angelspade
Well-known member
OK, understood...That makes total sense. I thought you were implying that the mod had an affect on the other channels as well. Thanks for clarifying.
J
jasonP
Well-known member
Tomorrow I’ll upload a picture and from the schematic location of what I’m taking about. It only affects the crunch channel and by making the cap smaller it lets less bass go to the next gain stage, reducing the flubbiness or looseness of the bass allowing the bass knob to have more useful range and keep the low notes tighter then before. I tried a couple different ones from .001 to .0015 to .0022uf and found I like the .0022uf over the stock .01uf which to me I had to run the bass knob on like 1 and it was still loose and uncontrolled.
angelspade
Well-known member
Great...Thanks brother
jchrisf
Well-known member
I'm sad I missed the JVM Forum before I actually got one. Did they archive the info anywhere?
J
jasonP
Well-known member
JVM page on FB has the documents for all the mods but I don't believe anyone ever addressed the crunch channel. Here is the cap I changed on the crunch channel to reduce some of the bass.
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angelspade
Well-known member
There was some interesting info on there for sure...I read some of it. But specific to all the different mods on that forum, it seems that at the end of the day many found that the vast majority of the mods did not really improve the amp and most prefer it stock. The Satch model included some of these common mods and I can tell you that the one I played sounded completely tame and neutered by comparison. The mod specific to the crunch channel referenced by JasonP is interesting for sure however. Also, as I have mentioned previously if Ground Zero (@RedPlated) were to develop a mod specifically for the JVM, I would likely acquire a second as a donor for that purpose. His mods seem to retain the original character while making them tighter, more aggressive and generally meaner sounding. All his Marshall mods sound killer.
angelspade
Well-known member
THANKS!!!!
jchrisf
Well-known member
This is similar what Jason from Headfirst did to the similar capacitor for the JEL mod of a 2204. Same size too. Take the bass out early and put it back in the negative feedback. The JVM has the Resonance though.
BABMusic
Well-known member
I'm amazed that so many of you guys understand these schematics and can easily go in there and mod the boards. My limits are turning the bias knobs.
I will say that my experience with the JVM and DSL is that there's a slightly looser bottom when palm muting, as compared to my Mesa Mark series or my Friedman. That's if I'm using humbuckers. If I use a single coiled guitar, the bottom end is tighter. This is why so many pros us an SD1 or Tubescreamer in front. I was told the newer DSL with Sweetwater mod may have removed the looser bottom on the high gain mode.
I will say that my experience with the JVM and DSL is that there's a slightly looser bottom when palm muting, as compared to my Mesa Mark series or my Friedman. That's if I'm using humbuckers. If I use a single coiled guitar, the bottom end is tighter. This is why so many pros us an SD1 or Tubescreamer in front. I was told the newer DSL with Sweetwater mod may have removed the looser bottom on the high gain mode.
angelspade
Well-known member
Mesa Mark Series amps can be dialed in fairly tight in the lows and I think I may prefer them for modern metal over any stock Marshall. That said, I've owned a lot of hight gain amps and I find the JVM to be pretty tight in the lows generally speaking. Not a loose or woofy amp in my experience.
J
jasonP
Well-known member
Here is the location and where I placed the cap to make it easy with out pulling the board. https://www.amplifiedparts.com/products/capacitor-kemet-r82-series-polyester-5mm-spacing 2.2nf.
Attachments
BABMusic
Well-known member
Just for reference, the JVM with gain on 4 (in red modes) is equivalent to the Friedman BE50 gain on 10 in HBE mode.
jchrisf
Well-known member
You got another one?
BABMusic
Well-known member
No, not yet. It may take a while.
angelspade
Well-known member
Yeah...The JVM gain is pretty over the top. At living room volumes I run OD1 Orange mode gain at 4 (11 o"clock), and on OD2 Red at 5 (noon). When I raise the volume up significantly, I back the gain off a bit along with the treble and presence.
BABMusic
Well-known member
I think it's nice to give players more than enough gain, even if it is ridiculous for most of us. A few people might really want that kind of mushy sound for some music they are working on. I found with the red modes that I usually could not push the gain past 5 without it becoming more mushy. Using an overdrive worked better for me with the gain lower at 3 or 4, and the JVM takes the SD1 in a magical way. Something about SD1 + any Marshall amp I've tried works so perfectly.
Will probably be at least a month before I can even consider buying another amp because I re-injured my lower back late last night. I was leaning forward for probably 30 minutes doing some soldering on my guitar, and I forgot my lower back doesn't like that. Low back injuries are so disabling and it's annoying that they take so long to heal. So, won't be able to lift a JVM or even my Friedman for a while.
Briman24
Well-known member
I had a jvm205h for 2 or 3 years and loved it. As usual I kept chasing and traded it for a peavey wolfgang arch top.
The jvm definitely can be dialed in to sound like an jcm800.
The jvm definitely can be dialed in to sound like an jcm800.
ChurchHill
Well-known member
Sorry to hear that. I can definitely relate. Take care of yourself!
BABMusic
Well-known member
Well, at least I can walk (although I look like an old man). And, I can play guitar a little bit, so that's at least something.
You know, I was considering ordering a custom Jose amp that would have the Dirty Shirley exterior. Dave said he could easily do it, but I forgot that the transformers are that nice gold color. I think it would look off if I had the outside silver and the transformers gold. I think sticking to the original black and gold would work best, given that the transformers cannot be changed.
Briman24
Well-known member
Funny thing is, I was working on a guitar last night also doing soldering and fret work which requires alot of back and forth movement with arms using files and fret erasers etc. I got up to go to bathroom and my back was killing me. Not as bad today but not good. Sigh......getting old sucks
