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My new JCM 800 4010 Combo!

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  • #1

    My new JCM 800 4010 Combo!

    I made a thread earlier, and I was talking about this amp.

    I got it [img]/images/graemlins/smile.gif[/img] [img]/images/graemlins/smile.gif[/img] [img]/images/graemlins/smile.gif[/img] [img]/images/graemlins/smile.gif[/img] x 1848932398

    Its modified quite a bit, im not sure what all was done to it. I was wondering if anybody had any ideas.

    PICS!
    http://img.photobucket.com/albums/v3...CM800front.jpg
    http://img.photobucket.com/albums/v3...Pedalboard.jpg
    http://img.photobucket.com/albums/v3...x/Controls.jpg
    http://img.photobucket.com/albums/v39/nonamemx/Back.jpg

    These were added on the back. I have no clue what they do [img]/images/graemlins/laugh.gif[/img]
    http://img.photobucket.com/albums/v3...rycontrols.jpg

    Should there be a tube here? Everthing works fine, I think.
    http://img.photobucket.com/albums/v3...underbelly.jpg

    I think I paid too much, but Im too happy to be dissapointed with trifle matters like that [img]/images/graemlins/smile.gif[/img]

    Thanks!

    EDIT: The powertubes are EL34's, the open preamp tubes (are old and the writing is impossible to read) look like they are in the 12AX7 vein. The closed tube. . .dunno, cant see it.

    The speaker says that it is 15 (not 16) ohms. Im running it on 8 ohms, instead of 16 ohms, is that alright?

    Thanks!
    Tags: None
  • #2
    Re: My new JCM 800 4010 Combo!

    You want to match the speaker load to the amps output impedence. Since the speaker is fixed to the cab, and it is 16 ohm, I'd run it @ 16 ohm to match, not 8.
    8ohm out is for when you run a 16ohm extension cab along with the internal speaker.
    While you can run it @ 8ohms, the result may harm your amp in the long run and it will probably have a volume reduction and different low end response. If there is a slight mismatch, it should be at a lower ohm rating, not higher.
    The way you are running it now puts more load back on the amp.
    I'd be careful about plugging a tube into the additional tube socket until you have it checked out by a tech. The extra 12ax7 is defintely a mod and seems interacting with the two extra inputs in front, but that is just a guess. That looks like an effects loop send and return on the back, but again, a guess.
    Have a good tech go over it.

    Pricewise, if yer happy with it...then it is worth to you what you paid. I'd only have issues if there one had to invest money into it or choke on a resale.

    Just my .02

    Comment

    • #3
      Re: My new JCM 800 4010 Combo!

      Thanks for the help, but you see, the speaker is a Celestion G12-65, and says very clearly that it is 15 ohms, and NOT 16 ohms.

      And are you saying that 8 ohms is HIGHER than 16? If the speaker is 15 ohms I should run it at 16?

      Is the cable that connects it to the amp 1 ohm or something, making the total 16 ohms? why would they put a 15 ohm speaker in there? Im sorry, but Im confused.

      I took another look at the back, the 3 of the 4 preamp tube sockets look identical, I believe they are the stock sockets. The empty one on the end, looks a little different, it has different screws, and a slightly different design, I think it has been added on.

      The normal low and high inputs work alright, but the 2 added ones on the left dont do anything that I can tell. If it was an effects loop on the front, i would be able to hear my guitar in the "return" jack. I dont hear anyhthing. I think they might be disconnected.

      Thanks for anyone who can help me [img]/images/graemlins/smile.gif[/img]

      Comment

      • #4
        Re: My new JCM 800 4010 Combo!

        Run the ohmage at 16 ohms. All celestion 16 ohm speakers are actually 15 ohms...I don't know why, but you should be running 16 with that speaker.
        As for the rest of it, nobody here can tell you what is going on without the amp in front of them, all we could do is speculate. That amp has been very modded...two of the front inputs have been added...who knows what someone did to it.
        Take it to a tech famaliar with Marshalls and have him go through it.

        Comment

        • #5
          Re: My new JCM 800 4010 Combo!

          JCM 800's are definitly supersonic.
          You took too much, man. Too much. Too much.

          Comment

          • #6
            Re: My new JCM 800 4010 Combo!

            HOT DAMN!

            I switched it to 16, and its gotten more bass (and more balls)

            Thanks guys. [img]/images/graemlins/smile.gif[/img]

            I think it WAS modded, but I think they have returned it to its original state, but left all the hardware behind.

            Comment

            • #7
              Re: My new JCM 800 4010 Combo!

              I've got a 4010, yours is a vertical input 4010 (like mine) and that extra tube, as well as the two volume knobs on the back are not original. I figured you knew this from your post, but thought I'd throw it out there. Mine's got a G12 M70 16ohm in it. Pictures at 11 if your interested.
              When you take a shower in space, you have to press the water onto your body to clean yourself, and then you gotta vacuum it off. - Ace Frehley

              Comment

              • #8
                Re: My new JCM 800 4010 Combo!

                I knew the knobs and jacks on the back were added, they are covering up some lettering! [img]/images/graemlins/laugh.gif[/img]

                When you refer to the extra tube, do you mean the empty socket? Yeah, it looks different from the others, so im pretty sure it was added.

                I know the 2 inputs on the right are the real ones (and the only ones that work). Can you tell me which one is what? The top one sounds a bit tamer, so Im guessing its the "low gain" imput.

                The writing is worn off of mine.

                and the Gold knobs came with the amp, I didnt put those on. They look good, IMO, but you cant see what youve got it set on.

                Pictures would be great, 442 [img]/images/graemlins/smile.gif[/img]

                Comment

                • #9
                  Re: My new JCM 800 4010 Combo!

                  Here's a few pics of mine, near mint [img]/images/graemlins/laugh.gif[/img]
                  The chicken heads aren't quite as classy as the brass ones you have, but the inside of this thing is original(rebuilt in 1998). Mine is a later horizontal input model - yours is/was more desireable. Many of the mods on these SCREAM, if you figure out what was done, and it was done right, you got a killer amp, if it's back to original, it's still a killer amp, especially with that SD-1 overdrive you have on your board.
                  Mine takes EL-34s too.
                  My DI jack fell inside the chassis, I need to fish it outa there. - That's the hole next to the two speaker outs.
                  I think the top input is your high input and the low is the bottom input.

                  When you take a shower in space, you have to press the water onto your body to clean yourself, and then you gotta vacuum it off. - Ace Frehley

                  Comment

                  • #10
                    Re: My new JCM 800 4010 Combo!

                    Hah, it looks fine. Im not an appearance whore. I would gladly take a solid finish over a quilted maple finish anyday.

                    At least you still have numbers on yours. Do they go to 11? [img]/images/graemlins/laugh.gif[/img]

                    what does the sticker say, the one thats under the chassis, to the right of that last preamp tube, near the wall of the amp.

                    Is that where the manufacturers date was put? mine was ripped off [img]/images/graemlins/frown.gif[/img] Are there any other ways of dating it?

                    Comment

                    • #11
                      Re: My new JCM 800 4010 Combo!

                      [ QUOTE ]
                      Run the ohmage at 16 ohms. All celestion 16 ohm speakers are actually 15 ohms...

                      [/ QUOTE ]

                      ...except for the 8 ohm version [img]/images/graemlins/tongue.gif[/img] [img]/images/graemlins/cool.gif[/img]
                      but thanks for saying it in plain to the point english Chuck! [img]/images/graemlins/grin.gif[/img]
                      __________________________________________________ _______________
                      "If there is a slight mismatch, it should be at a lower ohm rating, not higher."

                      running into a 15 ohm speaker is lower than 16....
                      The 8 ohm speakers are not 8 ohms either, but you still run the amps impedence selector @ 8 ohms, which is the closest possible matchup. (I wonder why I bother sometimes) [img]/images/graemlins/sleep.gif[/img]

                      I love that brown/fawn cloth 442, that cloth strikes me with more appeal. wish I still had some of my Marshalls that had that.

                      Comment

                      • #12
                        Re: My new JCM 800 4010 Combo!

                        Hmm, I dunno how to date them.
                        Mine says 4010 USA stamped on the label, then an inspeciton date, then 'JR 11-6-86 written in ink on that sticker - the original build date was in 1986? It was recapped I think in 1998, but may have been 2002, I bought it early 2003 and I can't remember for sure what the seller told me.
                        Sounds like it goes to 11, but only labeled to 10 [img]/images/graemlins/laugh.gif[/img]
                        Knobs are labeled preamp, master, treble, mid, bass, presence.
                        Here is the label from mine.
                        The front is cut off, but there isn't much but empty label cut off.
                        When you take a shower in space, you have to press the water onto your body to clean yourself, and then you gotta vacuum it off. - Ace Frehley

                        Comment

                        • #13
                          Re: My new JCM 800 4010 Combo!

                          You can also date JCM's by serial. (and production JMP's post '69, otherwise parts and construction are indicators )

                          Warning.... that label link will take time to load even with cable!

                          11/6 is my Bday dude! That amp for sale?

                          Comment

                          • #14
                            Re: My new JCM 800 4010 Combo!

                            Charvelguy is right, my serial is on the back of the chassis, stamped in on the lower right and starts with a U, 1986.
                            And, I resized that pic [img]/images/graemlins/smile.gif[/img]

                            Here is the web page for marshall date codes

                            Not for sale right now, but never say never [img]/images/graemlins/tongue.gif[/img]
                            This is the first amp that I've ever not wanted to sell [img]/images/graemlins/frown.gif[/img]
                            Your first on the list if it goes though, that kinda coincidence can't be ovelooked!
                            When you take a shower in space, you have to press the water onto your body to clean yourself, and then you gotta vacuum it off. - Ace Frehley

                            Comment

                            • #15
                              Re: My new JCM 800 4010 Combo!

                              "This is the first amp that I've ever not wanted to sell
                              Your first on the list if it goes though, that kinda coincidence can't be ovelooked!"

                              I agree-if it ever comes to that, keep me in mind. I may actually have money that week.

                              Comment

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