[superjohnny]

Instead of using the 4.75KÙ resistors in R2/R3 for the power supply I added a 100KÙ & 2.2KÙ.

stupid mistakes really piss me off. I'd have been baffled all night if I hadn't followed your advice about measuring not only the voltage, but also the resistance. That's what you get when you stay up till 2:00am building your amp I guess

Quote:

Once all the components are in place, solder two 2" hookup wires to the board, in the holes marked V+ and V- in the annotated image. You should do this on the underside of the board. For the moment, just leave the other ends dangling loose, but don't let them touch while the power is applied.

Is it necessary to hook up the 2" hookup wires? Can't you just measure the voltage anywhere on those bridges?

I know mine's wrong right now, but by putting the lead on the multimeter in the v+ & v- holes I get a reading of about +8.7/-0.3. It's not the measurement I'm looking for (resistors all out of sorts & what-not), but at least i'm getting a fairly accurate read.

I'm not trying to question your tutorial Mr. Tangent, I'm just trying to better understand it.

 

[superjohnny]

Quote:

Originally posted by tangent Measure resistance from V+ to vground and V- to vground.

4ohms on the +v, 0ohms on the -v

After replacing the resistors with 4.75kohm resistors I still have the same issue.

 

[esquilax]

stupid question: in that pic above, the ground busses on the perfboard are jumpered together at two ends. isn't that a ground loop?

 

[superjohnny]

<edit out fixed issue>

I won't give up on this project, I won't quit and I won't fail. If this turns into the most expensive CMOY amplifier ever built, so be it

 

[superjohnny]

I haven't listed the parts, maybe that'll help. Caps ordered from digi-key, Vishay resistors from Mouser.

This is what is currently installed on the board:
2-220 µF 35V electrolytic capacitor, radial leads
R2 & R3 are both 4.75v resistors
All the power-supply jumpers + the two M jumpers on the bottom/outside.

Thank you!

 

[superjohnny]

<EDIT> [size=small]Now I got it![/size] It was a bad solder joint with the -batt

Now the -v reads about -9.3v and the +v reads about +9.3v

HOT DAMN I'M BACK IN THE CHIPS!

 

[tangent]

Quote:

Is it necessary to hook up the 2" hookup wires?

No, not necessary. I just found it convenient, since I could hook grabber leads from my meter up to the wires.

Quote:

the ground busses on the perfboard are jumpered together at two ends. isn't that a ground loop?

Only technically. Loops are only a concern if you can develop significant voltage drops across them. Those traces are probably on the order of 10mohms per inch, and the maximum distance from one point to another is about 2 inches. To get 10mV of voltage ripple on the ground bus you'd need 500mA of current flowing through it. That certainly isn't going to happen.

Quote:

HOT DAMN I'M BACK IN THE CHIPS!

I'm glad to hear that your persistence has paid off. Now don't go doubling down on a pair of aces.

 

[superjohnny]

In this picture the cap on the left spans three holes as well, but plugs into a line on the circuit board that's not used or connected to the rest of the circuit. Shouldn't it be connected to the hole next to the r.in?

Same with the right cap, shouldn't it be connected to the hole next to the l.in?

I just figured out that my board is different from the board used in the tutorial. Instead of having two sets of single holes on the +v side of the board it has 3 sets. I really hope this doesn't mess me up, I've come so far

 

[ProFingerSk8er]

the gray parts on that image are made out of copper, which means they are connected, just think of them as flat wire you are solding onto.

so the R/L in are connect to the caps they're next to

"I just figured out that my board is different from the board used in the tutorial. Instead of having two sets of single holes on the +v side of the board it has 3 sets. I really hope this doesn't mess me up, I've come so far "
this dosent matter at all, if you look closly you will notice the caps and resitors are corssing the single holes, which means they'r not even being used

 

[superjohnny]

I've got some 0.1 µF 50-plus volt full-size film cap's that I haven't used. I think I'll just pop those in instead of trying to make more bridges.

Quote:

so the R/L in are connect to the caps they're next to

This is just what I need. I'm getting really close to completing it. Thank you

Quote:

Next, take the hookup wires going to the V+ and V- points on the power supply and run them to the V- and V+ points of the op-amp — pins 4 and 8. I recommend you do this on the bottom side of the board, since you'll be adding a bunch of wires that have to be on the top of the board later. The more wires you can put on the bottom, the cleaner the top side of the finished amp will be, which facilitates later repairs and tweaks.

This part was really hard. I was soooo afraid I was going to solder across the bridges.

 

[superjohnny]

[size=medium]IT WORKS![/size]

There's no humms, hisses, spits, pecks, knocks or thumps. It's really loud too

OMG OMG Thank you guys so much!

 

[superjohnny]

I can't believe how long it took me to wire the case. I went back & forth about dual power-supplies for a long time and finally decided that it would be too much trouble to try to fit all that stuff in a mint tin. It was hard enough getting it to fit with only one battery. It sounds great. I only wish I could compare it to a headroom airhead or bithead or some other "real" amp.

I'll post some pr0n when I get my digicam back.

Thank you Mr. Tangent