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173 Posts
Jerry-
You wrote:
As you can see, your former advice of "I doubt you will find a cheap decoder that will accomplish your goal of running older 4135s type sound units satisfactorily in analog and digital modes" turned out to be incorrect (thanks to the Mr. Koopmann's circuit) as I have now been successful in finding exactly what I had been looking for (a $15 decoder that works with my 4135S LGB Sound Systems) PLUS I have been successful in doing it within my stated goals of "frugality and no desire for technical reading."
My advice was incorrect? You should know me better than to think I would provide you with incorrect advice.
" border=0> Since all decoders have PWM motor outputs, none of them can satisfactorily power an older LGB analog sound unit. In order for a voltage-synchronized sound unit to work with a PWM supply signal, you need to add a filter.
Considering the design constraints communicated in your initial request, recommending you construct a filter circuit seemed to be out of the question. If I remember correctly, you originally wanted a single decoder to power the 4135S and an LGB Forney. You wanted the decoder to plug into the Forney’s DCC Interface and you did not want to modify/change any LGB electronics. The decoder had be 100% LGB compatible, including compatibility with older MTS serial devices, and it had to be programmable via LGB equipment. You also wanted the loco speed and sound unit chuff speed to be synchronized in both analog and digital modes. The solution had to be cheap and could not involve technical reading.
Needless to say, you have relaxed some of the constraints outlined in your original request. Judging from your posts on the various fora, you have performed quite a bit of technical reading â€" reading LGB Telegrams back through 1996, Digitrax decoder manuals, Sierra-Soundtraxx technical bulletins, etc. You have also polled the members of these same fora.
My original advice was quite accurate:
http://groups.yahoo.com/group/LGBFamily/message/4325
Since you did the research, performed the testing, and decided which compromises were acceptable, you have successfully engineered a solution to fit your design requirements.
Best regards,
Bob
You wrote:
As you can see, your former advice of "I doubt you will find a cheap decoder that will accomplish your goal of running older 4135s type sound units satisfactorily in analog and digital modes" turned out to be incorrect (thanks to the Mr. Koopmann's circuit) as I have now been successful in finding exactly what I had been looking for (a $15 decoder that works with my 4135S LGB Sound Systems) PLUS I have been successful in doing it within my stated goals of "frugality and no desire for technical reading."
My advice was incorrect? You should know me better than to think I would provide you with incorrect advice.
" border=0> Since all decoders have PWM motor outputs, none of them can satisfactorily power an older LGB analog sound unit. In order for a voltage-synchronized sound unit to work with a PWM supply signal, you need to add a filter. Considering the design constraints communicated in your initial request, recommending you construct a filter circuit seemed to be out of the question. If I remember correctly, you originally wanted a single decoder to power the 4135S and an LGB Forney. You wanted the decoder to plug into the Forney’s DCC Interface and you did not want to modify/change any LGB electronics. The decoder had be 100% LGB compatible, including compatibility with older MTS serial devices, and it had to be programmable via LGB equipment. You also wanted the loco speed and sound unit chuff speed to be synchronized in both analog and digital modes. The solution had to be cheap and could not involve technical reading.
Needless to say, you have relaxed some of the constraints outlined in your original request. Judging from your posts on the various fora, you have performed quite a bit of technical reading â€" reading LGB Telegrams back through 1996, Digitrax decoder manuals, Sierra-Soundtraxx technical bulletins, etc. You have also polled the members of these same fora.
My original advice was quite accurate:
http://groups.yahoo.com/group/LGBFamily/message/4325
Since you did the research, performed the testing, and decided which compromises were acceptable, you have successfully engineered a solution to fit your design requirements.
Best regards,
Bob
