Alternative Speakers for HMDCC Decoders

[Pendragon Sailing]

Has anyone fitted a third party supplied speaker to a HMDCC decoder?

I’m considering upgrading the supplied sugar cube speakers with some thing a bit more ‘substantial’.

Having read the Manual, I note that 8ohms is the required impedance.

I see also that the decoders have solder-pads on the underside marked ‘spkr’, so can I assume that these can be used?

Finally, does anyone know if the tiny speaker plugs supplied with the sugarcube can be obtained separately?

many thanks

[P-Henny]

Finally, does anyone know if the tiny speaker plugs supplied with the sugarcube can be obtained separately?

The connectors are branded as JST (Japanese Solderless T???). If purchased from a catalogue component supplier then you have to order the housing and the crimped terminals as two separate items. Crimping these very tiny terminals on wires is doable but very fiddly and needs good eyesight aids and steady hands with small mini pliers. Speaking from personal experience.

EDIT: The rest of my original reply has been redacted in light of a reply posted by 96RAF further below and replaced with this updated comment.

The more common JST SH connector (I originally suggested in this reply) has a 1.0mm pitch. The JST SUH connector range shown on RAFs posted product datasheet image has a pitch of 0.8mm. These SUH connectors by JST are (I believe) relatively new connectors from JST compared to the availability of their earlier SH & PH connectors. A quick search on ebay for pre-wired versions came up blank for SUH versions.

[RB51]

Japanese Solderless Terminal

R-

[ColinB]

Road and Rails and YouChoos do very suitable speakers. If it is a 21 pin decoder, on the PCB it plugs into you will find pads labelled S+, S- or SP+, SP- which are the speaker connections. No need to solder to the decoder. If it is an 8 pin then you need to solder the speaker to the supplied lead once you have cut off the original speaker.

[Pendragon Sailing]

Thanks for the tips and advice, chaps. Much appreciated

[Bulleidboy]

I fitted a Zimo High Definition 28mm round speaker (8ohms) into a Hornby Rebuilt Merchant Navy Class - the loco was fitted with a TXS 8pin decoder. Works well, and was an easy fit into the circular space below the weight in the tender, originally intended for the TTS speaker.

[96RAF]

[Brew Man]

I replaced mine with one from Roads and Rails. As Colin said, don't bother with a new lead and plug, just cut or unsolder the existing lead and re-solder it to the new speaker. The only requirement is that you replace with an 8 Ohm one, but you know that.

[P-Henny]

@96RAF Thanks for the product datasheet image showing the speaker connector. I have edited my earlier reply in light of the new information the datasheet contains.

JST PH range connectors have a pitch of 2.0mm, the JST SH range connector has a 1.0mm pitch and these even smaller JST SUH range connectors have a pitch of 0.8mm. I have home DIY terminated PH & SH connectors and did struggle with the smaller SH ones. I think even I would give up trying to DIY terminate these even smaller 0.8mm SUH ones.

[Pendragon Sailing]

As a follow up to my original question, I have not been able to source the correct sized JST male plugs to fit the female speaker sockets on the decoders. Also, even if I had, I think I’d have struggled to connect them given their tiny size.

My solution has been to splice/solder my alternative speaker to a section of wire (with the terminal) cut off the speaker supplied with the decoder. This seems to have worked very well, but make sure a heat-shrink sheath is used on both joints to provide strength and protection.

[96RAF]

It has been suggested that given the spare enclosures one ends up with, speakers be supplied as spares or even say 5-packs. It would also make good sense to supply the speaker wiring and plug separately for those who wish to install their own preferred speaker.

FYI - google the plug sku and there are several hits from the usual suppliers, but as stated best of luck trying to solder or crimp those terminals pins on and assemble the plug.