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LEE JACKSON GP-1000 88 replica for sale

Discussion in 'Children Of Bodom' started by RR480, Nov 13, 2012.

  1. RR480

    RR480 TWCC Player

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    hello guys, I have Lee Jackson GP-1000 88 replica with modification for more gain (like Alexi's)- wiring same as the original one, parts are new, not 24 years old(so you don't have to worry about non working device) aaaand because the same wiring is used, that beautiful SOUND is the same. It is fully working prototype with the original GP-1000 sound and maybe I can post some videos on youtube, if anyone is interested...maybe I can make more replicas for sale...contact me by email:)
     
  2. Fastbodom

    Fastbodom I Spit on Your Grave

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    pictures and video's FIRST we want to hear the amp before we spend mightly alot of money for something wich is an prototype.
     
  3. aka_obscure

    aka_obscure VIP member

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    As I know NOT the only circuit gives a tone. Really good components makes a tone. I saw in mine gp1000 components, wich you can`t buy now and they sounds really good. There is a schematic in internet but you can`t find "those" components wich gives a right tone.
    Anyway if youy make a really good replica I will take one for making stereo. Give a demo.
     
  4. MaximHateCrew

    MaximHateCrew ~ Needled 24/7 ~

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  5. TheWeightedCompanyCube

    TheWeightedCompanyCube The Engineer

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    Knock knock :)

    First, let me introduce myself - I am 'the maker' of the mentioned replica, RR480 is the player.

    The prototype is built around the original schematics and what is important, with as-close-to-original-as-possible parts too. I've used WIMA polypropylene caps, metal film resistor with low temperature coefficient, low ESR electrolytic main filtering caps and the PCB was scanned and rebuilt to match original exactly.

    Only major difference in our prototype are the pots - I bought models without push/pull switch (could not find them at my dealer's), so there is a switch next to the Dist, Bass and Treble pots. Models with push/pull switch are on their way, so I will probably replace them or save them for another prototype.

    The prototype is currently in a stage of mechanical adjustments - I used my metal bender to quickly shape the 1U rack box from 1mm steel plate. It works, but can't match build quality and looks of regular 1U rack box. However, a new 1U rack is ordered and when time permits it, I will swap the contents to new housing, probably with push/pull pots too.

    We will try to upload some photos (if I will find the courage to let the ugly prototype be seen :) ) and mainly, make a video.

    One more thing - RR480 said, that many tube amps/preamps have a standby switch - to let the tubes warm up before switching on the high voltage supply and input. I've added a standby switch, but wanted to ask, what would you prefer - a replica looking just like the original, or a tuned up replica with a standby switch+LED indicator and possibly a bypass switch (which will connect the output to input directly, or via adjustable amplifier (volume++ only, no distortion)).
     
  6. Fastbodom

    Fastbodom I Spit on Your Grave

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    hey TheWeightedCompanyCube, Very cool your working on this project, first of all there might be some idiots that will come in this thread and just say something idiot what ever, ignore that and keep focussing on this project. if this amp Really works and gives us the Same Sound and output not only in sound but in numbers and diagrams to i will be highly intrested, WHAT not about you could make an replica of an SP-1000 poweramp to ??

    anyway, as you discribed about the standby switch. i think its an cool feature to have that, but it really doesnt mather actually cause the sould will come eventually if the tubes warm up wich takes like 5 seconds?
    mainly important is that the looks doesnt mather. it has to be safe from electronical shocks to the human body when your in contact and the Sound Has to be the same ! as an real GP-1000, prove me it rocks and ill be intrested to have one. its always fine to have an backup amp when your on the road.

    another question, is this one going to be an replica of an GP-1000 87'th model(fender model) or an 88th model ?(marshall model)

    this link might have some usefull information about capacistors in the 88 model : http://www.premierguitar.com/Magazi...e_the_Design_of_Lee_Jacksons_Rack_Preamp.aspx

    "quoting : An interesting difference between the ’88 models and the ‘87s is the tone stack capacitors: The '88 has a .1uF midrange capacitor and a .2uF bass capacitor as part of the tone stack. The '87s have the Fender spec .047 and .1 respectively. This ’88 spec seems rather innovative… and sounds really good! ''
     
  7. Rune

    Rune Member

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    A bypass switch for direct recording is good, but not really needed since you need a poweramp to get a good sound out of it.

    What I would like to have is an effects loop with both send and return for keeping effects in signal (delay, chorus and so on).

    A even better gain modification that drives it a tiny bit more than what I've done to the originals. (So that I could play harder music like black-metal or similar on it.)

    Furthermore....a standby switch is only nesissary for amps with power staged tubes, the gp-1000 only got three preamp tubes so it's kind of not needed. Preamp tubes get perfectly saturated within a minute of power while power amp tubes needs a good 1-5 minute warming up.

    And pricing, not more than $300/€250 or people won't even be interrested.
     
  8. TheWeightedCompanyCube

    TheWeightedCompanyCube The Engineer

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    Hey there.

    We have finally managed to make some videos. Unfortunately, only with microphone integrated in camera and the sound is quite.. eh.. shitty :D Don't worry though, there is a plan involving high quality microphone, good sound card and another small recording session.

    Also, excuse RR480's playing skills in some parts of the songs, he was (and i quote) 'f***ing freezing'. :devil:

    Aaand finally, to the videos:

    http://youtu.be/odfGA8E4Ihg (quick warm up)

    http://youtu.be/2QB6PldwF4k (with music in background.. i turned it down a bit after the intro, but it wasn't enough.. flooded camera's tiny microphone)

    http://youtu.be/W0NxxJ5rEJE (no background sound, at 1:25 I moved the camera close to the front of the speaker and the sound came much closer to reality.. should have been there all the time.. well, i'll know for the next time)


    And also to your questions and suggestions:
    @Fastbodom, yes, we would like to make a replica of SP-1000 too, but the problem is, that I can't find the schematics anywhere and also can't find anyone willing to borrow me one for a week or two. I would carefully remove the covers, measure the internal parts values, create circuit diagram and return it to the kind soul who borrowed it. Sadly, I don't suppose anyone would have the balls to send their SP-1000 away. Mechanically and electrically speaking, there is nothing to worry about, it is a quite simple job.

    About the standby switch, alright, thanks for the clarification. I will change it from 'high voltage enable' to 'ground input jack', so when activated, it will disconnect and ground the input, so you can remove guitar cable without the nasty clicks.

    For the exact year, it is a replica of 88th model. It has the mentioned gain modificator and I will also try to get a bit higher gain like Rune suggested.

    @Rune - if I understand correctly, the effects loop is usually connected before the Distortion circuit, right? Anyway, no problem, it is a simple mod.
     
  9. Rune

    Rune Member

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    Thanks for the videos! Sounds gainy enough because you put the gp-1000 replica output directly to the crate amp input this puts it in front of the amp and acts like a distorition pedal. This gives the amp more control but preserves the crate sound and doesn't give us the real sound of the gp-1000. I want a test where it's either connected to the return part of an effects loop of a combo/top or plugged into a poweramp and further to a cabinet.

    Mabe I could post pictures of my sp-1000? close ups n stuff?

    Effects loop:

    Doesnt really know the techincal info on this but its supposed to be after the distortion and tone controls, but before the master outputs volumes. When you connect anything to the return only, it cancels the amps signal and only master volume works. Thats if you'd like the sound if a another preamp or distortion pedal and want to give it tube sound. When connected only to send you get no sound but sends all your signal of the gp-1000/amp to the connected pedal/effects unit/amp. So both connected gives you an option to put signal fx's in their correct path. reverb, delay, phase, chorus and so on sounds best after distortion but before any volume adjustments. There are two different effects loops; serial and paralell, but I guess you have to google for more info.

    By the way, where are you guys located and do you mod the different voltages? (110v/240v)
     
  10. TheWeightedCompanyCube

    TheWeightedCompanyCube The Engineer

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    Hey,

    the gp1000 was connected to the input, but the Crate was switched to clean channel, where it is supposed to sound like a regular poweramp (no gain modifications, only the low/mid/high equalizer). Anyway, we are able to connect it to a poweramp and i suppose there was some cabinet laying around. And I think that the Crate combo has a return effects input, so we will check that too. If not, I have H&K one which has effects input.

    If you could make closeup pics of the sp1000, I suppose I would be able to recreate it. But without direct access to the thing, it is almost impossible to get exact voltages and so on. Could you give me your email via PM, so we can talk about the details?

    About the effects loop - ah, so after the Distortion, but before Master.. sure, no problem with that. (gp1000's configuration is input jack -> preamp tube -> tone controls -> volume -> distortion tube (bypassable for clean) -> master tube -> master volume -> output jack)

    We are from Slovakia, and yes, it is possible to make it work for both 110V and 240V. I could connect a selector switch inside the preamp, or simply hardwire it according to anyone's wish. I don't like having the selector switch on the rear of the case, you never know when someone will try to switch it to 110V when connected to 240V.. It would double the voltages inside, destroy tubes and most of the expensive components. Possibly even the combo or poweramp connected to it. Not nice.
     
  11. Fastbodom

    Fastbodom I Spit on Your Grave

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    Rune Nice questions :)

    im going to +1 about the voltage, 230V is what i prefer but doesnt make sence. its all possible,

    on the Effectloop wich Rune talked about. if this Runes the pureness of the GP-1000 authantic sound. leave it away. i really like to have something good and reliable on the road when your touring, not something wich got experianted with and could break down anytime.

    if TheWeightedCompany cube is not intrested in those SP-1000 pictures Rune., I am !,


    the video's Sound good to me, can you go like Volume FULL, destortion Full and pulled, Trebble Full and pulled, middle full, Midshift 3, Bass 12o clock pulled, Master 2 output 10'o clock record in your next vid, And if that is even possible with an guitar wich got an J50BC Or HzH4 pickup. i could compare the sound to my setup as im running the preamp to an combo marshall amp on return part(effect Loop) that rune is mentioning to
     
  12. TheWeightedCompanyCube

    TheWeightedCompanyCube The Engineer

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    @Fastbodom, don't worry about the effects loop suggestion, it is a simple adjustment involving two cables and two jack sockets. If nothing is connected to those sockets, it will behave exactly as original. But of course, it is possible to make this mod as an addon.. you want it, it will be there. You don't, I won't touch the signal path :)

    I am uploading another video, where I fiddle with the knobs while RR480 is playing the same riff. As I've read many times, the mid shift knob has the biggest influence on the sound and it is exactly how our replica behaves :D But more to the point - RR480 used pretty much the exact settings as you specified (our knob indicators start at 6'o clock and end around 4'o clock, so don't get confused). Maybe the masters were a bit louder and Bass too. Anyway, I wrote your request down, will make a video using that settings (and connected to the return path of the combo). ;)
     
  13. TheWeightedCompanyCube

    TheWeightedCompanyCube The Engineer

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  14. Fastbodom

    Fastbodom I Spit on Your Grave

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    its starting to get way more intresting :D the amp sounds pretty good ! whats your opinion Rune ?

    some few questions id like to get awnserd, what Volt will the amp be made, where are you guys from? europe or USA ?

    will the front or faceplate be painted or indicated atleast ? if not painted maby press letters and numbers (wich you can hit into the plate with an hammer ? ) you'll get me ;)
    like these
    [​IMG]

    Next to that. what price range are you guys aiming for ? compared that to the price of all the parts and the man hours building the amp.
    let us know !

    btw how about advertising ? you want to keep it low profile ? or do you want to make a big batch ? id quess the more people willing to buy one the cheaper the amp will get ?
     
  15. Rune

    Rune Member

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    Sounds very similar to my USA copy of the GP-1000 (got new Groove tubes in it). They give the amp that chrunchy sound that you can hear on the later Bodom albums. I'd like to hear some soloing if your friend is up to it, maybe some easy bodom stuff and I'd still like to see pictures of the mainboard and back. Where is the on off switch? And do you got a IEC input for the power? I live in Norway so 240v fits my bill as well.
    Effects loop should be before the master tube and master volume then I guess.
    I'll give you my email once I got the pictures done (SP-1000), guess it's no hurry since you got the GP-1000 as main focus for now.

    I would like to buy the prototype with effects loop and direct output for recoring/mixing board, if I can get it cheap enough, doesn't even need a better rack casing, like that metal polished feel of it. :p It's not like I need it (already got two modded originals; late 87 and early 88), but it would be great for those extra attributes and it would be more light weight so I could drag it off to friends and rehershal places with more ease.
     
  16. TheWeightedCompanyCube

    TheWeightedCompanyCube The Engineer

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    This is really picking up some speed. Me likes :D

    @Fastbodom - as I've said, I can make both 110V and 240V versions. Here in Slovakia (Europe :) ) we use 240V. The power transformer we use has both inputs, so it is only a matter of connecting four wires correctly. I am thinking about putting inside the chassis a voltage selector switch (not accessible without screwdriver), or hardwiring it according to each order.

    The final version will be installed in black professionally made 1U rack. The front indicators will be painted or made as a sturdy sticker. I have good experience with stickers from local company, but painting them will look professional.

    I am currently looking into a file with all price calculations. Can't tell you the exact number now, it still needs some math to be done. I have seen them go on eBay for 600-700 USD, there is one for 1200 now (nobody wants it.. what a surprise). We definitely want to go significantly lower, but I really don't have the exact number yet.

    The thing about advertising and all sorts of stuff.. is quite complicated. I wanted to make only a few pieces for starters.. And also talk to Mr. Lee Jackson if he is not holding a grudge for releasing a replica of his work. I know he wants to make a new version in a pedal form, but it was 2010 when he said that first pieces will go to production soon. Now it is almost 2013 and I am just trying to fill a hole in the market.

    @Rune - glad you like it :) tomorrow we will have another recording session, will try to record some soloing. I did not make any pictures, but there is another video looking at the open preamp from the top.
    http://youtu.be/zX4w29U2-OY

    I tried to make it as close to original as possible, but the last stage of completion was quite rushed, because RR480 wanted to try it out badly :D It needs some cable management and of course better tube holder part with some protectors and ventilation holes. But this is the case with every first prototype. AS you can see, the pots are not on the board, but connected with short cables. Final version will have them on board (as I've said earlier, the push/pull pots are on the way). The board layout is exactly same as original (was created from photo).

    The on off switch is not there yet, but will be in place of the standby switch on the right of the front panel.

    Input power is IEC, yes.

    SP-1000 pictures -> brilliant. If we somehow manage to make a replica of it, I will make you a GP-1000 with all modifications you want for the price of parts. You don't have to hurry, but would be nice if you just quickly made 1 or 2 pics of the guts.. so I know what can I expect later.

    If you wanted, I am even able to make smaller, lighter, non-rack version. It could probably fit in half or 3/5 space of the regular GP-1000.
     
  17. Rune

    Rune Member

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    Mr. Lee Jackson was actually close to relaseing his GP-1000II earlier this year, this would include the modifications we have been talking about except gain modification, direct output and standby-switch, but he was open to put in mods for free or cheap. He was going to sell his for $599 plus shipping, but there were fewer than 10 people wanting to buy it within a month of only makreting via a link at his website which also was hard to reach. Lee Jackson isn't the smartest man alive...obviously. So it got cancelled. I got a little late on this because I had just bought my ENGL rack setup (e570 + e840/50), and money was short + the ENGL can really almost make the same sound. Only lacking a little bit mid-drive (which is what the GP-1000 is legendary for).

    The one on ebay for 1200-1000 USD won't sell ever because of two reasons, it's a lot more expenisve than what it cost originally. And it got this dude who wants to be paid in cash and cannot ship??? :tickled:

    Well the most expensive unit I have seen that got sold is the one mitch sold (-warheart-). Think he got around 600 for his or something, but regularly they sell for 400 +/-. And the gain-mod is like $5 parts and 15 min with a soldering iron and a screwdriver+wrench.

    300 USD would be fair for the retail price for this. But at first you need a market so you might lower it to 250 or something like that.

    I'd love a small cheaply made one to drag around, and I could provide any needs for pictures, I even have some spare gain mod caps/resistors that I used for my originals, they where originally produced for gain modding JMC-800 back in the 80's and sound killer. I could ship some of those for free as well.

    Well at least we know that shipping would be cheap since all interrested at the moment are residented in Europe. :p

    Seems just like the original board with a few slight modifications, but I see one major error which could ruin the whole amp. The tubes are on the inside of the amp with no grills or air venting at all. This makes the tubes really hot and burns them faster, and if you keep it on too long it could actually burst into fire. But as you said it's just a prototype steel rack unit.

    I'll go open my SP-1000 later tonight and I'll take a couple of pictures and get back at you.

     
  18. Rune

    Rune Member

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  19. TheWeightedCompanyCube

    TheWeightedCompanyCube The Engineer

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    Hmmmm. That does not seem very hard to reproduce. I almost forgot it is quite old tech, so no state of the art technology. Could you get one more pic of the power transistors mounted on the sides? Or just tell me what is written on them. And if there is a label on the transformer specifying voltages, that too. You will probably have to undo the black tape around the transformer.

    Thanks a lot!
     
  20. Rune

    Rune Member

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    [​IMG]
    [​IMG]
    [​IMG]

    If you need better or more pictures I'll fix some at a later point. :)
     

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