SC20 Low input = SV20/Origin20? MDF of plywood?

Discussion in 'Marshall Amps' started by mikhail, Dec 21, 2020.

  1. mikhail

    mikhail New Member

    Joined:
    Sep 29, 2020
    Messages:
    10
    Likes Received:
    4
    Hello!
    1. I have some DIY pedals experience and lookin on amps schematics i notice that JCM800 have one more preamp stage in front of erlier "plexi". But Low input looks the same.
    How it sounds in real life? Can SC20 sounds like SV20 in low sensitivity mode?
    2. Have Origin 20h and dislike heavy MDF chassis. What material used in Studio series?
     
    Mitchell Pearrow and Old Punker like this.
  2. RCM 800

    RCM 800 Well-Known Member

    Joined:
    Dec 20, 2019
    Messages:
    874
    Likes Received:
    1,755
    I know on my 2204 if I crank the low input it gets close to breakup but its loud AF at that point but to me it sounds plexi'ish. Kinda like Dickie Betts early stuff with the singing smooth lead tone. Ill bet the SC20 would be similar just not as loud.
     
    Mitchell Pearrow and Old Punker like this.
  3. Old Punker

    Old Punker Well-Known Member

    Joined:
    Jun 17, 2020
    Messages:
    781
    Likes Received:
    1,845
    Location:
    Ontario, Canada
    I have wondered about this myself. :scratch:
     
    Mitchell Pearrow likes this.
  4. K2JLX

    K2JLX Well-Known Member Gold Supporting Member

    Joined:
    Apr 20, 2018
    Messages:
    393
    Likes Received:
    813
    Location:
    The colonies
    I think the studio is Baltic birch, perhaps that’s wishful thinking for my own Sv20h!
     
  5. mikhail

    mikhail New Member

    Joined:
    Sep 29, 2020
    Messages:
    10
    Likes Received:
    4
    You can check this removing the back cover))
     
  6. K2JLX

    K2JLX Well-Known Member Gold Supporting Member

    Joined:
    Apr 20, 2018
    Messages:
    393
    Likes Received:
    813
    Location:
    The colonies
    I did at some point in its life, just don’t recall I was swapping v1 for a Blackburn Mullard I63.
     
  7. ken361

    ken361 Well-Known Member

    Joined:
    Aug 30, 2009
    Messages:
    4,085
    Likes Received:
    4,123
    Location:
    detroit rock city
    its birch plywood on the studios
     
  8. ken361

    ken361 Well-Known Member

    Joined:
    Aug 30, 2009
    Messages:
    4,085
    Likes Received:
    4,123
    Location:
    detroit rock city
    Low sensitivity on my 800C isn't very loud:( unless I boost it which I should try soon!
     
    Mitchell Pearrow and tce63 like this.
  9. Edgar Frog

    Edgar Frog Well-Known Member

    Joined:
    Sep 18, 2020
    Messages:
    222
    Likes Received:
    476
    Location:
    Santa Carla, CA
    Can't answer other question but the SC20H and Origin 20H weigh about the same according to Marshalls specs. The Studio is 20.7LB and the ORI20H is 21LB. Abot the weight of a hamburger. :)
     
    Mitchell Pearrow and tce63 like this.
  10. mikhail

    mikhail New Member

    Joined:
    Sep 29, 2020
    Messages:
    10
    Likes Received:
    4
    It may be more quality and heavy transformers in Studio!
    Also MDF is bad in screw holding
     
  11. Gene Ballzz

    Gene Ballzz Well-Known Member

    Joined:
    Feb 19, 2013
    Messages:
    2,555
    Likes Received:
    2,340
    Location:
    Las Vegas, NV
    Kinda yes, but NO! If you can even sorta read/understand a schematic, the one below gives a good example of the kinds of differences there are between Marshall's 4-hole, parallel channel design and their "cascaded" single channel approach. While not all values and specific circuitry will necessarily carry over from the old designs to the new SC & SV STUDIO SERIES, the basic concept and topology is fairly similar.

    Note the differences in the cathode treatments especially of the INPUT II triode of the 1987/1959 compared to the second triode of the 2204/2203, which is the LOW INPUT that equates to the "darker" toned INPUT II of the 1987/1959. Very different cathode treatment! Note that on the "cascaded" design, you also lose the benefit/option of parallel channel jumpering a bright channel and a darker channel together, along with all the gloriously complex tonal variations it can provide. Yes, the 1987/1959/SV design has "technically" less gain than the 2204/2203 but with two paralleled channels of less gain each.

    My experience has taught me that you have a much better chance of getting a 4-hole 1987/1959 (with the proper drive device in front of it) to sound like a JCM800-2204/2203 than you do of ever getting that same tonal complexity of a 4-hole from a "cascaded" model! Of course once a 4-hole 1987/1959/SV gets driven hard enough to sound like a 2204/2203/SC, its really crankin' loud, unless you add the same kind of MASTER VOLUME as in the 2204/2203 or if that 4-hole happens to have an effects loop in which you use a MASTER VOLUME device, like a JHS LITTLE BLACK BOX or similar. Notice also how simple the MASTER VOLUME of the 2204/2203 is and where it located in the circuit, at "B" which is exactly the same location you would put it on the 1987/1959 as well as being the perfect location for an effects loop. This has already been provided on the SC and SV STUDIO amps.

    It should also be noticed that the HI INPUT triode of the 2204/2203 is very nearly identical to the bright INPUT I triode of the 1987/1959, but with the lack of having the extra channel to parallel with it. It should be additionally noted that grid stop resistor of the HI Input of the 2204/2203 is 68K Ω, while the grid stop on the HIGH INPUT of each channel of the 1987/1959 effectively comes out to 34K Ω, due to the switching in the jacks, and the LOW INPUTS of the same amp are 68K Ω.

    Bottom line is I would always go for the 4-hole design, over the "cascaded" design, any day of the week!

    Have Fun!
    Gene


    image.gif
     
    Last edited: Dec 21, 2020
  12. Edgar Frog

    Edgar Frog Well-Known Member

    Joined:
    Sep 18, 2020
    Messages:
    222
    Likes Received:
    476
    Location:
    Santa Carla, CA
    It definitely should have a better OT/build for the extra money. But I've never had any issues with MDF and screws, just have to be carefull and thread properly and not over tighten. The same goes for ply as well. It may be more resilient with screws in most cases but still very easy to strip out as well if care isn't taken.

    I was just pointing out that the weight difference was negligible if that was the main worry of just shedding weight. If your head is getting a lot of moisture or beat around a lot the MDF could be a concern for sure but you really shouldn't be submitting the head to that anyways no matter what it's made of.

    The Origins seem to be sealed pretty well with paint and tolex so they should be decently resilient to light moisture anyways. I want a SC20H as well but doubt that will ever happen. Would make an awesome complement next to the ORI20H IMHO.

    EDIT:
    I haven't had my head open since after the 1st day just to make sure all tubes were seated properly but if I remember correctly it was solid wood beams where all the screws secured the back and face plate. So even better than ply in that regard.


    :)
     
    Last edited: Dec 22, 2020
    Old Punker and Mitchell Pearrow like this.
  13. solarburnDSL50

    solarburnDSL50 Well-Known Member Platinum Supporting Member

    Joined:
    Aug 8, 2008
    Messages:
    17,503
    Likes Received:
    13,537
    Location:
    Wetville

    It sounds like shit.

    In both my 5153 GB'B 412 or Orange 412. Work that top input. She's good to go there.
     
  14. _Steve

    _Steve Well-Known Member

    Joined:
    Apr 29, 2020
    Messages:
    387
    Likes Received:
    326
    Location:
    Los Angeles
    Depending on the level of exactness you want you can get in the same 'territory' by cranking up the master and turning down the preamp volume. This reduces the level of clipping and gain in V1b which is the main departure of the master volume circuits along with the master volume control itself which you're bypassing by cranking it up.

    Of course you'll never get exactly there, and as Gene said you wont be able to run parallel channels which is what many people consider the magic of the plexi. However a lot of plexi owners don't strap the channels and just plug straight into the bright channel. So depends what you're after ;)
     
    Old Punker and Mitchell Pearrow like this.
  15. Mitchell Pearrow

    Mitchell Pearrow Well-Known Member VIP Member

    Joined:
    Jul 2, 2018
    Messages:
    13,328
    Likes Received:
    25,086
    Location:
    Moreno Valley CA
    :welcome: To the forum
    Nice range of amps you have mentioned, you need all 3 of them, each has its own purpose, and each one does it well, the Origin will get closer to the plexi.
    Cheers
    Mitch
     
    Old Punker, scozz and tce63 like this.
  16. ken361

    ken361 Well-Known Member

    Joined:
    Aug 30, 2009
    Messages:
    4,085
    Likes Received:
    4,123
    Location:
    detroit rock city
    Did try the low input with my strat neck and 2nd position boosted with a chasetone EP3 preamp and it sounded excellent! lots of loud clean headroom! kinda similar to my deluxe reverb and no noise from the single coils impressive. Not real bright like the regular input but very nice chime.
     
    tce63 and Mitchell Pearrow like this.
  17. ken361

    ken361 Well-Known Member

    Joined:
    Aug 30, 2009
    Messages:
    4,085
    Likes Received:
    4,123
    Location:
    detroit rock city
    20 watt mode master maxed with the gain at 8 I think.
     
    tce63 and Mitchell Pearrow like this.

Share This Page