Search results

  1. I

    Jcm 900 16 ohms output does not work!

    Hi, I checked the output with a multimeter and it seems to be OK. I measured de impedance between GND and the 8 ohms pad and between GND and the 16 ohms pad (from the jack) and it seems to be ok, the impedance is low enough to think that the OT is ok. So I measured the input impedance of the...
  2. I

    Jcm 900 16 ohms output does not work!

    Hi guys, I have a JCM900 (4100) amp and a JCM900-1960A. Since the post "Marshall Amp Forum > The Amps > Marshall Amps > Amp-cab impedances mismatch (or not?)", I changed the way I use them, and now I use the amp and the cab in 16ohms configuration. Today, as almost every day, I switched on...
  3. I

    Amp-cab Impedances Mismatch (or Not?)

    Hi, thanks for your response. So it seems to be a 16 ohms output connected to a 4 ohms load. I will plug the jack in the 16ohms input of the cab from now on. Just to know it, do you know any way to measure (with a multimeter for example) the output configuration of the amp like I measured the...
  4. I

    Amp-cab Impedances Mismatch (or Not?)

    Hi, here are the photos of my amp. I hope they will be enough to know the output configuration of my amp. Do not hesitate to ask for more photos in case you consider it. Thanks a lot!!
  5. I

    Amp-cab Impedances Mismatch (or Not?)

    Voodoo Amps, that is the reason I am concerned why. If all in the amp and the cab is no-modified, I have the amp 16ohms and the cab 4ohms. Really bad. I use the amp with the master volume of both A and B channels on the mid-range normally. Perhaps this has not been enough to damage the amp? thanks
  6. I

    Amp-cab Impedances Mismatch (or Not?)

    Ok American Viking, I am going to be able to upload the photos on saturday, plese hold on ;-) I compared yesterday this photo in the other thread and my OT wiring, and it is exactly the same, it seems to be 16 ohms. I believe that this wiring is the default wiring of this head (I saw it on some...
  7. I

    Amp-cab Impedances Mismatch (or Not?)

    Thank you for your great response, V-man. I agree you, I should change the way I use my amp and connect all properly, but I would like to ensure that the amp's OT is configured to 16 ohms (not 4 ohms). If I had bought the amp new from a shop, I would change the connection and problem solved...
  8. I

    Amp-cab Impedances Mismatch (or Not?)

    Hi guys, I bought a JCM900 (4100) amp and a JCM900-1960A cab both together and both used (secondhand) 2 years ago. The man who sold me the amp and the cab told me to use "from this jack in the amp to this jack in the cab with the switches like this". He was doing it in that way for around 10...
  9. I

    Speaker Load on a JCM900 4100 Hi-Gain

    Hi guys, it's a long time since the last reply was posted in this thread, but is the best I have found! I have a really BIG problem with my amp + cab. The amp is a JCM900 (4100) and the cabinet a JCM900 1960A. I bought both the amp and the cab used (secondhand) and I have always plugged the...

Latest posts



Top