woah, i missed that.
damn, lee jackson straight up copied that huh?
high gain lee jackson gp 1000
Moderators: pompeiisneaks, Colossal
Re: high gain lee jackson gp 1000
Yes ......Paul had been doing this circuit for a long time before Fender..but Lee did work at Fender at that time these amps where made with Paul.Gorhrut wrote:woah, i missed that.
damn, lee jackson straight up copied that huh?
Re: high gain lee jackson gp 1000
This is close what Ive done before. I just did this quick drawing using the Concert schematic.... Its not exact...but it will give you the idea.
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Re: high gain lee jackson gp 1000
ok, i think i understand.
thank you for breaking everything down and putting on paper for me
thank you for breaking everything down and putting on paper for me
Re: high gain lee jackson gp 1000
ok, back to what rune had initially asked about...
this is what his tech suggested:
"There are both 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. 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. So isolate routing and then you can do some basic gain-mod"
so here is the relay underside on pcb
[img
840]http://i.imgur.com/0OWVcly.jpg[/img]
i figured the problem is the relay, so lets remove the relay from the schem and just connect the traces, so i got this
[img
854]http://i.imgur.com/bA5lr4o.jpg[/img]
and the tech had said the traces being too close was the issue so i did this
[img854]http://i.imgur.com/SAh7I0x.jpg[/img]
so the coupling cap from v1b connects to lug 3 dpdt. 5 and 2 go to ground and master out. 1 connects to the distortion pot. 4 goes to the wiper of the internal trimmer. and 6 connects to ground.
to take it one step further, i mapped out pre-distortion traces(red) and post distortion traces(blue)
[img854]http://i.imgur.com/39DQH8K.jpg[/img]
there were still alot of traces really close to each other so i figured why not replace the traces with sheilded wire and separate them a bit more(sorry got the colors flipped in this one) (also, removed relays connections to power section)
[img854]http://i.imgur.com/rCpwE7h.jpg[/img]
do you guys think this might fix the oscillation issues?
this is what his tech suggested:
"There are both 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. 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. So isolate routing and then you can do some basic gain-mod"
so here is the relay underside on pcb
[img
840]http://i.imgur.com/0OWVcly.jpg[/img]
i figured the problem is the relay, so lets remove the relay from the schem and just connect the traces, so i got this
[img
854]http://i.imgur.com/bA5lr4o.jpg[/img]
and the tech had said the traces being too close was the issue so i did this
[img
854]http://i.imgur.com/SAh7I0x.jpg[/img]
so the coupling cap from v1b connects to lug 3 dpdt. 5 and 2 go to ground and master out. 1 connects to the distortion pot. 4 goes to the wiper of the internal trimmer. and 6 connects to ground.
to take it one step further, i mapped out pre-distortion traces(red) and post distortion traces(blue)
[img
854]http://i.imgur.com/39DQH8K.jpg[/img]
there were still alot of traces really close to each other so i figured why not replace the traces with sheilded wire and separate them a bit more(sorry got the colors flipped in this one) (also, removed relays connections to power section)
[img
854]http://i.imgur.com/rCpwE7h.jpg[/img]
do you guys think this might fix the oscillation issues?
Re: high gain lee jackson gp 1000
@rune,
if you dont care about being able to switch to clean, you can just set it up like this.....
remove the relay here and from the power section and then take off the footswitch jack on the back of the gp. scrape away the old traces with an exacto knife or the corner of a screwdriver. i cant promise that this is exactly what the tech from finland would do, but from his description, this is my best guess.
[img854]http://i.imgur.com/WrXOLIG.jpg[/img]
if you dont care about being able to switch to clean, you can just set it up like this.....
remove the relay here and from the power section and then take off the footswitch jack on the back of the gp. scrape away the old traces with an exacto knife or the corner of a screwdriver. i cant promise that this is exactly what the tech from finland would do, but from his description, this is my best guess.
[img
854]http://i.imgur.com/WrXOLIG.jpg[/img]
Last edited by Gorhrut on Fri Dec 05, 2014 3:46 pm, edited 1 time in total.
Re: high gain lee jackson gp 1000
Nah, you totally unplugged the distorted signal on those pictures. I'll do some paint stuff later if I got the time.
Re: high gain lee jackson gp 1000
where is the distorted signal disconnected? signal com out of v1b goes to c9(2200p coupling cap) and goes straight to the distortion pot. this goes through v2a and v2b out thru c4 and then to the internal trimmer(p100) then wiper of p100 routes to master out pots and then into v3a and b.
it still goes thru the exact same paths that it is originally, i just removed the relay and the dist push/pull from the circuit.
it still goes thru the exact same paths that it is originally, i just removed the relay and the dist push/pull from the circuit.
Re: high gain lee jackson gp 1000
Nevermind, the solder was so close I thoight R15 and D7 connected...
Internal pot does go to ground and just found out it goes to masters too, thanks for clearing that.
I thin you would get rid of the ocillstion if you only removed relay, wires (resistors) to relay power section and D5 and coupled in between. If you still get oscillation, just cut/drill out traces going back to the now removed relay.
Internal pot does go to ground and just found out it goes to masters too, thanks for clearing that.
I thin you would get rid of the ocillstion if you only removed relay, wires (resistors) to relay power section and D5 and coupled in between. If you still get oscillation, just cut/drill out traces going back to the now removed relay.
Re: high gain lee jackson gp 1000
might actually try this on my clone since I'm still promised a new PCB from my techs even if the project is dead.
Re: high gain lee jackson gp 1000
yeah, let me know if it works...
Re: high gain lee jackson gp 1000
wont be doing any cutting today, but removing the parts and wire two points with regular sheilded cable is quite harmless.
Re: high gain lee jackson gp 1000
Its easer for me if you know what the parts are and the value on them... not just d5 r4 z7...you know....Rune wrote:Nevermind, the solder was so close I thoight R15 and D7 connected...
Internal pot does go to ground and just found out it goes to masters too, thanks for clearing that.
I thin you would get rid of the ocillstion if you only removed relay, wires (resistors) to relay power section and D5 and coupled in between. If you still get oscillation, just cut/drill out traces going back to the now removed relay.
You are just going to butcher the circuit board.... I would put the pots, relay and a few other parts on a new board that bypasses this part of the circuit. You will also figure out what works and what doesn't.... without butchering up the original circuit board.
Learn ..slowly... where the problem is..but also learn how the circuit works and what the parts do ......D5 has no effect on the audio.....its part of the power supply to the relay ..and its not a problem...as far as the oscillation. Remember that thread on the Bodom forum ..it will show you where ...thinking you know more then you really do can lead you (that thread is just goofy).
For a better layout for the relay.... just go look at the Dumble.
Re: high gain lee jackson gp 1000
Okay, so removed the relay, D5, R15 (which essentially is a wire). Did no cutting at all. And rewired from points in pic 3 and 4 in Gorhruts post . Got audio and it sounds just the same. With noise and all. Maybe if I wired it from the internal pot I'd get better results. The layout of the clone is a tad better and easier to work with even if its smaller. And maybe if I cut some traces it would get better....
What thread on the Bodom forum? And what would it show me?
Lee Jackson GP-1000 got more natural distortion than the Dumble amps I've heard. Or???
What thread on the Bodom forum? And what would it show me?
Lee Jackson GP-1000 got more natural distortion than the Dumble amps I've heard. Or???
Re: high gain lee jackson gp 1000
The one on the Ultimate Metal Forum.Rune wrote:Okay, so removed the relay, D5, R15 (which essentially is a wire). Did no cutting at all. And rewired from points in pic 3 and 4 in Gorhruts post . Got audio and it sounds just the same. With noise and all. Maybe if I wired it from the internal pot I'd get better results. The layout of the clone is a tad better and easier to work with even if its smaller. And maybe if I cut some traces it would get better....
What thread on the Bodom forum? And what would it show me?
Lee Jackson GP-1000 got more natural distortion than the Dumble amps I've heard. Or???
Dumbles will do all styles of music. Its the same basic idea. I would say the Dumble has a more natural distortion over the Lee Jackson.
Last edited by Cameron on Fri Dec 05, 2014 11:00 pm, edited 1 time in total.