2100

  1. SixStringSting628

    JCM800/900 NFB Resistor composition and wattage question

    I’m gonna be swapping out the 27k NFB resistor in my 2100 MKIII for a 100k resistor. I’m just trying to find out which resistor composition and wattage Marshall uses for the NFB’s. Thanks.
  2. SixStringSting628

    JCM900 2100 MKIII NFB Resistor Number

    Hey, just wondering if anyone could tell me which resistor on the schematic is the 27k Negative Feedback resistor. I want to swap it out for a 100k resistor to make it like 2203 spec. Can I just swap it out? Edit: Nevermind, I did a ton of research and got all the answers I need haha
  3. SixStringSting628

    JCM900 MKIII NFB

    Has anyone reduced the NFB on their JCM900’s and newer amps? I’ve read that the JCM900 2100 MKIII and SL-X are quieter (maxed out volume, not the taper) and more tamed sounding than the JMPs and 800’s (quieter than the 50 watters even) due to a higher Negative Feedback ratio. The article I read...
  4. SixStringSting628

    JCM 900 Tremolo Sound on Half Power Mode and Pentode/Triode Switch Backwards?

    Hello everyone. I have a beautiful 1990 JCM 900 2100 MKIII that has a mystery. When I switch the amp to half power, it gets 3dB LOUDER and sounds fuller and punchier, which leads me to believe that the half power switch is wired backwards. Part of the circuit board by the High/Low power switch...
  5. SixStringSting628

    High/Low Power Switch Problem JCM900 MKIII

    Hello everyone. I have a problem with my High/Low power switch on my 1990 JCM900 MKIII 2100. I decided to try out the Low power (50w) mode the other day and noticed that it seemed louder than the 100watt mode. I decided to measure the volume with a decibel meter. The meter I used was able to...
  6. E

    Sold: Jcm900 Slx 2100

    Selling my 100 watt jcm 900 SL-X. This is the 5881 model and is unmodded. Its a great sounding amp but I want something lower gain and a little squisher. $750 shipped.

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