Anacrusis, I asked about the gear in which you tried the Mullard and Telefunken tubes for my benefit and for the benefit of others who might read this thread and have not read through your other thread. Admittedly, I had not committed your system to memory, and I did not refer back to your other thread to research the answer.
Thanks for the answer to my question about the gear in which you tried the Mullard and Telefunken tubes, which is the DK VS-1 Mk III integrated amplifier.
The comparison you are making between Valvo E188CC and Telefunken E88CC is somewhat apples to oranges, and I can understand how there might be a dramatic difference. If you ever have the opportunity to compare Mullard E88CC to the Telefunken E88CC, this will be a better barometer of how the two tubes stack up. I mention this only as a point of education because I know your goal was to produce a reasonably precise tube reference as they apply in a specific circuit.
FYI, if the Valvo E188CC are made by Mullard, they will have a two-line date code etched into the glass. The first line of the date code will have three characters, and the second line will have three or four characters depending on whether the tubes were manufactured before or after 1961.
The second line will usually begin with a capital R or B signifying manufacture at the Mitcham, UK plant (R), or the Blackburn, UK plant (B). The next character will be a number signifying the last number in the year of manufacture. If the tubes were made prior to 1961, then the second line of the date code will have only three characters.
The third character will be a letter corresponding to the month of manufacture (A=Jan, B=Feb, C=March, etc), and the fourth character will be a number 1-4 that corresponds to the week of manufacture. The fourth character will only exist on tubes made after 1960.
Finally, if the Valvo tube has a Delta, or triangle etched on the bottle, it is manufactured by Phillips in the Herleen, Holland plant. I have owned Valvo E188CC tubes that were labelled this way, and therefore they were Phillips tubes branded as Valvo.
Thanks for the answer to my question about the gear in which you tried the Mullard and Telefunken tubes, which is the DK VS-1 Mk III integrated amplifier.
The comparison you are making between Valvo E188CC and Telefunken E88CC is somewhat apples to oranges, and I can understand how there might be a dramatic difference. If you ever have the opportunity to compare Mullard E88CC to the Telefunken E88CC, this will be a better barometer of how the two tubes stack up. I mention this only as a point of education because I know your goal was to produce a reasonably precise tube reference as they apply in a specific circuit.
FYI, if the Valvo E188CC are made by Mullard, they will have a two-line date code etched into the glass. The first line of the date code will have three characters, and the second line will have three or four characters depending on whether the tubes were manufactured before or after 1961.
The second line will usually begin with a capital R or B signifying manufacture at the Mitcham, UK plant (R), or the Blackburn, UK plant (B). The next character will be a number signifying the last number in the year of manufacture. If the tubes were made prior to 1961, then the second line of the date code will have only three characters.
The third character will be a letter corresponding to the month of manufacture (A=Jan, B=Feb, C=March, etc), and the fourth character will be a number 1-4 that corresponds to the week of manufacture. The fourth character will only exist on tubes made after 1960.
Finally, if the Valvo tube has a Delta, or triangle etched on the bottle, it is manufactured by Phillips in the Herleen, Holland plant. I have owned Valvo E188CC tubes that were labelled this way, and therefore they were Phillips tubes branded as Valvo.