Prototype Mainline on e bay

[Strikkflypilot]

Interesting offer of prototype Mainline on the bay.
No link here, not advertising, just curious about the upgrades

Edit: Appears to be gone already.

 

[JamieMcC]

Yep I was scratching my head about those extra tubes and curious enough to save a pic for reference.

 

[Strikkflypilot]

Thanks for the picture, Jamie!

 

[Doc B]

It is a 6C45 based headphone amp, but not really a Mainline. Too many differences (I would not call them improvements) to call it that.

 

[drewh1]

it is now up for sale on Audiogon. $1800  lot's of photos.

 

[Strikkflypilot]

It is a 6C45 based headphone amp, but not really a Mainline. Too many differences (I would not call them improvements) to call it that.

Thanks for the clarification, Doc.

 

[Paul Birkeland]

I actually built this some years ago.  It roughly splits the time difference between Doc B's big headphone amp with the wood front and the current Mainline offered today. 

 

[mcandmar]

I'm also really curious about that tube in the shield, is it a rectifier tube?

 

[Paul Birkeland]

Yes, I was experimenting with small form factors, which necessitated the use of a power transformer with a little more voltage than I wanted.  One way to shed some of that extra voltage was with a rectifier tube.  (Hence some of Doc B's comments)  I have absolutely no recollection of why I put a tube shield around a rectifier tube, but it may have been in part to keep it in the socket while transporting the amplifier.