Looks like this will be a flaming thread. Yeah I got it, I was being over the top flamboyant and angry, sorry for that. Just didn't like gorhruts and a couple others here badmouthing my ebay auction.
I worked quite hard to get all the information on this amp, but yeah dosen't matter now that the info on the main thing I need is too cryptic. Just looking for help like any other guy in here.
high gain lee jackson gp 1000
Moderators: pompeiisneaks, Colossal
Re: high gain lee jackson gp 1000
A word to the wise, walk small and ask nicely, what these guys don't know isn't worth knowing most times, those that play the game go away enlightened and happy folks, those that don't end up as sad freaks like burgess 
Re: high gain lee jackson gp 1000
Kind of did, and I've said I'm sorry for my outburst and explained why. Now I need some advice and this place seems like the place to ask about stuff like this instead of spending 7-800$ in total for the same thing from an old tech in another country.
Re: high gain lee jackson gp 1000
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Last edited by matt h on Fri Mar 27, 2015 7:06 am, edited 1 time in total.
Re: high gain lee jackson gp 1000
If you are talking about the EQ/tonecontrols on the preamp, they are placed behind the first gainstage in the circuit. So they doesn't really do anything at all (almost). Even the distortion pot doesn't really add that much distortion. The only effective knobs on the preamp is Preamp volume, mid-shift and master volumes.
Now if you're thinking of placing an EQ after the preamp that's another story, but not what I want to use. I mainly enjoy the "tone" as it is with minor tweaks. What I really would want is more distortion/sustain without the damn oscillation/crossover-distortion buzz that comes when the tone decays. Now this amp gurus I've got some info from says it is a design flaw and not judging Lee Jackson or anything because this is one of his first designs and wasn't really intended for modern Metal.
Now if you're thinking of placing an EQ after the preamp that's another story, but not what I want to use. I mainly enjoy the "tone" as it is with minor tweaks. What I really would want is more distortion/sustain without the damn oscillation/crossover-distortion buzz that comes when the tone decays. Now this amp gurus I've got some info from says it is a design flaw and not judging Lee Jackson or anything because this is one of his first designs and wasn't really intended for modern Metal.
Re: high gain lee jackson gp 1000
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Last edited by matt h on Fri Mar 27, 2015 7:06 am, edited 1 time in total.
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beasleybodyshop
- Posts: 1089
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Re: high gain lee jackson gp 1000
This is why it's hard to talk 'lectronics with metal heads.
(sigh)
As someone who grew up trying to sound like Metallica, I can confirm this.
(sigh)
As someone who grew up trying to sound like Metallica, I can confirm this.
"It's like what Lenin said... you look for the person who will benefit, and, uh, uh..."
Re: high gain lee jackson gp 1000
The point is to modify the preamp myself in order to get more distortion. I get that I could buy a good rack EQ and try to dial in the tone better, but that's really not the request here. I kind of know what needs to be done, but I thought I'd ask here for guidance.
I have a tech that did this mod in the first place, although he have not performed this mod in about 10-12 years now, he got notes and the equipment needed for the job. But he is only sharing the basics to me, because he is making a living of this kind of thing. And he said and this is direct quotes:
"cause I did not take quality pics of mods, I can only give "more common" instructions, but I guess during the work my idea crystallizes, and thus job can be easily done. There are bith pre- and post distortion signal pcb foils cursing along, and if you increase gain, you get an extra present in form of 20... 150kHz oscillation. It makes the tone harsh. I'm afraid Lee founnd this too. Sometime nearby oscillation can be nice, but it is uncertain to keep in control (different gain factors in tubes etc). So isolate routing and then you can do some basic gain-mod"
He also said: "This is caused by some poor design of "spider-network" around the relay at PCB. What I've done is rewiring and pcb chopping around there and then this amp is free gain without high frequency instabilities and more shearing."
Also has some other emails saying basically the same in different words.
Thats what I want to do, not changing the tone that much, only the distortion.
I have a tech that did this mod in the first place, although he have not performed this mod in about 10-12 years now, he got notes and the equipment needed for the job. But he is only sharing the basics to me, because he is making a living of this kind of thing. And he said and this is direct quotes:
"cause I did not take quality pics of mods, I can only give "more common" instructions, but I guess during the work my idea crystallizes, and thus job can be easily done. There are bith pre- and post distortion signal pcb foils cursing along, and if you increase gain, you get an extra present in form of 20... 150kHz oscillation. It makes the tone harsh. I'm afraid Lee founnd this too. Sometime nearby oscillation can be nice, but it is uncertain to keep in control (different gain factors in tubes etc). So isolate routing and then you can do some basic gain-mod"
He also said: "This is caused by some poor design of "spider-network" around the relay at PCB. What I've done is rewiring and pcb chopping around there and then this amp is free gain without high frequency instabilities and more shearing."
Also has some other emails saying basically the same in different words.
Thats what I want to do, not changing the tone that much, only the distortion.
Re: high gain lee jackson gp 1000
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Last edited by matt h on Fri Mar 27, 2015 7:05 am, edited 1 time in total.
Re: high gain lee jackson gp 1000
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Last edited by matt h on Fri Mar 27, 2015 7:05 am, edited 1 time in total.
Re: high gain lee jackson gp 1000
Still, I don't want any "easy" route, that is not the point of the whole project. And still it wouldn't help much. Ive tired ODs and EQ pedals in front of the amp and in between the preamp and the power amp, but can't dial away the buzzy decays at the note trails. I could minimize them by reducing treble frequencies, yes, but they are still there, and I want to get rid of it without spending 800$ or a tad less.
Re: high gain lee jackson gp 1000
Dustin, not all metalheads are the same. 
1) Rune- so.. You're trying to get rid of the noise that the clipping diodes are making on the tails of notes? And, you want more gain? Do I have this correct as what you're trying to do/make happen?
2) The crosstalk you're speaking of, if inherent in the PCB design, you're not getting rid of that because it's a design flaw and you're working with PCB. (Whereas how most of the builds 'round here go, components mounted on a board, you can typically move stuff, wires, etc.) You could gut that channel out and rebuild it on a separate board if you want to really get into it. That's not the answer you want to hear, and I know that. But, that's life. Or, if you don't use the clean channel, you can just plain kill it.
*poof* no moar crosstalk if one leaves the room.
1) Rune- so.. You're trying to get rid of the noise that the clipping diodes are making on the tails of notes? And, you want more gain? Do I have this correct as what you're trying to do/make happen?
2) The crosstalk you're speaking of, if inherent in the PCB design, you're not getting rid of that because it's a design flaw and you're working with PCB. (Whereas how most of the builds 'round here go, components mounted on a board, you can typically move stuff, wires, etc.) You could gut that channel out and rebuild it on a separate board if you want to really get into it. That's not the answer you want to hear, and I know that. But, that's life. Or, if you don't use the clean channel, you can just plain kill it.
*poof* no moar crosstalk if one leaves the room.
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Reeltarded
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Re: high gain lee jackson gp 1000
Buzzy tails? Clippers?
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
Re: high gain lee jackson gp 1000
^Reel,
That's what I was wondering about. Is that an artifact of using clippers in any of your experience? In some amps, diode clippers sound super awesome. In my measly one experience with trying them, they weren't what I was looking for.
However, I have a built in noise gate with two 1N4148's, and if you play clean/lightly, you can hear them working on note tails. If this was the case, I was gonna propose an idea of removing them if he's not overly attached to them seeing as they're not in the original schem that's posted on page 1, and make up the "gain" elsewhere. (More to this story that I won't get into here)
Am I way off with thinking the tail may be diode induced? Hard saying not hearing, too. An actual schematic of as built would sure friggen help here...
*edit* This is assuming the diode clippers are a mod that he/tech has installed and is not original.
That's what I was wondering about. Is that an artifact of using clippers in any of your experience? In some amps, diode clippers sound super awesome. In my measly one experience with trying them, they weren't what I was looking for.
However, I have a built in noise gate with two 1N4148's, and if you play clean/lightly, you can hear them working on note tails. If this was the case, I was gonna propose an idea of removing them if he's not overly attached to them seeing as they're not in the original schem that's posted on page 1, and make up the "gain" elsewhere. (More to this story that I won't get into here)
Am I way off with thinking the tail may be diode induced? Hard saying not hearing, too. An actual schematic of as built would sure friggen help here...
*edit* This is assuming the diode clippers are a mod that he/tech has installed and is not original.
Last edited by Meat&Beer on Fri Nov 28, 2014 5:59 am, edited 2 times in total.
Re: high gain lee jackson gp 1000
So you mean if I don't use the clean channel I could just nap out the wire driving it through the main PCB and problem could be solved? Kind of don't think that would work as planned but....tempting.
No don't use the clean channel, and it isn't very good either, of course If I wanted a good clean there are a lot of suggestions for shaping that one out too.
Yes buzz/fizz as the note decays, most prominent on the low E string while palm muting, but also present at the other strings as you let them ring out.
Edit: No the buzz is present without the clippers too, but not as prominent.
No don't use the clean channel, and it isn't very good either, of course If I wanted a good clean there are a lot of suggestions for shaping that one out too.
Yes buzz/fizz as the note decays, most prominent on the low E string while palm muting, but also present at the other strings as you let them ring out.
Edit: No the buzz is present without the clippers too, but not as prominent.