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Re: Why do we use the some old "boring" types of tubes?

Posted by Rob Mercure (A) on August 23, 2006 at 10:14:25

In Reply to: Re: Why do we use the some old "boring" types of tubes? posted by Jim McShane on August 23, 2006 at 09:24:45:

Jim,

My typo with the "l/r" - was looking at the RCA Manual but I had a brain poot - sorry. As far as line voltages go I've been working with electricity and as a technician since I was 16 - I'm now 52 and have been "bitten" enough to be wary.
Notice I did not recommend a 35W4 type rectifier (yeah, low current capacity, but I'm making a point) only the damper diodes with the extremely high heater to cathode voltage ratings - and these heaters should be after the fuse and switch and the heaters separately fused - again, while attempting to demonstrate a point I wasn't trying to detail an entire circuit for anyone (although I would be more than happy to - I already had the resistor calculations done from my previous constructions). In my experience the 5 VAC rectifier winding on most trannies is "heartier" than either the 6.3/12.6 heater or the B+ windings - yeah, I agree that there are some that wouldn't be able to source the current but I wasn't suggesting subbing in a 5AR4 circuit - I specifically used the 5U4GB as an example (and a 5U4 may stress a 5AR4 tranny and EL34s may stress a 6L6 heater winding, etc., etc.).
Not that your points aren't quite valid but I almost feel you were looking for something to criticize - but I hope not.

Rob

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