Members rdpar Posted September 25, 2010 Members Share Posted September 25, 2010 I have this Marshall jmp 50w master lead head made in 1976. It is so bright that I have to turn the treble all the way off to get a good sound and it is still pretty bright. Any ideas on how to tame the beast. using kt88 tubes jj tubes Link to comment Share on other sites More sharing options...
Members charveldan Posted September 25, 2010 Members Share Posted September 25, 2010 Use old Rola Celestion speakers, or re-issue Greenbacks. If your useing V30's or similar that's your problem as JMP's are brite amps. Link to comment Share on other sites More sharing options...
Members .homewrecker. Posted September 25, 2010 Members Share Posted September 25, 2010 First mod that should be done to any old MV Marshall is clipping the bright cap. Boosts the gain a tad and tames that high end. Link to comment Share on other sites More sharing options...
Members rdpar Posted September 25, 2010 Author Members Share Posted September 25, 2010 yeah it sure is a bright amp. I'm using a jcm900 lead-1960 cab. so what ever came stock in that is what I got. Probably 70watt celestions. thought I would buy an mxr 10 band eq pedal and try that. I tried an alesis meq-230 and it worked fine to roll off more highs. so hopefully the eq pedal will work. thanks Link to comment Share on other sites More sharing options...
Members rdpar Posted September 25, 2010 Author Members Share Posted September 25, 2010 hey homewrecker. where do I find out how to do that. Link to comment Share on other sites More sharing options...
Members .homewrecker. Posted September 25, 2010 Members Share Posted September 25, 2010 hey homewrecker. where do I find out how to do that. I had a tech do it to mine when I had him go through and replace the caps, if you're not familiar with amps I'd highly recommend taking it a tech for a once over, something that old might need the caps replaced. But if you trust yourself I'm sure there's a bunch of DIY sites that can show you how to do it. Link to comment Share on other sites More sharing options...
Members rdpar Posted September 25, 2010 Author Members Share Posted September 25, 2010 yup just found a good forum. vintage amps bulletin board. thanks. will do it tomorrow.no problem. Link to comment Share on other sites More sharing options...
Members .homewrecker. Posted September 25, 2010 Members Share Posted September 25, 2010 yup just found a good forum. vintage amps bulletin board. thanks. will do it tomorrow.no problem. Good deal man, I've also heard that when the pre is maxed it takes the bright cap out of the circuit, but I'm not certain of that. If that's still not helping I'd go with a tube swap, personally I'm not a fan of JJs but just but 5 or 6 pre amp tubes and swap them in and out of V1 until you find one that does what you want. Link to comment Share on other sites More sharing options...
Members joemudge4 Posted September 25, 2010 Members Share Posted September 25, 2010 I've run every 2204 I've ever owned the same way... Bass, Middle, Trebble: 10Presence: 0Pre and master to taste... I like them both on about 6. With humbuckers, it should sound pretty balanced with those settings. If not, it might be biased too cold... Link to comment Share on other sites More sharing options...
Members charveldan Posted September 25, 2010 Members Share Posted September 25, 2010 IMHO you should consider another amp before you ruin a Classic 34 yr old JMP. Link to comment Share on other sites More sharing options...
Members JB6464 Posted September 25, 2010 Members Share Posted September 25, 2010 IMHO you should consider another amp before you ruin a Classic 34 yr old JMP. ^+100,000 Leave that vintage amp alone and don't butcher it. Link to comment Share on other sites More sharing options...
Members .homewrecker. Posted September 25, 2010 Members Share Posted September 25, 2010 IMHO you should consider another amp before you ruin a Classic 34 yr old JMP. Clipping the bright cap is FAR from ruining a vintage amp, you literally just snip one wire. Link to comment Share on other sites More sharing options...
Members charveldan Posted September 25, 2010 Members Share Posted September 25, 2010 Clipping the bright cap is FAR from ruining a vintage amp, you literally just snip one wire.If it's stock & in good shape it's one of the finest amps made. He sounds young, it starts with a nip & tuck, then it's extra gain stages>>> pretty soon it's not a JMP anymore. Hate to see that happen to a classic, but i can't save amps cept my own...my.02 Link to comment Share on other sites More sharing options...
Members rdpar Posted September 25, 2010 Author Members Share Posted September 25, 2010 so charveldan what would you reccomend I do to tame the treble excess. Oh and for the record if you are older than me God help you:) I'm just after the tone that is in my head and this amp is just too trebley.I am taking all suggestions. I sure don't want to butcher the thing Link to comment Share on other sites More sharing options...
Members TylerSavage Posted October 21, 2010 Members Share Posted October 21, 2010 I have the same amp, and mine is uncomfortably bright with all of my guitars. LPs, JP Juniors, teles, etc. Thing is, it didn't used to be this bright.. I swear it wasn't AS bright. Always somewhat bright when the master or pre is turned down It sounds great when pre-amp and master are cranked, but then it's also unsuable. High sensitivity input when near 10 just squeals with any guitar. Massive hum + hiss. I replaced the filter caps about a week ago, no change. I tried snipping the bright cap, but then the amp lost all balls. brightness was gone, but it also didn't have the note articulation that it used to have. I've brought it to two 'well known' tech guys here, and one told me "it's just a noisy amp", and the other said to change the pre-amp tubes, which I did and it did nothing. What am I missing *sigh* - if you have great results let me know. maybe I just need a smaller value bright cap Link to comment Share on other sites More sharing options...
Members Norton666 Posted October 21, 2010 Members Share Posted October 21, 2010 Is it a 2203 or a Non Master Volume model? Either way they are great amps , but they are painfully bright. Clipping the bright cap definitely isnt butchering the amp. Its very simple to remove and replace if you decide to. I do it on ALL of my old Marshalls. Link to comment Share on other sites More sharing options...
Members vic Posted October 21, 2010 Members Share Posted October 21, 2010 cant you change the bright cap to a lower value one ?? Link to comment Share on other sites More sharing options...
Members lumpy555 Posted October 21, 2010 Members Share Posted October 21, 2010 just trade it for a peavey xxx its the tone in your head! Link to comment Share on other sites More sharing options...
Members TylerSavage Posted October 21, 2010 Members Share Posted October 21, 2010 just trade it for a peavey xxx its the tone in your head! dude.. gross. I have a 2204. it's painfully bright when turned down. Turned up it's bright, but there's so much else going on you don't notice it. Crushing tone, but so much noise it's anything but useful (a seperate problem entirely) a friend of mine has a traynor yba-1 that I installed a PPI-MV into, and it works flawlessly. I might do the same to mine, and have a PRE-PI as well as PPI-MV. Most of the Here's video of me playing it, where I could crank it, . You can still hear the highs really coming through over everything, gets lost in the mix after the start (ignore talking haha ... ) Link to comment Share on other sites More sharing options...
Members TylerSavage Posted October 21, 2010 Members Share Posted October 21, 2010 cant you change the bright cap to a lower value one ?? That's what I plan on doing, prrrrobably tonight. Come to think of it - I think it's got a 47pf cap on it right now. Looking at the schematic that's not right at all! However, clipping it made it way too dark. I've got some work to do...maybe a rotary switch with like 5 different cap values! Link to comment Share on other sites More sharing options...
Members tommythelurker Posted October 21, 2010 Members Share Posted October 21, 2010 Come to think of it - I think it's got a 47pf cap on it right now. Looking at the schematic that's not right at all! Are you sure it's not 470pf? I believe that's what it should be. Link to comment Share on other sites More sharing options...
Members FourT6and2 Posted October 21, 2010 Members Share Posted October 21, 2010 Head over to http://forum.metroamp.com Post that photo of your amp's circuit and I you'll get plenty of info on how to mod your amp to sound to your liking. You can even take a look at some of the amp-build instructions they have to get an idea what every part in the amp actually does. You could convert your amp to partial bass/superbass spec to make it darker and tame some of that high-end. But, removing the bright cap is probably step one. Link to comment Share on other sites More sharing options...
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