(05-10-2014, 12:43 PM)pwdrive Wrote: According to this:
http://books.google.co.uk/books?id=IEoWAwAAQBAJ&pg=PA488&dq=uch71+tube&hl=en&sa=X&ei=ETsxVOOxFIrzaqjCgdAG&ved=0CCMQ6AEwAQ#v=onepage&q=uch71%20tube&f=false
There are (apart from the heater specs) some small differences between the ECH71 and the UCH71.
Lawrence.
Based on above there appears to be no electrical differences between the ECH71 (as above) and the ECH21 (in my valve data book)
But having said that the specs in the Babani book (above) do not give inter electrode capacitances for the ECH/UCH71, my valve data book does give some for the ECH/UCH21 heptode section, they are as follows: cgk = 6.8 pf, cak = 9.5 pf, cga = 0.002 pf.
Those capacitances seem to (I think) tally up with the inter electrode capacitances given for the ECH/UCH71 in the data sheets from frank.pocnet.
All this seems to indicate no electrical difference between the ECH21 and the ECH71, ditto between the UCH21 and the UCH721.....possibly...
EDIT: Just for reference my own valve data book I used is the Radio Valve Data 8th edition (1966) Iliffe Books, not a bad book, also includes early semiconductors etc. The only problem is that they seem to have been published using absolutely non acid fee paper...
Lawrence.
