[Zemo]

Well, the buffers are 4 stacked...so I suppose one of them could be shorting on the bottom of the case...so I looked under the board, and couldn't REALLY see if anything was touching or not...but I DID notice that the board doesn't sit flat...it's kinda crooked....I'm about to try using the board while propping it up a little to make sure there's no shorts....I'll let you know how that goes!

Thing is though, the case doesn't conduct electricity (I tested it with my multimeter...)

 

[Zemo]

Nope, propping the board up didn't help...the power lasted for quite a while (as it did last time I tried) but it still stopped after a short bit.

.....help me.....please....

is there ANYWAY for me to contact shutukagi? The dude sold me an amp that was supposed to work, but it doesn't, and I have no way to contact him!

 

[JMT]

How did you pay him? If by PayPal surely you have his Paypal e-mail address. If by check or money order, you must have his physical address to send snail mail.

 

[tangent]

Quote:

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.....

Hmmm...if that means 3.7 ohms, it sounds like a shorted out input jack. If it means 3.7K ohms, the measurement is a little weird; does it change much as you rotate the volume knob?

I reiterate: get that amp out of the case and remove the input jacks.

 

[Zemo]

the reading of 3.7 (when the switch was set to 20kohms) was when the unit was off and no batteries were in it. I played with the switches (on/off, crossfeed on/off) and there was no change. Then I popped some batteries in it. still a reading of 3.7 with the unit off (crossfeed on OR off). Then I switched the unit on. With the crossfeed both on and off the reading was -0.01 on both base to tip and base to sleeve. Keep in mind the switch was set to "20k Ohm". Gosh, rereading that, it's confusing...here's a little table for you:

Batteries Power Crossfeed Reading
no off off 3.7
no off on 3.7
no on off 3.7
no on on 3.7
yes off off 3.7
yes off on 3.7
yes on off -0.01
yes on on -0.01

note: after letting the amp run itself dead (you know where the LED goes dim and sound stops) I took another reading. I got no reading at all.


I FINALLY was able to contact Shutakagi!!! HUZZAH!!! He said he knew the 1/8th jack cutting out was due to the cable, not the jack. He also said there were never any power problems when he used his own generic 9v rechargable batteries. I'm seeing if I can get him to send me the batteries he used (and a replacement mini-mini).

FYI: the batteries that I'm using are "Energizer e squared titanium technology" 9vs.

 

[Zemo]

I wish I COULD take the amp out of the case, but I'd need to desolder the RCA jacks, and I don't know how, nor do I have the resources (soldering iron, pump(?), braid(?)).

I'd also need to find an allen wrench that will fit the volume knob.

 

[tangent]

Oh, wait...crossfeed. That explains the odd input measurement.

Power on and off shouldn't change this measurement.

Now what is odd is the fact that apparently the inputs are shorted when you turn the crossfeed on. That shouldn't happen.

But now that you've contacted your builder, I don't see why you'd have him send you parts and such. I'd send the amp back to him, since you planly aren't willing to take it apart. You can't do much with it without doing so.

 

[Zemo]

I'm willing, I'd just need to talk to my (EE major) friend to see if I could get access to a soldering iron and a resistor (to increase the gain).

What changed the meausurement wasn't the crossfeed, it was the power on/off (with batteries).

I'd really like to keep this amp, it's a good amp, and it was a good price....I just need it to work correctly. Just tell me what I need to do to fix it, and I'll just try to do what you say! I'll try to get a soldering iron and resistor today.

Apperently, Shutakagi doesn't feel he's responsible for sending me a faulty amp, as it was working fine for him.

 

[eyevancsu]

If you need an iron and some resistors, just go to radioshack and get a cheapy iron for a few bucks, same for the resistors, or if theres a fry's nearby, go there for the resistors, they seem to have better selection but more expensive. These stores dont have the best products, but if all you need is a few parts, go ahead.

ivan

 

[Zemo]

will do, I'll check that out today.

 

[Zemo]

ok, the amp is out of the case..what now?

 

[Zemo]

after taking the amp out of the case, I tried it, and the power problem persisted. I took off the screws holding the crossfeed board in place, and moved it out of the way so I could make a physical inspection of the board, and I couldn't see any obvious problems....

 

[tangent]

Okay, so now you know it isn't grounding out against the case.

Measure from each input channel to ground with the power off, again.

If you can, put the meter inline with one of the battery terminals and measure current at turn on and watch it as the amp dies. Leave the headphones out of the jack so you have plenty of time to watch it.

 

[Zemo]

how do I measure each input channel to ground?

What I've done in the past is plug a cable into the output of the amp, and measure from the ground to R and L. (and I got 3,700 Ohms unless the amp was on with batteries in it)

I just plugged in a working mini-mini into the amps input and got readings of 2,260 Ohms from ground to L and R, regardless of whether the amp was on or off, with or without batteries.

And how do I measure the current? What setting on the multimeter, where do I touch the probes?

 

[Zemo]

I ended up soldering 2 220ohm resistors onto each channel's R3 spot to get the gain where I like it...so that problem is fixed now....but what about the power problem? I still don't know what you mean by: Quote:

If you can, put the meter inline with one of the battery terminals and measure current at turn on and watch it as the amp dies. Leave the headphones out of the jack so you have plenty of time to watch it.

Thanks again for all your help, and I can't wait to get this amp working!