My official JTM45 kit build thread. Pics & CLIPS ADDED

mushmouth · Post by **mushmouth** » Fri Aug 17, 2007 3:58 pm

I am truly testing George's theory that anyone who can solder can build his JTM45 kit. I bought a new multimeter that I don't know how to use yet, so this should be fun.

First question: Once you've installed the transformers and choke, how do y'all (without a jig) support the chassis while you're working on/in it? What's a practical solution?

novosibir · Post by **novosibir** » Fri Aug 17, 2007 4:35 pm

A wooden U-frame.

Larry

mushmouth · Post by **mushmouth** » Fri Aug 17, 2007 5:06 pm

I don't know what that is. Have a pic or a link?

Leader · Post by **Leader** » Fri Aug 17, 2007 9:29 pm

mushmouth wrote:I don't know what that is. Have a pic or a link?

mushmouth · Post by **mushmouth** » Fri Aug 17, 2007 9:53 pm

GENIUS. Thanks.

2x6's? 2x8's?

I'm up to the last part of Step 3. I'll be firing up the soldering iron after the wife and kids are in bed. Pics to come.

mushmouth · Post by **mushmouth** » Sat Aug 18, 2007 10:48 pm

I'm now daisy chaining the tube socket heater wires in step 4. Going fine so far, taking my time and making it clean. As soon as I finish this step, I'll update with pictures of the steps thus far.

mushmouth · Post by **mushmouth** » Sun Aug 19, 2007 2:23 am

Pics so far:

Kit arrives:

Some assembly required?

Step 1--Trannies, choke, and preamp tube sockets installed:

Step 2--Output and Rectifier tube sockets, fuse holder:

Step 3--dual 32uf can capacitor, circuit board mounting bolts, wiring the heater windings:

Step 4--Wiring high voltage tap, daisy chaining tube socket heater wires

mushmouth · Post by **mushmouth** » Sun Aug 19, 2007 12:19 pm

QUESTION:

Reading ahead, I don't see mention of it -- On the circuit board mounting bolts, the instructions have you put two nuts on each. Do both nuts on each bolt STAY under the circuit board when it's installed, or are the second nuts on each supposed to be used to fasten it down when you mount the board in place?

SECOND QUESTION:

I'm noticing on step 5 where there are closeups of the output tube sockets that george took the leads and ran them into the post holes and wrapped them around the top of the post before soldering them. When I soldered mine into place, I didn't wrap them around the post, I ran them into the post holes and filled the post hole with solder. Since I didn't wrap the lead around the post before soldering, do I need to worry about the integrity or strength of those connections??

toner · Post by **toner** » Sun Aug 19, 2007 4:54 pm

I haven't built the kit but I think I can safely answer your questions.

I think the second set of nuts are for mounting on top of the board. There's no reason to have two below the board.

RE: Soldering tube sockets - Personally, I would re-do them and wrap them tightly on the pins. The general rule when soldering is to first make a solid physical connection and then solder.

Nice job so far, looks good!

mushmouth · Post by **mushmouth** » Sun Aug 19, 2007 5:07 pm

toner wrote:I haven't built the kit but I think I can safely answer your questions.

I think the second set of nuts are for mounting on top of the board. There's no reason to have two below the board.

RE: Soldering tube sockets - Personally, I would re-do them and wrap them tightly on the pins. The general rule when soldering is to first make a solid physical connection and then solder.

Nice job so far, looks good!

Ugh. I was hoping you wouldn't say that! lol Everything has been cut to exact length with no extra slack. That's going to mean starting over with new wire on all the sockets and for the wires coming off the transformer, I don't know...

toner · Post by **toner** » Sun Aug 19, 2007 5:19 pm

mushmouth wrote:...Everything has been cut to exact length with no extra slack. That's going to mean starting over with new wire on all the sockets and for the wires coming off the transformer, I don't know...

Don't cut leads to exact length! (repeat 3x)

In that case, I wouldn't worry about what's already done. If the solder joints are clean, you'll be okay, IMO.

mushmouth · Post by **mushmouth** » Sun Aug 19, 2007 5:28 pm

I think I'm still going to redo all but the fuse holder wiring, as I can still get enough length out of the other transformer wires to redo the rest of them. As for the tube sockets, I don't want a problem down the line because I wanted to save a few hours now, so I'm going to redo those too. Red and black wire is cheap.

Thanks.

Flames1950 · Post by **Flames1950** » Sun Aug 19, 2007 8:14 pm

Actually I think the two nuts at the top of each board mounting bolt are both for under the board. One acts as a "jam" nut, otherwise they seem to loosen up on their own way too easy. If you only use one (or that's all that has been supplied) consider using Loctite to keep them from working loose. (Only on the underside-of-the-board nuts of course!!!)

Personally I don't wrap the leads around the socket pins like that, although I often make a simple right "angle" hook to help keep everything in place for soldering (only works if you've tinned the wire with solder before inserting into the pin though.) God help you the day you have to replace one or more of those sockets, and you've wrapped the lead around there like that -- if you get it loose you'll have solder splattering everywhere, or you'll end up just cutting it and then you're short wire.........the mechanical connection thing is nice but I think people really don't give credit to the strength of a well-done solder joint.

NY Chief · Post by **NY Chief** » Sun Aug 19, 2007 8:48 pm

heh heh, don't tell mush....we got another addict in the making here...

mushmouth · Post by **mushmouth** » Mon Aug 20, 2007 12:09 am

I'm a perfectionist, so that's akin to addict behavior and yeah, this is a bad new hobby with that in mind.

I re-did all the heater daisy chaining. I did wrap those around, but heeding Flames advice from this point forward, I had thought of the same thing, removing them will be a real bitch if a socket goes bad, so I'm going to opt for a nice snug right angle from this point forward. A happy medium. Step 5 begins tomorrow night. Stay tuned for more pics then and a 95% chance of more newbie questions. lol I appreciate the input greatly...

So far pretty fun. Even with some re-doing. Hey George, prolly gonna need more red and black wire.

ETA: Finished step 5 and the first section of step 6 last night. As soon as I finish step 6 in a bit, I'll add a couple new pics.