Can it be done some how? If i add a 100 ohm resistor in series with the 8 ohm speaker will it work?
Using the 8 ohm speaker with the 100 ohm resistor is not advised since the most of the power will be dissipated in the resister and not the speaker. If you attempt to use the 8 ohm directly on the Loksound, you will damage the Loksound unit.
you could purchase a 100 ohm speaker or use twelve 8 ohm speakers in series. That should sound good if you have space.
The idea of connecting a 100 ohm resistor in series may sound good on paper, but it will give you very little output because it will limit the current, which in turn will create very little voltage potential across the speaker. 100 ohm speakers take full advantage of the decoders output and produce the correct amount of linear motor action, moving enough air to produce sound.
Is there a speaker size you need that is not available?
Yes, i have a Y6b 2-8-8-0 which have 32mm hole for speakers.I already have 8 ohm but at 100 ohm i found only 28mm.
I WOULD WRITE LOKsound with your problem. There may be a European speaker available that is not sold here.
100 ohm speakers are not the norm, and they know that, but works with their amplifier. A miniature audio transformer with 12/1 windings also would work.
UNTIL THEN, Better to mount their spealer on a piece of plastic over the hole as an adapter.
Maybe you could use some styrene to make a smaller speaker hole. An 8 ohm speaker would be almost a short to the Loksound, and probably blow it, and as the other posters said, the resistor would severly limit the sound from the speaker. Better to use the 28mm speaker, and find a way to mount and seal it. 4 mm isn’t that much. Should be fairly easy to seal that up.