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Hi could use some help with a Mackie SWA1801 Thanks.

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  • Hi could use some help with a Mackie SWA1801 Thanks.

    I Had replied to nevetslab post but upon posting noticed his last post was in January so wasn't sure how often he is online so I created a new post instead. Sorry nevetslab if you do reply wasn't trying to be rude to ask you then repost.

    Well anyways I figured I start by introducing myself. I'm Sergio and basically consider myself an amateur but I do have a slight background in electronics by completing an electronics course and I actually repair power tools and am around electronics and components all the time. MY ISSUE/HEADACHE LOL is this damn Mackie swa1801. I play in a band as well and have two of these mackies and an extra amp board as a spare. Well the spare is dead and the second Mackie is down. I tore into this amp and replaced R2 22ohm 20W which I thought was the main issue considering that the amp didn't power on. Well there was more a lot more. Bulging HV Caps the usual Q3,Q18,Q6,Q14,Zener Diodes, Resistors and more. Basically I replaced almost all the transistors, diodes, Caps, even U2 NE5532AN. I powered up the amp using a lamp limiter and great its up and running no blown fuses nothing smoking. Great I think. Well I have major Distortion past 1/4 way of gain. Because of the distortion is one of the reasons I tried to replace U2. Made sure the input board was ok by running another cable from the parallel input to another amp and speaker and signal was good. Also measured the resistance of the Speaker itself and was good even pushed in on the speaker cone and check measurements to make sure nothing was glitching. This amp is driving me crazy and I'm at the point where I spent so much time troubleshooting that my brain is acting up and I must be overlooking something simple. Few main components that I have not changed out are both l3 5uh, C1, C33, and HCPL-3100's. I replied here hoping that nevetslab or someone else that is more acquainted with these amps may be of assistance and possibly point me in a direction. Thank you in advance. Sergio.

  • #2
    A local shop used to be the dealer for Mackie, after awhile they dropped carrying Mackie powered speakers (still sell the mixers though) because of the number of failures they used to have with the Mackie SWA1801 & SW1501 sub amp modules.


    • #3
      Yeah these things are a pain in the butt. They sound decent when working correctly. Now I'm stuck with repairing these. Oh well just some troubleshooting and I should figure it out. I'm close but the bias circuit is throwing me for a loop. Just have to keep my calm and actually think. lol Thanks for the reply.