[Edwood]

My first attempt at a Pimeta. So far so good.

It took me awhile to figure it out, but I couldn't get the LED to light up, but when you leave out the zenier diode for the RFET, you are supposed to solder the RLED leads to the RLED hole that is farther away than the RFET holes.
I made a couple mistakes like puttinf wrong resistors in. I'm very happy with my new Metcal SP440, makes desoldering parts a breeze.

So, I got to testing the power supply. Taking the readings from the batteries (two in series), I get like 17.XX volts and from the various sockets, either nearly the same (17.XX volts) or about half of that (9.XX volts). Does this sound about right?

And at the C2 and C3 electrolytic caps, I get like ~7.34 Volts. Does this look right?

I was going to take the reads again and post all of them, but looks like my DMM is toast.

-Ed

 

[Kenny12]

wow ur very neat

 

[pne]

yea, looks top notch. unfortunately when i build i have a billion little baggies and components scattered across my desk

 

[Edwood]

Quote:

Originally Posted by Edwood So, I got to testing the power supply. Taking the readings from the batteries (two in series), I get like 17.XX volts and from the various sockets, either nearly the same (17.XX volts) or about half of that (9.XX volts). Does this sound about right? And at the C2 and C3 electrolytic caps, I get like ~7.34 Volts. Does this look right? I was going to take the reads again and post all of them, but looks like my DMM is toast. -Ed

Can anyone answer this question?

Thanks.

I'm itching to put the OP amps and buffers in, but I don't want to fry them.

-Ed

 

[Edwood]

Quote:

Originally Posted by pne yea, looks top notch. unfortunately when i build i have a billion little baggies and components scattered across my desk

LOL, if I zoomed back, you'd see my disaster area of a desk.

I just like to keep my parts sorted. I will eventually get a bunch of baggies and file them in little drawers or something.

-Ed

 

[MisterX]

Quote:

Originally Posted by Edwood Can anyone answer this question? Thanks. I'm itching to put the OP amps and buffers in, but I don't want to fry them. -Ed

Do you realize you quoted yourself?

Without knowing exactly were and what you measured it is hard to give you a usefull answer.
But, umm, yea, the voltages at the caps should be half the supply volatge.

Measure the voltage's at the opamps (pins 4 and 7 for the ground 4 and 8 for the left/right channels (relative to ground)).

 

[MisterX]

By the way.
Nice job so far.
Are you sure this is only your second amp?

 

[Edwood]

Quote:

Originally Posted by MisterX By the way. Nice job so far. Are you sure this is only your second amp?

Heheh, it helps to have nice toys/tools for soldering.

I am not new to soldering, but new to electronics soldering. And most certainly Amp building.

-Ed

 

[Edwood]

OK, here are the voltage readings.

Keep in mind that I rounded the readings to be the same relative to the other sockets. Since it is battery powered, the voltages were slowly dropping as I was taking readings, but they were pretty constant. i.e. When I read 7.33V on one, it was also 7.33V on the other. But over time, it dropped slowly, became 7.32, 7.30, etc. But if I measured like voltages quickly, they were identical.

So how do these look?

The power supply was two 9V batteries in series.

-Ed

 

[Edwood]

Well, it's playing music for the first time.

Sounds good.

I measure 0.013VDC coming out of the the output for Left and Right. Not bad.

I didn't realize that I had only Dual to Single Brown Dog adapters. And the AD8620 is a dual OP amp. Argh.

So I'm using the AD8610 for Ground and OPA2132 fr OPALR for now.

-Ed

 

[Syzygies]

Ok, I plan to build this soon, so I almost went to datasheets to check pinouts, then I thought: With no signal, every measurement is within 0.04 volts of 0, 1/2 V or V, where V is your battery voltage. Nothing is smoking or getting way too hot, and your battery voltage isn't in free fall. So how could any of these numbers be wrong?

At a certain point, you've just got to go for it.

I'd bet that with practice or some debugging one could center the virtual ground better than this?

(It's too bad there's nothing in common use between DMM's and scopes. I want a DMM with complex number readouts, designed to work with a simple signal generator.)

 

[Edwood]

Woohoo! Digikey rocks.

I got parts in yesterday for the Mint. So the Mint's up next while I'm waiting for those Brown Dog adapters for the Pimeta.

-Ed

 

[aeriyn]

Damn, Ed, your PIMETA is prettier than mine!

Well, mine is missing one rail cap at the moment, has clogged up holes on the OPAG position and the Q1L position and has a dead TLE... so... *cries*

And my opamps are still not here. >.< The mail sarks!

 

[Edwood]

Finished a Mint today.

0.010 VDC Measured at the outputs. Sweet.

Heheh, I slipped a little bit when soldering one of the BUF634U's, so it's a bit crooked. But it's secure and no shorts, I'm just an*l that way. I'll do better on the second Mint I build.

With the AD8620 it certainly sounds better than the Pimeta with the humble OPA2132.

I have it populated with 470uF Panasonic FC's.

Going to cut it half tomorrow and case it up in a tin.

It's so much smaller than the Rat Shack proto board based CMoy. Will definitely have room for two 9V's.

Now I just need to find better battery carriers. I hate those cheap vinyl ones.

-Ed

 

[Dreamslacker]

Nice work.. I only wish I could afford a desoldering station. Hehe... Surviving on desoldering wick and pump now.. At least I managed to get a Weller Soldering Station for S$118 (US$72).
Actually, I figured I could buy a desoldering station from accumulated cost of buying desoldering wicks... LOL..

Are you using CAT5E twisted-pair wires? They look to be..