[johnwmclean]

Come on, we know you’ve made them!
Your mistake will be someone else’s gain,
in the fact they may not be made again...
post generously the more mistakes the better!

"Everybody makes mistakes.
Some confess, while others do not.
Those who confess immediately
By new mistakes are rarely caught."

Sri Chinmoy

 

[FallenAngel]

Measure, measure, measure, measure, measure, measure and measure the damn enclosure again. Make sure your layout is complete with to-scale drawings on paper before ordering the cases and you have taken input, pot and output wiring into considerations

 

[MoodySteve]

Get extra 1N4148 diodes in case the you're not able to zero the offset on the ß22 boards. I think it's by far the easiest solution to that problem.

If your σ22 has much lower-than-expected output voltage, make sure you don't have your V+ and V- hooked up in reverse.

I'll post more later if I think of any.

 

[TimmyMac]

Don't solder the compensation caps across the wrong pads.
Get a few extra MOSFETs and metal oxide resistors.

 

[poo]

I don't have anything useful to add other than support for an excellent thread idea! Keep the admissions flowing!

 

[hardnrg]

this is for my σ11 (half a σ22), but if it's to learn lessons, fine lol, here's mine:

thought I'd blown the toroid because I didn't scrape the enamel off the secondary wires enough for the screw down terminals to make decent contact, bought another toroid, spent about a day trying to figure it out... felt really, really stupid when I realised the problem

 

[johnwmclean]

Quote:

Originally Posted by hardnrg /img/forum/go_quote.gif thought I'd blown the toroid because I didn't scrape the enamel off the secondary wires enough for the screw down terminals to make decent contact, bought another toroid, spent about a day trying to figure it out... felt really, really stupid when I realised the problem

am I missing something here...
What was the problem? Please enlighten.

Edit: hardnrg, I now understand the problem you had!

 

[vixr]

make sure anything soldered to the ground plane is actually soldered...it seems to take forever for the solder to flow onto the pads.

 

[amb]

Quote:

Originally Posted by johnwmclean /img/forum/go_quote.gif am I missing something here... What was the problem? Please enlighten.

hardnrg was referring to some power transformers (such as Amveco/Talema) where the wire leads are enamel coated. If you simply strip the wires, insert them into the PSU board's terminal block and tighten the screws, the wires might not make contact. You need to scrape off the enamel coating first.

This issue does not apply to transformers from Avel-Lindberg, SumR or Plitron.

 

[johnwmclean]

Quote:

Originally Posted by amb /img/forum/go_quote.gif hardnrg was referring to some power transformers (such as Amveco/Talema) where the wire leads are enamel coated. If you simply strip the wires, insert them into the PSU board's terminal block and tighten the screws, the wires might not make contact. You need to scrape off the enamel coating first.

I understand now, sorry hardnrg I misread your post, my “mistake”

AMB, your confessions please! You must have some stories

 

[Covenant]

Quote:

Originally Posted by johnwmclean /img/forum/go_quote.gif AMB, your confessions please! You must have some stories

Ti doesn't make mistakes. He is the secret divinity of DIY. You must construct your B22 on an altar consecrated to him for it to be built without flaw.

 

[johnwmclean]

Quote:

Originally Posted by Covenant /img/forum/go_quote.gif Ti doesn't make mistakes. He is the secret divinity of DIY. You must construct your B22 on an altar consecrated to him for it to be built without flaw.

He’s gotta have some dirt somewhere, it’s all under that altar I’ll bet.

 

[amb]

lol...

Actually, my own β22 builds were all uneventful and worked the first time. I take my time with the process, checking and re-checking each part before I solder it, one at a time. I inspect and measure every solder joint, and I do the same for all wiring/connections too.

The only time a mishap happened was not a build problem. Rather, I got carried away with driving inefficient speakers, at a high volume, in a large room and over an extended period of time... The amp has the default small board-mount heatsinks and it overheated. One of the MOSFETs and a few other parts fried...

 

[ivant]

Quote:

Originally Posted by hardnrg /img/forum/go_quote.gif this is for my σ11 (half a σ22), but if it's to learn lessons, fine lol, here's mine: thought I'd blown the toroid because I didn't scrape the enamel off the secondary wires enough for the screw down terminals to make decent contact, bought another toroid, spent about a day trying to figure it out... felt really, really stupid when I realised the problem

Same exact thing happened to me with my σ11. Only I didn't buy a new transformer but sent an angry mail to the distributor for delivering a "faulty" transformer instead.

Oh and wiring the 2x15v transformer in series when it should be wired parallel for 12V output.

 

[johnwmclean]

Quote:

Originally Posted by amb /img/forum/go_quote.gif Actually, my own β22 builds were all uneventful and worked the first time. I take my time with the process, checking and re-checking each part before I solder it, one at a time. I inspect and measure every solder joint, and I do the same for all wiring/connections too.

That’s gold, it was worth starting this thread to get information like that.
Thanks AMB, truly inspirational.

There must be more sinners out there, bump for confessions!