[tangent]

Best way to test Ivan's theory is to remove the jack from the panel and plug your headphones into the jack as it flops around on the end of its hookup wires.

It doesn't look like you have a wall-powered amp, though. If it's just battery-powered, the only thing connected to the case should be the amp's signal ground. If there is a DC jack in there that I missed from looking at your pics, Ivan's nailed the problem -- the jacks are clearly grounding out on the case.

Oh, jeez, now that I look at your pics I see the dilemma about getting the amp out of the case. He went and attached jacks to the sides of the case. Ugh. If you put everything on the panels, you can get the amp apart to work on it much easier. Double ugh. You're going to have to either lift the amp board up and out of the case while the jacks are still attached, which only works if there's enough slack in the wires, or you're going to have to desolder the jacks from the wires to get it out.

If you don't mind the work, removing the jacks from the wires is a good troubleshooting step anyway. When the amp is freed from the case, use alligator jumpers to tie your headphones and source to the circuit. If it works that way, either one or more jacks are damaged, or there's some kind of case grounding issue going on.

 

[Zemo]

There's not enough slack in the wires....I'm going to have to desolder, arn't I? dang it!

And no, my amp isn't wall powered. Even if it were, the wall wart plug is on the back plastic panel, not attached to the metal case itself....wouldn't that be adequately grounded? I'm not sure I understand completely what you guys are saying...you gotta remember, I know nothing!

should I still remove the jack from the case and plug in the source while it flops around? it'd take some work (cause it's in a tight place), but I might be able to wiggle it out...

WHAT DO I DO ABOUT THE POWER PROBLEM??! that's my main concern right now...

 

[tangent]

No need to shout. I haven't been talking about your power problem because I think the output intermittency may be related. If the system is grounding out somehow, it can drag everything down with it, including the LED. The power problems look like a symptom to me, not a cause.

I would remove the amp from the case and see what it does that way. You'll only have to desolder the RCA jacks...the 1/8" jack's mounting nut is on the outside so you can just unscrew that.

 

[Zemo]

Sorry! wasn't trying to seem angry or anything!

ok, trying to get it out of the case....how do I desolder anything? and how will I re-solder it?

an FIY: the RCA inputs work fine. They don't cut out at all

Also, I got the 1/8th free, and I tried plugging into it, and I got nothing....not even after jiggleing the jack....wait....wait a second...if I jiggle it enough, I get a little bit of the right channel....hmmm...

 

[tangent]

Quote:

how do I desolder anything?

With a soldering iron.

Quote:

how will I re-solder it?

With a soldering iron.

Perhaps you should do a Google search for "soldering tutorial".

Quote:

the RCA inputs work fine. They don't cut out at all

...but the amp's LED still dims and dies soon after turning it on while using the RCAs?

Quote:

I tried plugging into it, and I got nothing....not even after jiggleing the jack....wait....wait a second...if I jiggle it enough, I get a little bit of the right channel....hmmm...

Plainly that jack is broken. You can either desolder it, or just clip it off the wires with wire cutters. It's better to desolder it if you don't have much slack on the wires going to that jack.

Even if you don't have a fresh jack to put in its place, try removing this jack. A jack with internally shorted contacts can cause the symptoms you're seeing.

 

[Zemo]

So i've got a buddy here, and he just so happened to have a digital multimeter laying around, so I used it....so, I was checking for continuity and junk (cause that's about all I know HOW to do right now...and I couldn't find any obvious problems in the amp. So just for ****s and giggles, I checked the mini-mini.....NOTHING!!! the only thing that had continuity was the TIP!!! GAHH!! So I borrowed a mini-mini from a friend and guess what..it worked!!

So, the mini jack is fine...but the power is still a problem. And now, I have a multimeter at my disposal! Any ideas?

 

[Zemo]

you know what? This would be a WHOLE lot easier if you wanted to IM me...my AIM handle is SaxyTy74, and my MSN handle is my email address (zemo3#juno.com..replace the "#" with an "@"....I don't want those email harvesters sending me **** ads...) I'll be on all night tonight..

 

[tangent]

I don't do IM.

Take your good mini-to-mini and plug it into the output. Measure ohms from ground to left and to right at the other end of the cable. What do you get?

 

[Zemo]

I hope I did what you mean...I left the amp off, and it didn't have batteries in it, or anything plugged into the input....and I THINK the ground is the base of the plug, right? And since I don't really know how to use the Multimeter.....

I had the switch set to 20k ohms, and the reading from the base of the plug to the sleeve, and the base to the tip was 3.70.....

 

[Zemo]

So, I noticed something....This multimeter has a setting that it will beep when there is continuity...so I touched the two battery terminals with the probes, and obviously no beep. I kept the probes there and turned it on, and I got a beep, as would be expected....but the beep only lasted for a second, then stopped....like the circut got cut after a second...is this supposed to happen?

 

[PeterR]

Quote:

Originally posted by Zemo So, I noticed something....This multimeter has a setting that it will beep when there is continuity...so I touched the two battery terminals with the probes, and obviously no beep. I kept the probes there and turned it on, and I got a beep, as would be expected....but the beep only lasted for a second, then stopped....like the circut got cut after a second...is this supposed to happen?

Yes, this is normal. You're not measuring anything useful there, just the PS caps getting charged...

 

[Zemo]

Dang, I thought I had something there....

Anyways, I contacted an EE prof here on campus who seems interested. We'll see if he wants to help me out with the gain increasing and see if he wants to try to troubleshoot the power problem....

Update:still can't contact Shutakagi....

 

[Zemo]

anymore ideas?

 

[Zemo]

STILL can't contact Shutakagi....

I tried it out again today, and the amp lasted for a lot longer then normal, so I thought to myself that some sort of miracle made it work right! Well, as SOON as I put the last screw in the case and sealed it up, the LED went dim and the sound went out...dang.

Anymore ideas, all you DIY-ers?

 

[eyevancsu]

Is the body of your case metal? if it is, is it possible that the meta board has some exceptionally long leads and touch the bottom of the case (inside the case) and somehow cause a short?