[Makemineadouble]

I hav'nt had the tender off my Evening star, but normally there's plenty of room for a sound decoder, you just need to cut away bit and bobs and make a false floor of the coal load, as I did with my Hornby 9F's.
What you need to know is the height of the speakers as they are normally the problem to get in.
speaker postn
I would'nt go larger than 20mm in the 9F.

 

[Makemineadouble]

Soundtraxx DSX sound only decoder, generic L1 tank loco you should find it listed at Loys if your intrested.
My 9F's don't sound too shabby. Please bear in mind I installed these several years ago.

 

[Makemineadouble]

Did you simply plug-in a decoder ?, without removing the chokes and capacitors ? this might explain it.

 

[Makemineadouble]

I'm interested in what sound decoder your going to fit. I have three older 9F's the Hornby body with loco drive chassis, they all have the soundtraxx DSX sound only decoder in the tender. They do sound good and pull very well.
Perhaps you could grace us with a few pictures of your installation