Reverb tank issue on my Matamp

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by sub rosa, Sep 8, 2008.

  1. sub rosa

    sub rosa Member

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    Okay, the reverb has ceased functioning on my amp. These are the symptoms:

    • Audio is still coming through the amp as if the reverb were simply turned off.
    • When I turn the reverb up the background hiss increases
    • When I tap the springs I get the reverb effect, that "kicked combo" effect so there's obvious a signal from the tray.
    There are no visible problems with the tray and I have checked the amp tubes also. It has been suggested that the tranducer(s) themselves could be faulty.

    Anyway, what are the general causes for this sort of problem and should I be looking out for any other amp signals that it could be a deeper problem?

    Also, am I ok to run the amp with the tray disconnected? It seems to run ok but I don't want to damage it by doing this longterm if this is a nono area.

    Thanks.
     
    Last edited: Sep 8, 2008
  2. sub rosa

    sub rosa Member

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  3. GearHeadFred

    GearHeadFred Member

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    If you get the "splash" when you kick it, it means the transducer and RETURN path (cable, recovery, etc.) are working fine. The problem is in the SEND path - either the tube that sends the signal to the pan, or the cable, or a connection in the pan itself.
     
  4. sub rosa

    sub rosa Member

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    Thanks - appreciate your assistance. I'm awaiting on a new pan anyway as I thought I would use this as an excuse to upgrade it. I will wait until it arrives.

    Is there any risk of damage to the amp by using it with the pan removed currently?
     
  5. nitehawk55

    nitehawk55 Member

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    No , just leave your reverb off .

    Did you get good help from Matamp ?
     
  6. WaltC

    WaltC Member

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    I've worked on a couple of Matamp reverbs and those used an EL-84 tube to drive the reverb and the EL-84 had its own filament power loop and the reverb circuit was separated physically as well as electrically from the rest of the amps circuits, so running w/ the tank disconnected should be no problem. Make sure you check the cable feeding the tank, its connectors (both ends) and solder connections as well as the tube that drives it. All can be the source of your problem.

    Also check inside the tank and make sure that the small, thin wires that connect the input jack on the tank to the input transducer are still connected. If one (or both) are loose that can cause the exact problem you describe. You can resolder them if you're careful, but both the wires and the transducer can be delicate so solder carefully.
     
  7. sub rosa

    sub rosa Member

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    WaltC - thanks for your comments.

    nitehawk55 - yes, in all the years I've been dealing with the factory I've always had great assistance. I got this amp when I lived in the UK (picked it up from Huddersfield) but now I'm the other side of the world I'm trying to explore all the 'basic' possible causes of the issue before hassling them.
     

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