Need help connecting headph. amp to cdp or preamp

My current set-up inludes a Linn Genki, Kairn pre and LK140 power amp. When I connect my RA-1 headphone amp to the Genki's regular outputs I get bad distortion through my Sennheiser HD-580s. The distortion goes away when I use the variable outputs on the Genki (which I believe are designed to accommodate users who want to run the Genki through a power amp without a pre). The only problem with this is how low the volume gets, which leads me to suspect something's not quite right.

One suggestion I received was that the output voltage of the Genki might be overloading the RA-1, and that I might want to connect it to the tape out my preamp. Would this work? How would I avoid sound coming out of my speakers -- shut off the power amp?

I'd love to hear from anyone who has a similar set-up. In particular:

1. If you connect the headphone amp to the CDP, what outputs do you use?

2. Does it make any sense to connect the headphone amp to the preamp or to the power amp, or is that redundant. If you can do this, what's the best way to hook it all up?

1) a headphone amp in general is designed to be connected to either line output of the source or the tape output of preamp.
2) RA1 amp is mainly designed to work with Grado headphones that do not have a high impedance and might not be a good driver for Senns. I had an experience auditioning a setup with Senn HD600/RA1 and I wasn't happy with the sound getting too bright and no bass extention.
3) You're right about connecting to the preamp tape output which probably will give you the best setup without reconnecting your headphone system.
I use the Grado with Senn HD600...the combo is fine. The direct out from my CD is good, but your's may be higher voltage...check with Linn.

If you hook it to the tape monitor, you should be able to turn down the volume on the should bypass the volume control.
I run my Stax headphone amp on the tape out from the preamp. The headphone amp has a passthrough to the tape deck. Therefore, this doesn't interfere within anything else and doesn't require hooking and unhooking cables frequently. My preamp has a mute so I can shut off the signal to the amp but still listen to the headphones. Reducing the volume or shutting off the amps also works. Best of luck.
I tried connecting the headphone amp to the tape out on my pre, but still no luck. I have checked and rechecked the connections and they are fine.

My CDP is connected to the direct outs on the preamp. The headphone amp is connected to the tape outs. The phones have always worked fine with the RA-1, so it's not that. I just can't get any sound and am about ready for the ball peen hammer solution. Is there something I'm missing? What should the "mode" setting on the preamp be? CD? Tape? I tried both to no avail. I am at a complete loss.

I suspect that there is a impedance mismatch with your line components.
Try to go to any local dealer to plug them into the different preamps and see what's cookin' there.