JTM45 Kit Build Started!!

Flames1950 · Post by **Flames1950** » Mon Aug 08, 2005 11:58 pm

At least one other person is building one now as well, anyone else out there putting one together already?

George, I'm not far into this yet but I've gotta say these instructions are far improved from the 100-watt instructions, and way more beginner friendly from what I can see so far. Even telling you about how much wire to leave hanging so you don't waste any. Some MM specific stuf may be helpful as we've already seen. But the detail here almost demands of your time to re-write your 100 watt plexi instructions. (I take it there's still some steps to be written, since the stuff on determining a bias resistor value is missing?) This level of info should really pay off.

I didn't have much assembly time today since I wasn't planning to build this one at work (and for some stupid reason I thought I should pay my bills tonight, sheesh........) but here's the progress so far:

I confess to being a little puzzled by the choke holes. The footprint doesn't match either the included MM 3H choke, or the 10H Heyboer I'm likely to use in its place. And the internal fuse mounting hole is missing. No biggie, other than I'm not firing up the drill at 11PM, we just got Jakey to sleep.....

Post by **VelvetGeorge** » Tue Aug 09, 2005 1:14 am

Thanks for your comments on the instructions. I knew there was lots of room for improvement. The steps you have are already being edited and refined. To be honest I hadn't even spell checked them yet, so you'll find some typos.

Great start on your build. How do you like the panels? I thought they turned out sweet!
Sorry about the fuse holder hole.

You got the wrong choke. I didn't check it (figures). Then I found some 3.3H's in the shipment that was supposed to be all 7H's. Which is what you should have gotten. I'll send one out. It's the MM JT45C-7H.

George

thetsigma · Post by **thetsigma** » Tue Aug 09, 2005 6:01 pm

I just wanted to say that I too did have a little trouble with the hole in the chassis where the choke leads go, I had to get out the ol' drill and enlarge it a bit to get the grommet to fit in, but everything's fine now. Tonight I start wiring the PTP board. I'd post pictures but I currently am not sure where my camera is.

Flames1950 · Post by **Flames1950** » Tue Aug 09, 2005 7:14 pm

The back panel fit great with no filing needed. I Dremeled a little off the holes of the front and it looks awesome too!!
As an interesting note, I didn't have any Super 77 at work when I did the panels, and being an impatient bastard I tried some of that very thin plastic-y two-sided carpet tape, which looked very similar to what the metal panels on my 70's Marshalls are stuck on with. It worked great.
Good thing on the choke, I haven't gotten the drill out yet so I'll chill out on that step for a bit (there's always heater wiring...yecch.) I can send the Merc 3.3H back to you in the box the new one arrives in later this week.

Post by **VelvetGeorge** » Tue Aug 09, 2005 7:19 pm

Sounds good. Glad to hear that the two sided tape worked out. My screener is looking for some to use on the panels. I want them to be peel and stick.

George

Flames1950 · Post by **Flames1950** » Wed Aug 10, 2005 12:03 am

VelvetGeorge wrote:Sounds good. Glad to hear that the two sided tape worked out. My screener is looking for some to use on the panels. I want them to be peel and stick.

George

I'm sure your screener can probably come up with something a little easier than the actual carpet tape, it kinda wanted to stretch in the holes instead of cutting cleanly.
Back to that heater wiring. I think my heater wiring gets worse looking every time I do it instead of better. Must be the anticipation of what a PITA it is.......

Post by **VelvetGeorge** » Wed Aug 10, 2005 2:01 am

FWIW I hate wiring the heaters too. But what are you gonna do?

George

Flames1950 · Post by **Flames1950** » Wed Aug 10, 2005 9:57 pm

Ah, it still turned out OK, the wire just never twists as tight as I'd like. I guess we could all ship our heater wiring chores to Omar......

Ricky Lee · Post by **Ricky Lee** » Wed Aug 10, 2005 10:35 pm

Hi Flames, 45 build is starting to looks nice. The heater wires I always stick one end of the paired wires in a drill chuck and slowly run the drill while holding the other two paired ends, tightens things up real nice. You probably know that, but just wanted to stick my two cents worth in and say hi. I've been looking at ways to make a heater wire harness that utilizes the black and red wires without having to do all that measuring and cuting and all. In other words just lay the harness in and start up the solder iron. Wiring those heater wires is the thing I always dread about building an amp. Good luck on the rest of the build.

Flames1950 · Post by **Flames1950** » Thu Aug 11, 2005 12:20 am

I've known about the drill trick since before I ever opened an amp, my mom used that trick with an old hand-cranked pin vise drill to make cording for pillow edges. But I never get around to hunting down her old pin vise drill, so I keep torturing myself instead.
Got most of the power supply stuff wrapped up tonight:

George, these instructions are really impressive for the first time kit-builder. I'm at about Step 9 and I haven't found anything major that's been missed. In fact the only things that haven't been mentioned are things that will probably get revised in later chassis runs, like the missing fuse holder hole, and having to relocate the internal cap can's mounting holes.

NY Chief · Post by **NY Chief** » Thu Aug 11, 2005 12:13 pm

The drill trick is cool. Did it that way making twisted pairs for mil spec wiring jobs (radar sets and such). For guys who do more than a few amps I would suggest a wiring template board and make harnesses all twisted, cut to length, pre tinned and cable tied before going near the actual build. It would be a drop in pre-made harness. My .02.

Flames1950 · Post by **Flames1950** » Sat Aug 13, 2005 1:16 am

Hey thetasigma, how's your build coming along?
I'm so close I can taste it, but I need to get a rectifier from George along with a 270K mixer resistor that was missing (can't find the carbon films in a 1 watt rating around town, only metal oxide.) Did you get that e-mail about ordering that stuff George, I thought I sent it after your downtime........

It's time to hit the sack, but all that is left is to wire up the tube side of the board and do the main AC cord and fuses:

Flames1950 · Post by **Flames1950** » Sat Aug 13, 2005 3:52 pm

Well except for the missing 270K and a rectifier (I had to order the kit with no tubes to save a $$ but George has both coming soon!!) this baby is ready to flip the switch and bias. I'm assuming I'll start with the median value of bias resistor provided and get a plate voltage reading, and work from there, unless I can find someone who still stocks the old style rectangular sliding pot.

F'in sweet, I've been flipping George crap off and on for probably a year for this moment........

white room · Post by **white room** » Sat Aug 13, 2005 4:10 pm

Flames,

Beautiful job man

I know that baby is gonna sound sweet.

I'm so envious that you all can just call me Green from now on

Flames1950 · Post by **Flames1950** » Sat Aug 13, 2005 4:15 pm

Thanks, Green....umm....white room......
I know it's gonna sound sweet too, but the poor postman is gonna get sick of me running at him at breakneck speed every day this next week to see if my rectifier is here.........