Looking For Lee Jackson XLS-1000 Schematic

[888guitars]

Looking For Lee Jackson XLS-1000 Schematic

[vintagekiki]

http://web.archive.org/web/20170406051621/http://www.metaltronix.net:80/metaltronix-schematics.htm
Metaltronix M1000

[888guitars]

Thanks! It might be close

[johnkel]

I'm am currently working on an XLS 1000 and have some questions about it, such as the "More" section. I also have drawn a schematic of the input section.

[vintagekiki]

Upload your schematic and let's hear the questions.

[johnkel]

OK will do as soon as I figure out how,. I have a call into Jackson support and am curious about their response. They were not too keen on support for the XLS, it is ancient but still. I contacted them by they said no schematics available which I believe, Lee seems to be more of an intuitive type of tech rather than a numbers guy. The question is really about the "more" section, from what i can see it's not tied to anything! It's 1/2 of one of the gain stages with all the components and the plate supply but nothing going in or out, weird, Now it's possible I'm an idiot and am missing something but I've been over the circuit board at least 20 time tracing that section out and it comes out the same each time. I'll get my drawing up here ASAP. I also have the output section almost done. The whole amp is basically a 59 Bassman/Marshal JTM45 with some mods. But so isn't every amp?

[vintagekiki]

https://ampgarage.com/forum/viewtopic.php?f=6&t=24407
high gain lee jackson gp 1000

[g1]

The question is really about the "more" section, from what i can see it's not tied to anything! It's 1/2 of one of the gain stages with all the components and the plate supply but nothing going in or out, weird,

'More' is a pot isn't it? So aside from that tube, what is the pot connecting to?

[johnkel]

Here's the drawing I did of the XLS1000 pre section.

[KTer]

Did you figured it out? I have always wanted to compare schematics of Ampeg VL to XLS. Those amps seem to heave a lot in common. Maybe this one was modded? VL's have second gain pot before third stage on the lead channel

[johnkel]

No I haven't figured out what's up with this amp. I tried to contact Jackson to discuss this model and they weren't interested. I wanted to find out from them is this a production ef up of a deliberate fraud. Either way it's significant because the "More" knob was a big selling point of this amp. I also chased down some XLS owners and the consensus is they couldn't say if the more knob did anything, most of the responses were from memory, but they pretty much said the same thing. I did review Jackson's Ampeg and Crate designs and they are very close to this XLS version, the Crate VL extra preamp is probably how the XLS is intended to be wired. I'll wire in the floating preamp circuit as in the Crate and see what happens.

[g1]

If your schematic is correct, they may be trying to induce sag at node E of supply? Or possibly some kind of coupling between the two halves of V2.
Or psychoacoustic effect.

[teemuk]

Sag in E node? Maybe, but there's no signal for alternating the current draw dynamically. And I think there would be more efficient circuits for sagging/dropping the E node voltage than a single 12AX7 stage with high plate load impedance of 100kohms. It's current draw is pretty much insignificant.

I also very much doubt the "coupling of halves" theory seeing that plate power supply nodes are different for each half and that cathodes are not connected in any way either. 12AX7s, as is, are naturally designed to inherently couple as least as possible.

I rather suspect a circuit tracing error, or even more likely some sort of modification by previous owner to disconnect the stage. By quick glance, the "More" stage looks to me like a lowish gain triode stage with user variable gain achieved by using (variable) negative feedback from plate to grid. That or tracing errors. The stage would have likely received its input from the volume control and would then drive the gain stage with 10k cathode resistor. Gain would have varied approximately between unity and maybe 5 - 10. Enough to boost the amp to greater distortion at max settings and not make much difference at lower ones.

Circuitry is very much the classic "modified Marshall 2203" on the OD channel (and "Fender cleans" on the other). "More" stage would provide an extra boost to standard 2203 circuit. So maybe someone just tried to revert the circuit back to its origin.

Edit: And yes. Ampeg VL1002 isn't probably too far from this design.

[KTer]

I might be wrong but I think it should be wired as VL is. You can check out schematics fo Ampeg VL503, its third channel seems to be identical to what you have posted except for input stage. That more knob have less effect on XLS and VL503 than the same knob on VL501/1001 and 502/1002 becouse of how the voltage divider is set up by resistors connected to it. Lee said that XLS are extension to VL series, and VL503 was last of VL's before XLS so it makes sense to be that way. Again, I'm just speculating

[KTer]

You can check out schematics for Laney GH100L, it's the same preamp desing as VL1001, but it's using relay to disconnect that additional stage with ''more'' knob (in thi case it's called ''drive'') reverting it almost to JCM800. I think that someone wanted to convert amp to be closer to JCM800 specs