Mackie SRM450 v1 - Audio Scrambler

[TheGhostyz]

Hi!

So, I'm new to the whole PA Speaker lot. My organization has a pair of SRM450v1 speakers. They were used for a few parades and multiple events over the years and were greatly... until recently.

After Christmas and sitting in storage, they are suddenly very staticy. I've tried different cables, new 3.5mm to guitar jack cables, nothing changes.

Audio still comes out, but very staticy. Almost like they are blown, but the volumes were /NEVER/ set to maximum, NEVER stored outside and NEVER dropped. They are dust-free and spotless.

Any idea what could have caused this? Potentiometer? Speakers blown?
The bass is absolute great still. but sounds like mumbled garbage audio wise.

 

[Wayne A. Pflughaupt]

This isn’t a forum for pro audio, but I’ll put my money on the potentiometer. What happens when you turn the level control with signal playing?

Also, the problem could be with whatever the front end component is (i.e. mixer), and not the speakers.

Regards,
Wayne A. Pflughaupt

 

[DVDdoug]

Both of them shouldn't be "blown" in the same way at the same time...

Is the static there all of the time, or only with the signal? If it's with the signal, make sure you are sending them a good signal from whatever is plugged into them.

And looking them up online, I see they have some kind of DSP processing. is there a reset button?

 

[NielsMayer]

I have a pair of these. The volume pots are indeed staticky. Try twisting them a couple of times, or find a spot that is less noisy .... or if you dare, spray whatever it is people spray on volume pots to fix this (i haven't done it). Also the power supply needs recapping. But if you turn it up to any kind of normal PA volume you can't hear it.

The V1's supposedly sound better than any of the later ones as they have a Toroidal analog power supply transformer and a fairly large amount of caps in the analog supply. As a result they are incredibly heavy compared to the later ones that have switching supplies without as much reserve. They are somewhat rare and special as a result if still functional.

If anybody wants to make an offer I'm game as long as local/no-shipping/FF. They actually sound quite good and sometimes if I wanted to hear a "horn sounding" speaker, i'd use them over more refined gear... but for my use, inside, at home, at non PA volumes, the hum (more pronounced on one channel) of the needing-to-be-recapped power supply is annoying.

What does it cost to do a power-supply recap and volume pot replacement on such speakers anyways? Anybody know a reputable but not overpriced place in the orange county CA USA area?

PS: @DVDdoug -- the V1's are pure analog. Analog crossover in the pre-amp section. No DSP whatsoever, which is what makes them so great. They don't have some crap ADC running at the front end at 48/16 and some pathetic DSP crossover algorithm written by some church-of-Monty-snakecharmer that bloviates stuff like "you can't hear imaginary numbers so I threw them all out".

 

[NielsMayer]

Looks like @beavernuggetz fixed their V1 potentiometer:

Mackie SRM450 v1 - No audio output

For curiosity's sake, I'd attempt to test the comparator and opamp you replaced on a breadboard or something. I won't be entirely surprised if they turn out to be working fine, meaning the actual problem was bad solder joints. The speaker seems to have been through some things, so finding some...

www.audiosciencereview.com

 

[TheGhostyz]

It's not "static" in the traditional sense. If you were to take bubble wrap and crinkle it but also have music playing.

You can hear lyrics perfectly fine, but there is a level of suppression and also hollowness to it, hard to explain. I will look into recapping, thank you!

 

[NielsMayer]

There's a schematic and image of the board here: https://www.audiosciencereview.com/...-srm450-v1-no-audio-output.60197/post-2204195