high gain lee jackson gp 1000

[Rune]

Is it possible that the trimpot on yours is LOG and mine is Linary, I get high pitched screams like that on 50% on the clone, sadly. How did you connect the couoling cap C9 and plate resistor R14 then? Try adding a diode in paralell to R204 or R3, those seem like the places I tend to get noise on. Should really have recorded the noise I get.

The hum is on all GPs, something isn't grounded right.

[Cameron]

Is it possible that the trimpot on yours is LOG and mine is Linary, I get high pitched screams like that on 50% on the clone, sadly. How did you connect the couoling cap C9 and plate resistor R14 then? Try adding a diode in paralell to R204 or R3, those seem like the places I tend to get noise on. Should really have recorded the noise I get.

The hum is on all GPs, something isn't grounded right.

Taper has no effect on your problem.

[Cameron]

Here is a clip I did.... quick and crappy but you get the idea....

[Cameron]

finished modding. removed relay and all components that went along with that. moved v1b coupling cap onto the pin and ran wire straight to the distortion pot. had to leave the plate resistor because both v1a and b plates connect to b+ on the board. ran wire from p100(pot on back of preamp for mine) to the master outs. somehow managed 0 lifted traces/pads first time modding pcb. overall sounds really good.

i ran a test before modding. removed guitar cable from amp, all tone controls max and onboard trim maxed. there was high pitch squealing like crazy. adjusting the volume and distortion changed the pitch of the squeal but volume stayed the same. wish i had recorded it, it was pretty crazy... also got radio station when i touched the volume pot...

now that mods are done i tried the same test and squealing is gone. tried everything to recreate the squeal but couldnt do it. (guess thats a good sign) and no radio stations. only thing is a moderately loud hum that was there before. i didnt use shielded cable cuz i didnt have any on hand but ill switch it out when i do and see if that helps.

will post pictures tomorrow, and sound clip when i get my new poweramp...

For the plate resistor....... put one end of the resistor on the socket...run a wire to the resistor from the circuit board....this wire does not need to be shielded...
When you get some shielded wire ...you should be able to get it sounding better.

[Cameron]

finished modding. removed relay and all components that went along with that. moved v1b coupling cap onto the pin and ran wire straight to the distortion pot. had to leave the plate resistor because both v1a and b plates connect to b+ on the board. ran wire from p100(pot on back of preamp for mine) to the master outs. somehow managed 0 lifted traces/pads first time modding pcb. overall sounds really good.

i ran a test before modding. removed guitar cable from amp, all tone controls max and onboard trim maxed. there was high pitch squealing like crazy. adjusting the volume and distortion changed the pitch of the squeal but volume stayed the same. wish i had recorded it, it was pretty crazy... also got radio station when i touched the volume pot...

now that mods are done i tried the same test and squealing is gone. tried everything to recreate the squeal but couldnt do it. (guess thats a good sign) and no radio stations. only thing is a moderately loud hum that was there before. i didnt use shielded cable cuz i didnt have any on hand but ill switch it out when i do and see if that helps.

will post pictures tomorrow, and sound clip when i get my new poweramp...

You should be on V2 not V1 ....Leave V1 alone for now.

[Smokebreak]

Thanks for sharing, Mark. The other day I hacked the Lee Pre in an ODS type, and it was just kinda ok. Concerning your Deluxe, it looks like you split the plate load on the 3rd stage for the purpose of snubbing the B+ side, but took the coupler off the plate? Also, is that a small ceramic across the bias feeds?? I'm gonna give this one a shot. Dig the clip.

[Meat&Beer]

now that mods are done i tried the same test and squealing is gone. tried everything to recreate the squeal but couldnt do it. (guess thats a good sign) and no radio stations. only thing is a moderately loud hum that was there before. i didnt use shielded cable cuz i didnt have any on hand but ill switch it out when i do and see if that helps.

Congrats man! Great job. My guess is that (some of the) hum is coming from the heaters. This can be addressed with lead dress of said wires. On page 4, Rune posted some gut shots, they're the brown twisted together ones on the tube sockets. If yours look like this, they could be tidied up a bit for sure! Not saying that's a guarantee, but it certainly wouldn't hurt.

For the plate resistor....... put one end of the resistor on the socket...run a wire to the resistor from the circuit board....this wire does not need to be shielded...
When you get some shielded wire ...you should be able to get it sounding better.

Um, you may want to exercise a little caution if you do this one... This is the B+ supply, and I'm not sure how fast the pre discharges its voltage after power down. Just be mindful that there may be some residual juice there, check with a multimeter (DC) to confirm.

Also, if you hang a resistor off the socket, and connect a wire from the other side of the resistor to where the supply comes off the board, it'd be in your best interest to cover this exposed area of wire with heat shrink. (Hell, some black tape will do, temporarily.) You don't want to accidentally touch it when the amp is on, and you don't want it touching anything like the chassis or other components when it's live, either.

Cameron, that clip sounded not too bad at all!

[Meat&Beer]

Por ejemplo;

[img:575:101]http://bad-domain/DumbleLite/BuildersGu ... age030.jpg[/img]

[Rune]

Okay so took out coupling cap C9 and plate resistor R14 and did the same thing to them as Gorhrut, connected them to the tube socket and wired to distortion pot and plate resistor #2 R15. And guess what same annoyong noise. So guess my first thought on the problem was correct. the internal pot and its connection through the relay to distortion pot is where the problem is. Unless the tech was lying... my pot is wired bit different on the clone, and actually adds more noise than the original. The best design is the one in gorhruts amp, easiest to prevent noise, and also probably why he had little to begin with.

So no more time today. But added this little cellphone clip of the noise. Just some palm muting while holding the cellphone. Oh forgot; the pot is set to 50% and thats where ot starts to feedback and hum badly. Tone also alters a bit. Can get the noise lower on 25% or 15 (but then it kills a lot of headroom and sustain).

Loved the tone on the Deluxe Cameron! And thanks for all the help thus far!

[Gorhrut]

for some reason i cant download the clip rune posted. i can easily run my pot at 100% but i prefer turning down all the way and then back up just enough to let sound through. this makes it more shrill sounding(which i like, idk y) and cuts some hum. ill check to see if my pot is log, and ill post a pic as soon as possible. i might also post a sound clip but i dont have my poweramp yet so it would just be the gp straight to monitors....

camerons sounds good!!!

[Rune]

Weird, I recorded it with my samsung S4 and uploaded it here through it.
Now I'm at my computer, and I can download it fine and use Windows Media player to play the file. I've noticed that it is kind of shrill on the absolute lowest settings, actually, it makes sound with it on zero on my clone.... I don't like it that shrill, but then again I like the low-mid raw edge from Zakk and Bodoms earliest albums. Not the crunch from later Bodom ones (with a lot of bass added). Didn't you have a modded VHT 2/50/2, used to have one of those, but I love my ENGL e840/50 more, so I sold it. No regrets there, used the money from the deal to buy a 89 custom shop Jackson RR.

[Gorhrut]

[img1872]http://i.imgur.com/GfP3YzP.jpg[/img]
overall gp pic



[img1872]http://i.imgur.com/e1TMhW0.jpg[/img]
tube sockets.



[img1872]http://i.imgur.com/B5rpwRM.jpg[/img]
relay area



[img2340]http://i.imgur.com/R3CZP49.jpg[/img]
p100. mine is A1M. so logarithmic @rune....



[img1872]http://i.imgur.com/C2RX4Ma.jpg[/img]
master outs

[Gorhrut]

@rune.

i ended up selling my modded 2/50/2 to cover some bills and things. now i got settled in a new house and things have settled down and i got money again so i bought a used 2/90/2. should be here this week.


i prefer the tones from aydy and beyond so the "crunch" is what im after...


got the download to work. ill compare it to my gp and get back to you...

[Rune]

Hehe that looks pretty much like my clone now, except the internal/backside pot and it's new wiring. Now I do got some shielded cable for that stuff so I might do it later tonight. Got kids n wife you know, so don't always have the time to noodle around with guitars and amps.

The VHT 2/90/2 should have a more aggressive tone due to the KT88's in it, kind of want one of those, but I have so many amps (power amps also) and (god forbid) a Kemper to keep me happy.

Ah yeah that solves why the squealing/hum starts at different settings on the pot then. I know my tech used LIN....

Dude, what is the second pot on the back of your amp? EDIT #2: Nevermind saw the hookup now and it's just the fuse.

EDIT: OH thats an 87 you've got there Gorhrut! That explains a lot!

[Gorhrut]

it is an 87 i updated to 88 specs.

no second pot on the back. just master outs, trimmer, and fuse, and hole where footswitch used to be. there are two small holes next to the master that i had drilled for switches to try diff. things in the circuit.