22-09-2020, 01:30 PM
A technical solution I will share here.
Last week I was working with a couple of variations on RF amplifier circuits using Russian 6к1б valves and found that one of them did not appear to behaving as it should. I removed the valve from the circuit but realised I really needed to compare it with others to get a good indication as to how it was. I finally decided to build a test module for wire ended valves with a socket for easy connection. I had previously though about a ZIF IC socket so obtained one of these. It was 18 way so enabling me to double up on connections (ie two 1's to external connection etc to two 9's), two rows of nine running counter to each other. This enables easy connection of circular wire connection and inline wire connection types easily. I should say that my valve testing system is homemade and modular in design so I can easy adapt for new applications. It has no direct go / no go indication but does have a basic audio signal O/P at 100mV so that I can get a quick estimate of gain. I generally use two digital meters for voltages and an old AVO for anode current. The photograph I attach shows the offending 6к1б under test to the bottom centre. I have also placed my b9A / b7G test box in the picture for comparison as the system connections are the same.
Yesterday I did the testing comparing the offending valve to two other NOS items and a non variable mu (the 6к1б is variable mu) corrosponding (I think) 6ж1б sharp cutoff valve. The test box was found easy, if a little fiddly, to use, with testing of new valves being made safer by use of lengths of sleeving to stop the leads shorting. I have also made up a little croc clip lead for use with rod pentodes which have the remote / top anode connection.
These comparison tests proved useful and indicated that the valve was not at fault and I have now a useful connection box.
Knowing how many here use wire ended valves hopefully this may prove useful or spark ideas.
Tracy
Last week I was working with a couple of variations on RF amplifier circuits using Russian 6к1б valves and found that one of them did not appear to behaving as it should. I removed the valve from the circuit but realised I really needed to compare it with others to get a good indication as to how it was. I finally decided to build a test module for wire ended valves with a socket for easy connection. I had previously though about a ZIF IC socket so obtained one of these. It was 18 way so enabling me to double up on connections (ie two 1's to external connection etc to two 9's), two rows of nine running counter to each other. This enables easy connection of circular wire connection and inline wire connection types easily. I should say that my valve testing system is homemade and modular in design so I can easy adapt for new applications. It has no direct go / no go indication but does have a basic audio signal O/P at 100mV so that I can get a quick estimate of gain. I generally use two digital meters for voltages and an old AVO for anode current. The photograph I attach shows the offending 6к1б under test to the bottom centre. I have also placed my b9A / b7G test box in the picture for comparison as the system connections are the same.
Yesterday I did the testing comparing the offending valve to two other NOS items and a non variable mu (the 6к1б is variable mu) corrosponding (I think) 6ж1б sharp cutoff valve. The test box was found easy, if a little fiddly, to use, with testing of new valves being made safer by use of lengths of sleeving to stop the leads shorting. I have also made up a little croc clip lead for use with rod pentodes which have the remote / top anode connection.
These comparison tests proved useful and indicated that the valve was not at fault and I have now a useful connection box.
Knowing how many here use wire ended valves hopefully this may prove useful or spark ideas.
Tracy
