Mainline ten years in

[JamieMcC]

Big thanks to all the team at Bottlehead HQ my Bottlehead Mainline has recently passed its tenth year of  trouble free operation. It's in regular use and I'm very happy to report still sounding superb and as grin  inducing as ever.

Best wishes
Jamie.

Ps next year is ten years for my Eros I'm listening to some LPs at the moment 😁

[Paul Birkeland]

Still on the original 6C45s too?

[JamieMcC]

Hi Paul yes still using the original 6C45 tubes (other than the 12au7) which was rolled simply to try about five years ago. Funny how time flies Its never even entered my thoughts that I'm still running on the original tubes must be thousands of hours on them so far as I have also used my Mainline for preamp duty Infront of a solid state power amp for many years as well as for headphones use .

I have acquired several new pairs of 6C45 tubes as well so looks like I'm easily covered for tubes for the Mainline to the end of my days.

Only thing I do is a bias check  every 6 six months or so if and when I remember.

Any thoughts on preventative maintenance/servicing I should  consider to keep things running smoothly or is it a case of don't mess with things if all working well for the time being?

Cheers

[Paul Birkeland]

Doc B. did the original build as a studio preamp/headphone amp ages ago, and the only part that failed (every 8-10 years) was the biasing device used for the 6C45.  We changed this for the Mainline somewhat by accident, so this may be a component that needs new tubes every 5-10 years and not much else for many decades. 

[JamieMcC]

Thanks for the info that's great to hear.

I have a Hickok 600a Tube Tester (mind I've not turned it on for probably five years) I will see if I can find any test settings that might be suitable for the 6C45 tubes

[Doc B.]

I think the failure rate was actually a bit less than that. That studio amp had a rather flexible bottom cover, and at least once the failure was due to the bottom getting pushed in against the bottom of the biasing PC board. I remember it clearly because the repair was done in a big hurry in a hotel room at CES sometime in the 2000s. It shorted it out a second time when I set the case on an ottoman whose cushion pushed on the bottom and thus I got to do the repair twice and added a layer of insulating tape at the contact point. Luckily back in those days I brought a rolling tool case full of tools and spare parts to shows. In contrast the last Mainline I had went out on loan often and did many demos without ever breaking.