Pre S.E.X. Order/Build Questions

[RDF]

Hello All 

I currently use HD600's and LCD-2C's with my Schiit Valhalla 2. I love the tube sound, but while still very appealing, the LCD-2C's (70 ohms, sensitivity 101db) lack a little something. My research indicates that the S.E.X. would be a good match for them. Is this correct?

Additionally, I would like to use it to drive speakers. How should the S.E.X. be wired, 4,8,16, or 32ohm? (The LCD-2C's still being the priority.)

What happens if a tube blows, do I need a matched pair?

What are the alternatives to the 6FJ7 tubes if they were to become unavailable?

Thanks to everyone in advance
Robert

[Paul Birkeland]

Hello Robert,

I think the SEX would be a good match.  What kind of speakers do you intend to use with it?  Typically we suggest wiring for 4 ohm operation when headphones are a priority, as this trades away power that you don't really need for a lower noise floor. 

If a tube blows, you just need to snag a replacement.  The 6FJ7 has been a tube for decades in zero demands, so they are a bit tough to find but at the same time still somewhat common.  If you build your SEX amp, turn it on, then never turn it off, you can expect about five years of tube life.  If you run the amp 2-3 hours per day, tube life will be in the decades.

[RDF]

Paul, thanks for the reply. The speakers I have right now are some old Polk Monitor 60's (8 ohm 90dB). I wouldn't expect much out of them with the S.E.X.
However, the goal is to eventually run a pair of Zu Dirty Weekend (8 ohm 99dB) or a pair of Klipsch Heresy 4's (8 ohm 99dB) or Cornwall 4's (8 ohm 103dB).
But again, the LCD-2C's are the priority, at least for now.

Thanks, Robert

[Paul Birkeland]

The Heresy and Cornwall speakers will prefer the 4 ohm configuration.  DW and Polks may work a bit better with the 8 ohm configuration.

[Thermioniclife]

On my S3X I mounted a 4pdt switch by the inputs to select between 4 and 8 ohm transformer settings.

[RDF]

Thank you guys for the help! I'm ordering the S.E.X. this week or the next, but I can't find my Fluke meter, ugh.

Robert

[Karl5150]

Dig out that meter and warm up the iron - enjoy the build and the music it brings. Don't forget the pics.
(It just occurred to me that this is possibly the only site where wishing someone luck, asking for advice and posting pictures of their SEX doesn't get weird, or get you sent to HR)
Karl