JonPearson1994
New member
I have recently gotten my SL-X modded; i have had it for a while but just now got around to getting it tweaked, which I always had in the back of my mind.
Now, this is the third SL-X I've owned over the years. This is the second 5881 model. I keep coming back to these amps because they have a kind of rude, aggressive sound to them that I find missing from the current Marshall lineup, and they have a proper amount of gain for metal where the 2203/4 and 1959/87 by themselves fall a bit short.
This one came to me much as I remembered it - gainy and super fun to play, but a bit difficult to dial in. All JCM 900s are pretty bright, but the SL-X models have a problem with mud once they start getting high on the preamp volume dial (for those unfamiliar these amps have two gain controls located at different places in the circuit). You have a limited range of tweakability for this reason, where you need a lot of high end to fight mud but then you can end up with a harsh sound.
Set aside the tonal issues for a moment - I knew from past experience that these amps have issues with the rectifier for the DC heaters cooking the board. The rectifier is underspecced, so it heats up and causes all kinds of trouble. I went about rebuilding the heater supply circuit on a terminal strip and replacing the filter caps.
I got the idea that it would be cool to try some mods out, but I also don't have much space or time for experimentation like that, so once I got the heaters and filter caps sorted, I took this over to my buddy Jon at Berrier Audio Works and had him take a stab at modding.
The results are killer! I recorded a video (pardon the rambling, that's my southern kicking in) showing off a bit of the sounds:
Overall, this fixes the biggest problem I have with the amp, which is the flub when you push the gain. Now I can dial it all the way up with no issues, though I don't need to dime it to get sounds that I like.
I've considered whether a choke is worth it, but honestly it is pretty tight as is, and even with the choke I think I'll probably still like the boost for the lower stuff so it seems like it might now be worth it.
Now, this is the third SL-X I've owned over the years. This is the second 5881 model. I keep coming back to these amps because they have a kind of rude, aggressive sound to them that I find missing from the current Marshall lineup, and they have a proper amount of gain for metal where the 2203/4 and 1959/87 by themselves fall a bit short.
This one came to me much as I remembered it - gainy and super fun to play, but a bit difficult to dial in. All JCM 900s are pretty bright, but the SL-X models have a problem with mud once they start getting high on the preamp volume dial (for those unfamiliar these amps have two gain controls located at different places in the circuit). You have a limited range of tweakability for this reason, where you need a lot of high end to fight mud but then you can end up with a harsh sound.
Set aside the tonal issues for a moment - I knew from past experience that these amps have issues with the rectifier for the DC heaters cooking the board. The rectifier is underspecced, so it heats up and causes all kinds of trouble. I went about rebuilding the heater supply circuit on a terminal strip and replacing the filter caps.
I got the idea that it would be cool to try some mods out, but I also don't have much space or time for experimentation like that, so once I got the heaters and filter caps sorted, I took this over to my buddy Jon at Berrier Audio Works and had him take a stab at modding.
The results are killer! I recorded a video (pardon the rambling, that's my southern kicking in) showing off a bit of the sounds:
Overall, this fixes the biggest problem I have with the amp, which is the flub when you push the gain. Now I can dial it all the way up with no issues, though I don't need to dime it to get sounds that I like.
I've considered whether a choke is worth it, but honestly it is pretty tight as is, and even with the choke I think I'll probably still like the boost for the lower stuff so it seems like it might now be worth it.
