JMJ AC30's: test drive...

Discussion in 'Amps and Cabs' started by Moods, Sep 14, 2006.

  1. Moods

    Moods Supporting Member

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    I received a JMJ chassis from Matt Romasco early today. Matt does some really fine work. The amp resembles an old JMI era AC30 in it's features, layout and tone. Nothing but top quality parts with a very simple, neat and clean layout. I am very pleased with the build quality on this amp.

    More importantly, the amp sounds killer. Not hyped up like most Vox clones I've tried. Lots of tonal options with 3 different channels. Very simple but very effective IMO. The JMJ definitely has the classic growl and bigness of my old 61 and the top boost channel has that kool crang my old 63 had. Over the past 10 or so years I have purchased just about every Vox and Vox clone I could get my hands on. This one sounds and feels "right" to me. Betting some nice tubes would give it another kick but they definitely are not necessary.

    The real test drive will start tomorrow night with the band.

    A great addition to anti-booteek amps. :p

    <M

    BTW Matt couldn't have been any easier to deal with. Excellent communication and my amp actually came early!!!
     
  2. themusicboxstudios

    themusicboxstudios Member

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    man ... i'd love to have one of these sitting next to my LDW and Bassman ... i'd have just about everything covered (yeah right :p )!

    how long was the build time?
     
  3. e-z

    e-z Member

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    Are you going to put it in a combo cab or head cab? Do you think the EF86 will be a problem in a combo?
     
  4. EL34

    EL34 Silver Supporting Member

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    what transformer set did you go with?
     
  5. AshlandBump

    AshlandBump Silver Supporting Member

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    Did you get the power scaling option on yours? If so, how do you like it?
     
  6. cg

    cg Silver Supporting Member

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    what do they run?
     
  7. Moods

    Moods Supporting Member

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    About 5 weeks with 10 weeks quoted. I just read a post that said it takes 5-6 months. Not my experience at all. For some reason I think JMJ has been getting tied in with the Hayseed threads... Valvetech has a huge backlog of orders. For what ever reason people assume they are taking as long as a Hayseed. I got lucky with my Hayseed and found a brand new minty one used.

    <M
     
  8. Moods

    Moods Supporting Member

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    I went with the head cab/extension cab. The EF86 will absolutely have a problem in a combo cab unless you have a really good, really hard to find non-microphoic EF86. Mine slightly rattles even in the head cab... with dampening. It's the nature of the beast. Sounds killer rattles and all. Over all the JMJ is very quiet for this type of circuit... the quietest of all AC30's I a have tried.

    <M
     
  9. Moods

    Moods Supporting Member

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    I did get the power scaling option and the jury is still out on that one. I will need to play with my band to know if it works well. I am playing tonight. So far I prefer the master on my Brit over the power scaling but I've heard there is a feature called a limit dial that can be added to the circuit to keep the dynamics even.

    <M
     
  10. Moods

    Moods Supporting Member

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  11. dunkbox77

    dunkbox77 Member

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    how is it similar / different to the hayseed?
     
  12. fullerplast

    fullerplast Senior Member

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    Matt does great work. Turnaround time is 5-10 weeks typically and he keeps you informed every step of the way. He usually finishes early. Top quality components and construction, probably the most "accurate" repros being done (less tremelo). I put accurate in quotes because there actually is no single AC30 version that is actually copied but putting the three best AC30 front ends in one package makes it a great and versatile amp.

    I have mine in a combo cab and have no problem with the EF86. Matt adds some damping to the EF86 socket that seems to do the trick.

    The power scaling works especially well over 50%. As you scale down further, you do need to also reduce your input gain to keep the same relative pre/power stage grind. The power scaling also works as a soft standby "switch", gently bringing power up to the tubes or back down. No sudden pops or inrush current and I'm sure that the tubes and components are happier about that. I think that if you wanted to use the amp at very low power, an additional pot to reduce the signal to the power stage (basically a PPI MV) would be useful. But face it, AC30's will always sound best loud!:AOK

    [​IMG]

    [​IMG]
     
  13. dunkbox77

    dunkbox77 Member

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    how easy/hard is the chasis to get in and out (ie to change tubes), etc.
     
  14. fullerplast

    fullerplast Senior Member

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    Exactly the same as a vintage JMI. Take the back panel off and the chassis slides out on a tray. So the answer is: very easy, but not as fast or easy as a Fender for a tube change. Easier and faster than a Fender for just getting the chassis out.
     
  15. dunkbox77

    dunkbox77 Member

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    thanks fuller - looks like you got your combo cab from Northcoast? looks sweet.
     
  16. Moods

    Moods Supporting Member

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    Matt wrote to me "These tubes (EF86) just simply don't work in combos and good ones are getting hard to find". Meaning the majority of EF86's out there aren't great and I agree with him. With a good NOS EF86 you shouldn't have any problems but the majority of what's available are quite microphonic at higher volume levels. I have a bunch of old EF86's and some are great with no issues. This has nothing to do with the amp... it's strictly the tubes. Sorry if you thought I was implying anything else.

    I agree with the second comment. And I wouldn't purchase a 30 watt amp to play Madison Square Basement. The PS works nicely to knock of some volume and seems to be relatively transparent at ligher settings... perfect for my needs. I have smaller amps for smaller duty. :AOK I'm not going to mess with the Power Scaling... should work fine when and if I need to use it.

    <M
     
  17. Moods

    Moods Supporting Member

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    I don't really want to go there since any comparison to the Hayseed seems to explode/implode.

    Check your PM.

    <M
     
  18. µ¿ z3®ø™

    µ¿ z3®ø™ Member

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    i received my hayseed 30 and my JMJ 30 within a few days of each other.
    wait time for the hayseed was 7 months. wait time for the JMJ about four weeks.
    i can mirror moods comments about the sound of the JMJ. in a recent trip out to a friends house whom has several excellent jennings era amps, the JMJ really held it's own. if U want that 'old school' vox sound, go for the lower value 16+16 filter caps.
    really great amp.
    my amp tech (also an amp builder) was really impressed w/ the build and he was particularly taken w/ the original style tag board. minutiae for me, but details like that always add up.
     
  19. fullerplast

    fullerplast Senior Member

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    Yes, Northcoast actually does better work than Vox/Korg IMHO. Also if you want the Vox grillcloth, logo, and hardware, to my knowledge they are only ones licensed by Korg to use them.
     
  20. Moods

    Moods Supporting Member

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    Mercury Woden

    <M
     

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