LEE JACKSON GP-1000 88 replica for sale

[Rune]

Yeah the JE-1000 works! Got really expebsive parts, but it is very solid. As well as the SP-1000.

 

[gorhrut]

So I did some minor work on the amp today, it is so damn cold in Norway so it is hard to stay at my rehersals for more than an hour, so I tried wiring the trimpot ground to input, now that's not where it should be grounded. Because when connected there the amp squeels like hell when not playing and the pot only changes it's frequency a little bit.... Also took some pictures of studying the placement of R17... I'll get back at doing/testing the rest of this stuff tomorrow...

grounds should go the the cathode ground of their respective stage and then that should go to the chassis ground point. which could be difficult on pcb since there might not be a place for this in the design. that is why i am changing my gp to turret board construction. better for modding and working out problems.

i cant say for sure what is going on with your gp. the only time i had squeeling was before i modded the relay network and then i was modding the input jack and had some squeel.(both times it only squeeled when there was no guitar plugged in) i fixed this by moving the 68k resistor on the input up to the tube socket itself. someone from the other forum said most likely all i did was fix a solder joint.....that might have been but its a good idea to move this resistor anyways. the closer it is to the tube socket the less room for noise to get in before the first tube, which will amplify rf/hum like crazy.


im sorry the gp is not working out for you, rune.

 

[Rune]

Yeah, but remember it is only the GPSP and as far as Im concerned I'll still get a replacement guts for it when TWCC figures out what's wrong. I mainly try to figure out this before that to have a working amp. If I decided to do the same mods on my original I think most of the issues would be solved by removing relay and moving C9 and plate resistor to Tube PCB. The GPSP has always had trimpot issues, it has never worked right... so might just be the pot or might be some issues with R17 and grounding issues. I don't think there is bad solder joints on gpsp, seems unlikley he would do sloppy work on same design 3-4 times. My prototype acted the same way as well as the original prototype and Woodworms unit..... do you have some more quality pictures of the 68k placement and the backside (trimpot) pot on your unit? Just want to be 100% sure of the hookup before I attempt something like that.

 

[gorhrut]

unfortunately the only pics i have i posted on the other site, and i gutted my gp to redo it on turret board. all pretty straight forward tho....

for the 68k on the input jack just unsolder it and the shielded cable from the jack and move the resistor on to the tube pin(keep resistor leads as short as possible) and then use the same shielded cable to resolder it. you can do this to all grid stopper resistors to cut down on some noise.

for the trimpot, page 11 of the thread on amp garage shows pretty well what i did. 1 wire off of .022uf coupling cap from pc board goes to lug 3 of 1m pot(trimpot) 1 wire from ground plane on pc board goes to lug 1 of pot. and then lug 2 of the pot goes to the masters.

 

[Rune]

Yeah but is seems like they are soldered to the back of the pot as well, is that really necessary? I know the connections and where they go lug wise. Thanks for confirming it!

 

[gorhrut]

no, no connections on back of pot.

and no problem dude

 

[Ngetal]

Hey lads, I hope I'm not too late to the party. Awesome thread and kudos to all of you involved in making this thing a reality. Been looking for a GP1000 on and off for years now and this might be the thing for me - I like modded stuff. I have a JE-1000 replica that I built with some mates based on some schematic we found but I'd surely be up for that too.

I dropped an email to TWCC yesterday - no reply yet but seeing how busy he is usually, I won't be worried for a few more days I so want to buy this thing!!

 

[gorhrut]

sorry to inform you ngetal but it seems the gp clone has some unresolved issues. rune has been working his ass off to try and figure out the issues but even if he does i dont know if twcc is still producing these.(he very well may be, idk) you may be better off waiting for one on ebay, or if youre skilled enough you can make your own. its a very simple circuit.

actually, there is one being offered on another forum i am a part of. i might be able to get you the info on that one. just an fyi, gp's are not the best platform for modding. they are totally pcb constructed and it is very easy to lift a trace.

 

[Ngetal]

Yeah, read about the issues but will have to go back to the sound samples as what I heard so far is great. I have time and would rather wait then get an original one, I already prefer this. I lack the required skills and time to tinker with it but most enhancements have already been done here that I'm looking for: standard mods, room mod, 2nd eq etc.

What I would add to this:
- 9V input so I don't need a battery for the JE
- 2 separate eqs for clean and dist (on the same footswitch as the clean/dist)
- 2 footswitchable power amp volume controls for solos and stuff

 

[Ngetal]

Also, a question: what speakers/cabinets would you recommend for this amp? I would mainly be playing/recording at home so I don't need anything big or fancy, thinking of getting some 2x12 or even 1x12 cab.

 

[srob7001]

I don't have this amp set up, but you really can't go wrong with some vintage 30's.

 

[Rune]

Yeah, the sound clips are great, at least some of them are, but they were all recorded before we made the last version which was given to Alexi, me and sold to Woodworm, unfortunately the latter version had some even worse issue than the prototype... and with the necessary mods activated it got even worse, so there is some noise issues there still, and I have to order some parts to resolve it I think. TWCC is working contracts all over the world as a engineer, I'd rather contact RR480 on PM if you wish to order, even with my quest to get it right, TWCC could get the info and test it in no time if you'd like one.

My 88 is supposed to go to the Bodom tech later this year for modding, so I'll resolve the issue(s) one way or another.

For old Bodom 4x12 Marshall 1960B with 75T's
For new Marshall 1960BV with V30, ENGL 4x12 with V60 or Orange 2x12 V30. All been used in studio or live in recent years too so, get a Sennheiser e906 or a Audix i5 for recording.

 

[Rune]

Further mods could be done to the unit as whole yes, but, then it would need to be a 2 space rack unit. It is pretty packed as it is...

 

[Ngetal]

Thanks for the tips, lads. I PM'd RR480, will see if he has time to check his messages

I wouldn't mind a 2 space unit as long as it has all the features I need.

 

[gorhrut]

http://youtu.be/IpjQZH6ETds

this is my first video on this youtube channel. i made this channel to help introduce people to amp modification/repair. all mods will be done on my customized gp1000 preamp. if you guys want to hear what effect different mods have, let me know!!!

please like, comment, and subscribe. i will have several more videos in the near future and it is my intention to GREATLY improve the video quality and information quality.

 

[Rune]

http://youtu.be/IpjQZH6ETds

this is my first video on this youtube channel. i made this channel to help introduce people to amp modification/repair. all mods will be done on my customized gp1000 preamp. if you guys want to hear what effect different mods have, let me know!!!

please like, comment, and subscribe. i will have several more videos in the near future and it is my intention to GREATLY improve the video quality and information quality.

Nice, did you change the cathode resistor in those vids? 1,5k or 820? That turrent board design is really working well. That's what TWCC should have done in the first place and it is totally possible to add any kind of switching system by wiring it so far away from the signal as possible. Also, I've noticed that having the SP-1000 part on in the clone will give it slighly more hum... That could be changed, but I think the whole amp needs to be about as big as a VHT power amp to get something like that hum free. Best way would really be to design it like a handwired oldschool fender or dumble amp and make it more like a preamp 16" rack unit instead of having a full head, most of the heads are just blank space nowadays anyways and does nothing to the sound, just makes it harder to drag around. I guess some companies like Orange understood that and made all their amps smaller in size regardless of output.

 

[gorhrut]

im going to do cathode resistors in another video. yep, the turret board is great!!

my hum issue is definitely 60hz/electromagnetic interference coming in via the pickups. there is a transformer on an overhead power pole about 20ft from my house. that thing is the culprit. tried my gp at another place and it is quiet. so at home all i can do to stop it is get a noise gate. isp decimator pro rack g looks amazing but that thing is EXPENSIVE.

the transformer for the SP does the same thing INSIDE the amp. the toroid transformers in the gp and sp are supposed to be quieter than standard EI transformers. the guys on amp garage have something they call "the headphone trick" idk exactly how to do it but you use headphones to find the quietest possible position in the amp for the transformers.

 

[Rune]

What about the hush in the rocktron, can it put the noise away?

Both transformers is located as far as possible from their PCBs, but they are next to each other and that might be a problem... Anyways a little hum isn't annoting me, that shitty noise my gp's are making is realy bumming me out. But moving cables and tidying seems to relsove it somehow. Anyways might ship the original off to the Bodom tech soon enough...

 

[gorhrut]

nah, the hush doesnt cut it. in fact the hush in the intellifex seems to do almost nothing. i even tried it before the preamp, right after the guitar, and still it had almost no effect.

what are you having the tech do to it? just the relay network fix?

 

[Rune]

The guy might have more interresting mods and the relay thing isn't all. All cables running too close to power source stage are making this noise. And foils too I belive since he mentioned that. Having the amp open wide for unlimited distortion (in a good way) is what I want.