02-11-2018, 10:00 PM
(01-11-2018, 09:36 AM)ppppenguin Wrote: Dave, do you mean PCC83? The ECC83 can be used in 300mA series chains so there's no such thing as a PCC83 that I've ever heard of. Presumably given the context B9G is a typo for B9A.
Not sure about you constant pwoer idea. While it's probably true, it's a big hammer to crack a fairly small nut. Apart from a few small B7G triodes I think all P series valves need more than 6.3V heater. So easy enough to use a variable PSU and meters to see what's happening.
Hi Jeffrey, My apologies, I think I was thinking of the PCC84/85, but was probably staring at a ECC83 that's on my desk at the minute. And yes, I always make the mistake of B9G/A.
As for the heater power idea, having gone through the various envelope sizes Vs. Heater consumption I've realised that it might not be as easy to quantify them using this method, although I will add that this idea was mainly for testing unknown valves, possibly in an automated test jig.
I'm glad this thread has started a good debate, it's good to see everyone's ideas.
On the subject of Buck/Boost converters, this is a good idea, however I've noticed the heater consumption on startup can sometimes be 2-3x the normal rated current. An EL84 puts my L30/2 lab pack into current limit at 2A for a second or so then settles to about 0.7A so a converter would have to have plenty of overhead.
Dave.
