How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

[tyger23]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

You could probably accomplish this with a RatShack 25W pencil iron, some tweezers, and one of their vacuum desoldering pumps.

http://www.radioshack.com/product/index.jsp?productId=2062745&filterName=Type&filterValue=Desoldering

The trick is knowing how to use your tools. Here's a big hint - sometimes you have to add solder to be able to suck it away.:eek:

Personally, I go at it by holding one side of the component with the tweezers and pulling slightly up on it. Then, I touch the solder (on the back side of the board) with the iron. Once the solder melts, the component lead will pop out of the board, leaving the other side attached. Then repeat for the other side of the component. Once the component is out, use the desoldering pump to suck any solder out of the empty hole so that the next component can go back in.

Caps are a bit more challenging since you can't raise up one side of the component. Generally, if your iron has a wide and hot enough tip, you can lay the iron across both leads simultaneously and pull out the cap with tweezers.

[Æ]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

There are caps across the diodes included in the factory design. Is this what you were looking for?

Yes, thank you.

[tc]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

Buy some solder wick and a desoldering pump, and have at that dead clock radio in your closet for practice.

+1

After first chatting with Ty, I got out my little Weller Pencil Iron, some wick and a desoldering pump and DESTROYED an old DirecTV receiver. By the time I got through with it, I could "passably" desolder and solder back into place. I have stacks and stacks of old security alarm resistors that died noble deaths until I to where my solder joints would pass.

[AJ]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

Tyger, did you find a schematic for the AMP100, or did you just trace out what parts of the circuitry you needed?

[philthien]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

Another solder "trick" is to use the iron to remove the old components from the board. Then once they're gone, if the holes are still filled w/ solder, use a numbered (tiny) drill bit in a pin vise to drill a hole in the solder for the legs of the replacement components. When you add additional solder, you get a nice connection. And you also don't run too much risk of overheating the traces and having them lift on you.

I do this quite often on motherboards where I'm replacing caps. Works better than my Hakko desoldering unit because there is so little clearance between the fine holes, and the legs of the caps.

You MUST make sure the drill bits are very fine. I got a set from Harbor Freight w/ .5mm bits:

http://www.harborfreight.com/30-piece-hss-mini-drill-set-94606.html

If the bit is larger than the hole, it will remove the through-plating. You don't want that.

[tyger23]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

Tyger, did you find a schematic for the AMP100, or did you just trace out what parts of the circuitry you needed?

Took me about 2 days, but I hand traced the entire schematic for the audio path. I requested a service manual from AudioSource, but they were kind enough to never send me a reply. :D

[tyger23]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

For anyone who's curious - I've now spent about 2 entire days with this mod and constantly flipping between this and my NAD C 315BEE using my newly constructed A-B switch.

The two are so close (sonically) that it's hard to pick a winner. As I mentioned before, there's just a touch more "warmth" in the AudioSource, which is likely due to the slight increase in distortion. However, for less than half the cost of the NAD, I know what my "go-to-amp" is going to become ;).

• AudioSource AMP 100 = $99 at PE + ~$40 in parts (including shipping) + about 2-3 hours labor = $140.
• NAD C 316BEE = $379 at Crutchfiled

Hmmmm... tough decision???

[Æ]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

Another solder "trick" is to use the iron to remove the old components from the board. Then once they're gone, if the holes are still filled w/ solder, use a numbered (tiny) drill bit in a pin vise to drill a hole in the solder for the legs of the replacement components. When you add additional solder, you get a nice connection. And you also don't run too much risk of overheating the traces and having them lift on you.

I do this quite often on motherboards where I'm replacing caps. Works better than my Hakko desoldering unit because there is so little clearance between the fine holes, and the legs of the caps.

You MUST make sure the drill bits are very fine. I got a set from Harbor Freight w/ .5mm bits:

http://www.harborfreight.com/30-piece-hss-mini-drill-set-94606.html

If the bit is larger than the hole, it will remove the through-plating. You don't want that.

Not always a good idea, since many holes are through plated and drilling takes a chance at removing some of the copper clad.
Better to just clip the component out, but leave the component leads or legs long, that way you can grab them with pliers or tweezers as you heat the solder till it melts.

Another way to clear a stubborn hole of solder is to actually blow it out while it is molten, as opposed to sucking it out. If you are unable to get solder wick started, you can add some additional solder to the hole, pad.

[AJ]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

I use a solder sucker and have no issues with through plated holes. I find them easier to work with, actually since they make it harder to lift pads/traces. My procedure: Put the PCB in a vise so you can get at both sides of the board. Pull the component without cutting the leads. heat up one side of the pad and suck the remaining solder out the other side.

[Michael P]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

I'm mostly a lurker on this forum but ... I wanted to jump in and say that this is one of the more technically impressive and charitable DIY efforts that I've seen. I used to have an Audiosource amp and I'd agree that they are well suited to this type of modification (because they're so cheap but include all of the basic infrastructure for a decent sounding amp). I hope that lots of people will try it!

[Pete Basel]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

I was going to suggest that you use an A/B switch, good that you did!
Be very careful about level matching as I'm sure you know, but you might
be surprised with what you hear even with a .25 dB level difference.

[50 watt head]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

What a great mod and thread -- high five, tyger!

Too bad IC1 isn't socketed from the factory, I've never felt comfortable when soldering/unsoldering DIP devices. This mod looks like such a worthwhile project, though, I shouldn't let that deter me.

[philthien]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

Not always a good idea, since many holes are through plated and drilling takes a chance at removing some of the copper clad.
Better to just clip the component out, but leave the component leads or legs long, that way you can grab them with pliers or tweezers as you heat the solder till it melts.

Another way to clear a stubborn hole of solder is to actually blow it out while it is molten, as opposed to sucking it out. If you are unable to get solder wick started, you can add some additional solder to the hole, pad.

I did include that warning in my post, but it is always wise to repeat it.

I've replaced hundreds and hundreds of bad caps, and it all boils down to this: If the bit is smaller than the hole, there is little risk to the through plating. That is because the solder is so soft compared to the board, or the plating. The bit pretty much just follows the solder and digs it out. But the bit MUST be smaller than the hole.

Solder wick and blowing may work okay, but... Most of the damage I see from work performed by others is due to too much heat. They just lay down so much heat, that traces lift right off the board. The beauty of the drill bit trick is how little heat is required. Once you get the component leg out of the board, you're done with the heat (until you're ready to install the new component).

[TN Allen]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

Perhaps someone else has mentioned using a round toothpick, I've used this method with good success.

This really is a great thread, so good, I'm thinking of doing the modifications, although, I had intended to sell the amp I have and put the proceeds toward another Dynaco 120 upgrade.

[Psycoacoustics]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

Perhaps someone else has mentioned using a round toothpick, I've used this method with good success.

This really is a great thread, so good, I'm thinking of doing the modifications, although, I had intended to sell the amp I have and put the proceeds toward another Dynaco 120 upgrade.

I'll give ya $50 bucks shipped to Chicago towards your Dynaco! :D