Jeb's Build

[Jeb Jeb]

Hey thanks Alex - Appreciate that and the encouragement!

would appreciate a bit of advice on soldering -  on the transformer terminals, is the idea that the entirety of the hole and the terminal be covered in solder to create one solid block? or just enough to firmly secure the wire to the terminal?

I thread the wire through the hole and crimp tightly around the top or side to create a good tight connection.  When I apply the solder it sticks to the terminal and to the wire but still leaves most of the hole empty - is this still okay?  It seems secure, but in the manual pics it looks like the hole should be full of solder too.

Have attached a pic of a couple of joints.  Would appreciate any pointers!

[adydula]

Hey Jeb....

You dont have to fill the entire hole with solder. The main thing is to make a good electrical joint with the solder being the electrical "glue".
Attach and crimp the wire to the terminal hole and heat the joint well and let the solder flow around the crimped with and terminal so they get
"Glued" together well, a nice shiney joint. When its cooled down you should be able to see a nice shiny joint with a little flux on it from the soldering process.

Dont worry about the flux or resin stuff left over on the joint....some like to take a q-tip or small bristle brush and clean with alcohol but this also can make a mess!!

One thing when I built my crack (and I have built many, many amps and circuuts in 35+ yrs!!) is to follow the instructions very carefully..being an old timer I can solder this stuff from the schematic but the items used in this kit have some small important things like upper and lower holes etc....and the crack designers have utilized these mechanical things to the utmost...to make it easier for a DIY first timer to be successful...(wire layout to help minimize noise, hum etc...).

The point I am trying to make is if you did fill in an entire teminal hole and had to later wire something to it, you have no hole!! So solder when they indicate and not before!

Enjoy you kit building experience its really neat when you turn it on for the first time and hear wonderful music!!

Post any questions here and many folks will help you!

Alex

[Jeb Jeb]

Hey Alex - thanks so much for those wise words!  so helpful!!

 One things i've find on a number of joints is that I had the wire's insulation slightly too close to the joint and it melted a little bit as the solder flowed - not so much that it is *inside* the joint or mixed in the solder but some is now touching the joint - I'm not sure if this causes any problems, besides being a bit unsightly? the insulation won't melt anymore when powered up because it's touching the terminal will it  - do the terminals get any hotter than the wire itself?

This is my first DIY audio (as you probably guessed) and i'm enjoying it - but I would say it is challenging me quite a bit! Partly because I am a safety freak so am double checking, triple checking!   But I am determined to get there in the end   just finished p.26 - going to call it a day for today.   Hopefully make it through to the end of wiring, tomorrow.

Cheers,

Jeb.

[Doc B.]

Alex's tips are excellent, but I do have to pick one small bone regarding terminology. One of the tenets of mil-spec soldering classes is that "solder is not glue". It is used to cover the joint and maintain the integrity of the electrical contact surfaces against corrosion. For optimal reliability the connection should be mechanically sound before it is soldered so that the wire does not move as the solder cools and solidifies. In the days of point to point wiring the test to pass was wiring up a circuit and demonstrating its reliable operation without any solder applied to the joints.

[mcandmar]

Some light reading on the subject http://www.electromet.com/documents/milstd2000a.pdf

[Jeb Jeb]

Cool, thanks Doc.  I want my build to be mil-spec!

As per yours and Alex advice - I'm trying to make sure all my joints are crimped and sound with good contact and no movement  prior to soldering.  That's actually what's taking me the most time and fiddling.

Any thoughts on the point above about wire insulation just touching the joint - is it a technical no-no or just slightly unsightly?

Got the LEDs on the tube socket in place earlier - prob the fiddliest bit so far.  Can't wait to stick the bottlehead badge on the front when it's all tested and working. Saving that till last. Must be earned!

Best wishes from this side of the Atlantic.

[adydula]

Hey Doc.... agree on the Glue part I use that as an analogy.... to many soldering is one of those mysteries in life!! LOL....I call solder my special electrical "glue" that transforms before your eyes under high heat..that's why I used the "" for "glue:......:>)

Soldering when done right promotes a good electrical and mechanical bond.... crimping a wire or lead so it doesn't move while soldering is very important to getting a good joint!!

I used to work on fuel gauges for jet aircraft and did lots of DARPA inspections for the US AirForce planes and they were sticklers for good solder joints, wire braiding etc...

Happy Soldering everyone!
Alex

Oooops almost forgot... the insulation on the wires touching a joint should not be an issue, but may get in your way when trying to solder. I would try to remove the amount of insulation DocB has stated in the instructions it should be enough to connect and solder with the insulation being just abit away etc....I found more often than not that the length of the wires to be cut were always long enough if not a bit too long for some.

[Grainger49]

You might try stripping the wire a little more, say 3mm, than you have been.  That way you have enough bare wire to get a good mechanical crimp and don't sniff burned insulation when you solder.

[adydula]

Agree the smell of burning teflon or other insulation is NOT a good thing.....

Alex

[Strikkflypilot]

Not only that, but when the joint has been made, it is also possible to push the insulation back towards the joint over the core if that is what You want, since the wires are so short.

[Jeb Jeb]

Thanks guys - you're right -  for my own crimping style I just need another few mm stripped back.   As you say, prob another 2 or 3mm on the standard 6mm that most of them are.

I see why some people do multiple builds - you learn a lot along the way!

[Jeb Jeb]

Just had an hour or so to spare so just got the UF4007 rectifiers installed.  I think this was the trickiest bit so far for me - quite fiddly with quite a lot going on in each hole and a challenge for me to get a good contact with the soldering tip without doing any damage.

 If anyone has a minute just to take a look at the pics of my work below I'd appreciate any feedback in case there's anything about the joints that leaps out as being poor before the caps go in tomorrow and anything gets covered up. I probably put a little bit too much solder on 18U and got a little bit between the rectifier leads just as they enter the terminal hole.  I'm guessing this isn't a problem since they're joined at the terminal anyway?

Cheers! thanks for your help & encouragement!

Jeb

[adydula]

Hey...looking good....you might want to trim off any excess leads. like it mentions on page 27 of the manual. "trim excess leads" It might be hard to get at if your cutters are big etc...they dont look that long or excessive and I don't think they will touch anything. The only wires near will be the RCA inputs three wire braided ones see on page 36.

If u can clip them off great, and when u do clip off excess leads make sure these small pieces are removed and dont go flying somewhere in the amp!! They could short something out later etc..

Keep up the Great Work...oh the diodes to me look like they are installed in the right direction as well.

Alex

[Jeb Jeb]

Cheers Alex - once again !!

I have some pretty small nippers & I'll clip back the excess leads a liitle more during tomorrow's session.

Is the little blob of solder between the rectifier leads just as they enter the terminal 18L at the bottom an issue? There was a bigger blob there originally but I managed to suck up most of it - they're joined at the terminal so it doesn't make any difference right? It just means the joint is a bit longer - correct?

Jeb

[Doc B.]

Yeah, those leads look to be trimmed pretty short already. I'd say you're good to go forward.