[tangent]

Lift the battery partway out of the holder so that only one terminal is making contact. Put the meter inline with the other terminal, completing the circuit. If it's an analog meter, polarity matters -- if you don't get the needle to move in one orientation when the power is on, swap the probes.

As for the input resistance issue, you don't need the mini-to-mini now that the amp is out of the case. You can measure directly at the solder joints on the input jacks. Trace the wires to the board to find out which one goes to IG, and that will be your ground. The other two will be left and right input.

 

[Zemo]

ok, I did that, and I get a reading of .02 or .002 depending on where my switch is...what should I have the thing set to? should I have the red probe in the V(omega)mA spot or the 10ADC spot? The switch should be in the Ampere position right? wich one? 10A, 200m, 20m, 2m, 200(mu)?

I'm sorry, man, I know next to nothing about this...

I set my meter to volts, just for kicks....I have 4 batteries here...and I tested them all....they're all 9v batteries....but....I got some wierd readings.....maybe this is the source of my problems...for some reason NONE of the batteries are 9v....I get 3.37v, 7.3v, 7.88v, and 8.49v....that's bad, isn't it?

And I still don't know how to measure current....

 

[Zemo]

I wired in series the 8.49v, 7.88v, and 3.37v batteries, and tried the amp....same results.....LED slowly got dim, sound stopped....

*sigh*....next option?

hopefully I'll hear from the EE professor soon (tomarrow is monday).

 

[tangent]

Quote:

what should I have the thing set to?

Start off on the highest setting, then step down slowly until you approach the maximum for the range you pick. If you pick too low a range, you'll damage the ammeter or blow a fuse, depending on whether it has fuses or not.

Quote:

should I have the red probe in the V(omega)mA spot or the 10ADC spot?

Start with the red probe in the 10A position. If you can't get the needle to move much by the time you get to the lowest range on the meter, switch back to the highest range and then move the red probe to the mA position. This is an extension of the above comment -- you're starting in the high range and moving down until you can get some decent resolution on the meter, but not so far down the scale that you break something.

Quote:

10A, 200m, 20m, 2m, 200(mu)?

The expected current draw for your amp will be somewhere under 100mA, but if it's broken it could easily be much higher. So, start in the 10A range, then try 200mA. If you don't get any joy in that position, try the 20mA range, but be prepared to pull the leads off imediately if you peg the meter.

Quote:

for some reason NONE of the batteries are 9v

Batteries normally drop in voltage as they run down, so maybe your numbers are okay. The one that tests at 3V is dead, though. Also, if the numbers slowly creep upward on a battery that has just been removed from your amp, that means the amp is drawing way too much current, and the battery voltage is slowly recovering now that the load is off.

 

[Zemo]

alright, I think something is wrong then...with the probe in the 10ADC spot, the mutimeter will complete the circut, but the reading always has a 2 at the right side of the screen, and the rest is zeros. Moving the switch only moves the decimal place. So I get a reading of 0.02 or 00.2 or something along those lines. With the probe connected to the V(omega)mA spot, the mutimeter won't complete the circut, and therefore, I can't get a reading.

 

[Zemo]

*sigh*....I paid $180 for this amp.....and it doesn't work....how much would a comparable amp cost? How much do PPA's cost? Not that I'm abandoning ship, mind you, but I just want to know what my options are. Thanks again for your help, and I desperately await your reply!

 

[guzzler]

IMO, i'd remove all connections to the board and build from scratch from there; but don't do this unless you're absolutely convinced you can sort it out, those 9x EL2001 are far too good to lose! are the ICs (the opamp, and the buffers) on sockets? If they are, you could build a META from just the board as these are the hardest to get, and most expensive parts on the board!

a PPA will set you back a lot more; however, I don't think you will have the necessary skills to spec or put it together so you'll have to get someone to build it for you! probably about $250-300 for a PPA

g

 

[Zemo]

so you want me to desolder everything and just start over from scratch? no, nothing is on sockets....that's a LOT of desoldering....which I'm not at all good at...

I'm not sure I'm sorting this all out....you recommend desoldering everything and soldering stuff onto a new board? so you think the board is the problem?

If I can't find any physical problems, then it means one of the parts went bad, right? well, should I test the individual parts? and how?

this amp is costing a lot more than origianlly anticipated....$180 for the amp, $10 for shipping, $10 for a soldering iron/solder/braid, $5 for a new mini-mini, $8 in batteries...That comes to $215 for this amp *so far*....I still have yet to fix the power problem..

 

[tangent]

It's really hard to guess what value you're seeing with a meter like that. It could mean 2 amps or 20mA.

Thinking about it... it has 9 EL2001 buffers? And an AD8620? 20mA is just barely in range for that kind of setup. It could be right. If it's 2A, I don't see why your batteries aren't getting hot, sincet that's severe overload for alkalines. They are alkalines, aren't they?

I don't think anyone's suggesting you rebuild it from scratch, just that you take it apart to the degree that the parts start working. I wouldn't go down to the level of desoldering resistors. If you get it down to that level, populating a new META42 board and moving all the expensive parts over (ICs, pot, casework) may make sense. You'd only be out the cost of the board, some resistors, caps, and sockets. I'd also abandon the TLE and any JFETs, but that's just me.

But this seems drastic to me. You have some local expertise there. They may be able to help you fix it without doing this partial rebuild.

 

[Zemo]

yes they are alkaline batteries....I'm pretty sure the reading was 20mA...what do I do to get the current where it should be?

And what exactly is "taking it apart to the degree that the parts start working"? what do I take off first? and what do I do to check to see if the parts start working? How?

I'm sorry man, you're going to need to walk me through this stuff step by step.

Quote:

I'd also abandon the TLE and any JFETs, but that's just me.

huh? what are you talking about? What is TLE and JFET? are they parts? should I get rid of them? what?

 

[JMT]

I am actually surprised that your builder is not responding in some helpful way. Although the purchase may have been for an "as is" amp, I do think the implication is that the amp would be in working order when it was received. The issues that you are experiencing sound, to me, more than just issues that occured during shipping.
Quote:

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

Have you abandoned all efforts to have him take a look at it?

 

[Zemo]

yah, he hasn't responded to my last few PMs....I just sent him another one, and hopefully he'll get back. He keeps telling me that the amp was working when he sent it out. The only difference between what he was using and what I am using now (other than source/interconnects/cans) is the batteries. I'm using 9v Alkaline, and he was using 9v rechargable.

I'm trying to get in touch with the EE professor that took some interest earlier, to no avail....

 

[Zemo]

Shutakagi contacted me and said he was willing to help me fix it, but not to fix it himself or refund it. That's alright, I want a META42. He is, however, sending me the batteries he used in it...we'll see how that goes.

 

[tangent]

Quote:

what do I do to get the current where it should be?

If it's 20mA, it probably is where it should be.

Quote:

what exactly is "taking it apart to the degree that the parts start working"?

Maybe I'm asking too much of you. I'm suggesting that you read through the META42 docs and find out how the major parts of the amplifier are supposed to work. Remove the crossfeed, for example, and remove the chips from the amplifier board. Once you have a few major pieces, test each piece. Whichever piece doesn't work right is the problem.

This may be more work than you're willing to undertake, but I can't help with that.

Quote:

you're going to need to walk me through this stuff step by step.

Sorry, I'm not willing to go much farther on this. I'd end up writing a book for you, and I already wrote plenty about the META42. http://tangentsoft.net/audio/meta42/

Quote:

What is TLE and JFET?

Yes, they are parts on the circuit board. I mention them only because they're below my threshold of pain cost-wise. Given a choice between taking the time to remove them from the baord carefully enough that I can re-use them and just buying new ones to put in the new board, I'll buy new ones. But that's just me.

 

[PeterR]

Hmm. With 20mA current draw you won't drain the batteries in 1 minute. Probably silly question, but have you ever tried fresh batteries after replacing that mini to mini cable?