Ethifi, I was using a Syrah before and now I am having a Chenin. I found no problem with Bendix, GZ32 and GZ34 with Syrah but for the Chenin, only GZ34 can be used. I was probably the first or second guy to own a Chenin and the first guy to realise this noise problem. I even shipped the whole unit back to Mick for inspection. I am using Sylvania 6F6G but there is no such problem found. I would suggest you to try out a pair of Sylvania 6F6G and see how it goes.
Eddy
Eddy