[viviorunitia4]

I'm building my first diy amp, a meta42, and I have most of the parts in place, but can't get the LED to work. I'm guessing that something isn't connected right, but I can't really tell what. I posted a picture of the top, and I can post a picture of the back, if needed, but the quality isn't very good. Any advice would be greatly appreciated

go to Viviorunitia4's Meta42 page to view the pictures

 

[JMT]

Check your power supply connection. It is hard to tell, but it looks as if you have the + lead connected to the top pad. With the META board version 2.2, for a single PS (one not in series) you should only be using the bottom pads. You also neglected to install D1 or D2.

 

[KurtW]

I agree with JMT about your power connection. As for D1 and D2, you don't need these but you do need to connect the two pads to the left of the D2 connection, or connect the switch pads on the other side. This is for the power switch, and an open connection is off.

Don't forget to short out R9 or you won't get any output.

You're getting real close...congradulations!

 

[viviorunitia4]

the part I received for D1 doesn't look like the one on tangents website, and I don't know which way to put it in
the pics can be seen on my website

 

[Vdubjunkie]

Quote:

A good way to threaten somebody is to light a stick of dynamite. Then you call the guy and hold the burning fuse up to the phone. "Hear that?" you say. "That's dynamite, baby."

Ok, totally OT, but is that Jack Handy?

 

[Kelvie1234]

You'll notice that the diode has a metal part sticking out...

make sure that lines up with the thicker line on the D1 marking on the board... then you'll know its the right spot.

The thing with diodes is, though, that if you stick it in wrong, you can just take it out and stick it back in the other way with no harm done.

 

[tangent]

Kelvie's got it: the box with the thick line on one side depicts the 10TQ series diodes. Put the pins in the holes within the box.

 

[viviorunitia4]

yeah, it is Jack Handy...

 

[viviorunitia4]

okay, I installed the diode and the power switch, and got the LED working, and then I put all of the remaining buffers and the opamp in their sockets and all of the in/out jacks, connected to my cd player and headphones, and got nothing.
Is it because the buffers and opamp aren't soldered in place? or could something else be amiss? I again posted pictures on my website

 

[tangent]

I don't see wires going to the PCB for the power switch. Since you're not using D2 and it doesn't look like you've jumpered one of the power switch pairs, you need to run a power switch to the board.

 

[viviorunitia4]

I have the power switch connected to the power switch pads near D1. Do I need to jumper over the extra power switch pads?

 

[Neophyte]

Also you may want to use some rubbing alcohol on the underside to remove all the extra flux!

 

[tangent]

Quote:

I have the power switch connected to the power switch pads near D1.

I don't see this in any of the pictures on your site, but nevermind that. I'm off on a tangent here: you say the LED lights up, so obviously power is getting to the amp somehow.

Try this: pull all of the chips out except 2001G, and check that you're getting the proper voltages at all of the chips relative to virtual ground. If not, pull 2001G out and check that 2001G is getting the proper V+ and V- relative to TLE2426's OUT.

If the voltages are all good, put the chips back in place, run a test tone through the player and measure AC voltage at the input jacks, between the pot and C1, between C1 and R1, at the op-amps' outputs, and at the output buffers' outputs. If you don't have a test disc or a signal generator, you can make a test disc with a PC and a CD burner -- search the archives.

Quote:

Do I need to jumper over the extra power switch pads?

Definitely not. That would keep power turned on all the time.

 

[viviorunitia4]

okay, when I touch the black probe (-com) on my analog meter, and touch the red (+v.ohms.a) to pin 1 of the buffers, I get 4.5 volts. when i touch pins 2 and 4, the meter goes backwards (needle to the left). If i switch the black and red probes (red to virtual ground and black to buffer), i get 4.5 volts on 2 and 4 and the needle goes backwards on pin 1.

For the opamps, with black to virtual ground and red to the opamp, pin 5 shows 4.5 volts, and pin 1 goes backwards. again, if red and black are switched, pin 1 is 4.5 volts, and pn 5 is backwards.

click here to see the pin numbering

by the way, I'm using one 9v battery

I hope this isn't too hard to understand, but is this right?

 

[tangent]

The proper pin numbers are given in the datasheet of each chip. Typically, pin 1 is in the upper left, and it goes counterclockwise from there. The pin you're calling '5' is probably 8.

You should find that pin 4 on the op-amp is also at V-.

Now put the chips back in and re-test everything. I'm most interested in seeing that pins 2 and 7 on the output buffers are no longer at V- (they should be at 0 with no signal), and the same for pins 2 and 8 on the op-amp.

If that gives sane results, do that signal trace-through I mentioned.