QSI to Soundtraxx swap

[CbarM]

Hey guys, I am swapping out a QSI decoder from an Atlas gold loco and putting in a Tsunami decoder. I have the old decoder out and I am curious which wire is the positive on the motor leads. There is a brown and orange wire. The brown one makes contact on top and the orange goes down the side and I assume it connects to a brass strip. I just want to make sure I do this right. Thanks for any input!

Also, does the leads for the trucks always go on the same side of the decoder (ex. the left side lead goes on the left side of the decoder)??

[CbarM]

Hmm...40 views n nobody knows? I figured somebody would have a lil insight to this...

[Selector]

Call Tony's Train Exchange and ask one of their techs. They are very knowledgeable. They'll tell you what is what.

[diburning]

That's ironic. Tony's is owned by QSI.

Orange is positive. Gray is negative. QSI also uses 8-ohm speakers so you don't even need to replace the speaker.

[CbarM]

OK well thanks alot, I appreciate the info!!

[Mark R.]

The QSI speakers are 8 ohm and the two are wired inseries for a 16 ohm load. I replaced the two speakers with a pair of identical ones from Tony's that were 4 ohm. Wired in series for an 8 ohm load and got much better response.


Mark.

[CbarM]

Ohhh...OK good to know. Can I just wire them independantly direct to the board or will that give me the same effect as having them wired in series?

[Mark R.]

Wiring both both independantly directly to the board (the 8 ohm factory speakers) would be the same as wiring them in parallel which would create a 4 ohm load on the decoder, and not advisable as it puts undue stress on the audio amp output.

Tsunami decoders will work with either an 8 ohm load (optimum) or 16 ohm load.

When dealing with multiple speakers, you ADD the ohm rating of the two speakers when in series - two 8 ohm speakers in series = 16 ohm load. When wiring two speakers in parallel, the load is halved - two 8 ohm speakers in parallel = 4 ohm load.

Hense my reasoning to go with two 4 ohm speakers in series to obtain an optimum load of 8 ohms.


Mark.

[CbarM]

Ohhh gotchya...so for now its best to leave em how they are wired up in series. Is there much of a noticeable difference to replace em with 4 ohm speakers from Tony's?

[Mark R.]

I'd suggest wiring them up to the Tsunami and seeing (hearing) what you think. If you like what you hear, leave them be. If you feel you really need a little more "punch", try the 4 ohm version.

Sound is a very individual thing. Some folks like them proto-typically set for the scale in that they are set to sound good when you are beside them, while others want people on the other side of an auditorium to hear their engine ! If you are one of the former, the two factory speakers wired in series will probably be more than adequate.


Mark.