Problem with SC2.2 V4

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  • #15347

      Hello Ted,

      I just bought a second hand Joemeek sc2.2 V4 (tested on 22.01.02)

      when the compressor is in baypass the sound flows perfect ,

      but when the compressor is activated, the stereo audio program becomes mono .

      any suggestions?


      Carlo Conen

      Sardinia ITALY

      Ted FletcherTed Fletcher

        This is actually a very interesting question….. It’s only very recently I discovered that in a few SC2 V2.2 V4 there was a problem with the design of the output stage.

        I can’t recall how it happened; and we knew nothing about it at the time.

        The SC2.2 was the first stereo compressor that used the ‘sum and difference’ routing….. the L and R signals are converted to Sum and Difference before compression, then at the output stage they are re-converted to L and R. The problem is that the output stage does not behave correctly and provides a very near ‘mono’ output….. BUT it only does this if the output is being used as a balanced line!

        I would ask that you try using the compressor in ‘unbalanced’ mode (that is, link pins 3 and 1 in the output XLR connectors) and there is a chance that the problem will be solved.

        Normally I can offer to correct any faults in any equipment that was designed by me originally, but in this case, it was an original problem caused by a mistake somewhere in the manufacturing process. I have only ever seen one of these faults, and that one worked perfectly in unbalanced mode.

        In case anyone needs the circuit diagram of this model, please email me at :(


          I’ll try your suggestion



            Hi Ted,

            I tried to use an unbalanced cable to the output, but compressor still returns a mono signal.

            do you think I can send to you the unit for repair ? can I write to you in private for repair cost ?


            Carlo Conen

            Ted FletcherTed Fletcher

              I’m really sorry to hear that you still have a ‘mono’ problem.

              Yes, please send me the unit and I will fix it.

              As an update for others reading this, I do ‘service’ older Alice, JoeMeek and TFPRO equipment of my design as an ongoing help to users. In most cases I charge a fixed fee of UK£50 plus the cost of return and cost of any expensive components that might be needed. 8-)


                shipping to ?

                5 Bay Court

                24 The Fairway,

                Aldwick Bay Estate,

                Bognor Regis, PO21 4HD

                It’s correct ? 😳

                Ted FletcherTed Fletcher

                  That’s correct. 8-)

                  As soon as I have the SC2.2 on the bench I will publish the result here….. just in case there are any others like it.


                    I Shipped by courier today :D

                    Ted FletcherTed Fletcher

                      I did say that I would post the results of this one on the forum…..

                      Exactly as ‘Conen’ says, the compressor had a mind of its own and produced a mono signal whatever went into it. As well as that, the compressor seemed sluggish and not working properly.

                      The first fault was a dry joint on the PC board in the ‘difference’ channel, this locked the amplifiers into a ‘mono’ mode.

                      The second fault was a failed transistor in the LED drive circuit to the optical compressor, this allowed a meter indication of compression…. but it hardly did anything.

                      So with the PC board fixed and the drive transistor replaced, it’s back to working as good as new! :D


                        :D I’m very happy

                        I can’t wait to to having it in the studio

                        thanks Ted.

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