New top of the line headphone amp

[Gary PC]

If you want our best preamp get BeePre. If you want our best headphone amp get Mainline. If you want both, mainline can do it but will require an adapter from the headphone jack.

That is great to learn - I definitely want to buy or build an adapter. Are details of an adapter to connect a power amp to the Mainline available?

[denti alligator]

If you want our best preamp get BeePre. If you want our best headphone amp get Mainline. If you want both, mainline can do it but will require an adapter from the headphone jack.

Interesting. But the BeePre couldn't have a headphone jack added? How close is the design of these two? You should make a Mainline/BeePre hybrid with three inputs and headphone jack.

[Doc B.]

The designs are different. Mainline is optimized to run headphones and has a high gain tube with an output transformer. BeePre is optimized to drive amps and has no output transformer. Because of this the BeePre has too high an output impedance to drive headphones of less than 600 ohms impedance. But it has a little bit better resolution and realism. The adapter to go from a stereo 1/4" headphone jack to a pair of RCAs from the Mainline is like 90 cents from Monoprice.

[dcham]

Looking as you have Neutrik SE input connectors on the Mainline, how easy / hard would it be to build a balanced input? You just need to swap out standard Neutrik D XLR female jacks in place of the RCAs. Of course you'll probably need another circuit board to handle a transformer-less or transformer balanced input.

[Paul Birkeland]

Looking as you have Neutrik SE input connectors on the Mainline, how easy / hard would it be to build a balanced input? You just need to swap out standard Neutrik D XLR female jacks in place of the RCAs. Of course you'll probably need another circuit board to handle a transformer-less or transformer balanced input.

You can always ground the cold pin on the XLR and use it that way.

There may also be room to mount a pair of input transformers on the Mainline to handle the balanced interface as well.

-PB

[Paul Joppa]

You can always ground the cold pin on the XLR and use it that way.
...

Only if the source uses a transformer output without a grounded centertap. Otherwise you will short one phase of the balanced source, and probably short it to chassis ground, not signal ground, as well.