I have a MRC Diesel AC Sounder sound board. It has a tiny pancake type speaker rated at 4ohms, 2 watt. Does anybody know if the amplifier could handle the lower impedance of two speakers in parallel?
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@Mossback Mike posted:I have a MRC Diesel AC Sounder sound board. It has a tiny pancake type speaker rated at 4ohms, 2 watt. Does anybody know if the amplifier could handle the lower impedance of two speakers in parallel?
You probably can use a larger or more efficient speaker in a baffle but no- I would not go less than a total impedance of 4 Ohms.
In other words- fine, connect 2 8 Ohm speakers in parallel, or one larger 4 ohm speaker, but there is no safe combination with the original 4 Ohm tiny where you add a second speaker
Agreed. In parallel, the amplifier is "seeing" 2 ohms. Almost a direct short. You run a significant risk of burning up the amp or at least the power transistor in there. Get two 8 ohms and parallel them or look on Amazon for a good (but more expensive than the overseas junk) 4 ohm speaker. They are heavier, so may require some support, but you will be happier with the sound and you won't blow the board.
I installed the MRC Diesel AC sounder in a MPC-era Lionel 8970 Diesel F3 locomotive. I used an upgraded speaker - an Ole Wolff Electronics OWS-3117TA-4. I used a large plastic bottle-cap as a sound baffle for the single speaker. Despite this, I am really disappointed with the results. The mechanical and electrical noise of the locomotive drowns out the diesel engine sound, and the bell and horn sounds are very faint. I bought the sound board last year - and it was half the price of an ERR Railsounds board. On the bench, the MRC Diesel AC Sounder sounds great - but it just isn't loud enough when you install in in a locomotive.
Is there a miniature amplifier that is compatible with this?
@Mossback Mike posted:Is there a miniature amplifier that is compatible with this?
I'll take a stab.
I wouldn't think so, if what you are asking is "Is there a small, off-the-shelf gizmo where I can send the speaker output as the input into another small amplifier to get a bigger speaker output?" The reason is that your existing board is providing a (relatively speaking) high current, low voltage output to drive the (albeit small) speaker (a situation that is called "low output impedance"). That would mean that the "input" to the gizmo amp would need to be expecting a low impedance input - and most audio amplifiers are expecting a low current, high voltage input (a situation called "high input impedance").
That's not to say that creating a simple circuit that would match the impedances as input into a common, cheap high input impedance audio amp board is difficult - or that you might even be able to get away with such an impedance mismatch. However, the solution is going to be context-specific and will require some level of electronics knowledge to craft.
Unless someone knows of such a "plug and play" low-to-high impedance board (which I'd like to know about, too, if it exists)?
