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  1. SparkyCal

    I'm Back- sort of

    I also found this on Amazon- made by Texas Instruments, so it's American made. https://www.amazon.ca/Texas-Instruments-Pieces-UA741CP-Linear/dp/B01HGMJ2EY/ref=sr_1_2?dchild=1&keywords=texas+instruments+op+amp&qid=1621441228&sr=8-2
  2. SparkyCal

    I'm Back- sort of

    AudioGuru- is there a particular op amp that you're found of? I figure, if I go in to pick up some parts, I may as well pick up a few extra ops amps that are more modern.
  3. SparkyCal

    I'm Back- sort of

    As I think about this, I kn ow that the power section of the circuit works as intended. I think the diode portion will work as well. So, probably the best thing to do is get the right op amp and then pop it into the socket and rewire the socket to make sure the wiring is correct. I don't thin k...
  4. SparkyCal

    Power Supply Leads question

    1. I have a power supply that I lost the test leads to. Unlike your normal banana plugs that sort of have splinters on the plug (the part that actually inserts into the power supply's - and + ports), the leads have slits, but they do not balloon out. Basically, they look like straight pins, but...
  5. SparkyCal

    I'm Back- sort of

    Hi Harald: That's probably a good idea. Here is a link to my local electronics store (It's about a 20 min drive- which is not bad). Here is the one they have: https://secure.sayal.com/STORE2/View_SHOP.php?SKU=192017 Maybe I will also see if they have other more modern ones, for future...
  6. SparkyCal

    I'm Back- sort of

    I am not near the circuit now, but pin 7 has always been routed to the positive rail, I believe.
  7. SparkyCal

    I'm Back- sort of

    Hey guys- maybe due to the fact that I have a PCB board holder that rotates the board, I had wired some pins incorrectly. So, I cut the wires to every pin and rewired. After doing that, here are my readings: Pin 2. 7.68 Pin 3 4.09 Pin 6. 9.0 Pin 7 8.20 This is with the 741 op...
  8. SparkyCal

    I'm Back- sort of

    Thanks Bertus.!!! It seems like that memory is faulty. I did not buy the 741's at a local store- I thought I did, but I'm wrong. Here are links to what I bought (long ago- when I was first coming here)...
  9. SparkyCal

    I'm Back- sort of

    I guess I am better off using the 4558 then? At this point, I just want to succeed in bringing the circuit to fruition. I will probably troubleshoot the existing circuit further. if that goes nowhere, I may build a new one using the 4558.
  10. SparkyCal

    I'm Back- sort of

    I have a ton of the 4558D's, but I was under the impression they were too dated.
  11. SparkyCal

    I'm Back- sort of

    Thanks. I have not removed the 500k pot, but I had not paid attention to where it was set at. I will rerun tests when I get a chance and report in.
  12. SparkyCal

    I'm Back- sort of

    Thanks. Let me check the rest of it and then swap in another 741 OP Amp and see if it makes a difference.
  13. SparkyCal

    I'm Back- sort of

    I think I've made some progress. Based on the comments here, I decided to take my multi meter and follow each connection to the op amp to make sure there are no shorts. By doing so, I discovered that Pin 2 was not connected to anything. I guess I was doing this project in increments, and when...
  14. SparkyCal

    I'm Back- sort of

    Hi Audioguru- I am not sure I understood. Do I use my multimeter to make the measurements, while the circuit IS connected to the power supply at 9V. or Do I use my multimeter to make the measurements, while the circuit IS NOT connected to the power supply ? I am thinking it should be...
  15. SparkyCal

    I'm Back- sort of

    Sorry. Audio guru. When you say it has no DC load, I had the power supply hooked up to power the circuit while measuring. Is that wrong
  16. SparkyCal

    I'm Back- sort of

    I am using the 741 op amp. Thanks for the measurements suggestions. I will report in once I have had a chance to follow up thank you
  17. SparkyCal

    I'm Back- sort of

    I just double checked. I think the pin mappings are the same between the one on the schematic, and the one I am using. Have a look:
  18. SparkyCal

    I'm Back- sort of

    Here is the Pin map for the UA741CP 1- null 2 Inverting 3 non inverting 4 negative Ground) 5. Offset 6 Output 7 Voltage + 8 do not connect I mapped the pins against the schematic
  19. SparkyCal

    I'm Back- sort of

    No, because that’s one of the first things I learned here. I always remap the pins but I will double check
  20. SparkyCal

    I'm Back- sort of

    I just read the first doc you posted Bertus. I will be honest and say that I can't follow the equations or the math, but the point of the article is well taken. I also learned this: Single-supply design was considered technically limiting because the older op amps had limited capability. The...
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