cheapskate modder recycles old parts

[TWANG]

I thought I'd give it a shot.

schematic called for 47uF in two spots.. so I jimmied up some old 22uFs to make 44uF and called it close enough.

 

A bit sloppy for now.. gotta see if it works.. and then see how it sounds.. after that I'll clean it up.

 

You can see I used the european blue/brown spots for two old caps.

 

 

then I connected in series.

hot to ground and ground to hot

on the back with jumper wires.

put my sgr back there, too.

 

[TWANG]

I'll add silicon later to hold them in place IF it sounds and works ok.

and no. nothing is touching there around c5. had to do a little fancy footwork but she's safe.

[layboomo]

Ahhhmm........Twang Caps in series = half the value!

 

"Caution: If the capacitors are different, the voltage will divide itself such that smaller capacitors hog more of the voltage! This is because they all get the same charging current, and voltage is inversely proportional to capacitance.

 

Worse yet, if one capacitor is slightly leaky, it will gradually transfer its voltage to the others, possibly exceeding their voltage rating in turn. And if one of them punches through its dielectric barrier, it can then damage others in a cascading fashion. This is why series capacitors are generally avoided in power circuits....."

 

IE.......you want those in parallel!

[TWANG]

Lay good catch and thanks.

 

I saw that last night .. and good thing it was too late for me to plug it in.

Rock Mumbles posted, too, in sewatt.

the caps should be all ok I was careful to choose the best ones and I take 'em out gently out of habit.

I just bozo'd the hookup.

 

 

I shouldn't be doing this stuff at 2 am.

 

I was working on another amp last night, too.. and tested it then pulled it.

for the first time ever I didn't check the caps.

bang!

 

nearly knocked me off my chair.

So there you go.. two am.. old man.. first a silly mistake then a serious one.

 

I hope everyone is reading this.. discharge the caps .. at least put them on the meter, which is what I do.

I keep saying I never find a charge in there of any significane. Ironic that I finally find it with my fingers.

[layboomo]

Just trying to help....glad you caught it before you powered up. Yeah we've all made those tired mistakes......sometimes it's just better to walk away and start fresh!

[m-theory]

Jeez, Twang...how is it you've not hurt yourself tinkering around with AC current? You seem to run into more than your share of mistakes.

 

There's something you should know about multi-tasking, in general. It doesn't actually work! It divides your attention and focus, and causes you to make more mistakes than if you were focusing on one thing at a time! Here's what you should try, in order to minimize or potentially eliminate mistakes:

 

1. Understand the fundamentals. You don't have to be an EE to build a simple tube amp circuit, but you'd better know what a resistor, capacitor, and wire does.

2. Don't work when you're tired, and limit the time standing over the solder fumes, so that you're not exhausting yourself.

3. Check component placement several times before soldering in place.

4. Walk away from a project once in a while.

5. Work on one project at a time.

6. Think like an electron, when things don't work right. All they know is how to take the easiest path. Everything about an electronic circuit is about electrons taking the easy way.

 

Think back on the times that you've made it right vs. the times you've made it wrong, and compare notes. I'm willing to bet you that in virtually every failed attempt, the root cause has been some errant component placement or poor solder connection, either due to a lack of understanding of the fundamentals or just plain sloppy work. As poorly as today's components are made, the fact is that new parts are very rarely the culprit to a failed build.

 

The point is, if you were to focus on one project at a time, focus and take your time to do quality work throughout the project, and get a better understanding of the basic elements of electronics, I think you'd rid yourself of 90% of your problems.

 

Not that working through problems isn't beneficial overall. We rarely learn from experiences that are pristine and models of perfection. It's through failures that we really learn, and only through those failed experiences and learning from them that we can achieve pristine models of perfection with any degree of consistency.

 

I deeply admire your passion for this stuff, Twang. You've got a ton of heart and soul in this stuff, and it's really cool to see you diving into so many different projects like you do. I'd just want to see you start to apply some of what you've learned, and, imo, the most important things you should know by now is that you MUST stay focused on one thing at a time, you MUST not work past the point of fatigue, and you MUST be meticulous and detail-oriented at all times!

 

Make sense?

[brianh]

1. Understand the fundamentals. You don't have to be an EE to build a simple tube amp circuit' date=' but you'd better know what a resistor, capacitor, and wire does.

2. Don't work when you're tired, and limit the time standing over the solder fumes, so that you're not exhausting yourself.

3. Check component placement several times before soldering in place.

4. Walk away from a project once in a while.

5. Work on one project at a time.

6. Think like an electron, when things don't work right. All they know is how to take the easiest path. Everything about an electronic circuit is about electrons taking the easy way.[/quote']

I'm gonna frame this and hang it over my bench...

[TWANG]

thanks lay I appreciate it!

 

m theory. yeah I do too many things at once, for sure.

and I tend to hurry.

those two faults of mine are responsible for 90% of my mistakes, in just about anything, probably.

 

and yes. I have been realizing that focus is one thing. but break time is just as important.

Another thing. and I'm not trying to make excuses..

 

early on I didn't see or understand nearly enough. but drove forward despite.

but lately. I'm sure it was this diabetes thing.

Not only did my vision go. and then come back when I got on the meds. but my general ability has gotten better.

I'm not forgetting things.. I'm not fumbiling and dropping all the time.. I'm not suddenly just crapping out into a nap..

 

I think my blood went glucose funky gradually and was affecting me without my knowing it.

all I can say is, the rebound is what is happening now that's problematic.

Certainly I had no business messing around that late in the day and that series cap thing just proved it.

 

So. thanks all.. I never take criticism grudgingly. I figure I have to capitalize on error and be glad I got the help.

[TWANG]

it sounds good!

just had it fired up.

now to goop some siliconin there so it wont shake apart!