slightly off topic but has anyone built the JTM45?

Bdcaron · Post by **Bdcaron** » Sun 06/27/04 5:06 pm

Graydon was selling chassis/panel, choke, OT/PT for the JTM45. But compared to this group it seems like interest has dwindled. I have the choke/panel/chassis/Cab and I'm wondering if I should build it or not.

This site has such awesome support. I'm not sure I'm comfortable with the yahoo site group level of support.

Is the amp a dog Was there problems?

Thanks
Bruce Caron

zenstate · Post by **zenstate** » Sun 06/27/04 5:12 pm

That's my next amp build...

I have a rusty sound city 50+ head which I'll steal the mains tranny and chassis, fuse holders, selectors, etc from.
I have a MARSTRAN OT from Brian Wallace and a Paul Ruby board. I have new valve bases.

I like the JTM 45 amp a lot, I have a really early PARK 45, I'm looking forward to this build as well....

Does this topic maybe belong in the BBQ section?

Groundpath · Post by **Groundpath** » Sun 06/27/04 5:42 pm

I have built a head and 4-10 cab(my first build). A very cool amp. I think the 18 is gaining popularity because the the JTM45 is quite a beast, Crank that baby for tone and the cops WILL show up

I put in a switch selectable master volume in mine but we all know that's not the same. Tons of stuff on the net for the build, Take your time and study it. You should have no problem. Good luck.

Bdcaron · Post by **Bdcaron** » Sun 06/27/04 6:04 pm

Thanks guys! At least I know I'm not the lone ranger. If you have any links or files that aren't on the Yahoo site I would appreciate the help.

tbone · Post by **tbone** » Sun 06/27/04 6:41 pm

The JTM45 is a very nice amp. Very loud,but one hell of a nice amp.
I did mine with KT66 tubes and a Marstrand OT.

I had some of my wifes knick knacks vibrate off the walls one day while playing mine cranked through my 4X12 cab .

House of Jim has some good info on the JTM45 on his site.

Tim

markd · Post by **markd** » Sun 06/27/04 7:30 pm

> Graydon was selling chassis/panel, choke, OT/PT for the JTM45. But compared to this group it seems like interest has dwindled. I have the choke/panel/chassis/Cab and I'm wondering if I should build it or not.<

You should build it, yes.

>This site has such awesome support. I'm not sure I'm comfortable with the yahoo site group level of support.<

I agree. The lazy slug that started that group should be horsewhipped. OK, it's me. Sorry. ha! I will help you, if you post any problems you have to the JTM45 site.

markd

HeeBGB · Post by **HeeBGB** » Sun 06/27/04 9:15 pm

I built the 45. Couldn't have gotten it going without the help of Brain Wallace at Marstran. Mine gets VERY muddy if the Bass pot is above 2.
I have tried changing some component values but it's still very muddy bass. I'm beginning to think it's the chinese KT-66's. Any help would be appreciated. At this point I MUCH prefer my 18 but I am still working on the 45. Actually it's sidelined because I just got an AC-30 chassis that I need to get working. You should build it just for the learning experience. I leardned a lot with that amp. More so than other amps I have built.

Greg

pete_skelton · Post by **pete_skelton** » Mon 06/28/04 2:52 am

The JTM45 is a lovely amp. I've built one, and for all the world I would swear that the thing has a reverb circuit built in. Its just so warm and resonates with the guitar beautifully. Its a loud beast though. Definitly not for apartment dwellers

peter

stevesuk · Post by **stevesuk** » Mon 06/28/04 9:31 am

The third amp I built was a JTM45 and it gets too loud before it gets crunchy !

I will put a MV in it one day, when I get bored with 36 Watters, which have the power when you need it and the tone ALL of the time regardless of where the controls are at.

I built my JTM45 a couple of years ago ? with Mark Ds help and the JTM45 site, there are some good diagrams etc. on there. Must pay it a visit to see how things are going.

I have KT66s in mine at the moment.

I do prefer the EL84 36 Watter TMB MV which is about as loud as you need before you need to mike up anyway.

Steve UK

Prophet · Post by **Prophet** » Mon 06/28/04 10:36 am

Hey Boys,

This is the next build! I built six 18 watters and ready for the JTM 45. We have a real block logo Marshall JTM 45 coming into the store and I get to go over it with a fine tooth comb to reproduce it. I use the heyboer trans for my 18 watt. Do they make a good set for the JTM 45? I will post some pictures in my gallery when I get them.

Cheers,

Tonio

AdamK · Post by **AdamK** » Wed 06/30/04 3:54 pm

I built a JTM 45 as my second amp, and it's pretty amazing. The descriptions already posted fit mine to a tee: fat and warm. Really fat. But not too tubby if you keep the bass knob low. I had a vertical 2x12 made (not as cool as the swansoncabs one, about 3" larger all around) by vibroworld, with the top open and the bottom closed, mesa style. C12B in the top, H30 in the bottom. That's not real traditional I know, but I like the sound of open back cabs...and needed to watch the flab too. Sounds cool.

I used Graydon's chassis and PT, and an OEI OT. That chassis is great, beautiful, but there's a little clearance problem with a standard (large) standby switch and the PT. I hear good things about Marstran's trannies too.

It 's loud, real loud, so I integrated a 50w weber MASS into the head to get some overdrive at "goofing around at home" volumes, and it would great - - Like all the MASSes I've tried.

I managed it with just the resources from the Yahoo group and some help from RayD with parts and a styling old-school-perfed-style red G3 board.

Build it, I say. You'll love it. But you woun't be putting away your 18watt anytime soon either.

AdamK

kinmike · Post by **kinmike** » Thu 07/01/04 2:03 pm

I built one, and if I can do it, anybody can. The support on that board is pretty good. Not quite as good as this site, but this is the best there is. I got my questions answered pretty quickly both general questions and troubleshooting. Andy Poupart, Mark, and John from BF really guided me through. I've always depended upon the kindness of strangers..LOL, these guys are great.

Don't want to disparage any products, but I think the octal gold tube sockets shorted on me, couldn't find any other explanation. Others on this board have remarked on this potential problem (not the nine pin, the octals). I replaced them with some other type from Angela to be safe.

As far as the tone goes, it's great! I got a good deal on some strong used Genelex KT-66's ($150). Be careful, if you try them you'll never wanna go back to the foreign tubes, you can really hear a big difference. The sounds I'm getting out of my new clone are the sounds that made me want to play guitar in the first place...Ya gotta love it...

Mike

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slightly off topic but has anyone built the JTM45?

slightly off topic but has anyone built the JTM45?