Sound quality issue in BLI M1 tender

[Lemosteam]

First let me set the stage. Some time ago @draskouasshat traded me some first gen BLI M1 parts for cad work. It included the entire tender. I put the tender on the programming track to verify it worked, an ID did. I do not recall any distortion.

Only the loco idle sounds played then, over and over.

Fast forward and I decided to replace the stock speaker, a la @jdcolombo 's T1 work.

Made an enclosure, wired the speaker, factory reset on the programming track, aaand, sounds great, until one of the standard idle sounds kicks in, after some clanking noise about three seconds in, sounds like a muddled grunting pig. It would always kick in right away after pressing the horn on my digitrax controller.m

I used this speaker: https://www.digikey.com/product-detail/en/SP-1813S/433-1136-ND/6099110/?itemSeq=278604829

I tried lowering the volume on the whistle no help. Not sure what to do now. Could it be that I soldered the wrong wires to the wrong contacts?

Help?  I can make a video later.

[jdcolombo]

Hi John.

The M-1 has a Paragon 3 decoder, right?  I'm pretty sure it does.  So my first reaction (can't use an 8-ohm speaker with a Paragon 2) isn't applicable.

I really don't have any clue what is going on.  From a general troubleshooting perspective, what I do when these things happen to me is first check to make sure the speaker isn't defective.  It happens occasionally.  To do that, I have a "test speaker" (just a known-good speaker in an enclosure with very long leads that I can connect to an installed decoder without having to remove stuff from the chassis).  I connect the test speaker to the decoder and see if the odd behavior continues.  If it does, then I know it is the decoder at fault.  If it doesn't, then I know the speaker is bad and replace it.

If the decoder is causing the problem, the first thing I try is a factory reset.  If that doesn't cure the problem, then I usually conclude that the audio amplifier chip is bad, and send the decoder back for replacement/repair (actually, they never repair them; they just send a new one, or at least ESU and Soundtraxx do).

It's possible that you have a defective speaker or defective decoder. 

John C.

[Lemosteam]

Thanks John, I was worried about the 4/8 ohm issue, but sounds like not.

The speaker is not glued in place so I still disconnect and can test an 8x11, even the old speaker and another 13x18 to see if the speaker is bad.

if I crossed the leads on the speaker terminals can that cause an issue?

Thanks I was simply surprised.

[cbroughton67]

John @Lemosteam ,

If the tender is from the first run of the M1, that's a Paragon 2 decoder and the factory speaker's impedance is much higher - 50-ohms I think. I'm pretty sure @jdcolombo mentioned this difference between the Paragon 2 and Paragon 3 somewhere in his thread. So, you're either going to need a 50-ohm speaker, string a half-dozen 8-ohm speakers together in series, or swap the decoder for a Paragon 3.

Chris

[jdcolombo]

Ah - I didn't know that the original M-1 was a Paragon 2.

This could easily be the problem.  The Paragon 2 will not work with an 8-ohm speaker.  It requires a 50-ohm (or higher) and the distortion you are hearing would be consistent with trying to power an 8-ohm load with an audio amp that was designed for a 50-ohm load.

Is there a way to look at the original speaker?  Usually the impedance is printed somewhere on the back side of the speaker.  If you see a "50" somewhere on the original, then that's the problem. The 8-ohm replacement speaker is drawing too much current from the audio amp (and in fact, you can blow up the audio amp chip if you continue to try to power an 8-ohm speaker in this situation).

John C.

[Lemosteam]

 

Done! Suckers coming out and I will try it in my T1.

[Lemosteam]

Would this one work?

If not I'll just put the original back in.

@cbroughton67 , would the paragon3 be a drop in?  Where can i find it?  Only through BLI?

https://www.mouser.com/ProductDetail/Visaton/K-16-50-ohm?qs=%2fha2pyFadujxH46hzuekOS1BOH%252bJ8RstDXj%2fSFLt52Fkb83WHQqG%252bA%3d%3d

[jdcolombo]

@Lemosteam

Yes, that one would work, but I doubt it would be much better than the stock speaker given the specs.  I don't know how the stock speaker was installed in the M-1 tender.  It might be the case that you could take the stock speaker, build a nice air-tight enclosure around it, and find that you have pretty good sound from it.

I STILL don't know why the T-1's stock speaker sounded so terrible.  I saved the two stock speakers I replaced, and one of these days I'm going to play around with different enclosures to see if the terrible-ness was the speaker or the enclosure.

John

[Lemosteam]

Thanks @jdcolombo,

I'll take some pics tonight.  It was similar to the T1, but not airtight for sure.

If I didnt ruin that speaker, than I have another for a different project.

[cbroughton67]

@cbroughton67 , would the paragon3 be a drop in?  Where can i find it?  Only through BLI?

It should be a drop-in, but for what BLI wants for a Paragon 3 decoder, you'd be better off getting an ESU Loksound or Tsunami2.

[Mike C]

It should be a drop-in, but for what BLI wants for a Paragon 3 decoder, you'd be better off getting an ESU Loksound or Tsunami2.

Second this !  The M1 sounds much better with a Tsunami 2 decoder !

[Lemosteam]

You guys will hate this , but since this tender is being swapped into a Bachmann K4 for a long distance tender, I'll just pull the electronics from the original K4 tender and leave the huge speaker in there.  This will let the original K4 wiring package and connectors from the loco chassis package work instead of trying to cobble the K4 wiring to the Paragon 2.  Now maybe all I need is a drawbar.

It's simply the most cost effective way to do this.

 

[jdcolombo]

You guys will hate this , but since this tender is being swapped into a Bachmann K4 for a long distance tender, I'll just pull the electronics from the original K4 tender and leave the huge speaker in there.  This will let the original K4 wiring package and connectors from the loco chassis package work instead of trying to cobble the K4 wiring to the Paragon 2.  Now maybe all I need is a drawbar.

It's simply the most cost effective way to do this.

 

Actually, my reaction is that as long as you're happy with the sound and operation, go for it.  There's no need to make a job more complicated than it needs to be.  I get into complex replacement projects only because I'm not satisfied with what came from the factory. 

If you're happy, all is good.

John C.

[Point353]

You guys will hate this , but since this tender is being swapped into a Bachmann K4 for a long distance tender, ...

Looking forward to seeing it.

[Lemosteam]

@Point353