New SI T-Amp, Different internals

[schmalex]

I got my amp about two weeks ago. I'm quite pleased with the sound. I just took it apart this morning and discovered a few differences. For one, the PCB on the pot has different printing on the top. The circuit seems to be the same configuration. The biggest mystery are these two metal donut shaped pieces. The speaker wire connections out of the main PCB are wrapped around them twice, then soldered to the terminals. They are glued on to the chassis, on the outer wall of the battery case. From what I can tell, looking at other pictures of dissassembld t-amps (TNT audio and the T-amp gallery) these must be new. Anyone know anything?

 

[Fenris]

They're ferrite beads to reduce RF emission. Many class-D datasheets recommend them.

 

[schmalex]

Why were these not included in the earlier versions? When did they show up? And finally, should I incorporate them into my rebox? I haven't read about problems with RF interference.

Thanks for the answer.

 

[Pano]

Those are some hefty ferrites. Bigger than the output inductors!

There are most likely there to reduce RFI.

 

[EdT]

Proberly a CE requirement if they want to be shipped to the UK.

 

[schmalex]

So, when I rebox it, should I incorporate the ferrite rings? Has anyone had trouble with RF?