Clone Kits For Jtm50

Discussion in 'Building the Classics' started by 6string, Feb 20, 2018.

  1. 6string

    6string Member

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    Im thinking about buying one of the clone kits but so far I have only seen the one offered by triode electronics. Been reading some good things about them but how do they compare to sounding to an original marshall jtm50.
    Any other options in clone kits out there that nail the original tone?
    Im not a wealthy man so I gotta work with what I have. If I was I would definitely be buying a Solodallas JTM50. They sound fanastic.

    Also any guides or tutorials that can help along the build? Ive read triode doesnt really give much in paperwork or telephone guidance.
     
  2. ampmadscientist

    ampmadscientist Well-Known Member

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    On the wrong side of the tracks.
    They don't sound like the original amp, they are just using that as a marketing tool.
    The parts are not the same, the transformers are not the same...etc...
    Nobody who sells kits is giving anyone a lot of guidance.
    If Solodallas sounds fantastic, then that's what you need to buy.
     
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  3. liontato

    liontato Well-Known Member

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    Kits get you in the ball park. I don’t have a good resource for building. Watch as many tutorials as possible. But be encouraged about kits. They can sound great. Ceriatone does nice work and reasonably priced. May save you some trouble from the building aspect. Nik is great. I bought a Dumble clone from him. Impeccable build and tone.
     
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  4. Crunchifyable

    Crunchifyable Well-Known Member

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    Best advice...study study study. Order your own parts, drill your own board, hammer your own chassis (it's harder than it looks...).

    Kits are for novices mostly. Or people who don't want to order parts from a million places and shoehorn the occasional odd part into the design.

    They charge a lot for kits. And always sell the fancy parts.

    If I go to build an amp, I will buy the cheapest pots mouser sells, the cheap resistors I got on ebay (except for anything over 1/2 watt), realtively common cheap capacitors. Basically the same stuff any random manufacturer would use to build a typical amp today.

    The reason is, it's never going to sound like the original. You can't and won't get original parts. and 90% of the tone you seek is coming from a pre-1970 greenback (year is arbitrary...but you get the picture). Like 7% is the amp circuit and the rest is mojo lost to time and space and parts variations.

    Best you can do is clone it and then mod it. Because after you build it, you will accept it's just a circuit. Possibly even a bad circuit (not so functional tone stack, incredibly bright, channel bleed, unbearable volume,) etc. etc.
     
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  5. 6string

    6string Member

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    Thanks guys. I am aware that the clone kits will get ya near the tone ya seek or close to it. I just dont have nor will I ever save up $3k+ for a Solodallas or Vintage marshall amp. I sold my vintage JTM45 some years ago and cant look back so Im trying to do the next best thing to get me in the ball park range of that tone Im desiring. Im not sorry I sold the JTM45 as it was just too loud to get the tone out of it. I didnt want to use any attenuator on the amp either. It was all original and couldnt see possibly hurting the amp. Now I would just be happy with a clone since most of the vintage stuff is really high priced and if something goes I just dont have the paycheck to afford vintage replacement parts. I was looking for something more economical that resembles that era tone or to suit my likes.
    I know Im after a JTM 50 Black flag tone or close to it.

    Crunchifyable. Any possible chance ya can link me any tuts? Or to any parts list I would need to build this? Or anything where to buy the turret board etc. I wasnt aware I could build my own chassis. I havent found anything on this yet. I would greatly appreciate the help. My local shop(Moyers Electronics) here isnt much help anymore. The workers changed(in attitude) and are nothing but grumps and jerky esp. when ya ask for help.
     
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  6. Crunchifyable

    Crunchifyable Well-Known Member

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    hammer. Clamps. Sheet metal from local hardware store. Ask for discount on rusty ones. Cheap.
    [​IMG]
    [​IMG]
    My board and power supplies...a functional mess.
    [​IMG]

    This guys videos are like solid gold.

    they break everything down into DETAILS very very slowly. Schematics, explanations.

    Tube amps aren't that complicated. But there are concepts that govern them.

    Once you understand the concepts that allow a tube amp to work, things like schematics will make sense.

    Marshalls and Fenders aren't that different. So the application is similar on those videos.

    JTM45 is basically a plexi with a valve rectifier.

    This is a parts list off metro amp http://valvestorm.com/sites/default/files/JTM_45_KIT_V2.1.pdf

    Personally...what I do is go thru the schematic and layout and make a list on a sheet of paper. It's very tedious. I also ordered a crap ton of 1/2 resistors on ebay for next to nothing but the values are often not what's needed so you need to be aware.

    I'd personally order 10x of every 1/2 resistor used. extra of all 1w and 2w resistors.

    The actual caps used in amps are getting harder to find. The axial caps that are preferred are something of a dinosaur and they are expensive. Like 60 cents each. Adds up.

    I built a 2204 preamp. I found schematics and layouts online. I got advice from people here who had built similar. I ordered a generic turret board on ebay...ordered resistors and caps and switches from ebay and mouser and another company (out of the far east...but with a US shipper).

    It sits on my bench now. It's like...a start but I don't know where I want to go with it. But it is pretty much indisputably the JCM800 sound that can be plugged into any amp or my daw.


    Took an entire day (like 6 hours) doing nothing but adding items to my cart on mouser. But hey I was motivated.

    In hindsight I wouldn't go as cheap as I did. I don't really like cheap tube sockets and cheap switches are terrible (unless they are all metal).

    As far as the turret board, I'd recommend building your own (some kind of fiberglass...and a drill bit.). Never done that...but it means infinite customization.

    I bought a cheap chinese turret board on ebay. it's very small and I can't really recommend it but it cost $13. You can get decent ones from US "shops" like tube depot etc for more. But there's a lot on Ebay.
     
    Last edited: Feb 20, 2018
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  7. 6string

    6string Member

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    Wow man!!! You really did a GREAT job. You're giving me hope here. :) I know when I last visited my local shop the moral there just depressed me in my thinking on this project. I didnt give up the hope in learning this but did question if I can do it. I cant thank you enough for the help you given thus far. I have to say the JCM 800 you did sounds fantastic. I dig it ALOT. Great job. I can only hope that I can achieve this goal of mine now. Thank you for the links a posted as well. Greatly Appreciated. I found this one a lil bit ago but http://site.triodestore.com/JTM50layout.pdf it doesnt list what manufacturer to go with like Mallory 150's or Sozo or what exactly the ratings are that are needed. It is kinda confusing. I messed around with an epiphone valve jr before and havent finished that yet. Im waiting on more $ to finish gathering the parts for it before I start on it. But this has been another project that I have wanted to do. Of course well advanced compared to modding the epiphone valve jr.

    I guess Im in for a some long searches to find out what type of parts would be best suited for marshall amps. I only know of the mercury magnetics as transformers(PT,OT)not sure what others are good or cheaper, and mallory 150's/sozo caps. Not sure about what type of resistors, choke, capacitors or power caps to use. Not sure if any orange drop caps are used?

    I wanted to build my own cabinet for it but also not sure what the measurements of the JTM 50 cabinet. I did a lil searching tonight but so far nothing of use.

    I found a video by Tube Amp how to build a JTM 45 plus. Its a short video and doesnt really say much about the brand of products used or needed. Helpful in some ways though.

    I found this video on how a super lead actually works. I think it maybe helpful? Its a bit over my head right now. Maybe after a few watches and some thinking about it all Ill understand it better in time?


    I found this video as well and it shows you how to build a turret board as you mentioned. But the only thing Im not finding are the measurements for this amp on how big its turret board is.

    Would you know where i can find some measurements for it? That and the cabinet. I found chassis's on triodes site as well as tube amp & kinda thinking going that route as I dont have a brake to bend it up. I can think of ways to bend it but Im not so sure its going to come out straight or eye appealing. Im also a bit nervous about drilling holes straight down the line as well. lol! I guess it doesnt matter as I usually only off a bit. But its noticeable when you look at it. Its not a straight line across at times. or a wavy line. I like to build things but sometimes I forget Im only human and not a machine that can accurately drill holes in a straight line. I usually get drill bit walk.
     
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  8. Crunchifyable

    Crunchifyable Well-Known Member

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    If I had the money I'd just buy a chassis off ebay. They have aluminum and steel ones predrilled for you, made for a JTM45, around $50-$80 based on material (was one dude out of arizona making them for pretty cheap).

    I don't know much about measurements and stuff...it's actually not something I've gotten to yet. For my own project, I just measured my other amps and amp heads. For me, the Marshall Class 5 was my main reference because I like the size of it and didn't want anything as huge as a jcm800 / full head size.

    JTM45, small box plexi, and 18w all use the same chassis and headshell. 17 X 6.5 X 2.5 chassis. You can find the details by just looking at the reproduction sellers' dimensions.

    That tube depot video is helpful on physically building it...but the problem is those videos don't explain how a tube amp actually works. So that's why I like uncle doug's videos...he has one for each part of the amp. Marshall...Fender...Supro....they are basically all the same as far as basic electronics, a few minor differences as far as biasing, etc.

    I guess to me I didn't want to bother playing connect the dots until I understood what I was doing.

    As far as that layout from triode....assume all resistors are 1/2w unless noted, all capacitors 400v unless noted. The brand of the capacitors doesn't really matter. Not in a technical sense. Just the value, the voltage rating. Obviously ones from a legitimate parts warehouse like Mouser, etc., are going to be more reliable than random ones from china.


    A good schematic will tell you all you need to know.

    As far as transformers...I'm of the opinion that's it's not really worth the money to spend extra on them. I'd suggest the ones from classic tone...relatively affordable and they have multi voltage options too.


    I like this schematic better because it separates the triodes. Easy to follow the flow of signal and power.

    http://mhuss.com/amps/JTM45/JTM45Classic2a.pdf
     
  9. chuckharmonjr

    chuckharmonjr Well-Known Member

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    DO NOT use aluminum for a chassis. You WILL end up having ground lifts due to eventual corrosion and metal type mismatch...a very dangerous situation when you are dealing with 500+ VDC. Now, that being said..Triode kits are quite excellent plus they have steel chassis as well.
     
  10. Metroman

    Metroman Well-Known Member

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    +1 on the Valvestorm.
    1 stop shopping for many Marshall circuits, and no compromise, high quality components.
     
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  11. ampmadscientist

    ampmadscientist Well-Known Member

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    "Im after a JTM 50 Black flag tone or close to it."

    Excellent choice :headbanger:
     
  12. ampmadscientist

    ampmadscientist Well-Known Member

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    He's right. The manufacturers who use aluminum are not using the aluminum as a circuit path.
    It is possible to use it, if the circuit is isolated from the chassis...but that is not how a normal (classic) Marshall is built.

    A classic Marshall uses the chassis as a current path.
    But with aluminum, that is exactly what you should avoid doing.

    And so, you will notice manufacturers use steel...which is easier to connect to (similar instead of dissimilar metals)
    And any amp which is aluminum, has the circuit current isolated from the chassis.
    The chassis "is " grounded, just not used as a current path.

    It's not that bad to build a Marshall a different way...it's just that most people want to build it the classic way.

    I have a big Standell
    [​IMG]
    from the 1960s. But it will not work because all the aluminum grounding has oxidized.
    To make this amp work: I gotta re-do all these grounds and lift the current off the chassis.
    The amp has gone total fail because of oxidized aluminum.
    I also gotta change the power lead to 3 wire for a mains ground...

    So you could be sure: aluminum that is screw / rivet grounded, does fail. Be sure of this fact. This amp is a perfect example.
    Back in 1960s, they did not realize this would happen.
    But since then, the safety codes for grounding have been changed quite a lot.

    Like for example: it is not legal to use the aluminum chassis as a current path.
     
    Last edited: Feb 22, 2018
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  13. 6string

    6string Member

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    I was searching ebay last night and found a few aluminum chassis for $50. It was for a JTM 45 though. I googled some more and found the correct chassis should be steel for a '67 JTM 50. I also read some of the 45's had a mixture of SS and GZ34 rectifier tube. I had a JTM45 with GZ34 and remember I really had to crank that to get that lovely tone. I think I have it down that I want a SS rectifier this time. :)


    Much thanks, I found a guy selling reproductions cabinets on ebay last night and was going to jot his dimensions down but will stick with what you listed. I think I prefer a smaller box as well. Im limited for room/space.

    Ill have to search for Uncle Dougs videos. I agree the video I linked wasnt really helpful in the parts that I know I will need help in. And youre right I rather know what Im doing that half fast it. Gotta have it all correct in your mind before you start doing guess work. Just makes it easier to do the job.

    Dually noted on the wattage for the resistors and voltages on the caps. I was a bit lost on the schematic by triode since it really doesnt state R1, C1 or the Voltage. Thats when I went to my local electronic store asking for a bit of advice and got shunned from them. So I just called mouser and the guy that answered helped me and I ordered the parts thru them. I saved money too. The local store had much higher rates on the stuff I needed for the epiphone valve jr.

    I agree I prefer the schematic you posted. It gives better info on what is what. Thank you I think I saw one of those JTM45 schematics last night but I wasnt sure if I could exactly base all the info from it to the JTM50 since it has a slight variation in build.

    I never heard of classic tone transformers. So Thank you again. I read a lil bit last night and found some others using marstran and another brand I cant recall at this time. Too much info and its not soaking into the brain cells yet. lol! But at least I know a bit more today than I did yesterday.


    Thanks chuck. I appreciate that input and will stick with a steel chassis when I start this project part order.

     
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  14. neikeel

    neikeel Well-Known Member

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    I’ve built a few.
    Simple circuit.
    Top quality tone will depend on good quality parts.
    Build it cheap and (Imo) you will get an ok amp but nothing special.
    I would go Valvestorm all the way, get Robert to put the build list together. I would use a Merren OT and whatever PT you can afford that puts 420v on the EL34 plates.
    Entirely my 2c.
     
    Last edited: Feb 22, 2018
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  15. TAZIN

    TAZIN Active Member

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    I also vote for Valvestorm. Great stuff and service.
     
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  16. ampmadscientist

    ampmadscientist Well-Known Member

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    Well, I put in the tube rectifier socket, and plug in a SS rectifier tube substitute if I want SS.
    But when you switch rectifiers, readjust the bias.
    This is going to give me some freedom to try different rectifier configurations, I'm trying some different diodes, etc...
    By using 3 different rectifier tubes, I can get 3 different B+ voltages....a variation of about 90-100 volts between the 3..5AR4/GZ34, 5U4, 5Y3...
    So, I get all kinds of options, because I used the octal socket.
    For me to play with, that's great.
    But you know me, I like to play with the circuits.
     
    Last edited: Feb 22, 2018
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  17. 6string

    6string Member

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    That's awesome and best of both worlds. I just came across a JTM45 video that had the switch for Tube/SS rectifier. I was wondering how to do that. I had my mind set on just SS rectifier till I saw this video. Now that I just read your post, Im thinking I would prefer this. I just need to learn how to do it along with the rest of it.

    I saw in another video a tech guy mentioned not to use a 5y3 tube as its made for tvs not amps and you can end up blowing something up. Is the octal socket different from the PT socket? Im assuming its definitely needed to achieve the switch mod?
    Yes with a cool name like ampmadscientist I can imagine what kinda cool stuff ya got on the bench and all sorts of wild creations your making over there. :)
     
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  18. neikeel

    neikeel Well-Known Member

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    I suggest use a GZ34 and have a Weber Copper top handy when you want SS otherwise you will have to rebias using lower rated rectifiers.
     
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  19. dmentzer

    dmentzer New Member

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    Video of a Triode JTM-50. Just for your reference.
     
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  20. 6string

    6string Member

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    Thank you neikeel, I appreciate that input and very good advice. I have a long way ahead of me till I start to figure out all of this stuff. But I am definitely going to keep your info on hand. I dont want to run into that issue of rebiasing the tube rectifier esp. ones with lower ratings. I think the only tube Im going to be interested is the gz34 and maybe possibly the 5ar4??? Not sure. I had a Fender 57 Twin Reverb RI amp and that had the 5AR4 rectifier tube in it and I dug it at times. Not sure how it would be in a JTM50 clone though???

    Man thats a sweet video dmentzer. That amp is amazing sounding. Love it! Incentive to read and study more on how to do all of this. I wish I could load my brain like a pc hard drive with this info so I can just start. lol! Patience is a virtue though. I really want to learn this.
     

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