New top of the line headphone amp

[xcortes]

Plus the change to exotic we437a to match the other exotic parts!

[Chris]

Ok great stuff.. thank you Doc.... Yes, i would imagine more than 2k also, i was trying to be on the low side.. this is very cool news and shows again just what an incredible value BH gear is.... Cant wait to get building the FEW kits i have on my list after i get settled again somewhere....

[tdogzthmn]

What are the optimum impedance for headphones being driven by the Mainline?  I have found my SEX to wonderful with a variety of headphones from 50ohms up to my K240DF which is 600ohms, but the best synergy is with lower impedance headphones where the Crack weaker with my lower impedance headphones. 

[Doc B.]

It can handle any headphone from 32 ohms up. I would say the sweet spot is more a matter of what headphone you prefer than a particular impedance. So far everything I have tried has sounded quite good - Grados, ATs, Senns, Audeze.

I would say it's a more neutral amp than SEX or Crack. So if you have a headphone than needs some fattening up in the bottom end to get it balanced those might be better choices. But the Mainline will give the best resolution and sense of dynamics.

[sbelyo]

Plus the change to exotic we437a to match the other exotic parts!

would  the we437a work in the mainline?

[Paul Birkeland]

We have not sized the chassis holes to accept the sockets for the WE437A, but you could punch out the 9 pin socket holes and install larger sockets (I have first hand experience doing exactly this in roughly the same circuit).

The Mainline has lots of room under the chassis, so I wouldn't expect one to run into any issues with a mod like this.  Other than the different pinout, the circuit will not need any alterations. 

-PB

[sbelyo]

Thanks...  I gotta start saving for the mainline now!

[dubiousmike]

Hey Doc - I was just curious what 6C45pi's you recommend for the mainline and what the kit will ship with.  Are EH goldpins the tube of choice or are the Sovteks just as good/better?  Do any other manufacturers make them?  Thanks!

[Doc B.]

Just got some EH's in. Internally they seem to be identical to the tubes we have been getting from Russia and Ukraine.

[dubiousmike]

Thanks Doc!  If and when you get a chance, I'd be curious to know whether you perceive any audible differences between them?

[Doc B.]

I must correct myself. We got Sovteks not the goldpins. They sound just the same as the other 6C45pis we have. IME the gold pin EHs are different only in that they have gold pins.

[Gary PC]

My pre-amp died, I have read here that the Mainline is tailored to headphones and the BeePre to amps but will the Mainline drive a power amplifier with this input?
􀂃 INPUT SENSITIVITY: 0.8V RMS for rated output at 1kHz.
􀂃 INPUT IMPEDANCE: 47kΩ.

It is a SS Plinius SA-100 100W/ch class A power amp driving Magnepan speakers.  I used a headphone amp (the one that died a The Max Headroom) as a preamp for years and it did a very fine job.  I had people dead keen to sell me a preamp that would bring out a demo model of something costing twice as much as The Max and they knew instantly on hearing my setup that they could not touch it.

[Paul Joppa]

Yes, the Mainline will drive a power amp, quite well, even with very long interconnects.

During our investigation of better preamps, the Mainline configuration (shunt regulated, current source loaded, single ended triode with parafeed output transformer) would probably have won, if Doc B had not kept pushing for a 300B. The BeePre circuit with other triodes was not quite cutting the mustard. Because a headphone amp needs an output transformer, we went back to that configuration for the Smack, and eventually refined it as the Mainline.

I love the sound of the BeePre, but if I didn't have one I'd use a Mainline, or a Smack, in a heartbeat.

[denti alligator]

Yes, the Mainline will drive a power amp, quite well, even with very long interconnects.

During our investigation of better preamps, the Mainline configuration (shunt regulated, current source loaded, single ended triode with parafeed output transformer) would probably have won, if Doc B had not kept pushing for a 300B. The BeePre circuit with other triodes was not quite cutting the mustard. Because a headphone amp needs an output transformer, we went back to that configuration for the Smack, and eventually refined it as the Mainline.

I love the sound of the BeePre, but if I didn't have one I'd use a Mainline, or a Smack, in a heartbeat.

So if one wanted to get a great headphone amp AND a great pre-amp, would the Mainline be an option?

[Doc B.]

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.