For those of you upgrading HO Atlas AEM/ALP-44 and Bachmann Acele HHP-8 locomotive HO Atlas AEM/ALP-44 and Bachmann Acela HHP-8 locomotives you can replace the original board with a Digitrax DH165A0 with a Soundbug (SFX004) for all the Atlas and Bachmann locomotives I mentioned above. You should replace the original speakers that came with the soundbug with a Digitrax SP13138 Round 13mm 8 ohm Speakers for the smaller Atlas locomotives so the shells can be put back in. Now for the Bachmann HO Acela trainset locomotives, you can replace the original board with a Digitrax SDH164D decoder.
Everybody has been helping me with my inquiries regarding this hobby and I greatly appreciate your informative feedbacks. It is to my understanding that I should greatly return the favor by my sharing my personal knowledge among you hobbyists.