Still in love....

[John 14:6]

Small problem i think is the fact that when you jumper the channels with the boost on and then turn the boost off you get a very bassy tone. A bit too bassy for my liking.

Try putting another JJ 12AX7 in V2 second gain stage and get rid of the stock Shuguang. This should help to tame the treble edge when using the booster and it should balance the boosted and unboosted signals much better. It worked for me.

[Mats A]

OK thanks. Is there a JJ in the V1 position? The inbuilt booster sounds real bad, to my ears anyway, if you don´t jumper the channels wich i normally don´t do on a 1959 Marshall.

[John 14:6]

OK thanks. Is there a JJ in the V1 position? The inbuilt booster sounds real bad, to my ears anyway, if you don´t jumper the channels wich i normally don´t do on a 1959 Marshall.

The red labled 12 AX7 under the can is a JJ. That is the first gain stage. The rest of the white labled 12AX7's are Shuguangs. It made a world of difference when I got rid of the Shuguang in V2 and put in another JJ.

[Capel]

Is there a schematic floating around for the JYM??

[PurplePlexiEater]

Still loving mine as a "host amp" for the 50th Anniversary 1-watt amps (in my case a JTM and JMP, both combos). I used to do the old school Van Halen thing and just run everything flat out, all the way up - this kinda works when you run just a couple of single humbucker, maple necked Charvels. The sound was kinda "dirty" or "grimy", but in a real cool way. I just set the EPA to a little under halfway, and it's perfect for our jam room - where our drummer plays an electronic kit, and the bass player uses and old 50 watt Bassman (w/ extension cab). It always sounds like I'm maybe a little loud to me, but apparently my volume is not overbearing to the other members - and I can still hear them. Volume wise, I'd call that a perfect scenerio.

Still, the sound wasn't perfect, but nonetheless way better than it had been (even using pedal effects in the loop - love a loop on a plexi). The sound drastically improved when I began running the 1 watt combos into the YJM's fx return, via the output jacks on low power mode - though I do still have to use one of those cables with the volume control on it - like the SNL Pacino bit, "I want one'a those mattresses, wid a glass o wine on it"). This results in a "way better than I even imagined" kind of sound.

Used this way, the only functioning controls on the head are the loop (obviously), EPA, and front panel presence knob (oh, and the "just okay" reverb). Then again, these are the only controls you need. At this point, the small amp becomes "tube swap heaven", as you can mess with the "output tubes" as well. But I find, with the combos at least, Marshall got the tube selection right, for the most part, straight from the factory. Also, as a consequence to running the rig this way, at least the first two preamp valve slots on the YJM are now out of the signal path - so most preamp tube swapping must go on at the small amp ("preamp?") level.

So far, it's really been working for me (attempting understatement)...

Jimmy