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Ampeg 1540HE 'Speakon' Mod

Discussion in 'Amps and Cabs [BG]' started by Stonie, Jan 1, 2012.

  1. Stonie


    Oct 19, 2011
    Hi all,

    Picked up a 20 year old'ish Ampeg 1540HE cab (4x10"+1x15") just recently in very good condition and although many will "slate" it in favour of the 8x10", I'm very happy with it as I like the more bottom end from it as compared to the 8x10" and which suites my style.

    The only annoying thing about it are the useless/unreliable jack connectors on the back (2 for 'Full-' and one each for Hi/Low 'Bi-'), so... I'm in the middle of looking to mod the cab with Speakon connectors.

    The cab itself can be run in either 'Full-' or 'Bi-' mode, but in order to do this the original jack connectors which are soldered directly to the internal high-pass filter pcb have built-in switches, of which, THREE 'make or break' connections have to be made simultaneously depending on which mode the cab is used.

    With a copy of the high-pass filter schematic and pcb layout for this cab in my hand, I've "racked my brains out" over the past several days as to how to achieve this, by possibly using the spare 2+/2- terminals with a corresponding loop in the 'male' Speakon plug to act as the switch(es) (the 1+/1- terminals used as per normal).

    Of course, it would be easy enough to just replace the two 'Full-' jack's with Speakons, but I would like to replace all four, for future 'Bi-' use.

    I've so far come to the conclusion that what I'm trying to achieve is not possible, so... are there any "Techie's" out there who maybe able to assist ?

    I can supply the schematic/circuit diagram to anyone if needed...

  2. Add a switch to the jack dish for changing from full range to bi-amp mode. It will do just what the switch inside the existing jack does.
  3. Speakon connectors lack the optional extra switch contacts so upgrading the cabinets input jacks to Speakons and maintaining the bi-amp capability will require adding a switch to provide the function provided in the oem 1/4" jack. I would do this and just remember you need to check that switch during set-up (a manual toggle switch will not automatically configure to your hook-up like the original).
  4. Stonie


    Oct 19, 2011
    Thanks for the suggestion about the switch.

    I'd also considered this option, but I would like to configure the cab with automatic switching somehow IF possible... if not, I'll go with the switch.

    Anyone else...

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