Cmoy amp question (help i guess)
Feb 6, 2005 at 5:03 AM Thread Starter Post #1 of 29

Cmoyamphelp

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okay just got mine too work on the 4 try (it was the audio jacks witch was cause the issues) and i am wondering my mine seems too be hard on batterys (not new but still have half the juice left) and my caps seem too be warm,is this normal

BTW i am only running 1 9 volt
 
Feb 6, 2005 at 5:18 AM Post #2 of 29
No, the caps being warm is not normal, sounds like you might have one in backwards (the large electrolytics). If you are building this from Tangent's writeup, the left cap should have the stripe or negative side down looking at the board as in his view. The right cap should be up, or towards the - battery connection point. If this isn't it, post pics (both top and bottom, close enough to see the soldering, etc.).
 
Feb 6, 2005 at 9:15 AM Post #4 of 29
Quote:

Originally Posted by Cmoyamphelp
hear are the pics

another


I also am wondering how i would go about getting the most power(sound wise) and how i can make this puppy ever better for bassey parts of my tunes



simple because I'm tired.

how you would get more "power" : tweak the gain resistor(s) - check tangent's page about it or headwize

how you would get it to sound better for bassy parts of music: put in bigger (higher uF) capacitors
 
Feb 6, 2005 at 11:03 PM Post #6 of 29
No you souldn't be hearing music without the battery hooked up. You have some serious problems going on (shorts, miswiring, etc.) which you need to fix before you go hooking this up to wall supplies, etc. Get it working properly off of battery first before you start messing around with other things. If this were working properly at the stock gain of 11, you will definitely know it, as full volume will be much louder than your ears can take.

In general, building and troubleshooting electronics involves narrowing the possibilities down by a process of trial and elimination. Go over your board carefully with a magnifying glass, comparing it to Tangent's instruction. Look for solder bridges, that you have the right component in the right place with good solder joints. Take voltage measurements of both the + and - pins on the opamp to make sure it is getting about 1/2 the battery voltage (+/- 4.5V when referenced to the virtual ground). Pull the opamp and ohm out all the socket pins to virtual ground. For example, the input pins (pins 3 and 5) should show your R2 (I think) resistor, or 100K ohms. Pins 2 and 6 should show R3, which stock is 1K. And so on. If they don't, figure out why and fix it.

From your picture, I can't see anything outright wrong on it, tho the picture is a bit fuzzy. You should have made sure the amp itself was working before you wired in a pot, etc. and cased it up, as those are just more varibles of stuff that can go wrong. Get the amp itself working, then put the pot in or whatever. Get it working right, then move on to the next thing.

A picture of the bottom side of the board would be helpful also.

good luck
 
Feb 6, 2005 at 11:57 PM Post #7 of 29
well i changed a few things,and well now i get fuzz (i changed to a 25v 220uf caps then back too the original 25v 470uf caps) and works with only a battery pack, so i guess somthing when right but i still now need too fix the fuzz
 
Feb 7, 2005 at 12:21 AM Post #8 of 29
The pics are too blurry to tell anything. Does your camera have a macro mode (for taking closeups of small objects)?

At any rate, the value of the electrolytic caps is not the problem... the 470/25V are fine (so are the 220s, the 470s are better tho...)

Do you have a DMM or meter? Everytime I've suggested something, you don't post that you checked this or that and it measured ___ this. You just come back and say you've changed something else. Kinda hard to help you this way
plainface.gif
 
Feb 7, 2005 at 3:36 AM Post #12 of 29
This is bad quoting myself, but... Quote:

Originally Posted by Pars
If this were working properly at the stock gain of 11, you will definitely know it, as full volume will be much louder than your ears can take.


You will know it if it is working. If you don't think that it is amplifying, then it probably isn't. If you still hear music with the battery disconnected, then that indicates a short between the input and output (bypassing the opamp). Meter? I am guessing you don't have one?
 
Feb 7, 2005 at 4:11 AM Post #13 of 29
yes i do have a volt meter,i'll mesure right now and tell you,i also when over it with a magnifind glass and every thing seems too be okay

pin 4=-4.85
pin8=4.90
9.95V battery pack
 
Feb 7, 2005 at 9:07 PM Post #14 of 29
Can you explain what you mean by you hear music with the battery disconnected? Is this just for a second when you disconnect the battery? Or is it all the time? The 470 caps have enough juice to keep the music playing for a second. But if you amp works for more than a second or two without power, something is wrong. Use your ohm meter to check IL to OL, and IR to OR, and I/OL to I/OR. There shouldn't be ~0ohm reading between any of these, except IG to OG
 

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