I recently bought the Jonathan Noble 300B PP from KJS . The amp came with Sylvania 5687 WB's as the driver tubes per pair of EH 300B golds .
The amps sound a little bass heavy , like the bass is louder than the mids/highs .
I just received 6x 2nd hand 5687's that I won on Fleabay for $21 . From their construction 5 of them appear to be Sylvania's , whilst the 6th appears to be Tungram . Two of the Sylvanias have test figures written on them in a black marker pen , reading 91/92 and 90/91 respectively . These are the two I decided to try .
Immediately the sound is more well-balanced , the sound is much better .
When I search google for 5687 vs 5687WB , I find differing opinions . Some say that their should be no electrical difference between the standard and military ( WA , WB , JAN ) versions .
Thoughts ?
I know that with the 6n2p and 6n2p-ev ( military spec ) the russians quote different figures .
http://www.diyaudio.com/forums/tubes-valves/53836-difference-between-5687-5687wa-5687wb-tubes.html
The amps sound a little bass heavy , like the bass is louder than the mids/highs .
I just received 6x 2nd hand 5687's that I won on Fleabay for $21 . From their construction 5 of them appear to be Sylvania's , whilst the 6th appears to be Tungram . Two of the Sylvanias have test figures written on them in a black marker pen , reading 91/92 and 90/91 respectively . These are the two I decided to try .
Immediately the sound is more well-balanced , the sound is much better .
When I search google for 5687 vs 5687WB , I find differing opinions . Some say that their should be no electrical difference between the standard and military ( WA , WB , JAN ) versions .
Thoughts ?
I know that with the 6n2p and 6n2p-ev ( military spec ) the russians quote different figures .
http://www.diyaudio.com/forums/tubes-valves/53836-difference-between-5687-5687wa-5687wb-tubes.html
