Biasing a Blues Deluxe or Hot Rod Deluxe

[LittleBigMatt]

This should definitely be a sticky! Cheers nocaster

[JayGee]

I hiss all over your CRT and raise you a microwave...2.5kV at an AMP! You would just not live.

You should see (maybe you already have) the monsters buried within the guts of a Rank Cintel flying spot telecine machine.

There's nothing like an EHT supply module the size of a suitcase to set your spidey-sense tingling, quite apart from the accelerating potential you really, really, really don't want to get anywhere near the scan coil drivers on one of those things!

There's also the small matter of the big warning notices saying "This machine *will* emit X-Rays if operated with covers removed", the monstrous 1/2HP motors for the feed/takeup reels (it takes a fair bit of grunt to accelerate a 3-foot diameter reel of 35mm film for 0 to 25 FPS in half-a-second or so), and what happens when the code for the new software controlled film transport servo you're developing goes insane and a few hundred feet of sharp-edged film stock starts flailing around the room like Indiana Jones' bull-whip...

Easily the most dangerous (and most fun!) piece of kit I've ever worked with from a personal safety point of view

--
JG

[ianpdq]

Nice one Kev but I think you should have put up a big red warning just in caseYou can die when you play with valve amps. Even if they're switched off. If you aren't confident stop reading. Don't come crying to me when you're dead.

[nocaster]

Done

K

[ianpdq]

[BTrizzle]

I've got an original Blues Deluxe and it doesn't look quite like the pictures, as in it's missing everything you're messing with. Can it even be biased or is it plug & play and hope for the best?

[ICBM]

I've got an original Blues Deluxe and it doesn't look quite like the pictures, as in it's missing everything you're messing with. Can it even be biased or is it plug & play and hope for the best?

The originals aren't adjustable - hope for the best, if you don't want to mod it. If it's a Deluxe it probably doesn't matter too much since the plate voltages are a lot lower than the Deville's, and you can get away with running them quite a bit hotter without risking blowing valves. It's still better to have it adjustable, but not essential.

If you do want to mod it, replace resistor R87 (27K) with a 22K resistor and a 10K trimmer in series.

[nocaster]

What rating of R's John?

K

[ecc83]

What rating of R's John?

K

GOT to be 1/2W carbon comps' Kev or it just won't SOUND right!

Anything matey, virtually buggerall power going on there.

Dave.