Lee Jackson Mod

Discussion in 'The Workbench' started by theamericanpsycho, Jul 14, 2010.

  1. theamericanpsycho

    theamericanpsycho New Member

    Joined:
    Feb 14, 2010
    Messages:
    19
    Likes Received:
    0
    Location:
    Pittsbugh Area. in a house.
    Ok, I own a 1978 Marshall JMP 2204, 50 watt master volume. I wanted a gain increase mod so I took my amp in and I was recommended the "Lee Jackson mod". I waited a while and I stopped in every now and then to ask about the progress and I waited a month to get my amp back. I was told the tech was changing the tubes from stock to el34s and 12AX7s and adding new caps and a few other things I cant remember. Now that I got the amp back home, I fired it up and....it sounds the same. I was thinking I got jipped, so I took the back off....yep, there was certainly new tubes. But I dont hear any gain increase. The guy I went through said I would still need boost pedals (EQ and overdrive) to get the sound I want, so whats the point of the mod? Does anybody know what this Lee Jackson mod is in detail? And why do I hear no difference at all other than a slight marshall growl? I even put the preamp up at 8 and sometimes 10 and thats it, slight little growl. I asked the guy if they did the one wire mod and he looked at me like I had 6 heads. He said he had never heard of it. Any takes on this?
     
  2. Lane Sparber

    Lane Sparber Well-Known Member VIP Member

    Joined:
    Apr 26, 2010
    Messages:
    2,553
    Likes Received:
    482
    Location:
    Queens, New York
    It sounds like you might need a new tech. I freely admit that I don't know what the "Lee Jackson Mod" is (he has a DVD or two out centered around modding Marshalls, so it could be a conglomeration of things). To that end, could you post pics of the inside of your amp so we can see what might have been modded? Be careful doing this if you're not familiar with high voltage circuits, as these amps contain lethal voltages long after the plug has been removed.

    -Lane
     
  3. PaoloJM

    PaoloJM New Member

    Joined:
    Jun 15, 2008
    Messages:
    1,514
    Likes Received:
    118
    Location:
    Cork, Ireland
    I would say there's no doubt that he needs a new tech...
     
  4. charveldan

    charveldan Well-Known Member

    Joined:
    Jan 31, 2010
    Messages:
    5,083
    Likes Received:
    2,240
    Location:
    Somewhere with a Friedman Marshall & Les Paul.
    Wondering why OP would consider a "Jackson mod" :wtf:from someone other than Jackson himself while still using his name?
     
  5. MKB

    MKB Well-Known Member

    Joined:
    Jul 15, 2008
    Messages:
    1,268
    Likes Received:
    306
    Yup, new tech indeed. I haven't seen the Lee Jackson video, but have worked on a few of his modded amps. Other than a few changed values, the major mods are a selectable midrange "boost" with a six position switch, and an added preamp tube between the tone circuit and the phase inverter. If he installed that mod, you most certainly should have gotten a LOT more gain. But if the total number of tubes in the back of your amp did not increase, he probably didn't do the gain mod.

    There is a simple one cap/resistor mod you can do to a 2204 that will increase the gain quite a bit, it's way cheap and reversible. I'd hope he would try that at least.

    One other thing; what type of guitar are you using, with what type of pickups? It's possible, if you are using a Strat or other guitar with low output pickups, that you may need more of a gain boost than what you can get from the 2204 circuit arrangement. You may need an added tube or an external boost to get the tone you want.
     
  6. Wilder Amplification

    Wilder Amplification New Member

    Joined:
    Oct 12, 2009
    Messages:
    6,163
    Likes Received:
    700
    Location:
    Fresno, CA
    Definitely needs a different tech (oh...did someone say that already :D)?

    What kinda sound are you looking to get out of your amp?
     
  7. Joey Voltage

    Joey Voltage New Member

    Joined:
    Dec 22, 2009
    Messages:
    1,717
    Likes Received:
    113
    Location:
    Brighton, MA
    There were many lee jackson mods, some increased gain, and added gain stages, and some were just voicing mods. If you can take a picture of the insides of the amp, and PM them to me, I will tell whether or not he did any of the lee jackson stuff, by the way, how much were you charged fr this mod? That goes for anybody, if anyone has any questions about questionable famous mods, I have inside knowledge about many sought after high priced amps and mods around, and can probably confirm their legitimacy
     
  8. surreal amplification

    surreal amplification New Member

    Joined:
    Jun 1, 2010
    Messages:
    141
    Likes Received:
    10
    You got totally shanked by some ass who bought some videos and thinks he's an amp modder. Even my 15 year old daughter knows what a one wire mod is. The lee jackson mod you wanted adds a tube gain stage after the MV. personally I dont like it.
     
  9. PaoloJM

    PaoloJM New Member

    Joined:
    Jun 15, 2008
    Messages:
    1,514
    Likes Received:
    118
    Location:
    Cork, Ireland
    Could never see the point of it. The same amount of gain could be achieved, with equal effort, by putting the gain stage before the CF and keep the tone controls operating. Seems like a mod by someone who doesn't now any better...
     
  10. Wilder Amplification

    Wilder Amplification New Member

    Joined:
    Oct 12, 2009
    Messages:
    6,163
    Likes Received:
    700
    Location:
    Fresno, CA
    Let's see...since the advent of "build it yourself" amp kits how many times has this happened? I can name at least 3 boutique amp shops that are all owned and operated by guys who can build off of a layout but can't hook up a PPIMV to save their life.

    Believe it or not I get PMs from a lot of these guys asking how to do simple things that any real tech should be able to look at a simple schematic and figure out for themselves (i.e. PPIMV installs, 6550 mods, etc etc). My whole thought on this is "You call yourself a builder, you run an amp shop, yet you can't even so much as do a simple valve type conversion!?!?"

    Then when they get the mods wrong and the customer is less than pleased guess who gets the call to fix all of it, pointless mods and all? ;)

    Does it irritate me? Big time. Why? Because it's like these guys want their careers handed to them and think that just because they can build/mod an amp going off a simple layout or because they've worked with some big named "guru" that they're now "instant techs". Yet if asked they couldn't tell you what a choke does, how to wire up a simple relay or an electron from a proton for that matter. Because it's been too loosely thrown around that "Tone is all that matters" when in reality there's a lot more to it than that. Lots of basic electronics theory required to see exactly what's really going on in these circuits.

    That being said, I agree it sounds like you got shafted on that mod.
     
  11. surreal amplification

    surreal amplification New Member

    Joined:
    Jun 1, 2010
    Messages:
    141
    Likes Received:
    10
    Im working on a traynor and the guy said it had a PPIMV. technically this THING in here is after the PI but its a dual 100 k pot.. ?? crossline mv is guess they were referred to as. so that went out.

    whats even sadder is people getting looped into a mod simply because the guy doing the mod is a killer player. They get the amp home and say "oh it doesnt sound like yours" Or people charging 500 plus dollars to cascade a preamp on a 1959 or 1987 and lower the filtering.
    hey John hows the killer kt88 thing going ?
     
  12. Wilder Amplification

    Wilder Amplification New Member

    Joined:
    Oct 12, 2009
    Messages:
    6,163
    Likes Received:
    700
    Location:
    Fresno, CA
    I've got everything but the chassis to build the power amp side of it for testing. Since I'm running two power transformers in it I'm gonna need a little bit wider chassis than a standard Marshall chassis size since I'll be mounting one behind the other. I'm really going OCD on the top mount component layout as I'm considering doing a semi-transparent front on the cabinet so the valves/top components can be seen from the front.

    Prolly gonna need a fan or two in the thing as well.
     
  13. Joey Voltage

    Joey Voltage New Member

    Joined:
    Dec 22, 2009
    Messages:
    1,717
    Likes Received:
    113
    Location:
    Brighton, MA
    Thats only one of the many he did, not all of them were like that, and not all of them added an additional stage



    It's not necessarily for the gain, That particular one does have an effect, that isn't the same as putting the stage in the more traditional place. I wouldn't just jump to the conclusion that Lee didn't know what he was doing. FWIW some of his other Mods do reallocate the added stage in the more traditional spot, just a different way of doing things
     
  14. surreal amplification

    surreal amplification New Member

    Joined:
    Jun 1, 2010
    Messages:
    141
    Likes Received:
    10
    we know
    but the OP wanted more gain....
     
  15. Joey Voltage

    Joey Voltage New Member

    Joined:
    Dec 22, 2009
    Messages:
    1,717
    Likes Received:
    113
    Location:
    Brighton, MA
    This is unfortunately the way of the mod world!, you can either defy, or join them, and hope that the better amp wins;) (I think we have already has this conversation though). on the flip side, a crappy player will make the best sounding amp sound like an early transistor amp.

    Now what REALLY bugs me is the lack of creativity in all of this. It is quite common to see people reverse engineer somebody elses mod, and use it to build their carrers. I find it disgusting


    What does wanting more gain have to do with adding gain stages? besides, the OP never said how much of an increase he wanted
     
  16. MartyStrat54

    MartyStrat54 Well-Known Member

    Joined:
    Feb 21, 2009
    Messages:
    25,999
    Likes Received:
    9,455
    Location:
    Licksville
    I have several point to discuss. Number one, what do you mean when you say your tech was changing the stock tubes to EL34 and 12AX7? Did you have a 6550 amp? Did you agree to this work? Second, did you discuss the mods with your tech in detail? Did he tell you that you would be getting more gain? Did he tell you that you would be getting more gain without increasing the tube count? I mean why did the tech say that about needing boost and EQ on the amp AFTER THE MOD? I look at it this way. A boost pedal is a mod, if someone is doing a gain mod and you still need a boost, then the mod wasn't worth a damn. If done properly, a modded amp should get really ballsy and crunchy on its own.

    Some of the responsibility is on the customers shoulders. They need to establish a rapport with the tech and be on the same page as they are. That way, you know what you are getting.

    Personally, I would have researched all of the Lee Jackson mod's before just agreeing to them. I think it is best that the builder has audio clips of his mod's. This may not be 100 percent accurate, but it gives the customer an idea of what the amp will be like.
     
  17. Joey Voltage

    Joey Voltage New Member

    Joined:
    Dec 22, 2009
    Messages:
    1,717
    Likes Received:
    113
    Location:
    Brighton, MA
    He's a famous modder. and they are heard on alot of famous '80's recordings. Dokken under lock and key, Steve vai eat em and smile, Zakk Wylde "No Rest For The Wicked", most Akira Takahashi (Loudness), Paul Gilbert, and Bruce Boullet racer X era, (Paul even used them during mr. big, and some of his solo carrer) the list continues.....

    Lee Jackson to the best of my knowledge hasn't done mods in over 20years.
     
  18. MartyStrat54

    MartyStrat54 Well-Known Member

    Joined:
    Feb 21, 2009
    Messages:
    25,999
    Likes Received:
    9,455
    Location:
    Licksville
    Oh, I know that the guy has been around. I also know that he has some famous clients. However, I think a A/B of a mod is easier to perceive than an amp being played by Steve Vai in a band scenario.

    Also, I started doing Internet searches on him about five years ago and there is quite a few negative comments about him.

    Looks like you either like him or hate him.
     
  19. Joey Voltage

    Joey Voltage New Member

    Joined:
    Dec 22, 2009
    Messages:
    1,717
    Likes Received:
    113
    Location:
    Brighton, MA
    I think had is the more operative word. The only problem with an AB mod comparison is that you would have to be in the same room playing both amps, which makes it all kind of difficult. Sound clips are okay, but even then it's an abstract,and an art in itself! The ultimate, and what I plan to do is record using a good player, a mediocre player, and then terrible one play through it, ehat way you can compare, hell I think I can even get my cat in on it.


    Isn't that with anybody though? LOL
     
  20. MKB

    MKB Well-Known Member

    Joined:
    Jul 15, 2008
    Messages:
    1,268
    Likes Received:
    306
    Lee Jackson's heyday was back in the early/mid eighties, when the first thing you did when you found an old Marshall was save up an additional $500 so you could ship it off to get it modded. Lee Jackson was the top of the heap back then. Unfortunately back then if you wanted a high gain Marshall tone, you either had to use pedals (with questionable results) or get your Marshall modded. Marshall JCM900's were a response to this trend, giving a Marshall with high gain out of the box.

    These days you can get amps with all the gain any sane person would want. I don't understand why people still want to modify their vintage amps, when in many cases they could sell the Marshall for its vintage value, then buy a new amp with tons of gain. Either get a high gain Marshall, or there are many boutique builders that can make you a vintage amp with gain mods. The problem with adding gain to a vintage amp is it radically changes the base tone in most cases, and often hurts or destroys the resale value. So what's the point?

    I'd bet many of the famous guitarists with modded amps spent a lot of time with the amp builder, working carefully on the mods until he got exactly what he wanted to fit his guitars and playing style. That's a lot different than just picking a mod out of the air and putting it in your amp without trying it out first. Like Forrest's box of chocolates, you never know what you're going to get.
     

Share This Page