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?
128x128zavato
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
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.
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!