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Randall MTS - got it today, already started modding

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  • Randall MTS - got it today, already started modding

    Got my Randall today... I really like it. However, I could see some situations where I would want the spongier/sloppier attack, and sometimes a tighter sound - all from the same module. What could I do?



    I got a spare faceplate with the amp - it only came with two modules, so the previous owner had a blackface plate that he used to fill the hole. So, I used it as my 'template' and added a switch between the gain and bass pot. It's the input cap - I put a .0022 and a .001, and can switch between either at will. One really nice thing about this is that if I want to switch caps again, it's a LOT easier than soldering on a board - a switch can take a lot more heat. To drill the faceplate I took the entire thing apart. Even though it says 'blackface' on the front, it's really a Brown. I didn't drill the Brown faceplate yet because if I didn't like how this worked, the faceplate would hide the extra holes in the front metal frame.

    I'll probably do my recto module like this for sure - I like how it sounds, but it's a little sloppy for rhythms. I'd like to be able to go back and forth at will. Here are a few random notes for anyone else who thinks about doing this:

    The faceplate is HARD to drill. I used a drill press and one of my older drill bits was glowing red hot. Went and bought a $30 set of super hard drill bits, and it still was hard to work. The chassis/frame was no big deal.

    Take the PCB out of the frame before drilling! You can get to the underside of the PCB easier then too, and solder it properly.

    As a matter of fact, don't put the faceplate back on and reassemble the module and test it with the switch. If you do like it, then drill the faceplate. Just be sure you're good enough with the drill to match up the holes.

    The mini toggle switch I used has about 1/16" of an inch between pots. It's really tight - I'd recommend measuring twice and cutting/drilling once. You'll want to put it about even with the gain and bass pots, because the top of the module front fits flush against the amp.

    I was able to go tighter than stock but with a little sag to tighter with very little sag on the Brown module. I might go a little higher for more sag, but I really dig the module with the .001 on there.

    I think sometime soon I'll be putting a structure switch on my XTC module. BTW, do you guys think I am totally destroying the value of these modules since I'm drilling holes? Just curious. I crossposted this to a few other forums - I have friends on some boards and not others, and probably a few that are on all of them!

    Pete

  • #2
    Pete -

    Gotta say I was pretty impressed witht he tones that guy over on the HCAF posted in the Lynch Box thread, the guy who owns all the modules....anyway, as an admitted amp slut - I thought they were pretty cool and I think the amp would be worth a shot. Your take on it is spot on - mod it to the way you like it, don't get too sucked into the "this module sounds exactly like (enter your amp of choice) "

    Post some clips if / when you get a chance.

    Thanks ~
    Steve E

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    • #3
      Thanks Steve. The real allure to me is if I get tired of a channel, I can just pack it off/trade it and get another one easily, and custom configure the amp to my needs easily and quickly. This is what the Duncan Convertible should have been back in the day, imho.

      The amp does have a small amount of 'same-ness' in each channel, which makes sense - it's all going through the same power section and first input tube, but the feel is all over the map. I could see playing a country gig with one of these and loading it up with blackface, tweed and plexi modules... doing some rock stuff with blackface, plexi and recto, or some metal with recto, XTC and one of the newer high gainers. I did notice that if you don't dime the gain on the XTC, it cleans up nicely with the volume control. I may run 3 high gain modules at once and just roll the volume down for cleans... but the blackface has a really good fender vibe too. I haven't have a chance to gig test it, or go through my main 4x12 cab yet, but so far I'm very impressed. if the fx loops work well with my gear, then I may have ended my run with the JSX. Only thing is, this bastard weighs MORE than the JSX. I think these things have plutonium in them.

      Pete

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      • #4
        Mhmm there are some opamps in there... What do they do? Clip the signal some more than the 12AX7s?
        If I understand correctly, the main head doesn't have a phase inverter and a driver right...? So are these two pretubes doing this job? In which case the real 'preamp' circuit is analog?

        Comment


        • #5
          Pete,

          So whatever you want to those modules to get the sound you need. I can't think you're going to ruin the value of the modules all that much. A lot of people seem to mod them, so if you get tired of one I can't imagine it would be too difficult to unload.

          Oh,yeah, CLIPS, CLIPS, CLIPS!!!!!

          Comment


          • #6
            Ah dude, that's the most badass mod I've seen done to one of these boards! Everyone goes either with one cap or the other, I've never seen anyone add the switch. Good stuff man, I gotta run to work, but I'll drop ya a PM later

            Comment


            • #7
              I really like the MTS. I have been seriously considering getting rid of my Legacy for one. I have been reluctant, though. I have been using the Legacy for almost 6 years now, and have become somewhat attached to it! I have also considered getting rid of my Marshall 2205, but I have a hard time getting rid of a "vintage" Marshall for a new Randall! LOL!

              Comment


              • #8
                Originally posted by pott
                Mhmm there are some opamps in there... What do they do? Clip the signal some more than the 12AX7s?
                If I understand correctly, the main head doesn't have a phase inverter and a driver right...? So are these two pretubes doing this job? In which case the real 'preamp' circuit is analog?
                I haven't seen a schematic of the entire amp or taken mine apart yet... I do know that the modules are running 'real' amp voltages, and that the tubes are being used for amplification. There are three 12ax7s inside the main chassis. here's my best guess:

                one 12ax7 is the input tube - all of the channels have this in common

                one 12ax7 is the fx loop send/return (remember, a 12ax7 has two stages)

                one 12ax7 is the phase inverter.

                The ICs on the modules could be for the switching circuitry, voltage regulation, and possibly for matching signal levels within the modules, or even something else. Not sure. I'd put the tone of this amp against any '100% tube amp' though.

                Pete

                Comment


                • #9
                  Nice work! I love my mts gear (rm100c, xtc, recto so far). keep up the good work. IMO the recto still sounds loose and boomy with the .001 orange drop cap mod. just curious what anyone elses opinion of this is. Mr. Scary is on the way!

                  Comment


                  • #10
                    Originally posted by Twisteramps
                    I haven't seen a schematic of the entire amp or taken mine apart yet... I do know that the modules are running 'real' amp voltages, and that the tubes are being used for amplification. There are three 12ax7s inside the main chassis. here's my best guess:

                    one 12ax7 is the input tube - all of the channels have this in common

                    one 12ax7 is the fx loop send/return (remember, a 12ax7 has two stages)

                    one 12ax7 is the phase inverter.

                    The ICs on the modules could be for the switching circuitry, voltage regulation, and possibly for matching signal levels within the modules, or even something else. Not sure. I'd put the tone of this amp against any '100% tube amp' though.

                    Pete
                    Ah that makes sense. I didn't know there were 12AX7s in the head. That figures then. I didn't mean to imply that it wasn't good sounding, I was just curious as to how it works basically.
                    What does the 12AX7 for the effects loop do? Just drives it harder to allow for a level control?

                    Comment


                    • #11
                      it's likely a send and recovery stage for the fx loop - it compensates for any loss from items in the loop. The amp has a parallel and also a series loop.

                      Pete

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                      • #12
                        Pete you can buy a lot of used modules on the evilbay for a $100. Buy 1 to modify and one to keep stock and you will have spent less than buying one new one. I am diggin' my MTS stuff.
                        RR24M -SLATQH- 2 SLSMG's- DKMGT- 3DXMGT's
                        CHS2 -Traditional- 2 SC90 Surfcasters
                        Tacoma DR14 DM14 JR55
                        Ibanez Artcore AM77, AF125NT,AS93

                        Comment


                        • #13
                          hey pete, quit screwing around with the randall and get back to making amps

                          i've been very curious to try one of those randalls out. did you get it new?

                          does anyone have a randall dealer they'd recommend?
                          I want REAL change. I want dead bodies littering the capitol.

                          - Newc

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                          • #14
                            Any guy who starts his mods before the garbage man has hauled away the styrofoam packaging can be my wingman anytime

                            Keep up the good work!

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                            • #15
                              LOL, thanks guys. Tim, I bought it used - rarely if ever do I buy stuff new because I'm so damn picky... and I hate losing my shirt when I resell or trade.

                              So far I'm REALLY enjoying the MTS. I need to mod the blackface module I have, the early ones have the wrong value resistor that gives it too much gain. It's really close even stock though... I've owned several BF fenders, and it's nice. The recto module is close to the mesa also. It's been forever since I played a 'real' bogner, so the XTC may be off - it still sounds great. The Brown is a VH tone, and I'm still messing with it. Not as instantly gratifying as the Pods are, but I think it could be close with the right tubes. The clean module is already traded, just need to mod it (it has the wrong resistor too) and it's gone for a super lead plus.

                              Two things that really kick ass on this amp - it uses midi for switching, so it will integrate perfectly with rack gear, and EACH power tube is individually biased. If your tubes aren't perfectly matched, no big deal, just dial em in seperately. Or run 6L6s on one pair, EL34s on the other. Or KT88s and EL34s. Or KT66s and EL34s. It also will take JJ 6V6 tubes.

                              Pete

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