Jeb's Build

Thanks Grainger - you've been really helpful!

Remind me to buy you a drink or two next time you're in Bristol, UK.
 
Just make your way up the little channel to the south of Wales.  Keep sailing until you hit Bristol.  You cant miss it. 

If you end up in Paris you've taken a wrong turn.
 
Jeb Jeb said:
it was the sides of the transformer itself I was wondering about, since I rubbed them just slightly to remove the slightly unsightly runs of varnish or glue or whatever it is holding everything together.

We don't generally recommend messing with the lamination stack on the transformer, as that goop is indeed what holds it together.  As long as there is no exposed metal, you can leave it as-is.  If there is exposed metal, you would want to apply more varnish.

-PB
 
Paul - thanks - damn on one side I can see a bit of exposed metal - only just, but some and can no longer see that shiny varnish surface. I guess I would rather be safe now than sorry and run into problems later.

Do you mean just any general purpose varnish? And would some black metal paint also do the same job?



 
PJ might have specific recommendations, but I'd just buy the smallest container of varnish that you can find at the hardware store, then brush it on with a small brush.

-PB
 
Cosmetically, any exposed iron will eventually rust. Technically, as long as there is no short between adjacent laminations it's good.
 
Cool -thanks again! since there was some metal exposed I put a thin layer of varnish around the stacks to prevent rust.  When I came back later I could see lots of tiny brownish patches (pic) - I hope that it's just bits of the old brownish varnish, rather than rust spots that formed with the addition of the varnish, if that's possible?.  In any case there's not too much I can do about it now.  The lesson - don't mess with the transformer stacks!  You guys said that.  ;)

I've begun the main build - and really enjoying it - about half-way through now.  So far so good .... I think!!  Proof will be in the pudding as they say.

on a couple of the first solder joints I made (on the IEC module and the transformer terminals) the insulation of the wire was touching the terminal so melted a little bit - apart from that the joint looks good and shiny and secure.  I've improved a lot with subsequent joints, always leaving a mm or two of bare wire but should I re-do those first ones or does it not matter if the insulation was touching?.  I've tried to take a pic of the first one I did.

Cheers! 
 

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Hey...I don't think your lightly sanding down the outsides of the transformer will hurt anything....all the best on your build! I would lightly varnish them as well as the rest of the experts stated....

Alex
 
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!





 

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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

 
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.
 
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.
 
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.




 
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.
 
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.
 
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.
 
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