[Boatanchors] Question: X-Rays from 3B28?

George Babits gbabits at custertel.net
Sat Feb 14 09:50:48 EST 2015

I wouldn't loose any sleep over X-rays from the 3B28.  I've never heard of 
that before.  The X-Ray deal goes back to the old B&W TV rectifiers with 
their 1B3(?) or something like that.  I have heard of x-rays from the 866 

My question is why would you waste a pair of 2500 volt rectifiers on a 450 
volt power supply.  The 5U4 or 5R4 would handle that with plenty of head 


----- Original Message ----- 
From: "William" <w_b_morton at hotmail.com>
To: "boatanchor" <boatanchors at puck.nether.net>
Sent: Friday, February 13, 2015 8:42 PM
Subject: [Boatanchors] Question: X-Rays from 3B28?

> Hello All,
> Been thinking of using a pair of 3B28 tubes to rectify an output voltage 
> to around 450VDC.  That value is above the critical anode voltage value of 
> 50V, so that should not be a problem.  Current is less than the 500mA max 
> listed in the table.  With the output voltage far lower than the ~1000V 
> values listed in the table, I think these things would not even break a 
> sweat.
> Two questions for the experts:
> 1.  Any issue seen operating arund 450VDC?
> 2.  The tubes have a sticker on the base with a warning regarding x-rays. 
> Why is there a warning on the tube base but nothing shown on the data 
> sheet?
> I had no idea these would present an x-ray risk based on what I saw (and 
> did not see) on the data sheet, so I picked up a pair.  Perhaps this my 
> learning experience for the week.
> Have a great weekend!
> Best Regards,
> William
> _______________________________________________
> Boatanchors mailing list
> Boatanchors at puck.nether.net
> https://puck.nether.net/mailman/listinfo/boatanchors 

More information about the Boatanchors mailing list