# QSI Magnum sound/decoder distortion or noise?



## Michael Glavin (Jan 2, 2009)

QSI Magnum decoder/sound board P'n'P in Aristrocraft U25 and Dash 9 DCC ready.

I'm experiencing some scratchy distortion type noise when I fire the air horns; the problem is present at various volume levels, albiet less notable or non existent at lower sound settings. I tried multiple speakers and or speaker systems, a different engine and swapped out the Magnum boards too, same, same, same noise….

I spoke to Tony and he suggested I try a hard CPU reset, the manual refers to a “RESET” function and a removable jumper to accomplish this task. The only jumper I can locate is soldered in place under some capacitors; can anyone confirm this is the “jumper”?

Maybe a venture onto my digital O-Scope would reveal the problem? I considered the speaker load might be the culprit, but then again I tried multiple single and multi-speaker set-ups some from QSI and others too. 

Regards, 
Michael


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## Greg Elmassian (Jan 3, 2008)

I have a number of the units. 

I believe there is a combination of factors. 

At high volumes, it's pretty easy to overdrive a speaker, and that will cause distortion. 

Also, I believe that the QSI distorts a bit at the highest volume levels. 

Also, I have found that the enclosures often buzz or rattle and this sounds like distortion. 

1. Plug your QSI into a high quality home stereo speaker at 8 ohms... any distortion you hear is coming from the QSI 

2. Now back to your loco, any ADDITIONAL distortion is the speaker or the enclosure. Hot glue anything that can vibrate, internal supports help also. Make sure nothing flexes if possible. Make sure you have an enclosure to limit speaker cone travel. 

Hope this helps, 

Greg


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## Michael Glavin (Jan 2, 2009)

Greg, 

I'm going to try an amplified mini speaker system for giggles ASAP. To date I have tried speakers installed and loose; out of the loco with and without backside enclosures, speaker impedance ran the gamut distortion is present in any case thus far. 

I don't think I'm asking to much in regards to volume level in as such that it would overdrive the speaker(s). Utilizing the Quantum Engineer to step the sound incrementally, I realize about fourteen distinct sound steps, at step eight the distortion is noted when triggering the horn, step eight likely represents about half the sound level the system produces.

Michael


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## Greg Elmassian (Jan 3, 2008)

Well, that's good data. The steps available in DCC are from 1 to 65 I believe, or maybe 127... 

From what you have observed, it may be distortion in the QSI output... so if you keep the QSI volume down, and get "more sound" from the amplifier, you might just win. 

Please keep us informed on what you find out. 

Regards, Greg


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## aceinspp (Jan 2, 2008)

I think you will find that different loco sounds ie GE, EMD and Alco have different effects on the speaker system. I have experienced this especially with the GE sounds. Later RJD


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## rpc7271 (Jan 2, 2008)

The "Jumper" you found is NOT a jumper. It is where the polyswirch used to be. The polyswitched gave QSI so much trouble the discontinued their use.


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## Michael Glavin (Jan 2, 2009)

It does look like that pad with "jumper" was intended for something, the poly switch makes sense. 

I thought I'd try a NEW sound file; so I tried to load the USB driver for the QSI Programmer Interface on my laptop, NOT (and I even read the instructions several times too)! Crashes every time it makes it to "copying to windiows/system32/drivers..." Tried this, tried that, new downloaded files, removed, started over to no avail, contacting QSI Solutions Tech Dept soon... 

Phoenix PB9 and P5 showed up, haven't decided what to hang these in yet but will temporarily experiment with the aforementioned locos. 

Michael


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## lownote (Jan 3, 2008)

You need to have the G wire disconnected. I had that problem for a while, drove me totally nuts. They suggest installing a spst switch to gut off the G wire. But you can also just pull the ribbon cable. It's in the documentation, but very easy to overlook


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## Michael Glavin (Jan 2, 2009)

I got the QSI Programmer running, the problem with loading the USB driver after recognizing the Programmer went away after I turned off my Trend Micros Systems Security Software. 

I loaded new sound files and realize the same problem with distortion, only at a step lower than previously. Tony wants me to return my Magnum boards for evaluation... 

Michael


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