Chipco, I will address your orientation question shortly, but two things:
1. I don't understand what your power supply is, but it doesn't sound like it could work. You need +15 and -15 to the board...do not plug anything in until you verify that you have -15V at pin 4 at +15V at pin 8.
2. If you are using sockets, start with standard opamps. Not only is this cheaper than blowing up your $$$ discretes, but it will let you verify that the board works. Then you can add the variable of the discrete circuits.
More from me tomorrow.
1. I don't understand what your power supply is, but it doesn't sound like it could work. You need +15 and -15 to the board...do not plug anything in until you verify that you have -15V at pin 4 at +15V at pin 8.
2. If you are using sockets, start with standard opamps. Not only is this cheaper than blowing up your $$$ discretes, but it will let you verify that the board works. Then you can add the variable of the discrete circuits.
More from me tomorrow.
Check out the picture below. If you stand the opamp up by rotating it to the right, then the top of the opamp is equivilent to the "top" or notched side of a normal opamp.
You can also double check that the pin marked "P" is going into pin 8 of your socket and that the pin marked "N" on the diagonally opposite side is going into pin 4.
You probably are already well acquainted but this is the assembly guide:
http://www.anidian.com/audio/construct/opa_1.shtml
This is probably the most basic power supply. If you only have 17VDC unloaded from a small supply, you probably can't get 15V regulated...but you might be ok. The wallwart idea is an excellant one--it gets the transformer completely out of the chassis and there are no safety ground issues.
http://sound.westhost.com/project05.htm
You can also double check that the pin marked "P" is going into pin 8 of your socket and that the pin marked "N" on the diagonally opposite side is going into pin 4.
You probably are already well acquainted but this is the assembly guide:
http://www.anidian.com/audio/construct/opa_1.shtml
This is probably the most basic power supply. If you only have 17VDC unloaded from a small supply, you probably can't get 15V regulated...but you might be ok. The wallwart idea is an excellant one--it gets the transformer completely out of the chassis and there are no safety ground issues.
http://sound.westhost.com/project05.htm
An externally hosted image should be here but it was not working when we last tested it.
Tiroth..
Here's what I have. Tranny is a 110VAC/12-0-12 going to some sort of Radioshack full wave bridge, 6A, 50PIV. I have wired the bridge with 4.7uF coupling capacitors. So there's the +/- DCV. The question is that pesky -0- from the tranny. Is that carried through to the "Supply" "Gnd" on the active filter without any modification and/or filtering?
Thanks for your patience. My previous experience with electrics is pretty much all 208/480 3 phase and if there is DC it's not the minus stuff.
One last thing... Could you email me a fish sandwich from Wooley's?
Here's what I have. Tranny is a 110VAC/12-0-12 going to some sort of Radioshack full wave bridge, 6A, 50PIV. I have wired the bridge with 4.7uF coupling capacitors. So there's the +/- DCV. The question is that pesky -0- from the tranny. Is that carried through to the "Supply" "Gnd" on the active filter without any modification and/or filtering?
Thanks for your patience. My previous experience with electrics is pretty much all 208/480 3 phase and if there is DC it's not the minus stuff.
One last thing... Could you email me a fish sandwich from Wooley's?
tiroth...
Any reason I can't just build a small power supply using a 12-0-12 with a bridge rectifier and some caps? I would house it in a seperate supply enclosure. C800 and C900 would provide additional smoothing, right? Value should be 100-200uF ~50V?
I have a board populated with some OPA's so I cook the sample parts rather than the discreet assemblies.
Any reason I can't just build a small power supply using a 12-0-12 with a bridge rectifier and some caps? I would house it in a seperate supply enclosure. C800 and C900 would provide additional smoothing, right? Value should be 100-200uF ~50V?
I have a board populated with some OPA's so I cook the sample parts rather than the discreet assemblies.
Yes, that's fine, but it should be regulated...the extra dollar's worth of parts is well worth it. I would use 7812/7912 since you likely are short on voltage for 15V regs. If your transformer is beefy though you might get away with it....
100-200uF is good for on-board caps. I'd like to see at least 1000uF before the regs.
And sorry, I tried sending a sandowichi through email before, it didn't work out...
100-200uF is good for on-board caps. I'd like to see at least 1000uF before the regs.
And sorry, I tried sending a sandowichi through email before, it didn't work out...
TiRoth...
I returned my mother to Fox Chapel last week... has the general level of anxiety increased in the Pittsburgh area?
I bought some of those little PE torroids... 12V, the size of a Duetz donnut (a South Hills bakery). It's a dual secondary. I was going to run it with dual rectifiers and filter it before the crossover boards and also add the C800-900 caps on the board. Will ~17VDC be OK for the OPA2134? That's about 1VDC of head room acording to the sheet. My sample three pin regulators are a few weeks out.
Second question. Each secondary has its own rectifier. Does the positive leg's rectifier negative go to the negative leg's positive to form the ground? That's what I have discerned from my literature review. I need somebody to tell me "yup". I can figure out the filter caps from that point on.
I returned my mother to Fox Chapel last week... has the general level of anxiety increased in the Pittsburgh area?
I bought some of those little PE torroids... 12V, the size of a Duetz donnut (a South Hills bakery). It's a dual secondary. I was going to run it with dual rectifiers and filter it before the crossover boards and also add the C800-900 caps on the board. Will ~17VDC be OK for the OPA2134? That's about 1VDC of head room acording to the sheet. My sample three pin regulators are a few weeks out.
Second question. Each secondary has its own rectifier. Does the positive leg's rectifier negative go to the negative leg's positive to form the ground? That's what I have discerned from my literature review. I need somebody to tell me "yup". I can figure out the filter caps from that point on.
Getting to the final stages... I have a power supply built and will need to get some regulators in... learned a lot this weekend!
I have a question regarding the input marked In+ Gnd next to the points marked "In- Gnd In+ Gnd. Are these for balanced inputs? If I am running single ended outputs, should I use the Aux/Gnd and jumper accordingly?
I have a question regarding the input marked In+ Gnd next to the points marked "In- Gnd In+ Gnd. Are these for balanced inputs? If I am running single ended outputs, should I use the Aux/Gnd and jumper accordingly?
...I need a little help please
I have my Mox boards built and have installed OPA2134 for testing. The good news is they didn't burn. No output.
So far...
I have a +/-15 volt regulated supply and I show 30VDC at pins 1 & 8 of the op amps. I have tried a variety of different configurations of input and output following the block diagram shown on the manual. Specifically, using +/Gnd or Aux 1 in put with the appropriate jumpers set...
Nothing. Not a sound. Where do I start looking? I am using a computer CDROM drive as input and it plays fine through the power amp but not a sound when piped through the MOX.
Help.
I have my Mox boards built and have installed OPA2134 for testing. The good news is they didn't burn. No output.
So far...
I have a +/-15 volt regulated supply and I show 30VDC at pins 1 & 8 of the op amps. I have tried a variety of different configurations of input and output following the block diagram shown on the manual. Specifically, using +/Gnd or Aux 1 in put with the appropriate jumpers set...
Nothing. Not a sound. Where do I start looking? I am using a computer CDROM drive as input and it plays fine through the power amp but not a sound when piped through the MOX.
Help.
Okay, let's try a few things in order then.
0. Have you actually measured +15 between pin 8 and ground, and -15V between pin 4 and ground?*
1. Verify signal exists between input side of R003 and ground
2. Verify signal exists between IC1 pin 3 and ground
3. Verify signal exists between IC1 pin 5 and ground
If you get this far, then the 1st input stage works. Since IC1B has no parts or options in circuit, it should work too, unless it was destroyed.
4. Check R001-004 values in circuit with ohm meter (and report!)
5. What size are C001-002?
If you get this far without an error, we'll go from there.
*this may seem like a stupid question since you know you have 30V between 4 and 8, but trust me
0. Have you actually measured +15 between pin 8 and ground, and -15V between pin 4 and ground?*
1. Verify signal exists between input side of R003 and ground
2. Verify signal exists between IC1 pin 3 and ground
3. Verify signal exists between IC1 pin 5 and ground
If you get this far, then the 1st input stage works. Since IC1B has no parts or options in circuit, it should work too, unless it was destroyed.
4. Check R001-004 values in circuit with ohm meter (and report!)
5. What size are C001-002?
If you get this far without an error, we'll go from there.
*this may seem like a stupid question since you know you have 30V between 4 and 8, but trust me
Thanks for the info...
Have you actually measured +15 between pin 8 and ground, and -15V between pin 4 and ground?*
Nope, but I will. Perhaps at lunch.
I'll try the rest also. My output from the CDP seems only about 300-500mV. It plays perfectly well through the power amp on it's own. Should I preamp for higher signal?
Have you actually measured +15 between pin 8 and ground, and -15V between pin 4 and ground?*
Nope, but I will. Perhaps at lunch.
I'll try the rest also. My output from the CDP seems only about 300-500mV. It plays perfectly well through the power amp on it's own. Should I preamp for higher signal?
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