Audio Pro Avantek (B7) subwoofer

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • OniJon
    Computer Expert
    • Jun 2012
    • 82
    • Finland
    #1

    Audio Pro Avantek (B7) subwoofer

    Audio Pro Avantek, B7 plate amp huge power draw on startup. It creates interference to my friends tv, pre-amp and lights. The symptoms are presumably age related, since it is 16 year old amp, any advice?

    I've measured it here and there (with Fluke 179) but without ESR meter, cannot say anything about the caps other than that Fluke shows that they have capacitance within tolerance. They're G-Luxon's and Jun Fu's, known BS brands. Should I just yolo this and change all the smaller preamp caps and see what happens?
    Tags: None
    • OniJon
      Computer Expert
      • Jun 2012
      • 82
      • Finland
      #2
      Re: Audio Pro Avantek (B7) subwoofer

      I got new info about this that could narrow the problem down. If you use power switch manually to power the sub, there is no problems to other devices. Automatic on-off sensing on it interferes with other devices.

        Comment

        • OniJon
          Computer Expert
          • Jun 2012
          • 82
          • Finland
          #3
          Re: Audio Pro Avantek (B7) subwoofer

          Here's some images of the amp if anything comes to anybody's mind
          Attached Files

            Comment

            • momaka
              master hoarder
              • May 2008
              • 12175
              • Bulgaria
              #4
              Re: Audio Pro Avantek (B7) subwoofer

              Originally posted by OniJon
              Should I just yolo this and change all the smaller preamp caps and see what happens?
              At that age, it probably wouldn't be a bad idea, especially if any of the caps were located near warm/hot components. I am just about to post a JBL amp of a similar vintage, and most of its small caps were in quite bad shape.

              Originally posted by OniJon
              If you use power switch manually to power the sub, there is no problems to other devices. Automatic on-off sensing on it interferes with other devices.
              So it looks more and more like the issue might be related to some of the small caps going bad. Reason I see this is because the smaller caps will be responsible for the pre-amp and main amp biasing. If any of them are bad, that could cause the amp output stage to turn ON instantly rather than gradually and/or connect the speakers to the output stage before it has settled. With that said, do you also hear the speakers connected to this amp "pop" or "bump" in/out when it is turned ON?

              Aside from changing the small caps, I also see some tan glue. I can't fully tell if this is the tan glue many of us know here to go brown/black and conductive over time. But if you see any of it has changed color (especially turning darker near hotter parts), then you have that dreaded tan glue. My advice for it: remove as much of it as possible from the board, especially any that's on components' leads.

                Comment

                • OniJon
                  Computer Expert
                  • Jun 2012
                  • 82
                  • Finland
                  #5
                  Re: Audio Pro Avantek (B7) subwoofer

                  Those biggest caps (6800uF) were so dry that when you shake them, they rattle. Never seen that before.

                    Comment

                    • Khron
                      Badcaps Legend
                      • Sep 2006
                      • 1350
                      • Finland
                      #6
                      Re: Audio Pro Avantek (B7) subwoofer

                      I've encountered something like that a few times - CapXon and/or some other no-name / crap brand.

                      Originally posted by OniJon
                      Those biggest caps (6800uF) were so dry that when you shake them, they rattle. Never seen that before.
                      Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans

                        Comment

                        Previous template Next

                        Related Topics

                        Collapse
                        • samson7point1@yahoo.com
                          Help troubleshooting an audio problem with an RCA SGT-250 CED Player
                          by samson7point1@yahoo.com
                          The Problem: This player has a toggle switch to select between Stereo, Mono R, and Mono L. Regardless of the setting it outputs the sound to both the L&R audio jacks. In the Mono R position, the audio output level is normal (from both the L and R audio output jacks), in the Stereo position the audio output is about half the volume, and in Mono L, it's about 3/4 the volume. Something about putting it into Stereo mode is causing the volume to drop significantly and I can't figure it out.

                          The player processes the audio signal using two different reference frequencies. The "R"...
                          PW300S circuit diagram
                          2 Photos
                          04-30-2024, 11:22 AM
                        • Delicieuxz
                          I replaced all electrolytics in subwoofer, still get a hum in speakers - audio clip
                          by Delicieuxz
                          I get a faint, low hum through my PC speakers, which connect to the subwoofer in a 2.1 speaker system. The hum drives me crazy and makes me stressed. When I turn off the subwoofer, everything is quiet and I start to relax, lol.

                          Here's an audio clip of the sound coming from my speakers:

                          https://vocaroo.com/16HaryHwTx78

                          I recorded with my phone's mic right next to the speaker, and the mic picked up a lot of speaker noise over top of the hum. But I don't hear that noise in the room, I just hear the lower-pitched hum that's buried beneath all the other...
                          11-15-2023, 09:50 PM
                        • exceptional
                          Help monitor audio gxw-15 subwoofer
                          by exceptional
                          Have a problem with one of my gxw-15 subwoofers. When pluging in power socket it shows power is ok (red LED), but when trying to turn it on it turns iff immediately (can hear relay clicking sound). Cause i have working second subwoofer i tried replacing several boards. So for now i can say power board is causing this problem. There are no visible damaged element on it. I wrote to Monitor audio and they sent me all schematics. What i have found is defective capacitor C535(short circuit), but after changing it ...same behavior.
                          Measured output FETs, diodes. Seems everything is fine......
                          10-17-2023, 03:51 PM
                        • old_marantz
                          Help monitor audio rxw-12 subwoofer
                          by old_marantz
                          I have a monitor audio subwoofer rxw12 that is clicking. Avsforms has a thread on this and I saw someone posted schematics here for it. Since I’m a newbie and no one here in salt lake will work on it, I guess I’m elected.

                          Supposedly the issue is “ smd type and located on the soldering side of the amplifier board”. Can you experts help me identify which one it might be? And what to order? How difficult to put these in? I’ve replaced caps before but just eyeballing what these resisters might be on the board, they look pretty small.

                          I saw some...
                          08-20-2023, 05:46 PM
                        • i_am_patch
                          Roland KR-3500/4500 Digital Piano. Crackling audio sound on all keys -Fixed
                          by i_am_patch
                          Hi All. I had a Roland KR-3500 Digital Piano (similar to the KR-4500) that exhibited a Crackling audio sound on all keys. After reading somewhere about someone with a similar issue who had replaced all the Electrolytic caps I decided to also go down that route. (Spoiler : It worked !) After some basic troubleshooting I determined that it could be noise feeding thru from the Keyboard scanning since the Demo tunes played back undistorted and the Audio amp / speakers were fine ( Inserted an Audio signal into the rear Audio input). After extracting the main board from the shield, I replaced 7 Capacitors...
                          04-30-2024, 08:20 PM
                        • Loading...
                        • No more items.
                        Working...