2204 and metro zero loss loop

Discussion in 'Marshall Amps' started by Adamguitar, Jan 27, 2020.

  1. Adamguitar

    Adamguitar New Member

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    Hi, long time lurker, 1st time poster. Anybody installed the metro zero loss loop and then regretted it? Alter the sound? I have a pristine 80’ 2204 that I’ve had for about 15 years and was thinking of adding this loop for time based effects and a volume/lead boost. This was the only reason the amp didn’t get much use over the years being in cover bands and needing those effects. Been using a 900 mkIII for the loop and dual master, but really prefer the 2204 sound. Just not sure about hacking it up. Plan on keeping, but you never know when bad luck strikes and you have to sell. Btw, great board with lots of good info. TIA

    -AG
     
  2. Gunner64

    Gunner64 Well-Known Member Premium Member

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    No. Don't hack it up. Build a clone, or buy one already built and hack that..:)

    I built a clone just for that very reason. I hate to see a great amp like that with extra holes drilled in it..and stuff.:cool:
     
  3. coolidge56

    coolidge56 Well-Known Member

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    Purchase an aftermarket rear face plate and hack that up instead. This would avoid drilling 2 holes in the factory original face plate which would hide the 2 holes in the chassis if ever you wanted to return it to stock.
     
  4. Mitchell Pearrow

    Mitchell Pearrow Well-Known Member VIP Member

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    :welcome: To the forum, I would not hack it, nor mod it, it will get pissed and do something foul.
    Cheers Mitch
     
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  5. pedecamp

    pedecamp Well-Known Member

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    Spend a little more for a Bad Cat Unleash then you'll have an outboard effects loop, no amp hacking necessary. :yesway:
     
  6. Adamguitar

    Adamguitar New Member

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    Thanks. That’s my worst fear, monkeying with the thing and then noticing that it sounds different. I may just go old school effects thru the front. I might have to try to use my JHS modded ge7 backwards, off for boost and on for rhythm with slightly scooped EQ.

    -AG
     
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  7. South Park

    South Park Well-Known Member

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    Unless you are a amp tech. You will need help . The signal chain is not something you want to alter. If you build a clone you can mod it when you got what is going on
     
  8. Matthews Guitars

    Matthews Guitars Well-Known Member

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    I installed one in my 2203. I went for a no holes drilled installation. I used speaker jacks 3 and 4 to mount the loop, and for the switch I used one of these from Stewart-MacDonald, in place of the master volume pot. (Resistive element swapped out for a 1 M from a new CTS pot, because those switched pots don't come in 1M but they're CTS.) This makes for a 100 percent reversible installation IF you have two spare speaker jack positions spaced on 1.5" centers.

    The loop works very well. No tonal alteration that I've heard.
    [​IMG]
     
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  9. shooto

    shooto Well-Known Member

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    You can house it off the chassis so you don’t have to drill it...that what I did with the loop in my 2204
     
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  10. shooto

    shooto Well-Known Member

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  11. pedecamp

    pedecamp Well-Known Member

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  12. spacerocker

    spacerocker Well-Known Member

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    This is why I bought a JVM410 in 2009. I have a 1980 2203 Which I loved the rhythm tone of - but found it too limited for the reasons you suggest.

    A stock JVM410H on Crunch orange or red sounds similar to a 2203/4, but a few simple mods can make it almost indistinguishable. If you can afford it - go down this route? You would then have a 2203 type crunch channel, a proper clean channel and a lead channel (OD1 or 2) plus 2 masters and a loop! I still have my 2203. I don't use it anymore - just keeping for posterity!
     
  13. Filipe Soares

    Filipe Soares Well-Known Member

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    I have a 2203KK with the metro fx out of the chassis. try that. the installation is pretty simple if you're into soldering and in my case there was no difference in the tone. it took me some days to figure it out because there's no much information about the kk with the fx loop around, but I think with the 2204 will be pretty straight forward.
     
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  14. neikeel

    neikeel Well-Known Member

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    The loop is completely transparent. I no longer install with a switch. if you have a 70s 2203 or 1959 with x4 jacks you are sorted, as Matthews Guitars pointed out, I like Structo’s solution too.
    The loop interrupts the preamp out to pi ( treble wiper wire) so it is possible for it to be totally reversible. The loop does need a power supply you can take from the choke/screen feed turret by varying the series dropping resistor size (comes in the kit).
     
  15. RCM 800

    RCM 800 Well-Known Member

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    Just pipe them in the front.
     
  16. ampmadscientist

    ampmadscientist Well-Known Member

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    It definitely changes the tone, it's not "transparent," It's FET transistors. (most loops are solid state no matter which)
    I found it didn't sound too bad when I tweaked the levels to match the amplifier.
    It really doesn't match all effects pedals, especially high level professional effects units.
    I didn't use the "bypass." I just left it in the circuit as part of the amp.
    I also made a balance control for series/ parallel/bypass which I though really helped a lot and I liked the final result.
    (we used pro effects not DOD, etc...) Most cheap effects from China I consider a joke anyway and would never waste the money.
     
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  17. Adamguitar

    Adamguitar New Member

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    I’m not an electrical guy by any means. I’ve done pickups, pots and switches in guitars but nothing like this. A lot of cool ideas, but sounds complicated for a hobbyist like myself.
     
  18. Jethro Rocker

    Jethro Rocker Well-Known Member Premium Member

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    I second at least tryjng a Bad Cat Unleash. Extra channel for boosts plus a loop. I notice a slight drop in low end when using mine. Put an EQ in loop.
     
  19. herbvis

    herbvis Active Member

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    I have one in my metro 2203. Excellent loop. no issues. Wouldnt drive without it.
     
  20. Filipe Soares

    Filipe Soares Well-Known Member

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    if you can solder and follow instructions you have 90% what it takes to do it.
     
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