has a decent headphone stage.

Way too confusing. Anyone have an easy solution?
you can dig out from your basement or garage an old receiver and use it as headphone amp connected to tape output of your receiver.
You can also feed multiple inputs to use separate headphone amplification as well.
He made it clear that there is no tape out, so he can do what I a (in my case a Chinese tubed version) headphone amp, run it from the preamp out (you have both single ended and XLR outs on that amp), and there ya go. My headphone amp cost maybe 40 bucks and after sticking a better tube in it, sounds fabulous, and you can adjust the volume with the amp's remote.
Wolfie's suggestion is a good one IF engaging the mute function on the INT-150 to disable its outputs to the speakers does not also disable the pre-outs. I don't know whether or not that is the case, and the manual does not provide an answer. Perhaps someone having specific familiarity with that model will chime in, or else an email or phone call to Pass Labs should provide an answer.

-- Al
Zavato hi, you could run you headphones direct of the output rca's of your CD player if the volume is the right level or you may have level control in the player and the cd player has a good output stage. Which cd player do you have and i see for you. This way can be the best sound if all the stars line up.

Cheers George
I'm pretty sure the mute button on the INT-150 will mute the pre-amp outputs.
George, note that he has three sources, not just a CD player. The model numbers are indicated in his system description.

Zavato, I think I have a fairly nice solution to propose, which I'll probably have time to write up in the morning. First, though, have I correctly determined by researching those model numbers that all three of your sources have both balanced and unbalanced analog outputs? It appears that the Sim Audio 260D with the optional built-in DAC provides both kinds of outputs, as well as the phono stage and the tuner which you indicated do provide them. (I realize that the INT-150 can only accept up to two balanced inputs, and up to four inputs total).

-- Al
I retract my suggestion. Hadn't thought of that...oops.
03-13-14: Almarg
George, note that he has three sources, not just a CD player. The model numbers are indicated in his system description.

Well if that the case he could use one of these after the CDP and put his sources into it as well and headphones and preamp or whatever into the outputs. There always a way Al.

Cheers George
PS: and there are many cheaper version of the Decware on ebay, but Decware are usually very good quality.

Cheers George
Agreed, George. I was also envisioning an approach using a line-level switchbox, as described below.

Zavato, before I get into that I want to mention a point that I think should be kept in mind. For some and perhaps all of your source components the RCA and XLR outputs are probably not independent of each other. It is not uncommon for components providing both kinds of outputs to provide the same signal to the RCA output connector and to the non-inverted signal pin on the XLR connector (usually XLR pin 2 in the USA). The manual for your Pass Aleph Ono, for one, has wording indicating its design is done in that manner.

Although as a practical matter it may not make a perceivable difference, it is therefore most ideal to not have both outputs connected at once. Otherwise there MIGHT be at least slight effects on sonics as a result of introduction of unequal amounts of noise on the two balanced signal lines (which would therefore not be rejected by the balanced receiver circuit), and as a result of having unequal impedances on the two lines (which degrades common mode noise rejection), and as a result of having unequal loading of the signals on the two lines. The approach described below pretty much eliminates those possibilities when listening via speakers.

My suggestion, assuming that the INT-150's mute function disables its pre-outs and therefore makes them unsuitable for connection to a headphone amp, is as follows:

1)If you already haven't, determine whether your two most critical sources (presumably phono and CDP) sound best when using their XLR or RCA outputs. The following assumes that their XLR outputs sound as good or better than their RCA outputs. If that is not the case the suggested connections can be revised accordingly.

2)Buy an RCA line-level switchbox that can accept at least four inputs (one more than the number of sources). The Decware ($279) suggested by George looks like an excellent choice. The DB Systems (follow the "Accessories" link) model DBP-2JAU/5 ($110, or more with various options), which I used many years ago with excellent results, is also worth considering. Further info on it is provided here and here.

3)Buy a headphone amp, preferably having an input impedance of around 47K or higher.

4)Connect the XLR outputs of the phono stage and CDP to the INT-150. Connect their RCA outputs to the switchbox.

5)Connect the RCA output of the tuner, for each channel, to both the INT-150 and the switchbox, via a splitter or y-adapter.

6)Connect the two output channels of the switchbox to the headphone amp.

7)When listening to the speakers, set the switchbox to a position for which no input is connected. The addition of the switchbox, the splitters, and the headphone amp will then have essentially zero effect on the signal path to the speakers!

Enjoy! Regards,
-- Al
Wow, Al! Always impressed with the effort you extend to provide help.
So this is what I did- it's inspired by Al.

My tuner and phono pre have rca and xlr outputs.
My CD player has an rca output and a SPDIF output.
I bought a Wyred 4 Sound DAC

I built my own rca switch box- most parts come from Parts Connexion

I built a Bottlehead Crack headphone amp

I bought Sennheiser HD600 cans.

Essentially I have a parallel headphone system.
The tuner rca our goes to my switch box
The xlr out from my phono pre is converted to unbalanced using a cable I made (klotz cable, neutrik female xlrs, vampire rca's. Hot, pin 2 goes to the rca center pin, 1 goes to shield and 3 remains unconnected). Phono then goes to the switch box. The CD rca puts also go to the switch box.

The switch box has 4 rca inputs but the switch is an Elma 04-1264 limited to 5 inputs. That way when I'm not listening to cans I can take the headphone system completely off grid.

The output of the switch box goes to the headphone amp.

The switch box uses the above noted Elma switch, 20 gauge Neotech OCC wire, Tiffany style rca's all in a Hammond box.

This little headphone system is so good, I find myself listening to cans even when I don't have to!

Now I'm waiting for a Cardas replacement can cable, and some NOS tubes for the Crack.
Well done! Enjoy.

Best regards,
-- Al
Thank You! This was a very enjoyable project- the headphone amp was kit built (and yes, I've already rolled tubes and made one mod and contemplating a 2nd as found on the very active Bottlehead forum) and the switch box was totally from scratch!

I'm itching to build another Bottlehead kit but I really don't have a use!