Nice phono stage with subsonic filter?

[Richard]

Sounds good Philip

[pre65]

It was.

Morgan is a very nice guy, and most helpful with his advice.

He signed my 3rd edition book, and presented me with a 4th edition FOC, BUT it's the Chinese version. (yes really)

[Greg.]

Infinitely Baffled, you have PM.

[bikerhifinut]

Originally Posted by Greg.

As my WAD Phono 2 has a subsonic filter, I don't suffer from speaker cone flap. Off course, it can also be caused by circuit instability. I remember a member here (who has not posted for several years) bringing his Phono/Pre 2 around and on switch on, my speaker cones started flapping. Switched off and refused to use his kit in my system. Whether or not he got it sorted, I have no idea.

Re reading this thread and that reminds me of the issues I had with my Phono3S and CF preamps that wouldn't be tamed from their LF instability. I finally nailed it by using a fully regulated HT supply which suggests to me that there was an issue somewhere in the original WD PSU board.
I've got a spare mains transformer and choke, and unpopulated PSU3 board in the box of goodies and at some point the intention is to build it all up using premium silicon and capacitors and I can then try it with the Phono3S.
I did notice the Phono3S seems to have a bit of corrosion/fluffy flux deposits round the valve bases and that also gave me thoughts that perhaps they could be part of the problem but as the effect was observed on a number of preamp circuits I concluded that the oscillation was being coupled through from the PSU.