Getting started in DIY Audio...could use some help

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Hi Guys,
I'm about to embark on my first step into DIY audio.
I will be building:
LifeForce 100W (new version of AKSA)
2x LifeForce 50W
GK-1M PreAmp
Orion ASP

I have been doing DIY for a while, so I have a bunch of tools...and I also have a fairly complete wood shop, but I want to make sure I've got all the angles covered. I will most likely be buying blank chassis and working on it from there...or I will make them fully out of wood.

Assume I have nothing, what tools and equiptment do you think I need to be building these components?
 
Off the top of my head:

Soldering iron - obviously - a good one such as a 30W Weller will be fine. Temperature controlled is better but more pricey. Stay away from el-cheapo's which will just get far too hot and ruin PCB's while blackening the bit. Get one with a stand and a sponge to wipe the bit on.

Desoldering tool - either wick or a pump. Personally I prefer a pump.

Multimeter - don't go overboard but dont get the $2 ones. Two is handy to have.

Screwdrivers, pliers, wire cutters etc. Electrical tape.

Some method to limit mains power - the best way is a Variac, the cheapest way is a short extension cord that has a light bulb wired in series with the Live wire.

Oscilloscope - very useful but pricey. If you're building from kits, you can get away with not having this I think.

Some old speakers - car speakers will do, dont pay too much as the idea is, if there is a fault and the speaker gets toasted, you won't be too upset.

I'm sure others will add things I left out :)
 
Well I've got most of that...but it looks like I need a bit more.
I have a variable weller soldering iron, a fluke 77-III, and most of the other little parts.

I don't have a desoldering pump. Q: Any specific ones you can recommend?

Q: Why exactly would I need the variac if I am already using transformers that are specific to these projects? Q: What does the lightbulb do?

Also, I've looked into oscilloscope but I don't think it would prove very useful to me at this point. Q: Can someone explain exactly how an oscilloscope is useful for a kit builder?

Q: Any other tools or workbench supplies?

Thanks Again
 
When u first power-up an assembled kit, u should never power it directly from mains, even if it is supposed to work that way. U have to either use a series bulb of 60Watts or a variac with a ammeter in series. Always start powering your assy with less voltage. This will prevent sudden damage to the kit in case something was wrongly wired.

Gajanan Phadte
 
whubbard said:

I
Q: Why exactly would I need the variac if I am already using transformers that are specific to these projects? Q: What does the lightbulb do?

Also, I've looked into oscilloscope but I don't think it would prove very useful to me at this point. Q: Can someone explain exactly how an oscilloscope is useful for a kit builder?


The light bulb in series with the power going to an amp will keep you from burning up output transistors and doing damage while you're troubleshooting a project.

It's an old trick that is very effective. If there is a problem and something is trying to draw more current than it should, the bulb glows brightly and limits the current keeping power transistors safe. This allows you to troubleshoot the problem without burning up time and good parts. When things are working properly the bulb glows based on power demand, ie. at lower volume levels it glows dimly and the circuit performs normally, kick up the levels and the bulb responds accordingly.

A 40-60 watt bulb is good for most sub 100 watt amps, while 100 watt bulb will let bigger amps start to breath before they start to glow and limit the power. With no speaker connected they will always have a dim glow unless there is a power supply problem. The biggest value is that, if something isn't right the bulb tells you so before you toast a pile of expensive parts. As in all things in life, try it and learn how it responds.

An oscilloscope allows you to view the signal integrty if you have a good quality sine/squarewave generator. Other than that it's a toy showing you squiggily lines and maybe your noise floor if you have something to reference it to.

I know, I know.

Regards, Mike.
 
gmphadte [/i] [B] Always start powering your assy with less voltage. This will prevent sudden damage to the kit in case something was wrongly wired. [/B][/QUOTE] Thank You! [QUOTE][i]Originally posted by MikeBettinger said:

The light bulb in series with the power going to an amp will keep you from burning up output transistors and doing damage while you're troubleshooting a project.

Gotcha.
Q: Does it matter where in the series I put the bulb?
Q: So if the bulb gets bright I should stop right away...or will the bulb burn out if something is wrong?

MikeBettinger said:

Other than that it's a toy showing you squiggily lines

Looks like i'll be skipping out on the oscilloscope...I think my etch-a-sketch will work just fine. :)

Below are the other questions that remain unanswered from my other posts:
Q: A good desolder pump?
Q: Other tools and workbench supplies?

Thanks guys.
 
Q: Does it matter where in the series I put the bulb?
It can go in hot or neutral- I'd put in hot out of force of habit.

Q: So if the bulb gets bright I should stop right away...or will the bulb burn out if something is wrong?
Yes ... No

Q: A good desolder pump?
I have the aluminum type that is available from almost any supplier - works fine and I use it more than my Pace power sucker.

this one is an example

Q: Other tools and workbench supplies?
A set of those $5.00 flush cutters .... works as good or better than the expensive ones, grab a few:)
 
whubbard said:

Q: Does it matter where in the series I put the bulb?
Q: So if the bulb gets bright I should stop right away...or will the bulb burn out if something is wrong?

What you will experience with the bulb is a bright glow as the filters in the supply charge up, which will die down to a dimmer glow as the amp settles in. If there is a bias problem or any kind of short, the bulb will glow at a high brightness. Once you connect the speakers any kind of offset or imbalance will cause the bulb to brighten, depending on how much the measurements are off.

Most normal amps will play reasonably loud and cleanly on a 100watt bulb before the bulb glows to brightly and the voltages drop below where it can properly function.

This is a quick and easy way to test for functionality and avoid toasting a rebuilt circuit due to a solder bridge or a missed bad component. Especially if you have a good channel to compare it to.

If all is working well you should be able to rough dial in the bias and offset adjustments with the speaker disconnected, take the amp off of the bulb for the real setup.

The only place you can get into trouble is when there is a stability problem that only shows up when full power is applied to the amp. But dealing with those comes with experience; with the bulb in series you can at least get to that point and it's not the norm.

Enjoy, Mike.
 
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