45/100

Discussion in 'Building the Classics' started by v846, Mar 11, 2018.

  1. v846

    v846 Member

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    Built this amp a few years ago using pretty much all modern parts, build on a Marstran 45/100 chassis, Marstran iron of course, alpha pots, last of my old Sozo stash from when they first came out in well whenever that was.

    Also posted at the Marstran forum

    David



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  2. danfrank

    danfrank Well-Known Member

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    Very Nice build! I built one of these 45/100 clones and it's one of my better sounding amps. Marshall really got it right with this amp design!
     
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  3. v846

    v846 Member

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    Thanks Dan, yes it is a nice sounding amp, my #1 at the moment.
     
  4. grainman

    grainman Active Member

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    build with passion...thats why no companies can compete with these kindda built...SOO PERFECT
     
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  5. v846

    v846 Member

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    build with passion ! I like that:cheers:
     
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  6. S.Marshall

    S.Marshall New Member

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    Clean build man, very nice!
     
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  7. ibmorjamn

    ibmorjamn Well-Known Member

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    That is perfect , very nice .
    I want to build a 45 and power scale maybe . I was thinking of a 6V6 at first but they are a little dark sounding to me.
    I bet your amp sounds good.
     
  8. ibmorjamn

    ibmorjamn Well-Known Member

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    Marstran is as close as you can get to the real thing (xfrmer)
     
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  9. v846

    v846 Member

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    Thanks ibmorjamn,

    Which version JTM45 you want to build, the earlier RS or the later Drake.
    Power scaling is cool but you also have other possibilities like the Fryette Power Station or the UA OX.
    I get great results with the Alex Attenuator just to bring it down a couple notches..

    db
     
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  10. ibmorjamn

    ibmorjamn Well-Known Member

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    I will have to research the tone . I had heard the RS was real good but I'm a novice at building . I will likely use the shelf parts from Mouser except I would use the good iron . Good advice on the attenuator. This amp is quite good I think . 65 RS or Drake ?
     
    Last edited: Mar 21, 2018
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  11. neikeel

    neikeel Well-Known Member

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    Hard to tell. A block logo 65 could be either. A script logo definitely a Drake, early gold block more likely an RS. I have a 64 with RS trannies and choke and a 65 with selectors on the transformers. They sound surprisingly similar, the 65 is lead and the 64 bass so only the 100pF cap on vol 1 pot that does add a little clarity until on 8-10volume. Both have mullard or brimars and nearly new GEC KT66s is I guess that helps.
    Funnily enough I just completed my latest 45/100 to ser. 7206 (DickinsonHendrix) specs. I used as much NOS of the same parts that you see in that particular amp as possible except Marstran chassis and trannies. It’s had a cap reform to specs and had 600v on the plates without tubes (my last 4 NOS GEC KT66s) so next step is with tubes and then I will post some pics and maybe clips.
     
    Last edited: Mar 23, 2018
  12. ibmorjamn

    ibmorjamn Well-Known Member

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    I have been all over the place on builds and era's for tone . I don't know why I want KT66's but they are also in the Vintage / Modern from what I hear .
    For a build I guess the further back I go the more basic the circuit gets (less complicated) I like small head cabs so what I ever I do will not be an exact clone and I won't be chasing the nos stuff mostly because I won't pay the price . I think the modern caps and resisters will be fine for me .
     
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  13. v846

    v846 Member

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    Neil,

    Can't wait to see your 45/100, work is always inspiring. One of these days I would like to build one with old parts.

    BTW my amp pictured is almost 7026 spec with 33K/500pf tone stack, just need to add the 32/32 uf cap & extra 10K dropping resistor. Oh and this has the 100pf brite cap on vol.1 pot.


    db
     
    Last edited: Mar 24, 2018
  14. v846

    v846 Member

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    ibmorjamn


    FWIW I built a 45 for myself (RS) and one for a friend (784-103) and my recollection was the RS is a bit cleaner & the 103 is more aggressive & dirty..Both sound great but my preference is the RS.
     
    Last edited: Mar 23, 2018
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  15. Metroman

    Metroman Well-Known Member

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    _57nb_zpsgfvlmqnu.jpg Pulsonic (2).jpg George at Metro did a killer job on my 2013 LTD ED GMP45...... BUT I'm In Lust for a JTM45/100...

    While IMHO there is no best between the RS, and Drake, I prefer the Drake. The Drake is still clean up to 7-8+ anyway, and that little bit of extra drive at the limit is IMHO.. Glorious, and only bettered by the JTM/45/100.. 50 watt 1986/87 is also nice but I really like KT66, and JTM preamp interaction vs most others. Its all good though with these nice old builds done the right way.



    You can get most of the Mustards/PEC ect ect from Valvestorm for what Id consider peanuts for what they are. I believe a complete kit JTM45/100 with Mustards/PEC, Transformers/Choke head shell, is around $1500. No tubes.



    I also used all NOS tubes in my GMP45. All of them were tested by Brent Jessee, in a single ended self biasing amp/preamp they use to test Mic tubes, tubes for critical applications, also tested an n Oscope, and Tektronix Curve tracer... $15 a tube, for all 3 tests, and at those prices you cant afford not to have them tested if the testing is available.



    1956 coated glass Marconi Osram KT66



    2 x Mullard 10M Master Series Gold Pins in V1/V2.. This is an insanely quiet, and very killer long lasting tube. HiFi people love this tube because of it frequency response, and Low Noise.

    1957 mC1 Mullard 12ax7 LP. I rolled this against the 2 x 10M in V1/V2, and the 10Ms won. Also put 10M in V1, Lp in V2 ect. Every way possible.

    I also like the Sylvania 12ax7WA in V1, V2 and PI for the $$$$



    I also rolled 2 x 57/58 mC1s in V1/V2, and the 10Ms sounded at least as good, and were more quiet at full output.



    Ive also been collecting speakers since 72, and am lucky, and have some really nice speakers.



    I also felt that the EC Collins Pinstripe/Bluesbreaker cloth makes a huge impact on the sound.

    I had Mather make copy of an oversized 1966 TVB cab with EC Collins cloth , and loaded it with 4 Pulsonic G12H.

    Its been the best sounding amp Ive ever owned since 1972. But like I said. I really want a JTM45/100. Mustards ect. I'll probably have my buddy Richie Hall build it for me. He and is brother Dana invented VVR KITS. They didn't invent VVR, but did invent it in kit form, and did invent it for Non Cathode Bias amps. So theyre great builders. Dana was also friends with Ken Fischer, and when Ken died Dana was voted by the Trainwreck forum to build the Ken Fischer Tribute Amp.



    I let Richie take my amp apart, and inspect it because he was curious about Metros builds. He loved the sound, but never got to inspect 1 until mine, and he said it was the best soldering job possible. Even as good as his... He was really impressed with Georges build, and the sound of the amp.






    [ 31613_zps6471fc92.jpg GMP45.._zpsn2df96ux (2).jpg kt66pr3_large_zpsbf4pbtoc.jpg
     
    Last edited: Mar 23, 2018
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  16. ibmorjamn

    ibmorjamn Well-Known Member

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    Wow , sure is nice stuff . Waves over my head . lol
     
  17. v846

    v846 Member

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    Nice amp Metroman, my JTM45 clone built in 2003 is similarity tubed with mC1s in V1, can't remember V2 & 3, pair of smoke glass KT66 and a Mullard GZ34 f1 I believe. Also uses PEC pots, carn comp resistors & as mentioned is running the RS.

    For cabs a I have two 1960A's from 1070 & 1973 respectively both have G12M's. Would like to get a bottom cab with 30 watters.
     
  18. coldengray

    coldengray Active Member VIP Member

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    Neil please post your build!
     
  19. neikeel

    neikeel Well-Known Member

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    Ok, but David's amp above is pretty spot on.
    Mine is up and running pretty nicely, plate voltage is scary 580v with GECs biased at 28mA (for now). Very jazzy with a LP std (until you turn it up that is!).
    Rather than hijack David's thread even more I will take some pics and i-phone clips tonight.
     

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