Wiring sugar cube speakers in series

[Davidarps]

I don’t use this forum a lot so forgive me if this has been discussed before. I’m going to wire a couple ESU sugar cube speakers in series for a SD 70 MAC. I tried it once before and it sounded terrible so it must have been wired wrong. I’ve read that you should make sure it’s wired positive to positive and negative to negative. I‘m just not sure which wire from the decoder is which and which teeny tiny tab on the speaker is positive or negative. Or does it even matter. Any help is always appreciated 

[rrinker]

Series is wiring plus of one speaker to the decoder, the minus of that speaker to the plus of the second speaker, and the free minus to the other speaker termina of the decoder. This doubles the impedence - so a pair of 8 ohm speakers in series is 16 ohms. Easier on the amplifier, but not as loud as a single 8 ohm speaker. 

Plus to plus and minus to minus is parallel, which halves the impedence, so 2x 8 ohm speaker in parallel have 4 ohms impredence. If the decoder isn;t designed for that low an impedence, you can easily blow out the amplifier part. You didn't mention what decoder you are using. The specifications for the decoder will tell you what impedence rating speakers you need.

If you have room for 4x sugarcubes, you can get 8 ohms by wiring 2 in series, and then another 2 in series, and put both sets in parallel. Each series set is 16 ohms, and 16 ohms in parallel with 16 ohms results in an 8 ohm load.

                          --Randy

 

[RR_Mel]

A picture can be worth more than words.

 

 

 

 

Mel

 

 

My Model Railroad   

http://melvineperry.blogspot.com/

 

Bakersfield, California

 

I'm beginning to realize that aging is not for wimps.

 

[gmpullman]

I really like the ESU sugar cube with the adaptable housing. I can generally fit two of them in a typical HO geep-type locomotive and I'm really impressed with the sound.

When I solder those tiny spring-tabs I use a piece of double stick tape to hold the speaker in place (plus a weight on the cardboard!) those tiny magnets like to jump right up to the iron soldering tip 

SD_9-decoder-sp1 by Edmund, on Flickr

In the photo above I wired a violet and green wire to the same physical place on the speaker. Don't know which is + or - just so they are wired similarly. As Randy explains, the violet and green wires between the left and right speraker will get joined. The remaining two outer leads will go to the decoder.

I audition every speaker setup before I install it in the loco. I have had some bad speakers before and I don't want to have to swap them out once installed. My test setup is a small amp using an MP3 player with some "full-range" music to be sure the speaker can handle the range.

SPKR_test2 by Edmund, on Flickr

Even in series, I have wired different speakers with good results. In this Life-Like FB-2 I used a 16 x 25 mm rectangle and an ESU sugar cube. Using the amp I can vary the volume, bass and treble to be sure the two speakers play nice together. Some do, others dont. Sometimes I make a cardstock baffle or even a temporary enclosure. Amazing what a difference even a simple baffle makes!

After the speakers are installed in the model I test them again:

SPKR_test by Edmund, on Flickr

I'm to the point where I'm going back to some sound installs I did maybe ten years ago and upgrading the speakers and sometimes the whole decoder. Once you hear some good speakers (and enclosures) suddenly the earlier ones don't sound so good.

Good Luck, Ed

 

[hon30critter]

Hi David,

Lots of sugar cube advice here:

http://sbs4dcc.com/tutorialstipstricks/wiringmultispeakers.html

http://sbs4dcc.com/tutorialstipstricks/sugarcubespeakernotes.html

Dave

[rrinker]

 Careful with the volume using that amp, Ed. Even if it's fake rated to double what it really is, that would still be 10 watts which can easily blow the little speakers which are only good for 1 or maybe 2 watts peak.

                                     --Randy

 

[gmpullman]

rrinker

Careful with the volume using that amp, Ed.

I agree, Randy. I learned a long time ago weather it is variable voltage test supplies or audio equipment, start at 0 and gradually increase.

Those sugar cubes and many of the "high bass" speakers I keep on hand will produce a pretty good volume without clipping. The MP3 player by itself doesn't have enough output and I had that little amp on hand anyway.

Still, I'm glad I do the pre-install testing as I do find the occasional dud. Even in factory installed sound I have come across several speaker failures.

Thanks for the heads-up, Ed