[tangent]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif Oh, wow... I didn't realize that those painted areas transferred electricity! *facepalms*

They don't. But they do mark where, on the bottom side, the copper is.

That particular confusion has come up more than twice. I may have to do something about it. I guess you're asking in advance of actually seeing the Radio Shack board?

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Some parts have been replaced or superceded by newer versions

Yes, it's about time to weed the parts table again...about as much fun, too.

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how difficult would it be to have two RCA L/R input?

Trivial. See the panel components article, linked from the CMoy tutorial.

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Also, would it be possible to add RCA inputs in addition to the 1/8" input?

The only easy way is to wire them in parallel, which only works if you're using them separately. If you plug two sources in, what happens depends on the sources. It might actually work okay, or it might sound rotten.

 

[splaz]

Now that you mention it some wire that isn't PVC would be great. I always get the issue of it melting when it's close to the tab I'm soldering so in the end the wires have the potential to short on each other or other tabs.

Any reason you couldn't just have a switch to choose the input tangent or doesn't that classify as 'easy' ?

 

[achina]

You could use a switched stereo jack. Connect the RCA inputs to the switched pins on the jack. When no plug is inserted the RCA jacks would be connected through the stereo jack. When a plug is inserted the RCA would get disconnected.

Edit: There could be a problem with ground though. Since the ground connection is not switched. Having ground connected to two different sources may cause problems.

 

[splaz]

Here's a pic of what achina is talking about, would probably be able to get better ones but these you can see what happens. Those 3 contacts lift up when you insert a plug but when nothing is inserted it shorts across, so you'd wire up the RCAs to the side that breaks, then wire the other side up to the board.

 

[achina]

Ah, yes that design would isolate the input grounds. I was thinking of the typical switched 1/8" jack which doesn't switch the ground.

 

[tangent]

Quote:

Originally Posted by splaz /img/forum/go_quote.gif Any reason you couldn't just have a switch to choose the input tangent or doesn't that classify as 'easy' ?

No, I don't call a DPDT (minimum) or 3PDT (better) switch "easy" in this context. I just got done explaining the mechanics of perfboard to this guy...let's not go pushing him into the deep end of the pool just yet.

 

[Joshatdot]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif Here's a question: Why isn't hookup wire in the parts list? Is there a place I can buy short runs of it for cheap?

I used old PC Front Panel wires for mine, you know the PC Speaker, Power LED, HDD LED, Power Switch, Reset Switch.

 

[infinitesymphony]

Quote:

Originally Posted by splaz /img/forum/go_quote.gif Here's a pic of what achina is talking about, would probably be able to get better ones but these you can see what happens. Those 3 contacts lift up when you insert a plug but when nothing is inserted it shorts across, so you'd wire up the RCAs to the side that breaks, then wire the other side up to the board.

That may be something to try on a different build... I could probably use a jack like that and then add the RCAs at a later date, right? Considering that any signal that goes through the RCAs must also pass through the 1/8" jack.

A few other quick questions... Do places sell alligator clips that are connected by wire, or is that just DIY? I'll need them if I want to perform the input test. Also, would some helping hands be a worthwhile investment?

 

[tomb]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif That may be something to try on a different build... I could probably use a jack like that and then add the RCAs at a later date, right? Considering that any signal that goes through the RCAs must also pass through the 1/8" jack. A few other quick questions... Do places sell alligator clips that are connected by wire, or is that just DIY? I'll need them if I want to perform the input test. Also, would some helping hands be a worthwhile investment?

Radio Shack sells a package of several different colored test jumpers with alligator clips on both ends of the wire - extremely convenient.

Helping Hands are often $1.99 or $2.99 at Harbor Freight, if you have one nearby. A lot of people pooh-pooh them in favor of expensive Panvises, etc., but the cheap ones can be fine for a lot of things. For a big board, you can just use two of them - works well enough. Use a little piece of electrical tape on the corners of a PCB, so the alligator clips don't scratch it up.

Navships - now "John's Wire Shop" on e-bay is a great source for teflon-coated wire. It's nice to have something that even when the iron touchs it occasionally, not a thing happens.

 

[infinitesymphony]

I'm trying to place my order through Newark, but the tax and shipping costs don't show up, even on the "confirm everything before clicking Submit Order" page. Has anyone else had this problem with Newark? If I have to order this blindly, what should I expect to pay in shipping costs for a ~$30 order?

 

[colonelkernel8]

Depends if its $30 of lead or $30 of feathers.

 

[Pars]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif I'm trying to place my order through Newark, but the tax and shipping costs don't show up, even on the "confirm everything before clicking Submit Order" page. Has anyone else had this problem with Newark? If I have to order this blindly, what should I expect to pay in shipping costs for a ~$30 order?

Many people here detest doing business with Newark because of their shipping. This is in my experience, but even a small light order that might even fit in a padded envelope will ship in a box, sometimes rather large. They are slow, and overcharge on their shipping. Most order from Digikey or Mouser instead. Both charge basic actual rate... I usually use USPS Priority Mail from either of them. Mouser no longer has a minimum order either.

 

[infinitesymphony]

I'm looking to order my parts from the same location, and from the CMoy parts list page, I read that Mouser tended to have "cheaper" parts. For example, the capacitors from Mouser are Nichicon while the Newark ones are Vishay Dale. Will these parts differences make a difference in the actual amp?

Edit: I've decided to go with Digi-Key, at least with this first amp. So, no Vishay Dale resistors in this build... We'll see about the next one.

 

[Pars]

Digikey-- The BC (or Phoenix Passive) 0.4W resistors are very good (PPC100KYCT-ND part number for the 100K, etc.). Panasonic FMs for the 470uf electros, some Epcos MKT 0.47uf input caps (495-1112ND, small, easy fit on a Cmoy). They're the only ones who carry the Panasonic pot if you go that route. And, it appears they actually have the TO92 cased TLE2426CLP railsplitter in stock (296-1994-ND, order a couple or 3).

Its been 2-3 years since I ordered anything from Newark, but I haven't heard anyone saying anything good about them. They may have changed though.

 

[pinkfloyd4ever]

not to hijack the thread, but I didn't wanna stard a new one for such a small question. How do you guys secure a LED to your cases, specifically an altoids tin that my CMoy is going in? Do you have to use some kind of LED holder or is there a reliable way to get it to stay in place with some type of epoxy or superglue or something?