Ok, tube historians

[Reeek]

I have 4 NIB (they came in paper wrapped cardboard tubes actually) 5751 blackplates from Hewlitt Packard. Are they really made by Hewlitt Packard or are they rebranded too?

Thanks for any input!

 

[Blue Strat]

HP never manufactured tubes. They, as many, produced lots of equipment that used tubes and hence distributed relabeled tubes to their customers who assumed that they MUST use HP tubes in their HP equipment The relabeling saga begins.

I've seen RCAs relabeled as HPs and probably others that I'm not remembering. If the "5751" marking is etched in the glass inside a rectangle (actually, a "flattened" octagon) near the top of the tube, they're indeed RCAs. If not, a photo would help a lot.

 

[Igneous]

Ive pulled a few HP stamped tubes from an oscilliscope. These were mixed with identical GE's.

cheers.

 

[Reeek]

Thanks, guys. I'll take a look and let you know what I see as MFG characteristics . . .

 

[Reeek]

They're definitiely RCA black plate 5751s and they are very balanced. One is rated at 1450/1450, one is 1350/1500 and the one in my Sano is 1400/1450. That nice, shiny black plate material too

I should have known that, Mike. Thanks . . .

 

[Igneous]

Very cool!

good find.