I received my optional speaker back for the Belka-DX yesterday and have replaced the original back cover with it.
I'm not sure what change to the receiver's PC board necessitated the change.
Both rear covers for the Belka-DX contain a LiPo battery. The back without the speaker contains a 2200 mAH battery; the back with the speaker only has room for a 1250 mAH battery.
The difference in listening time goes from about 20 hours to 12 hours - not an issue at all in my case, and the lack of a requirement for headphones is a major plus.
|New battery and speaker|
Although you may not be able to tell from the photos, both batteries contain a LiPo protection circuit.
I like being able to listen to the radio without headphones but, to tell the truth, I wish I'd known about Boris LZ2JR's upcoming rear panel that contains fold-out legs for the Belka. As it is now, to get any audio from the speaker, I have to have the radio sitting upright on its narrowest dimension, rather than facing me at a more operator-friendly 45-degree angle with legs.