I have a few of the inexpensive (not great but useful) digitrax SDN144 decoders. Would I be able to swap in a higher quality Zimo 4 ohm speaker for the 8ohm default one? I wish to use just one speaker in my new VO-1000. Would I be able to do it with additional electronics added… I’m not a electronics smartie, but well able to solder up whatever I am told.
Unfortunately the 8ohm Zimo is too big.
Thanks for any tips.
The ohm rating has nothing to do with the physical size … unless that just happens to be the only options offered.
Simply put, you should not use a four ohm speaker on a decoder designed for an eight ohm load. You could go higher (16 ohm), but not lower (4 ohm) - you will damage the audio output amp.
You could wire two four ohm speakers in series to maintain your eight ohm load, but if space is a consideration, that’s probably not an option. There are MANY sizes of eight ohm speakers available out there from numerous sources.
Mark.
Absolutely not. It’s already pushing it to use an 8 ohm with those decoders, you will need to turn off BEMF to prevent slowdowns when blowing the horn, although that’s not really an amplifier load problem, it’s a “the cpu can;t do all those things at the same time” kind of load.
Is this an N scale ot HO scale VO1000? If it’s HO, a Loksound Select Micro and a rather large speaker actually can fit, Bowser has done this with the factory sound versions. I bought a power chassis and swapped my existing shell from an older non-sound one. Sounds infinitely better than the old 8 bit Digitrax sound decoders.
You should be able to find small 8 ohm speakers - like the CT sugar cube speakers, to fit in an N scale version.
–Randy
No, not unless the SDN144 specifies it can use a 4 ohm speaker.
Since you don’t want to use a second speaker, you could get another 4 ohm inductor to put in series with it. Something like this. http://www.mouser.com/ProductDetail/Sumida/5406-391-34-00/?qs=sGAEpiMZZMukHu%252bjC5l7YRKILtFu0hlh0nMowAHeUNc%3D. Note that I am not recommending this unit, just using it as an example.
What I can’t tell you, without knowing a whole lot more about the speaker and doing come calculations, is how to match the resonance frequency of the inductor with the speaker to prevent it from acting like a low-bypass filter.
Since you say your not good with electronics this probably won’t help. All the on-line sites I can find that are related are for building crossovers. This one has a “first order” section which is actually the most simple Butterworth crossover. The inductor would be L1.
http://www.apicsllc.com/apics/Misc/filter2.html
As the others have said, the best thing is to find an 8 ohm speaker that meets your size needs. There are bunches and bunches of them out there.
But two 4 ohm speakers in series is equal to 8 ohms. Or 4 speakers of 4 ohm coupled in series/parallell…
Thanks, all.
Reason I asked was that I was just getting around to looking at the better quality speakers, and the Zimo I mentioned is one of those bass reflex types at about $18.00 ea. I have other 8 ohms in the drawer that would fit, but wanted to put a superior speaker in as a test since these decoders are noted for poor sound and I have a couple more to play with in the future.
So, if anyone knows of another of the top end 8ohm speakers no bigger than .63" or 16mm wide, oval or round I would be interested.
TONS of speakers that are 8 ohms and less than 16mm in the longest dimension:
http://store.sbs4dcc.com/sugarcubespeakers.aspx
No connection to this vendor, haven’t even bought anything from them, yet. Just what came up searching for a variety of speakers.
–Randy
Thanks, Randy.
It has obviously been a while since I added sound to a loco…three years, I guess…and still using up my stock of large ovals. These sugar cube speakers look intriguing. I get the idea of sound chamber extensions.
Anyone have a quick opinion as to the best of these cubes vs. some of the bass reflex or expanded range speakers offered by Zimo and others. Which wins in a comparison?