I have not tried the headphones you have listed, so take my suggestions with a grain of salt.
When I first got my DV332 (now sold), I installed NOS Svets and WE403Bs. I had the same hum that you described in my HD650s. Drove me crazy.
I tried (not in order):
- isolating my amp from the DAC and Airport Express
- putting foil under the amp as it rested above the other components (trying to minimize any RF interference)
- cheater (3-prong to 2-prong) plug
- GENTLY (!!!) pulling the pins out a bit on the tubes with some needle-nose pliers
- GENTLY (!!!) cleaning the prongs with a small piece of steel wool
- with and without the stock tube covers
- Herbie's tube dampers
Eventually, I swapped two new sets of Svets (I ordered a bunch) and new WE403Bs (ordered new set from a different vendor). After installing the four new tubes, adding the Herbies and cheater plug, and burning in for a day, there was blessed silence.
I could have taken the time to plug back in the old tubes one at a time to determine which was the culprit. I could have removed the dampers and/or plug, to check as well. But when I achieved silence, I forgot all about the scientific method and never altered the setup again (until I sold it recently).
I would suggest troubleshooting in this order:
1- burn in 24 hours or more
2- cheater plug
3- GENTLY (!!!) flaring out the prongs a bit
4- new tubes
Originally Posted by That dude
^I've followed your recommendation and got myself a pair of SVETLANA 6S19Ps and LM Erricson 403B. However, after switching to them there is a audible hum when nothing is playing of during quiet bits. The volume of the hum does not change when I turn up the volume. I still use the original "spring dampers". Is this normal? How can I get rid of it.