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Build a 1987/2204 or get a 1987x??

Discussion in 'Building the Classics' started by Marcus Johns, Sep 4, 2021.

  1. Marcus Johns

    Marcus Johns New Member

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    I’ve got a question regarding the 50w 1987/2204 for anyone that has experience with building a replica, whether I should build one or just buy a 1987x?

    I’ve built two other amps - the first one was a Mojotone 18w TMB (I added a power amp scaling volume control and a switchable ss/rectifier), it’s a nice sounding amp! It goes into a Marshall 1960TV with greenbacks (split to two for the 18w).

    My second build was a 5e3 (w/switchable 3-way feedback, a master vol, nos tubes, sozo blue coupling caps, F&T filter caps, Weber 12a125a speaker). Both builds with zero issues - I have 20yrs in an electrical engineering technician job and have a full understanding of electronics, appropriate lead dress, initial testing steps, etc.

    I’ve read through the Valvestorm procedure and I’m 100% confident in building tbe 50w. I’m looking at the VS chassis and components, sozo next gen caps and metro amp heyboer transformers.

    Not that I really need another amp as the 18w is plenty loud for me, but I’ve always wanted a plexi! I’m looking to build the neil special 2 in 1 - 1987 bright channel/2204 (via a push-pull 2204 gain knob) which should give me the best of both worlds. I’d just like to find out whether this would sound like a genuine vintage Marshall or if I would be better off just getting the 1987x. Price-wise the build is a bit cheaper than a 1987x (not a lot cheaper being in Australia, shipping from the US and our exchange rate is a killer) however it is still a bit of an investment and if I ever decide to sell a home built amp it would be significantly reduced value in comparison to a genuine Marshall.

    Let me know your thoughts, cheers.
     
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  2. neikeel

    neikeel Well-Known Member

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    I think this is a great amp, very versatile and with the specs you list will give you vintage plexi tones and when switched 2204 tones for a slightly more aggressive gain at lower volumes.
    If you are a pedal user you also get uncascaded 2204 option

    The beauty of this simple mod on this platform is you can tweak to your taste with different component values and types.
    The 50w I keep is stock 68 lead spec in plexi mode and the pull switch engages the cascade and the fatter 0.022uF coupler together with the treble peaker.
    I have not put a PPIMV on mine as I don't think I need it.
    Of course without more switches (personally I do not like a porcupine of dozens of mini toggles -YMMV) you will keep the 0.68uF over V2a and 47k/8ohm NFB of the '68. You could go for 71 spec 1987 without the cap and use 100k/4ohm NFB that would give you exact '71 1987 to '78 JMP50 tones.
    I am biased as I really like the 68 Lead specs. To give wider tonal options the only thing I did is reduce the size of the plexi bright cap down to 100pF and I used 8k2 cold clipper (vs 10k on second stage cathode but you could really hot it up with maybe 4k7 and a bypass cap a la SIR 34 if you wanted) but if you go really hot the layout may need to be tweaked for stability ( I can send you Steves alternative lead dress layout https://drive.google.com/drive/u/0/...3STVYd3c?resourcekey=0-87QvCmy53e6T0Mi8g1EZFA
    Building an amp is much more fun too.
     
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  3. Marcus Johns

    Marcus Johns New Member

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    @neikeel Thanks for the quick reply! (I think I’ve come across some of your posts over at Metroamp forum), I’ll keep some of these options in mind - I really don’t know which era plexi I want. The 1987 side bright cap was one thing I was wondering as the SDM site has this at 5000pF I think, I’ll keep in mind this might need to be changed to 100pF.

    I do agree, they are fun to build.
     
  4. Chris-in-LA

    Chris-in-LA Well-Known Member

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    A 50 watt Plexi is unbelievably loud. If 18 watts is enough for you, I’d consider a JTM45 with KT66 tubes. It’s also loud but more manageable than a 1987x. You can’t go wrong with a 2204, great sounding at almost any volume. Build both, more projects = more fun!
     
  5. anitoli

    anitoli Well-Known Member Gold Supporting Member

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    I have an 87X and it is a wonderful amp. No mods this thing is the tone machine. I can see why you are looking for this tone. Combined with a 1960TV cab good stuff.
     
  6. Dblgun

    Dblgun Well-Known Member

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    I vote for the build, like Neil said it would be fun. If you want Neils special you can build to suit rather than modifying the 1987X.
     
  7. Marcus Johns

    Marcus Johns New Member

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    Thanks all for the suggestions, I’m definitely leaning towards the build. The plan would be to start sourcing parts over the next 6 months if so (I already have the F&T filter caps, Belton tube sockets, Cliff jacks, some CTS pots and some other misc components). I’m thinking probably build it as per the stock 1987 initially and have it all working, then do the mods for the 2204 2 in 1.

    edit: I have 2 x 50UF dual filter caps, I see the SDM site has a dual 32U on the screens filter and dual 50U on the main filter, not sure whether using a 50u on the screens makes a difference?
     
    Last edited: Sep 5, 2021
  8. neikeel

    neikeel Well-Known Member

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    Use what you have - the amp on the site is a 100w IIRC
    I suggest 50+50 (100) on mains whatever you do. For me 32/32 in prreamp and 32 screens/ 32mains as that is nicest for plexi mode but the difference is incredibly subtle. I would go with what you have in your hand.
     
  9. ToneWitch

    ToneWitch Active Member

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    Utilize a different ground pattern if you plan on keeping it non master. Routing the input and output grounds to a bus wire on the back of the pots isnt the best practice.

    in my builds I uses 3 star ground pattern. Grounds for power with a star near the filter caps. Star for Input for jacks and pots in another just underneath the pots (in between input jacks and pots) And a ground star for output near the impedance switch.

    after building multiple replicas to marshalls exact specs I was able to make these amps unbelievably quiet with this at idle.

    I don’t ground to the back of the pots. The pots are grounded to their tabs by bending them with a twist and I run a solid 16g copper wire through them and straight down to the Star ground at the inputs.

    The difference is quite amazing.

    I use attenuators and these are easily built with large resistors of proper wattage and impedance for the build.

    the 1987x is a great amp. Very nice sounding and breaks up well. I usually omit the bright caps as it makes the amp “ice picky” sounding with them installed. Personally I would go for bass specs. It gives a very creamy tone. The lead specs can sound a bit harsh but the lead specs with a variac is $$$$. I tend to run mine with 100v instead of 120v from the wall.

    look forward to seeing your build.
     
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  10. Jason deBroux

    Jason deBroux Member

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    Do it ! I’ve been kind of drawn to the 1987/86 plexis lately and really like the tone.

    I’m also considering building one the mojotone kits and doing a 1987/86 4x10 or 2x12 @ 50 watts. That might even be too loud for me as I like how lower output amps can break up earlier so I can dime everything and work off my guitar controls.
     
  11. neikeel

    neikeel Well-Known Member

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    If you look at the ground layout it is modified. Even so I do the same myself using the Larry ground schem.
    You cannot build it to bass spec if you want to switch between 1987 and 2204 with one switch. You do get a pre pi MV which is not bad even in 1987 mode. You can balance the MV and vol knob to get both preamp and power amp working at no deafening volumes.
     
  12. Joe Connolly

    Joe Connolly New Member

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    I’ve built a 1987 model but with 6V6 output tubes. Single input with Bright and Normal volume controls that let you mix your signal as you like. Very smooth when cranked and great clean tones as well. I put it in a combo cab with a Greenback! Surprises guys when you show up at a jam for sure…
     
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  13. Stephen H

    Stephen H Member

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    Welcome to the forum Joe, cool idea, I'm about to build a 20W 6V6 version myself, same input idea but a head version with a GZ34 and will run it through a 1x12" cab.
     
  14. Stephen H

    Stephen H Member

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    Marcus, do you really need to ask? :D having built a couple of amps you know there's a great satisfaction in having built an amp yourself, I couldn't afford to buy one so I built a JMP 2204 style head and it puts a grin on my face every time, sounds very much like every other I've played, and looks unique too, both of which makes me want to play more.

    Good luck I'm sure you'll enjoy it whatever you decide. I'm sure if I had the $$ I would have just bought one, instant gratification and all that, when I want it I want it now, although I caught the building bug, so who knows... Cheers, Steve
     
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  15. Marcomel79

    Marcomel79 Well-Known Member

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    After having built my first amp i dont know if i would buy a finished one anymore. Its too much fun building one yourself
     
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  16. neikeel

    neikeel Well-Known Member

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    I did that with Princeton Reverb front end on a Bassman power section (no trem) in a Princeton cab. Using 6V6 but using a 5U4GB rectifier for even more US flavour and slightly lower volts on the 6V6s. It’s around 440v now.
    Might be worth considering if you don’t have a Fender type amp?
     
    Last edited: Sep 8, 2021
  17. Stephen H

    Stephen H Member

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    That sounds like my cuppa, I do have an F-type amp, a 22W ab763 DR I built but it Isn't as inspiring to play as M-type circuits for me, but a mixture of the two sounds like it could be low level heaven. I used a 5u4gb in my "2204" (with a jtm45 PT) and love it, I'm not after authenticity, just gr8 tones and feel.

    Cheers, Steve
     
  18. Emiel

    Emiel Member

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    I was in a similar position earlier this year: buying a 2204 or having a friend build me a 1987. Eventually I opted for the latter and couldn’t be more happy. To me, the 1987 is a bit more thicker and dynamic sounding and with a PPIMV, perhaps a bit more versatile too. Start with the ‘68 specs and go from there :)

    Regarding the bright cap, this video might be of interest.



    I’d get the stock 5000pf cap if you want full-out overdrive, or none or a 100pf cap if you run it clean(er). Or best of both worlds: a push pull pot so you can switch between both.
     
  19. Marcus Johns

    Marcus Johns New Member

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    Awesome, thanks all for the info! To build it is - 1987 (as per Valvestorm kit and instructions) initially, then a 2204/1987 bright 2 in 1 via push-pull gain knob.

    the Larry ground system looks good, I think I’ll implement that.

    I might also mount a SPDT ON-OFF-ON toggle switch on the top of the chassis (accessible from the back with back removed) to switch between 5000p, No cap, 100p. I was also thinking about another SPST switch to switch between 47k/8 ohm and 100k/4 ohm NFB.

    @Emiel
    What are the 68 specs?
     
  20. neikeel

    neikeel Well-Known Member

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    Same as the SDM layout
    V1a cathode is 820R/250uF
    V1b cathode is 2k7/0.68uF
    V2a cathode is 820R/0.68uF
    -first coupler 0.022uF
    -second is 0.0022uF
    Tone stack 33k/500pF
    Output couplers 0.022uF
    NFB is 47k on 8ohm tap.
    std vol 1 pot is 5nF
    Personally I would go straight to 2 in 1 (saves resoldering/throwing parts away.
    As long as you follow layout carefully it is very easy to set up. Only changes I mentioned were 100pF on plexi volume and 8k2 on v1a cathode
     

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